stodge

It's fair to say since Tuesday the models have been struggling with the mid range which is effectively T+144 tonight. The Atlantic LP faces off against the Scandinavian heights. Oddly enough, both lose - the HP sinks south and becomes a mid-latitude HP while the trough fills in situ as the Atlantic quietens down suggesting more opportunities for upstream amplification in the second half of the month. We need the Scandinavian HP to orient more favourably to draw in a new feed of ESE'ly air to keep the cold going (less chance of snow). Denmark's weather service is keeping them very cold through next weekend for example. The modelling has moved a lot since Tuesday - I wouldn't rule out seeing a few OP tomorrow or Sunday which keep heights to the north east and get more out of the cold spell - it's the direction of travel but we aren't there yet.

Evening all Plenty of excitement as we look on the cusp of our most interesting spell of cold weather since March 2018 and the first spell of proper winter weather for many since 2013. I've posted on recent days how I've had doubts about the longevity and to an extent the severity of any cold spell. On Tuesday I was convinced it would be over quickly but by last night GEM and ECM were suggesting a more nuanced evolution which "could" keep colder conditions in place for some areas for longer. A lot depended on whether we would see height rises in Scandinavia sufficient to either hold the Atlantic at bay completely or deflect the troughs to the south east. I wasn't wholly convinced but nor was I convinced by the usual GFS trick of blowing up hurricane strength depressions to smash away any block. Yes, the PV is re-consolidating but it remains weaker than usual and that should give more chance for height rises to the north east - the process would be a brief milder spell before colder air returns again but under a drier and more settled evolution than we are set to experience in the coming days. Let's see where tonight leaves us... T+120 is Feb 10th, T+240 is Feb 15th, T+312 is Feb 18th and T+384 is Feb 21st. 12Z GEM: at T+120 an ENE'ly flow covers all parts with heights to the north and east and a residual LP over Northern Italy. The next Atlantic LP is far to the west. Uppers below -8 over most of the British Isles with -12 uppers in the North Sea. From there, the Atlantic LP comes up against developing heights to the North east but as it approaches and raises heights to the south it can only re-align north-south in mid ocean. Heights over southern Scandinavia are looking to join with heights over France and Spain leaving the British Isles by T+180 with a SW'ly flow over western areas and a SE'ly flow over eastern areas in the gap between the two weather systems. Positive uppers have reached western and some southern areas and further east 850s are only just below zero. From there, the HP declines south into Europe while the Atlantic trough remains far to the west. Mild or very mild air has crossed the whole of the British Isles by T+240 though it remains very cold far to the east. We get about 5-6 days of cold out of GEM but the conversion to mild is straightforward as the Scandinavian heights simply collapse south. 1-0 to Mild. 12Z GFS OP - the T+120 isn't too much different to the GEM - an E'ly covers the British Isles and heights over Scandinavia face an Atlantic LP which looks to be aligning positively as a thin wedge of heights develops over Iberia. 85-s below -8 over most of the British Isles but milder air is already approaching from the west. From there, heights develop to the south while the Scandinavian heights remain in situ - the LP had elongated NE-SW with the main centre to the south of Iceland at T+180. While frigid air sits to the north and east, by T+180 the 850s are positive across most of the British Isles as the cold spell ends. From T+180, the Scandinavian HP is joined by the heights from the south and the new HP eases south as the LP moves north and east round the top of the HP over northern Scandinavia. By T+240, the HP is over Eastern Europe with new heights to the south west and the north west and a weak trough over the Faeroes. Less cold air with 850s either side of zero over the British Isles and the coldest air now further south east over the Balkans and Italy. Only a 5 day cold period for most from GFS OP but the medium term evolution to T+240 looks more interesting than GEM and certainly a relief for those wanting some drier weather. 2-0 to mild. 12Z Control - No Parallel tonight so here's Control at T+120. As you'd expect, it's following the OP at this time pretty closely. From there, heights build over south west Scandinavia as the Atlantic LP eases towards Iceland leaving a SW'ly air flow across much of the British Isles. The progress of milder air is slower than on the OP with only southern and western areas in positive uppers and colder air hanging on in the north and east by T+180. The Scandinavian heights look to head south after T+180 but don't and by T+240 heights remain over central and northern Scandinavia but the coldest air is heading into the Balkans while the British Isles has a SE'ly air flow. On the mild side, uppers of +4 in southern parts but still just below negative in the far north and west. Not dissimilar to OP and no sign of the Atlantic smashing through but we need th heights to set up more favourably so we get a sniff of the cold air rather than Greece. 3-0 to mild. 12Z ECM: the T+120 chart very much in line with other models and uppers below -8 for most if not all. From there, Scandinavian heights look to be developing kindly but by T+192 the HP has moved just too far south and a mild air flow is back over the British Isles with positive uppers for most northern and western areas. However, colder air remains close to the south east by this time but 850s are just negative. By T+240, the HP has slipped further south but maintains a ridge back toward the British Isles while shallow Atlantic LP run to the north and a hint of further upstream amplification is evident. 850s are up at +8 but that could be deceptive with some inversion possible. Hard to know at this stage. The colder air is now over the Mediterranean. 4-0 to mild by T+240. To be fair, inversion under that HP may not make it that mild in the south and east. The models have moved significantly away from powering the Atlantic through to building Scandinavian heights but the heights aren't sustained and collapse into Europe putting us on the mild flank of the HP. The Atlantic looks weak upstream. Moving on, a look at the T+312 charts from OP, Control and P1: There are a number of evolutions playing with the option of making the Scandinavian heights work and even retrogress (P1) and it'll be interesting to see if they gain more support in the coming days. Conclusion: the initial 5 day cold snap/spell is set and it does look as show the cold will move away from Thursday onward and we then look but west but north east. All models are showing stronger heights over Scandinavia than was the case yesterday or the day before but for now the heights aren't strong enough and collapse from a potential high-latitude to a mid-latitude block which drags milder air back over the British Isles. At the moment, there is only minority support for holding the heights to the north east and perhaps retrogressing them towards Greenland - a real result for cold fans. However, that option wasn't even on the table a couple of days ago - let's see if it continues to gain ground in the next couple of days. A milder interlude looks unavoidable but it could be just that. For now, we have 5 days to enjoy and I hope everyone gets some snow - I think my chances in lowland East London are reasonable on Sunday and Monday but we'll see,

Evening all A mixed day here in lowland East London with a spell of rain around lunchtime either side of which dry and indeed quite mild. Last evening's models suggested a rapid transition to much colder conditions but those conditions only lasting 3-5 days in the south and a shade longer further north though the "breakdown" was perhaps less convincing then the night before. Some of the models were showing a return of the PV to Greenland/NE Canada but the problem perhaps was the Atlantic energy, if unable to break through initially, finally broke through because rising heights to the south over Iberia prevented the negative alignment option. Let's see if our upcoming cold spell is perhaps improving in terms of longevity irrespective of that severity may come in the more immediate period. T+120 tonight is Tuesday Feb 9th, T+240 is Sunday Feb 14th and T+384 is Saturday Feb 20th 12Z GEM: at T+120 an E'ly covers all parts of the British Isles with LP over Biscay and heights to the north west and north east and a deeper LP approaching upstream from the west. Uppers generally below -8 and pockets of -12 uppers in southern and central England. From there, the next Atlantic LP also heads south east towards Biscay and by T+180 is approaching France with an ESE'ly air flow over the British Isles. Heights are now over Scandinavia as the trough has extended north west to a weak secondary LP over Iceland. Upstream, there are hints of further amplification. Milder air has reached the far south west with positive uppers over Cornwall and it's less cold over southern England but uppers remain below -8 over Scotland, Northern Ireland and most of Northern England. Moving on, the LP stays to the south and ends as a weak future over Holland by T+240. Heights ridging into Scandinavia persist ad there's an E'ly air flow over eastern areas. Further west, the Atlantic trough is moving towards the British Isles and a weak S'ly has set up over Ireland - all the signs of a possible battleground. Cold air with uppers below -8 remains over northern parts while uppers are below zero negative with the least cold air in the south east. 1-0 to cold spell longevity tonight - the north has a clear week of cold or very cold conditions while the south sees less cold air but the evolution has moved back to cold tonight with no clear breakdown by T+240. 12Z GFS OP - if you want a definition of a textbook E'ly OP at T+120 has it. LP close to south west England and heights to the north and north west. 850s below -8 from the Midlands north but -4 to -8 in the south so slightly less cold than the GEM down to the trough being closer to southern areas. From there, heights to the north and east persist but the Atlantic trough doesn't slide south east as heights rise into Iberia turning the alignment of the trough positive as a small lobe of energy crosses southern Britain at T+180. Less cold air has already returned to most parts of the British Isles with uppers just negative leaving the coldest air to the far north east of Scotland and the Northern Isles. From there, the trough remains to the west of the British isles as heights build in from the south west and a mild or very mild SW'ly is in place by T+240. Uppers of +4 cover the whole of the British Isles by this time. 1-1 - OP cuts the cold spell short so it's just 3-4 days in the south and not much more in the north and by Valentine's Day it's almost spring like even though there's no sign of a PV so could we see heights build to the east in further FI? 12Z Parallel - The T+120 chart looks better than the OP with a truer E@'ly and the LP further south over Biscay so much more like GEM. However, the next Atlantic feature is already deepening to the west. 850s below -8 over most of the British Isles at T+120 with pockets of -12 air to the south and east. From there, the Atlantic LP doesn't go anywhere quickly but spawns a new vigorous LP which threatens to move towards Ireland and in so doing raises heights to the south and introduces a SSE'ly air flow to most parts. Heights persist over Scandinavia. Milder air is close to the south west by T+180 but uppers below -8 persist over northern and eastern regions. From T+180, the "battle" between the air masses is quickly resolved as the Scandinavian HP declines south and a very mild SSW'ly crosses the British Isles albeit with the trough much weaker to the west and a hint of renewed amplification upstream as heights cover most of eastern and central Europe. 850s of +8 approaching the south and south west so again a very mild mid month. 2-1 to mild with the Scandinavian heights quickly collapsing south but a better overall evolution than GFS OP in that the cold hangs on for a couple of days longer. 12Z ECM: at T+120, it looks a bit like the GFS OP (which doesn't bode well) with the LP close to Cornwall but a noticeable ESE'ly flow especially over northern areas. Uppers below -8 over most of the British Isles, perhaps a little less cold to the far south west. From there, the E'ly fades as the next LP takes a more northerly track. By T+192, a SE'ly air flow covers the British Isles as a shallow LP approaches Ireland but weak heights persist over Scandinavia. Milder air with positive uppers has moved back over southern and western regions but it remains cold with uppers below -8 over the far north and north east of Scotland. From there, ECM goes its own way with heights persisting over south west Scandinavia and extending back north west and as a result the Atlantic trough elongates and fills in situ not reaching the British Isles by T+240. It's a stand off between milder air to the south and west and colder air to the north and east. For the south and west it ends 3-1 to mild but for the north and especially the north east it's 2-2 with the cold persisting throughout to T+240. Looking further ahead, the T+312 and T+384 charts from OP and Control respectively: Plenty of interest in far FI and more than a hint of an anticyclonic pattern developing which will please those fed up with rain and flooding. Control also ends anticyclonic - whether we can get the HP in a favourable position to advect any colder air remains to be seen. Conclusion: - there's a real split tonight. GEM and ECM are definitely toying with the idea of extending the colder spell into mid month but GFS isn't interested at all doing its usual thing of blowing up huge Atlantic depressions which crash through blocks with ease. That might happen but it's interesting the European and Canadian models are looking at other options. ECM would certainly be the most interesting longer-term evolution for cold fans but of course we have the early part of next week to enjoy or endure (delete as appropriate). I do think we need to get the LP as far south as possible as T+120 and hope we see stronger heights to the north east.

Evening all My comments last night drew some attention - I thought the 12Z suite of model output was uninspiring in terms of the severity and longevity of any cold "spell". Indeed, with GFS OP it never really got cold in the south and for southern areas it was at most a 3-5 day cold snap simply because the trough never cleared away from the south coast and eventually was able to return north as heights relaxed over Scandinavia and Greenland. Some earlier charts had suggested a cold spell of 10-14 days but this was more snap than spell though I appreciate for the north it was a much longer cold period. The fact was last evening every single model had killed the cold snap by T+240 but as a wise man once said, that was then but this is now. T+120 takes us to the 8th, T+240 to 13th, T+312 to the 16th and T+384 to the 19th. 12Z GEM: by T+120 an E'ly covers the whole of the British Isles with LP over western France and heights to the north but a new Atlantic LP is extending its energy east towards the British Isles. Uppers below -8 over most of the British Isles but from -4 to -8 over the far south east. From there, a wedge of heights slips south to the east of the British Isles but an intense LP forms in the Atlantic and swings NE past Ireland before moving north west and west in the circulation of the trough. All this does however is to raise heights to the south and turn the trough alignment positive bringing a SSW'ly over Ireland by T+180. Calm conditions elsewhere by this time with the coldest air confined to south-east England with uppers still below -8 with negative uppers elsewhere for now and milder air close to Cornwall. From there, not much changes - one lobe of LP gets across the centre of the British Isles but the main trough is still held to the west by the cold block to the north east. Milder air with 850s of +4 over southern England but colder air hangs on further north despite heights over Iberia. A little better than yesterday to be honest but it's still only 3-5 days of cold for the south albeit longer duration for the north. 12Z GFS OP - given how progressive the GFS usually is, I expect the cold snap to be over before it's begun. At T+120 a complex trough lies to the south of the British Isles with a secondary centre over south-east England and a main centre still far to the west. Heights to the north and north west and 850s below -8 for most of the British Isles but some slightly less cold air near the residual LP over south-east England. From there, the E'ly holds firm with the Atlantic troughs sliding SE into France. A more intense LP from lower latitudes comes into mid-Atlantic and stalls by T+180 throwing energy east towards the British Isles with a SE'ly over Ireland and an ESE'ly over the far north. Uppers of -8 or below persist over northern Britain but less cold air is coming in from the south west. From there, the Atlantic trough elongates as it tries to push east against the block and a secondary LP forms to the south and quickly deepens into an intense LP which looks to push the trough into a more positive alignment and in the interim pushes a lobe of energy east over southern Britain. A cyclonic SW'ly flow over most parts by T+240 with uppers either side of zero across all parts and the really cold air pushed away to the north. Not dissimilar to the ECM but you sense there's a real fight brewing against the persistent block and the evolution isn't as clear cut as it was yesterday. Nonetheless, the cold has gone from all parts by T+240 so a 3 day cold snap in the south and a 5-day cold spell in the north. 12Z Parallel - back tonight and at T+120 it's managed quite a clean ejection of the trough from the south and south east with an ENE'ly over all parts by this time. The upstream profile is less encouraging with the trough trying to send energy to the north. 850s from -4 to -8 over southern England but below -8 over most of the British Isles. From there, the E'ly holds for a while until, as we've seen, a vigorous LP from lower latitudes swings NE to invigorate the trough in mid-Atlantic but by T+180 the jet still looks quite far south but a lobe of energy is extending ENE towards Ireland with a SSE'ly air flow over most of the British Isles. Uppers of zero to -4 over southern areas but the colder air holds firm further north and east with uppers below -8. The first Atlantic trough moves over the British Isles and then slides SE but a new more vigorous trough forms in mid-Atlantic by T+240 and that causes heights to rise over Iberia and a mild SW'ly air flow to establish over the British Isles by T+240. Positive uppers have reached Ireland but 850s still below -4 over northern and eastern areas. It looks game over for the cold spell but again it's less convincing than last night and relies on a vigorous Atlantic trough setting up. 12Z ECM: at T+120 all parts are in an E'ly air flow with the LP having moved cleanly south over France. There's a new LP developing upstream with heights to the north west. 850s below -8 over most of northern Britain and -4 to -8 over southern parts. From there, the new Atlantic feature develops as a complex trough but moves steadily towards the British Isles and by T+192 is just off western Ireland throwing a S'ly air flow in front and spawning new heights over Iberia. Cold air persists with uppers below -8 in eastern areas but milder air is edging toward the south-west. From there, a new LP develops within the circulation of the trough and swings NE past North-West Scotland by T+240 bringing in a WSW'ly air flow to all parts. By this time, uppers either side of zero over all parts with the really cold air shunted well to the north and east. And so it goes - perhaps the evolutions are less convincing tonight but the net effect is the same - ECM, GEM, GFS OP and GFS Parallel all end the cold spell by T+240 so for most it's a 3-5 day snap rather than an extended spell - at least that's how it looks at the moment. Moving further ahead, the far FI charts from GFS OP and Parallel - T+312 and T+384: OP goes traditional zonal with lots of LP and a PV in its usual place but Parallel teases a more anticyclonic solution. We don't quite get a full-on Scandinavian HP - indeed, the HP sinks south before rebuilding over the British Isles. It's one to watch I think. Conclusion: it still looks a short-lived cold episode to this observer tonight. The breakdown is slightly less convincing and this "could" be the start of a backpedal from the models against the strength of the cold block which means I could be looking at similar T+240 charts next week as the cold persists. Maybe but I need more convincing - for now it looks the block won't hold and the Atlantic will do wnough to push the cold air aside by the end of next week.

If something like MOGREPS is showing a prolonged cold spell past T+240 fine, as you say, I can't say it. I can only go by what I see and looking at the Mean charts into medium and longer term, the fact is the Atlantic trough aligns positively drawing heights up to the south west and it's a mild SW'ly by T+240.

Indeed and if it were just one of the main models I wouldn't be concerned but looking across the board I don't see anything that prolongs the cold spell. Even the UKMO at T+144 looks poor as does JMA if you want to see the pieces for a prolonged cold spell. I'm not questioning it would be quite severe especially in the north but tonight GFS has backtracked on the severity further south and, as last night, there's no sense of longevity. Of course, the block could be more durable and the LP might continue to shift into Europe but I don't see it on the main models at this stage.

Yes, I think so certainly in terms of longevity if not necessarily severity. All the models are bringing milder air back in by T+240 so that's a 5 day cold spell maximum. I'm struggling to see any model prolonging the cold spell beyond that at this time. The problem is as the heights in Scandinavia fail and slip SE they stop the trough sliding into Europe and it moves up north over the British Isles.

Evening all A mild and pleasant day here in lowland East London and well done to those further north who saw quite a bit of snow (10-15cm in parts of Yorkshire). I confess it's with some trepidation I approach the MOD thread this evening. This is the point of the downgrades/backtracks and the "I told you so" comments from the trolls. Apart from GEM to an extent yesterday evening and JMA, all the other models were on board with the Easterly spell due to start over the weekend. The suggestion was for 7-10 days of colder weather before the Atlantic came back in as suggested by GFS based on a failure of Scandinavian heights in far FI. As a wise man once said, that was then and this is now so let's see what tonight's meanderings offer: T+120 takes us to the 7th, T+240 to the 12th, T+312 to the 15th and T+384 to the 18th February 12Z GEM: The T+120 shows the E'ly air flow in across the British Isles. Heights to the north and north west have finally pushed the trough to the south east and the next LP is looking to head SE to France. Uppers below -4 over all parts and below -8 over south east England and northern Britain in general. From there, the trough does indeed ease SE but is still in the southwestern approaches by T+180. The direct flow from Siberia has bene cut off as a small HP has formed over Poland and a weak trough over Northern Scandinavia. Milder air with positive uppers flirting with the Channel coast while pockets of -12 850s sit to the north. From there, the LP to the south west grinds its way NE across southern Britain to be off north East England by T+240 with a cyclonic flow over most of the British Isles. Upstream, a weak Atlantic trough aligns positively and there's a hint of heights rising to the south west and over NE Scandinavia. There's a brief push of milder air across southern Britain but by T+240 uppers are generally slightly negative with the coldest air in the north. It's good to see GEM finally latch on at T+120 but it's a 3 day cold spell in the south only (longer lasting in the north) and the T+240 evolution isn't encouraging. 12Z GFS OP - a wonderful run in the short and medium term last evening but it broke the cold spell down around mid month with a return to Atlantic dominated weather. At T+120 we haven't got the clean departure of the trough to the south and while the E'ly is in across Scotland, the LP is still centred over Lincolnshire at T+120 with the other part of the trough aligning negatively to the south west. Heights over Greenland and Scandinavia. Apart from the area close to the centre of the LP, negative 850s for all parts but as you might expect, coldest (below -8) over Scotland. From there, the trough doesn't want to clear away from the south persisting until T+180 and probably cutting off any severe cold flow for southern areas. Further north, the ESE'ly persists with heights building over Scandinavia. The LP is to the west of Biscay by T+180 and milder air with positive uppers has come back to Cornwall but it remains cold over northern Britain with uppers below -8. Moving on and the trough eases up across the UK but the Atlantic starts to become dominant as the Scandinavian heights withdraw and with pressure building near the Azores, the active Atlantic trough aligns positively and it looks all over for cold by T+240. The coldest air has eased north and by T+240 850s are either side of zero generally. To be honest, a disappointing run for the south where severe cold never takes hold and the issue may not be snow as much as some very large rainfall numbers which would exacerbate existing flooding issues. 12Z Control - no 12Z parallel this evening so we're off to Control for our second GFS fix and at T+120 it's similar to OP. From there, the trough remains close to or over southern Britain through to T+180 while the ESE'ly is maintained further north. Positive 850s over the far south of England but 850s below -8 over Scotland. Moving on and the colder spell breaks down as heights dissipate to the north and east and a vigorous Atlantic LP approaches from the west though at this point it's got a neutral alignment with no significant height rises to the south or south west. Positive uppers over southern and western Britain by T+240 but negative uppers persisting elsewhere. Control follows OP with a 3-5 day cold spell at best it would seem. 12Z ECM - at T+120 we have an E'ly over northern Britain while the trough persists further south as a shallow feature over south east England extending south east into Europe. 850s below -4 over the whole of the British Isles with uppers below -12 over Scotland. From there, it's a struggle to get the trough away from the south but by T+192 it has eased south east to Austria and Northern Italy leaving a NE'ly over most parts but with a new large Atlantic system approaching and heights rising over Iberia. 850s below -8 over most of the British Isles by T+192 but the sense of milder weather approaching once again. As expected, the Atlantic trough splits with the main core LP sitting in mid ocean while a lobe of energy to the east and north east forms a new LP which is approaching Ireland albeit on quite a southerly trajectory by T+240 and heights persist to the north. Positive uppers over southern Britain by this time but colder air persists to the north. Another model cuts the cold spell down to 3-5 days but at least there's some severity for southern areas. Looking further ahead, GFS OP and Control at T+312 and T+384 respectively: Neither OP nor Control offers any let up in the unsettled wet conditions and again it's hard to see there's much respite from rainfall even after mid month. Conclusion: a disappointing night for cold weather fans. We simply can't get the trough to clear to the south to bring in the severe cold from the east or north east. Obviously, the proximity of the trough offers snow fans plenty of hope especially, I'd argue, from the Midlands north and especially over high ground. The one thing I'm not seeing on any model is a period of dry weather - whether it's snow or rain I suspect flooding will continue to be a huge issue in the next fortnight and exacerbated by any snowmelt.

I confess the evening models generally look very good but I'm still concerned. JMA goes wrong here: The phasing of energy from north and west prevents the trough exiting cleanly to the south and we get stuck with LP close to or over the British Isles. GEM isn't too bad at T+180 but fails because the trough orients poorly and then stops the Scandinavian heights spreading south west towards the British Isles - that failure allows the Iberian HP to build in, the trough aligns positively and we're stuffed. These are nitpicks but a concern. Have to say, the ECM Control is a thing of beauty keeping the south cold or very cold right through to T+360.

Evening all Apologies for yesterday evening - my usual time to consider the evening model output was cut short. Unfortunately tonight you'll have to wind through my nonsense to the next burst of "winter is over" or "there's no point sugar coating it, it's a massive downgrade" or "it's only -12 uppers, we only got snow in my area if it's -14 uppers so it's cold rain for me" or the other troll-infested nonsense. Those who are still with me after that little rant - the worry again last night was ECM which kept too much energy in the north and north west to allow a smooth trough disruption south and allow the orthern heights to introduce the easterly. Still, as a wise man once said "that was then but this is now". T+120 takes us to Saturday February 6th 12Z GEM: quite a change to the evolution this evening suggesting we still haven't nailed this down even at T+120. The trough currently to the west and north west has filled and moved east to be over the North Sea. Heights to the north have developed over Greenland and have halted the LP coming out of North America forcing it back east or east south east while the Mediterranean is covered by abroad but shallow trough emanating from North Africa. Colder air has returned with 850s between -4 and -8 across the British Isles. From there, the strong push of heights from the north has pushed the trough south and by T+180 ot sits over southern and eastern England as an elongated shallow feature with an E'ly persisting to the north. Heights persist upstream at this time. 850s below -8 over much of northern Britain by this time but less cold air very close to the Channel coast so pick your snow line. From there, the cold spell quickly breaks down - the trough moves east but a shortwave forms and become vital in preventing a new build of heights from the Azores to Scandinavia. Instead, the Azores HP ridges into Iberia and pulls up a much milder SW'ly air flow by T+240. By then, positive uppers are back over western and northern parts and 850s are slightly negative further east with milder air encroaching. So it's a 5-7 day cold spell only on GEM before the Atlantic comes back. The PV looks to be making a come back as well so all in all a disappointing run for cold fans. 12Z GFS OP - the best of the bunch last evening. At T+120 this evening everything looks on track with the LP now over northern Spain and an E'ly across the British Isles. 850s of -8 or below from the Midlands north and from -4 to -8 further south. From there, the trough starts to come back NE towards southern Britain hovering close to the south east as a potential snow maker (you'd think). At T+180 the trough is now an elongated feature covering much of the continent with an ENE'ly flow across the British Isles on its northern and western flank. Uppers below -8 over the whole British Isles and below -12 over eastern Scotland so a tad brisk for many. With heights from Greenland pressure falls from T+180 to the north and north east of the British Isles with a series of secondary LP forming and moving south or south east. By T+240 the trough extends from one centre to the east of the Faeroes south and east into Europe while a new Atlantic LP is approaching with energy looking to phase with the existing trough and head south east into Europe. Uppers remain below -8 over most of the British Isles with some slightly less cold air to the south west. A superb run for cold and snow fans with lying snow over many parts if this verifies. 12Z Parallel - more progressive than the OP in recent days but still decent in the end though not food for the nerves. If I'm being honest, the T+120 looks a compromise between OP and GEM. The trough has been slower to sink south and it has phased with the trough coming north out of Africa. The E'ly is in across the north but has only just reached the south by this time. Uppers of zero to -4 over much f southern and south western Britain and Ireland with 850s below -8 over northern Scotland. From there, the trough moves back NE as it does on the OP to be over or close to south-east England by T+180 with an ENE'ly flow over most of the British Isles. A second GEM has moved SE towards Iberia with heights persisting to the north west. Uppers below -8 cover the whole of the British Isles by this time. Moving on, the trough eases SE towards Northern Italy and weak heights build over southern Scandinavia south west as a new Atlantic storm extends energy east but with a hint of negative alignment as it moves toward the block and cold pool by T+240. Calm conditions over most of the British Isles by this time. Less cold air has reached Ireland with a SW'ly flow picking up but uppers remain below -8 over most of the British Isles and below -12 over East Anglia. Not quite as good as GFS OP (that would have been difficult) and we'll see where it goes after T+240 but certainly plenty for cold and snow fans. 12Z ECM: - leaving the worst to the last I would guess - ECM has refused to play ball with the cold spell thus far. Will it fall into line or stand tall and proud? At T+120 it's all happening a bit more slowly than with GFS with the trough still over Britain though phased with the new LP over Iberia. Heights are trying to push south but the E'ly is only over Scotland by this time. Uppers of -4 to -8 over the British Isles by this time. Now the crucial bit - the trough does sink south and heights develop over Scandinavia leaving an E'ly over the British Isles with the LP just off Cap Finisterre by T+192. Uppers below -8 everywhere and below -12 over East Anglia and eastern Scotland. From there, the trough fills but remains close to south east England as heights continue to build over Scandinavia but not well oriented at T+240. An Atlantic trough is approaching slowly but still well to the west. Uppers still below -8 by T+240 with a push of -12 uppers over south east England by T+240. A significant turn round from ECM tonight moving in the medium term to the GFS leaving the GEM looking isolated at T+240. Moving on, the T+312 (Feb 14th) and T+384 (Feb 17th) charts from OP and Parallel respectively: Both break down the cold spell in far FI - OP tries to build heights into Scandinavia while Parallel ends almost spring-like with +8 uppers and a large HP over Europe. Control also ends milder and more anticyclonic. UKMO looks fine but JMA doesn't and along with GEM fail to develop the cold spell. Conclusion: we're almost there but we're not. It's good to see the main models all looking very similar at T+120 but GEM and JMA aren't on-side yet and that's a worry even at this distance. GEM is disappointing while both ECM and the GFS models look excellent at T+240. The indications are it will be a 7-10 day cold spell and quite severe for many - prolonging it further seems to rely on height rises over Scandinavia and to be fair we don't always see the strength of the Scandinavian block in early modelling where the bias is to being back the Atlantic but that relies on a powerful PV and an active zonal jet. It remains to be seen if the PV has enough strength this year to break down any Scandinavian block or whether it may be an opportunity to build far enough west to keep the British Isles either cold and dry or in the battleground.

Evening all Just time for a quick look at the models this evening (no sniggering in the cheap seats, please). I'll take the T+120 charts and maybe the T+180 if I've time. 12Z GEM: Not bad - the first problem is a residue of energy is left when the initial trough moves east toward the British Isles and that phases with the next Atlantic system. The T+180 looks good for northern Britain but marginal further south through the push of heights down from the north is forcing the jet further south. 12Z GFS OP: Very satisfactory evolution from the OP ending with a decent E'ly for most by T+180. The OP doesn't make as much of the residual energy coming out of North America. 12Z GFS Parallel: Parallel gets there in the end but it's not as straightforward as OP and the Atlantic profiles at T+180 are very different. The energy spills out NE towards Iceland but is held by the block so will it slide south further into FI? 12Z ECM: (T+120 and T+192): It's better than last night I suppose with the troughs inching further south against the heights to the north - it all ends a bit battleground, cold in the north, mild in the south UKMO looks to be getting there at T+144 and JMA is fine at T+192 Conclusion: as we leave a nerve-shredding weekend for model watchers, are we there yet (as we always used to say on the journey from London to Cornwall which might explain a lot)? ECM keeps the nerve ends frayed but it's better than last night. GFS OP is fine, Parallel is okay while GEM is a bit too marginal for the south but fine for the north. Further on, and it's fascinating to see the extended FI pattern consolidating away from an Atlantic return to either a continuation of cold into mid month or a real battleground.

Indeed, the range of options as early as T+120 suggests clarity is in very short supply this evening. I think it might not be resolved until Monday at the earliest.

Evening all A bleak day in lowland East London with plenty of cold rain - if anyone has had snow good luck to you, whether we see any as the front comes back south overnight remains to be seen. I'm not hopeful and it looks as though any colder interlude will be done with by Monday as milder air returns. From there, many of the models were looking at just a 3-4 day milder interlude before a return to something colder by next weekend. ECM was on its own last night with a messy evolution but it got cold in by T+240 to align with other models. From there, GFS OP quickly broke down the cold spell but both Parallel and Control went for extended cold spells lasting to mid month. T+120 tonight takes us to Thursday February 4th. 12Z GEM: by T+120 there's quite a complex synoptic evolution. Heights have built from the north east and over Scandinavia while the Atlantic trough is now extended from near Greenland south east and then south to the west of the British Isles and down to Iberia. Upstream there's a mid-Atlantic ridge before a storm system just exiting North America. An ESE'ly flow extends across Scotland and the north of England with lighter winds further south. Positive uppers confined to Devon and Cornwall by T+120 with 850s of zero to -4 over much of England and uppers below -8 over northern and eastern Scotland as well as the Northern Isles. Moving on and heights transfer readily to Greenland with 548 DAM air in situ by T+180. The Atlantic trough has been forced south and east into Europe but remains close to the Channel Coast at T+180 and this serves to intensify the E'ly flow over the British Isles bringing in very cold air with -8 uppers widely and -12 uppers over central northern England. From there, the European trough never shifts too far from southern Britain extending back west and then pushing a new LP east into France. For most of the British Isles, the E'ly persists to T+240 with strong heights over Greenland and ridging south east from Iceland. Uppers below -8 for the Midlands north and while it's less cold further south, 850s remain negative. That's about as good an evolution as you could want for snow-starved southerners. It may be the south coast will be marginal but you can forget M4 corridors - even I would expect snow from that set up. 12Z GFS OP - possibly the most progressive of the models yesterday evening breaking down the cold spell quickly by T+240 but let's see. At T+120 it's not too different from GEM though I note the Atlantic trough is a smidgen close and the storm coming off North America is already throwing energy east to test the upstream amplification. Cornwall keeps positive uppers with 850s of zero to -4 for most and uppers below -8 over northern and eastern Scotland. From there, the heights to the develop differently to GEM with a distinct HP cell over or to the north east of the Faeroes but with a ridge to Greenland and south to the west of the British Isles. The trough has moved south east but phases with an LP moving north out of north-west Africa and ends up over central France with a strong NE'ly airflow on its north west flank over southern and eastern Britain. A lobe of energy from the storm over North America has exited north east forming an LP which is now off SE Greenland. By T+180 850s are below -8 across most of the British Isles with a wedge of -12 uppers in the North Sea. Moving on, heights persist over south west Scandinavia to T+240 with the Atlantic trough first moving south east and now trying to break down the block as a new Atlantic storm moves out of Newfoundland. A SE'ly air flow covers the British Isles. Positive uppers are inching their way back in from the south west and have just reached Cornwall but cold air persists over most areas with uppers still below -8 over northern and eastern areas. OP screams battleground but as last night, you'd put your money (which I imagine is nice money) on GFS sending the Atlantic through by T+312 despite the trough heading south east on a negative alignment. 12Z Parallel - after a sticky start, this was the coldie's best friend especially in far FI. Let's see how it is tonight. At T+120, it has already diverged considerably from GEM and GFS OP. The trough which sits to the west on the other models is over the British Isles with a cyclonic flow. Upstream amplification is in place but a lobe of energy has already broken off the North American storm and looks to be heading NE towards Iceland or Greenland - I'm not sure I like where this is going. 850s of zero to -4 for most parts with the last vestige of positive uppers for the far south east and uppers below -8 over the far north of Scotland and the Northern Isles. From there, the evolution becomes more complex - the trough never really clears the British Isles re-invigorating over the North Sea and by T+180 sits as a small LP over North East England and East Anglia. Heights persist to the north east. Meanwhile, the trough out of North America has moved to the south west of Iceland, deepens in situ and now looks to be heading SE at T+180 while heights persist over the Azores and a new HP has come out of North America - confused, that makes two of us! Uppers between -4 and -8 over the British Isles at T+180 with milder air trying to come in from the west. From there, the new HP out of North America pushes higher DAM air into Greenland raising heights and by T+240 a new HP sits over SE Greenland. The trough is forces south east and then south and by T+240 is to the north east of the Azores with an ESE'ly flow over the British Isles. By this time, most of northern Britain is under -8 850s while -4 to -8 850s covers southern areas. Parallel gets there in the end in some style but it didn't look a convincing evolution to this observer. 12Z ECM - last night's party pooper - the mood after the equivalent run was ridiculous and not helped by some less-than-stellar EPS which brought about the usual doom-and-gloom trolls, let's see if tonight's offering is a cause for celebration or lamentation. Once again, T+120 is uninspiring - the trough remains just to the west of the British Isles but extends back towards Greenland. The upstream amplification is in place despite the first signs of energy transfer off Newfoundland. Heights remain to the north east. Over the British Isles the air flow remains from the south west. Positive uppers cover most of southern England with uppers of zero to -4 for most other areas so ECM clearly the mildest option at T+120. ECM option develops very differently to the other models up to T+192. The upstream amplification doesn't quite happen but the trough does clear through the British Isles pulling down a brief N'ly but by T+192 the Atlantic trough has elongated east to Ireland as a shallow but complex feature. Heights persist to the north and north west with milder air returning from the south west. Positive uppers have retuned to south west England and Ireland by T+192 with colder air confined to eastern areas. The next shallow LP crosses southern Britain and by T+240 is over Holland with a weak NE'ly over eastern Britain leaving a new Atlantic LP spinning in the ocean as heights try to build down from the north and from Iberia. 850s of -4 to -8 from the Midlands north, less cold air further south. Two nights running and it just doesn't happen with ECM which looks on its own tonight. It's a concern of course but ECM isn't the be-all and end-all of models as we know. Back to GFS and the OP and Parallel runs at T+312 (Feb 12th) and T+384 (Feb 15th) respectively Plenty happening on both evolutions - OP ends with a cold trough over southern Britain and renewed upstream amplification while Parallel finally breaks down the easterly from the south. Neither evolution is in any way convincing. Control goes very anticyclonic with HP over Scandinavia and eventually migrating to the British Isles. Conclusion: ECM looks on its own tonight sending too much energy into the Atlantic to allow the amplification to take hold and build heights into Greenland. The other models all get there in one form or another with GEM the best for snow fans at T+240. The lack of agreement form ECM is a worry and with differences starting as early as T+120 we'll soon know who is the big cheese and who ends up with egg on their proverbials. To be honest, looking at both JMA and UKMO at T+144 I'm also none the wiser so, as we always say, more runs are needed.

I'm clearly in a minority of one here - I don't get all the doom and gloom but then I only look at one set of runs a day - the 12s. ECM isn't the disaster some claim - the 850s at T+240 are decent and you wouldn't argue against another E'ly from that. GFS OP is okay but the writing is on the wall if you believe the Atlantic is going to produce such a huge and complex trough in the current atmospheric environment and the Parallel is superb for cold fans. I haven't gone through the Ensembles but I find with ECM with 50 members plus Control and OP it's a case of, as the song had it "All Kinds of Everything". The final observation is for snow fans it's not a question of deep cold but of marginal battleground situations going the right way as cold and warm airmasses collide. The frequency of these collisions define what some see as a "snowy" winter even if it's not a particularly cold one and you can have a month of battleground scenarios whereas a couple of days of -12 850s is a rarity and may not produce a flake.

Evening all A decent day in lowland East London despite a few morning showers but colder through the afternoon. I didn't view last evening's models with the euphoria of some others - the journey to something colder next weekend seems there albeit far from certain (even at T+180) but the severity and longevity of any cold spell or snap far from certain. GFS, which seems to run the atmosphere on steroids, quickly returned Atlantic dominance while Parallel gave us a nice warm E'ly (believe it or not) while ECM just went off on one of its improbable T+216 and T+240 evolutions. Clarity is much needed but I suspect it won't be found on today's wibblings but we'll see: 12Z GEM: T+120 takes us to Wednesday February 3rd at which time the Atlantic trough is moving across southern Britain with E'ly winds over Scotland and a cyclonic flow further south. Heights to the east of Iceland and upstream amplification ahead of a new storm moving off the eastern seaboard. Mild air with positive uppers persists in the south but it's colder further north with -4 to -8 850s generally and uppers below -8 over northern Scotland. From there, heights rise over the British Isles as a wedge of HP develops by T+180 from the Azores, through the British Isles to Scandinavia. A new Atlantic trough has formed from a lobe of energy off the storm over North America and has moved quickly NE to be near Iceland by T+180. A broad but shallow trough sits over Europe. The colder air mass has moved south with 850s below -8 over much of southern Britain and -12 uppers close to the east coast. Uppers of -4 to -8 elsewhere. Moving on, and the Atlantic LP spins to the north of Iceland, turns east and then south east as heights rise to the far north and by T+240 is moving SE into the North Sea. It is phasing with the residual LP over the Balkans. A wedge of heights persists from the Azores towards south-west Britain. Milder air has pushed back into western and south western areas but it remains colder to the east with a new wedge of colder air coming into Scotland behind the LP. A complex and messy evolution from GEM to be honest. 12Z GFS OP - at T+120 a complex trough covers southern and western Britain with centres over southern England and to the north west of Ireland and a third feature just to the north east of the Azores. Heights to the north and upstream amplification. 850s over the British Isles either side of zero at this time with the coldest air confined to the far north of Scotland and the northern isles. From there, heights continue to build to the north and the trough slowly fills and sinks south and by T+180 the British Isles in an ESE'ly air flow with 850s zero to -4 over southern areas and below -8 for much of northern Britain. Moving on and the E''y air flow persists but the heights are weakening to the north and the Atlantic trough has moved SE and is now starting to pivot back to a more positive alignment which will lead to heights rising again over southern Europe so I suspect the Atlantic reset is coming. At T+240, the cold regime is holding on with 850s generally below -8. 12Z Parallel - at T+120 the profile is similar to the OP with the controlling LP over North-west Ireland and a cyclonic SSE'ly flow over the British isles with heights to the north and upstream amplification - weak heights over Scandinavia at this time. Milder air with positive uppers over southern Britain but colder air persists over northern and eastern Scotland and the Northern Isles. From there, as with the OP, heights build strongly to the north and the trough fills and sinks south leaving an E'ly air flow over the British Isles. Uppers below -8 covering much of the British Isles by T+180 (Saturday February 6th). From there, the E'ly persists across southern parts as the HP relaxes slightly north west. Despite the continued air flow direction, the air source is further south so some milder air comes into the mix leaving uppers at T+240 zero to -4 over south east England and -4 to -8 elsewhere. Parallel loves its mild easterlies, doesn't it? 12Z ECM - the evolution was a real curiousity last night especially post T+192. At T+120 tonight, the trough orientation is slightly different to other models but we have heights to the north and upstream amplification. Uppers either side of zero over most of the British Isles but colder air with uppers of -4 to -8 persist over Northern Scotland. From there, the Atlantic storm which is just coming off the eastern seaboard at T+120 races north east to be just off Norway by T+192 with a second LP to the south of Iceland. HP over the Azores persists along with heights which were over Scandinavia and have already sunk south-east into Europe. Milder uppers approaching from the west but colder air persisting over eastern areas by T+192. Moving on, the trough splits - one element sinks south to the west of Ireland while the other starts to sink SE through Scandinavia with a moribund Atlantic and heights building through Iceland leaving a slack N'ly over the British Isles by T+240. Much colder air has moved south with uppers below -4 for most places and below -8 over Scotland. Nope, don't buy that ECM evolution at all - it's a model drowning in its own data contradictions. Looking further ahead, GFS OP and Parallel at T+312 (February 11th) and T+384 (February 14th) respectively: OP blows up a huge mid-Atlantic trough which breaks down the cold spell while Parallel is a coldie's nirvana with Easterlies and Northerlies throughout FI and a solid 10 day cold spell. After last night's horror show, Control is mostly cold or very cold and ends with a battleground. The 10 HPA suggest a new warming trend approaching mid-February but that's a long way off. Conclusion: while I don't really accept the evolution, ECM and GEM get to cold in the end - it's rather simpler with GFS OP and Parallel with the trough filling and disrupting south as heights build from the north. OP breaks down the cold spell quite quickly while Parallel is superb for coldies (Control not bad either). ECM does strange things with an Atlantic trough which seem to defy the laws of physics. NAVGEM and JMA are different again so the amount of uncertainty post T+180 is a concern - we can but hope Parallel has called this well. I just don't see how, in the absence of a strong PV and zonal jet we can be seeing a robust Atlantic - but some models want t push an Atlantic trough NE toward Iceland to break down the mid-Atlantic amplification so we'll see.

Evening All A pleasant day in lowland East London with a little afternoon sunshine and temperatures at 12-13c so very decent for the time of year. As ever, winter is the battle between colder and warmer airmasses and after recent years when the mild held sway with the cold held well to the north or east, this season has, perhaps because of the antics in the stratosphere, has seen the battleground much closer to home. The immediate future demonstrates this with another brief cold snap at the weekend for the south while the north and especially the far north of Scotland seems set to remain cold with the milder air never fully reaching higher latitudes. Another milder push early next week but towards next weekend clear signs of another change and perhaps, just perhaps, a more significant colder spell. Let's see what tonight's obfuscations leaves us: 12Z GEM: T+120 takes us to Tuesday February 2nd by which time the cold snap of the weekend has receded with Atlantic frontal systems moving in ahead of two areas of LP to the west and south-west of Ireland linking back to another LP much further west. Weak heights to the north east at this time and milder air with positive uppers across most of Britain with only the far north still in colder air with 850s below -4. From there, upstream amplification develops with heights building from north to south in mid Atlantic forcing the trough east over the south of Britain with a NE'ly setting in for northern parts and a cyclonic air flow further south. Colder air has pushed south by T+180 with uppers of -4 or below over northern England and colder air over Scotland. From there, heights continue to develop to the north and by T+240 an anticyclonic cell is over Scotland with a ridge south west and LP over the northern Adriatic. Hints perhaps of the Atlantic trough trying to move round the top of the HP to the west of Iceland. 850 of -4 to -8 cover the British Isles though the coldest air has passed to the south. A cold evolution from GEM. 12Z GFS OP - at T+120 not hugely different from GEM - slight difference in the orientation of the Atlantic trough and heights a smidgen more pronounced to the south. As with GEM, positive uppers over the south and west of Britain with colder air confined to the north at this time. Moving on and the impact of the upstream amplification becomes clear as the trough is pulled east and south and by T+180 is to the west of Brittany with a NE'ly airflow over the British Isles. Cold air with uppers below -8 for many areas with the mildest air confined to the far south. Moving on and the NE'ly flow eases away south as heights build across the British Isles with HP centred over England by T+240 but clear signs of the Atlantic trough trying to push back towards Iceland trying to re-introduce a milder air flow. Uppers below -8 confined to southern and eastern areas by this time. GFS OP brings in the cold but it looks a short-lived snap rather than a prolonged spell unless we see the ridge head into Scandinavia. 12Z Parallel - at T+120 small variations against the OP but nothing too significant to my eye. Again, we see the push of milder air to most parts of the British isles but colder air hangs on in north and north east Scotland as well as the northern isles. From there, as we've seen elsewhere, heights build from the north and the trough is pushed east and south - by T+180 a weak LP is over south-east England and the HP to the north ridges south west against the new Atlantic trough. The lost of the positive 850s have eased away from the south and uppers of -4 or below for northern areas and even colder air trying to come into Scotland on an ENE'ly air flow. Moving on from T+180 and heights continue to develop to the north and by T+240 a block has formed over Scandinavia with a ridge to Iceland and Greenland. Between that and residual LP over Europe, a strong E'ly flow has established over the British Isles albeit with the origin further south. That means the coldest air is over the north of the British isles with positive uppers approaching from the east and south east (strange as it may seem). Parallel brings in synoptics which by T+140 you'd think would be nirvana for coldies but the air isn't sourced from Siberia but from the Middle East so it's significantly warmer than you might imagine. Curious but fascinating synoptics - a warm E'ly in February - who'd have thunk it? 12Z ECM - by T+120 the trough is less elongated than on other models and orientated slightly more positive but the upstream amplification looks to be in place. The 850s look similar, +4 uppers across parts of the south but uppers below -4 in the far north and north east. From there, ECM goes off on its own - the trough starts to move east but the upstream amplification struggles as the two Atlantic troughs try to phase and a residual LP sits to the west of Iceland as heights build from the Azores and over Scandinavia. 850s of zero to -4 for all parts of the British Isles by T+192. It's a messy evolution if I'm being honest and I don't quite see how this small residual LP holds against the heights moving down from the north. From there, we reach T+240 with a chart more like midsummer than February. Heights over Scandinavia and Greenland but somehow the British Isles dodges a cold evolution with milder uppers coming back over Ireland as colder air sits to the east but there's no real momentum for anything on that chart. I'll be honest - I just don't understand the ECM evolution at all so it's the bin for this in my view. Looking at the T+312 (Feb 10th) and T+384 (Feb 13th) charts for both GFS OP and Parallel tonight: Both interesting in their own way - GFS OP keeps a blocked pattern throughout and threatens a N'ly incursion at the very end while Parallel collapses the block and goes back to a more stormy pattern but with the jet running close to southern Britain so the north stays cold even as the south becomes a little milder. Control is horrible for cold fans with northern blocking shifting south and forming a European HP allowing a long-fetch SW'ly to set up. The 10 HPA charts show little interest in further warmings into February as the PV consolidates albeit much warmer than usual. Conclusion: It does look as though after next week's brief milder spell we will see another push of colder air from the north at the end of the first week of next month. How long that lasts and how severe that might be are all very much up for grabs. GEM and GFS OP are quite promising and Parallel does well for a while but ECM isn't convincing and GFS Control rapidly collapses any block for a European HP so it's all very much in the balance tonight. I really don't know whether we'll see a snap or a spell - can the HP either build NE or NW or will it sink?

Yes, ECM Control achieves a nirvana for cold fans with the HP starting in the North so we get a nice E'ly but the HP then moves SW to the west of the British isles so the airflow moves slowly from east through north east to north over a week. To be fair, after the -14 uppers at T+288 it gets almost mild (-11 by T+360) for south eastern parts.

Evening all A pleasant day in lowland East London - milder and dry but I suspect rain is on the way as we move to a much milder scenario tomorrow though that looks temporary with a brief colder snap at the weekend before a new push of milder air early next week. From there, well, plenty of confusion and a shortage of clarity on last night's model output. GEM and GFS were hinting at a change in the pattern with heights over Scandinavia but ECM wasn't interested at all. Let's see what tonight's meanderings take us 12Z GEM: T+120 takes us to Monday February 1st and T+240 to Saturday February 6th. By T+120 a trough covers southern Britain with a shallow area of LP over the far south east with the trough extending back into the Atlantic while a new LP starts to deepen to the south west. A weak draw of heights draws to the north means a SE'ly air flow persists over northern Britain. Milder air with positive uppers has returned to southern parts but uppers of -4 persist over Scotland. From there, the trough remain sin charge but with heights continuing to persist to the north the trough becomes elongated by T+180 extending across the British Isles and Denmark to Poland. There's a hint of upstream amplification with a new LP coming out of North America. Colder air with uppers of -8 or lower persists over the far north east of Scotland and the northern isles while cooler air with slightly negative 850s has returned to most of the rest of the British Isles. There's more than a hint of the colder evolution from there and as you might expect, the trough disrupts south as strong heights build down from the north leaving the British Isles in a NE'ly flow by T+240. 850s of -8 or lower cover the British Isles. GEM goes cold with a vengeance - let's see if it's a trend setter or out of sorts. 12Z GFS OP: at T+120 it's moving things a little quicker than GEM for which this looks more like the T+126 chart. The trough has re-aligned slightly more positive as one LP moves slowly NE towards Ireland. However, milder air has barely made it to southern and western parts with much of the north and east of the British Isles still under uppers of -4 or lower. From there, the trough fills and disrupts east across the British Isles with secondary LP crossing or lying close to the south by T+180. A NE'ly flow has set up for northern areas with strong upstream amplification though I note the shortwave development off east Greenland with some concern. Colder air is encroaching from the north by T+180 - slightly negative uppers in the south, 850s of -4 to -8 further north and uppers below -8 coming into northern Scotland. From there, stroang heights develop from mid Atlantic initially just to the north of the British Isles but by T+240 the HP is centred over Scotland with a strong ridge to the south west and a second centre over Scandinavia. The HP is propped up by a deep LP in the western Mediterranean. An E'ly air flow across southern Britain but calm conditions elsewhere by T+240 with uppers geenrally -4 to -8 over northern areas and below -8 over southern and eastern Britain. GFS also goes cold but dry and bitter in the south. 12Z Parallel - by T+120 a lobe of trough energy extends south east across southern Britain with perhaps stronger heights to both south and north than on other models. Calm conditions over much of the British Isles with a light SE'ly over southern areas. As with the OP, milder air has just reached Cornwall and south west Ireland with colder air elsewhere and uppers below -4 in most northern and eastern areas at this time. Moving on, and in common with other models, the Atlantic trough moves east and fills across the British Isles so that by T+180 we have one LP over south-east England, a secondary LP west of Biscay and a third LP to the north west of Ireland with the trough extending north west to the west of Iceland. Heights to the north and significant upstream amplification. BY T+180 any milder air is confined to the far south east with colder air elsewhere and remaining cold over Scotland. From there, heights continue to build to the north and by T+240 we have an HP centred to the north east of Iceland with a ridge to east Greenland. To the south, a residual trough hangs on over the southern North Sea while a new Atlantic system has aligned negatively with lobe energy heading south east towards Iberia. An ESE'ly air flow covers most of the British Isles at this time with 850s of -4 to -12 or lower for all parts though milder air is trying to push back in from the south west. 3-0 to cold but I'm not sure about the longevity of a Parallel cold spell given the Atlantic profile which looks more active than OP. 12Z ECM - the mildest option yesterday evening. At T+120 heights from the north and south have cut the trough , part of which is heading south east into Europe with the main energy far to the west. A light NE'ly flow over southern and eastern Britain and a light SE'ly over western Ireland. As with other models, the 850s profile is uppers below -4 for most northern and eastern areas with positive uppers reserved for Cornwall and south west Ireland. Moving on and ECM diverges again from the other models with the Atlantic trough moving to a more negative alignment in the face of heights to the north and upstream amplification. The main LP is to the south west of Ireland with a SE'ly over the British isles by T+192. Positive uppers are confined to southern counties with uppers below -8 over northern and eastern Scotland. From there, heights build rapidly to the north and by T+240 there's a large HP centred to the north and east of Iceland with a ridge to Greenland and an E'ly covering the British Isles. The temperature gradient is steep - mild air isn't far from the south coast but it's cold over northern and eastern parts. I make that 4-0 for cold especially for northern and eastern Britain - further south, 3-1 to be charitable to mild. Looking further ahead, the T+312 (Feb 9th) and T+384 (Feb 12th) charts for OP and Parallel respectively: Neither OP nor Parallel keep the cold pattern in situ for long but that's GFS modelling for you (something is always happening). Neither goes spectacularly mild with the OP bringing away negative alignment and Parallel dropping part of the PV into the North Atlantic so both for the bin in my view. Control is very strange synoptically but mostly cold. Indeed, all I get from GFS in far FI is some wild solutions which suggest the output is struggling. If I'm being honest, the 10 HPA charts seem to be backing off more warming while leaving the PV weaker and less organised than you'd expect in February. Conclusion: much stronger charts for cold fans tonight with all the main models getting to a similar place by T+240. Heights build to the north and apt from GFS OP stay there. The longevity and severity of any cold spell in early February to be determined but after the next milder incursion next week (which looks more half hearted with each run) the North quickly goes back cold from midweek with the south joining the party later in the week. From there, GFS puts out some wild options in FI which suggest a lot still to be resolved.

Evening all The arrival of the milder air brought in a grey overcast and evening rain after a final overnight frost. Fascinating output last evening with GEM leading the way for an early return to colder conditions but other models keeping it mild until T+240 but GFS certainly went cold with a vengeance at the end of FI so it'll be interesting to see if the signal for a pattern change in the second week of February remains tonight. 12Z GEM: - T+120 takes us to Sunday January 31st. A weak HP area over Scandinavia is retreating as an Atlantic trough advances from the west but the tough is struggling to come in against the block and a SSE'ly air flow ahead of the trough is part of it as is the trough's slight negative alignment suggesting more progress east than north. Milder air with positive uppers has returned to the south west but uppers of -4 and below cover most northern and eastern areas at this time. Moving on and changes to T+180 are small with heights persisting to the north east over Scandinavia and the LP moving slightly north in response but unable to advance far to the east. However, a W'ly flow across southern Britain suggests milder air has got in but with returning PM air into northern and western parts by T+180 behind the cold front. From there, the Scandinavian HP continues to expand to the north and the Atlantic trough disrupts back west apart from a cut-off LP which sits over the British Isles at T+240 with a cyclonic flow in place. Colder air is moving into northern Britain on the northern flank of the LP in an E'ly flow but the south remains in less cold air at this time. Not as good as last evening but a clear signal for Scandinavian heights from GEM this evening after a battleground evolution in the medium term. 12Z GFS OP - the T+120 differs slightly from GEM with a more S'ly flow and less defined heights to the north east but the trough is aligned negatively for the moment. Milder air with positive uppers across Ireland and the far south west but colder air with uppers of -4 or below over northern and eastern areas. From there. the trough extends across the British Isles but heights building to the north cause the trough to disrupt but by T+180 a small secondary LP is over southern Britain while a slack SE'ly flow covers northern areas. Milder air is confined to southern Britain while uppers below -4 are over northern Britain. Moving on and heights continue to build to the north and the trough further disrupts to thr south and east leaving initially a slack NE'ly flow but by T+240 it's calm over the British Isles with much colder air (-8 uppers) over most areas and a push of -12 uppers from the east. OP ends cold if not very cold though the evolution from there isn't easy to define. 12Z Parallel - at T+120 again slightly different. A weak ridge of HP is over the British Isles by this time. Parallel has the trough further to the west than GEM or GFS OP but it is trying to extend a lobe of energy east towards the British Isles. Colder air persists over more of the British Isles with negative uppers persisting over all parts and uppers below -4 for eastern areas. As I suspected, it's not such a promising evolution for cold fans moving on from T+120 though we do see heights building to the north east while the Atlantic trough tries to move in but fails to make much progress east and instead a series of secondary LP move past the west of Ireland. A SSW'ly air flow covers most of the British Isles at this time and milder air with positive uppers covers England and Wales with only Scotland in slightly cooler air. From there, heights continue to build over Scandinavia and extend west to Greenland in the face of which the Atlantic trough disrupts west though keeping a residual energy lobe over the north west of Scotland. I also note a new LP over Iberia and North Africa. To be honest, I find this synoptic evolution a little odd but in terms of 850s, the south east remains mild with colder air slowly spreading south from Scotland. To paraphrase Fleetwood Mac, Parallel "goes its own way" but all three models so far have gone their own way from T+180. 12Z ECM - at T+120 a clear signal for negative trough alignment as the main core LP runs east towards southern England. A SE'ly further north and east with weak heights. Milder air with positive uppers coming into the south west but colder air with 850s below -4 over northern and eastern Britain at this time. From there to T+192, the trough to the west and north west dominates with the core LP sitting to the south of Iceland and the trough extending SE to north west Britain. A WSW'ly airflow of PM origin dominates by T+192 - positive uppers over eastern parts but a dip to slightly negative uppers behind a cold front to the north and west. From there, the trough extends east across northern Britain with heights to the north as a new Atlantic trough phases with the flow at T+240 and keeps a SW'ly air flow for southern areas. Uppers of -4 or below for many areas but milder air approaching again from the west. There's no point sugar coating it - ECM is a poor evolution for coldies tonight but it may be an outlier though it may not. To be fair, all four T+240 evolutions shown are very different suggesting there's a lot of uncertainty in the models tonight. I'll put up, as I always do, the T+312 (Feb 8th) and T+384 (Feb 11th) charts from GFS OP and Parallel: If I were a bluff old cynic, I'd say any trick to prevent the British Isles from getting a cold spell was being wheeled out tonight. The synoptics almost get there but then they don't. It may be best not to pay too much heed to the far FI charts given the huge uncertainty at T+240. Control doesn't do too badly with a solid 7-10 days of cold weather. The 10 HPA charts continue to show a weak and disorganised PV and Parallel forces another split in the second week of next month. Conclusion: a night when there are more questions than answers as the song has it. In the short term, the weekend's brief colder interlude is followed by a return of milder air early next week but from there plenty of options remain on the table. To be fair, all bar ECM show a strong rise of heights to the north and north east (Parallel adds Greenland heights as well). This causes the Atlantic to pull back and ideally we'd get a clean release of that energy but as you might suspect that doesn't always happen. ECM isn't interested in height rises to the north and keeps the trough and milder air in charge. Plenty to keep us interested and intrigued and to keep the nerves frayed as we go into February.

Evening all After yesterday's excitement, a much quieter day in lowland East London and pleasant in the winter sunshine after a very cold start. Milder weather is at hand however and the start of a 7-10 day milder interlude in the south but further north the extent and longevity of any milder spell very much up in the air (no pun intended). Moving further into February and hints continue of a new pattern change to something colder and perhaps more settled but we'll see. 12Z GEM: T+120 takes us to Saturday January 30th and with a shallow LP along the Channel and heights extending south east from Iceland, a NE'ly air flow covers the British Isles. A trough extends from the Channel across northern Europe while a vigorous Atlantic LP churns NE across the ocean far to the west. Uppers below -4 cover most of the British Isles but with milder air hanging on in the far south west and colder air moving into Scotland. The block to the NE, albeit weak, is enough to cause the Atlantic LP to disrupt with one portion singing NW toward southern Greenland and the other moving east towards the British Isles by T+180. SW'ly winds have moved back into southern and western areas with a SE'ly across northern and eastern parts. Milder air with positive uppers is confined to the far south by T+180 with colder air elsewhere and -8 uppers persisting over Scotland. From there, heights continue to develop to the south of Iceland and ease SE to southern Norway with an E'ly across southern and eastern Britain as LP moves south into Europe by T+240. Cold air with uppers below -8 covers most of the British Isles. GEM is about as good an evolution as any cold fan would want ending with a frigid E'ly and, you'd imagine, plenty of snow for southern and eastern parts. The GEM snow chart tells its own story. 12Z GFS OP - GEM is a near impossible act to follow. At T+120, quite different close to the British Isles from GFS OP with a weak HP over eastern parts and the Atlantic LP churning NE to the far west with little signs of further heights from Iceland and a residual LP over the Baltic. 850s just negative over most of the British Isles by T+120 - mildest air to the south west and coldest along the east coast. From there, the heights close to the British Isles soon fade as the Atlantic trough comes in and takes over just to the west of Ireland and by T+180 is pretty much still there with a complex trough in charge - the main centre is to the south west of Ireland and there is a ridge of HP over Scandinavia. Mild SW'ly winds over most southern and south-western parts of the British Isles by this time - positive uppers there and only slightly negative elsewhere. From there, the trough crosses over the British Isles but the LP is held to the east by the block over Scandinavia and by T+240 the trough is filling in situ with heights building upstream in mid-Atlantic. There's a slack cyclonic flow over the British Isles with slightly negative uppers in all areas except the far north where the air mass is colder. Not surprisingly, GFS OP is not as good for cold fans as GEM but some helpful signs at T+240. 12Z Parallel: at T+120 Parallel is closer to GEM with heights to the north west extending from Iceland and LP to the south over the Channel leaving a NE'ly flow across the British Isles. Upstream, a brief ridge is followed by a vigorous LP moving NE in mid-ocean. Uppers are below -4 in almost all parts of the British Isles with only the far south west keeping a little milder. From there, the Atlantic trough gradually moves in and disrupts north-west and east forming an elongated and complex trough with one centre to the south west of Iceland and the trough flow extending east across the north of Britain. Further south, a strong W'ly airflow is in place with a secondary LP deepening and moving toward the British Isles from the south-west. Milder air has extended across all parts with uppers either side of zero at T+180. The secondary LP duly moves across the British Isles and heights rising in mid Atlantic start to drag the whole trough east towards and across the British Isles by T+240. Two shallow LP, one over southern Britain and another to the north west are moving east with heights now rising again to the east of Iceland. The air mass over the British Isles remains average - mildest in the south, coldest in the north but nothing too dramatic. Once again, you'd think the evolution from T+240 would be towards something colder but we'll see in a moment. But first, 12Z ECM - by T+120 there's a weak HP to the north west of Scotland with an LP over northern France and that pulls a NE'ly air flow across the British Isles. Uppers of -4 to -8 over all parts of the British Isles by this time. From there, the Atlantic trough takes over and by T+192 there's a SW'ly air flow over all parts with one LP to the north of Scotland and the controlling LP to the south west of Iceland. By that time, milder air is into south-western parts but 850s are still slightly negative elsewhere. By T+240 ECM isn't very far from Parallel with the trough filling as it moves east over the British Isles and upstream amplification. Negative 850s over all parts by T+240 with colder air moving into the far north west. ECM ends similar to Parallel this evening with upstream amplification and the trough filling as it moves east across Britain. Time to look further ahead with the T+312 (Feb 7th) and T+384 (Feb 10th) charts from both OP and Parallel. You pays your money, you takes your choice - OP goes Scandinavian initially and then Greenland with some very cold air (-12 uppers) for south eastern parts in far FI while Parallel is possibly the one for snow fans (lots of cold troughs in -8 uppers anyone?). Either way, decent for cold/snow fans. Control reprises the sliding trough from earlier in the winter further into FI with much better 850s, you;d think that would be a snow maker as well. Parallel is the most dramatic on the 10 HPA charts with another vortex split in FI but all the charts show the PV much smaller and weaker than you would expect. Conclusion: will we get there? Well, yes, I think so. GEM gets us to a cold evolution very quickly and if this comes off, kudos to the Canadians. GFS OP, Parallel and ECM all take a slower route but at T+240 the signs are there with upstream amplification. It looks as though we will have another cold snap at the weekend before another return to milder air this time next week which again looks as though it will be an interlude before another colder evolution at the end of the first week of next month. So a 3-4 day mild interlude followed by a 2-3 cold snap followed by another 4-5 days mild before the pattern change to a hopefully prolonged colder spell. That's how I see it looking at the models - others may see it differently. I'd love GEM to be right but I don't see it.

Evening all Snow finally reached lowland East London this morning and early afternoon. Only a transient covering which quickly melted in the afternoon chill but still it snapped the three-winter snowless streak and it was out first snow fall of any sort since March 2018. A one-off or a taste of things to come? There's a lot of winter left (and including March we still have two months of opportunities for snow) and last night's output (with the notable exception of Parallel) was suggesting after a brief milder spell the pattern would be shifting again to something colder once more soon after the start of next month. 12Z GEM: T+120 takes us to Friday January 29th. Heights pushing south to the east of Iceland and residual heights over Iberia have compressed the trough channel south but it still covers the British isles and extends east to northern and north-eastern Europe while upstream a shallow trough sits to the south west ahead of a more significant LP moving out of the United States. A light E'ly over Scotland while slack conditions cover most parts and a W'ly air flow runs along the Channel coast. As might be expected, mild air remains to the south but colder air has returned to northern areas with uppers below -4. From there, quite a complex evolution with another LP running east across the Channel and Northern France pilling down a brief but cold NE'ly. By T+180, that has eased to a col across the British Isles with a new vigorous Atlantic trough winding up to the south and south west of Iceland. Heights over Scandinavia are trying to extend south-west at the same time. Cold air with uppers below -8 remains over eastern parts and the whole of the British Isles has 850s below -4. Moving on, pressure rises strongly over Scandinavia and by T+240 hp is over northern Norway but the Atlantic is still trying to push in creating a real battleground scenario over the British Isles. At T+240 the main LP is south of Iceland with a secondary feature in the south western approaches and a SE'ly airflow covers all parts. As might be expected, milder air remains to the south and west with colder air to the north and east. GEM ends with a real battleground which it didn't last night while the other models did. 12Z GFS OP - as with GEM, the trough has begun to disrupt south-east through the British Isles by T+120 with shallow areas of LP within the trough's circulation. Heights to both north and south with a light W'ly to the south and a SE'ly for northern areas. Milder air persists over much of the British Isles with only the far north east and Norther Isles still in -4 850s. From there, the Atlantic trough gets some re-invigoration from the LP from lower latitudes but it elongates east across the British Isles by T+180 as heights begin to rise over Scandinavia. Secondary LP are forming in the circulation to the south of the trough where the colder and warmer airmasses are meeting. After a brief push of colder air milder air has returned to most southern and western areas by T+180 but it remains cold further north and east. From there, the trough to the north west sends secondary LP across southern Britain and eventually starts to ease south as heights build to the north east over Scandinavia and extend west. A W'ly air flow continues across the south at T+240 but 850s have just gone negative leaving the coldest air still to the north and east. GFS OP not quite as exciting as GEM for cold fans but still moving in a decent direction looking at the upstream ridging/ 12Z Parallel: by T+120 one area of LP is to the east over Denmark leaving a NE'ly covering much of the British isles. A brief ridge is approaching the west but a vigorous LP is approaching from the south west. Milder air remains over southern parts but colder air with uppers below -4 is moving south from Scotland into northern England. From there, the deep Atlantic LP moves east along the Channel into northern France and disrupts south into Biscay as a ridge builds down from the north but this is transient and the pattern "resets" by T+180 with a new positively aligned trough extending south west from the south of Iceland and a new push of milder SW'ly winds approaching the British Isles bringing positive uppers toward western parts. Moving on, the mild regime sets up but heights build strongly to the north resulting in the Atlantic trough re-aligning negatively. By T+240, the main LP centre is over Ireland with the trough extending north west to Greenland and heights sit over the Azores. Mild air covers the British Isles by T+240. Not much battleground there to be honest despite the northern blocking - Parallel again sits in the milder camp. 12Z ECM - by T+120, as with GEM, a build of heights from Iceland south has pushed the LP systems further south with one shallow trough extending across northern Europe to southern and eastern Britain and a new LP approaching from the south west. A NE'ly covers northern parts with a cyclonic flow elsewhere. 850s are positive in the south but negative uppers elsewhere with 850s below -4 iin north eastern areas. The LP moves east quickly followed by a transient ridge but by T+192 we have a new Atlantic LP to the south of Iceland and a broad run of SW'ly air across the British Isles pushing positive uppers back across most parts after a brief colder incursion. From there, the LP over Iceland edges back west but a hint of upstream amplification and the air flow is more PM in characteristic from the west. 850s just negative over all parts of the British Isles so nothing dramatic. ECM ends with a bog standard modified PM westerly so showers for most you'd think. Moving on, a look at GFS OP and Parallel at T+312 and T+384 (February 9th) respectively. OP ends as a real battleground while Parallel gets to a cold evolution eventually but it's a real struggle with a lot of rain (and perhaps snow) to go before that. Control ends a bit battleground too but with a stronger anticyclonic influence from the south as well as from the east so the full on E'ly goes to the south. Conclusion: It now seems what was going to be a single milder interlude may be split by a brief colder incursion next weekend. From there, GFS and ECM want to bring back an Atlantic-sourced flow fairly quickly while GEM brings the Scandinavian HP into the mix and leaves the British Isles in a battleground scenario by T+240. GFS OP, Parallel and ECM pick up the battleground idea further into FI and it's an emerging theme for the first week of February and beyond though that will doubtless be dependent on other factors such as the MJO and developments in the stratosphere. I'll leave others to consider next weekend's colder snap and where any snowfall may occur.

Afternoon all Nice to see falling snow even in lowland East London this morning and a transient covering on some surfaces so winter 2020-21 NOT snowless. Nowhere near the epics of 2009, 2010, 2013 and 2018 of course but better than nowt. Currently +1c so a general melt has occurred - the question is how hard will it freeze tonight?

Evening all A glorious winter's day here in downtown East London and the question du soir is whether I will see falling snow tomorrow. I'm sure that's being debated elsewhere so I'll look further ahead and a milder spell coming from Tuesday lasting, well, that's the thing. Last evening, both GFS and ECM were looking at changes at T+240 which suggested the return of something cool if not cold and certainly not epic cold. There was plenty of that on the far FI charts from both GFS OP (via Greenland) and Control (via Scandinavia). On then to tonight's melange or should that be blancmange? 12Z GEM: T+120 takes us to Thursday January 28th. A shallow LP is clearing the north east coast with a strong W'ly flow to its south but a brief ridge upstream with another LP developing to the west in the circulation of a shallow but extensive mid-Atlantic trough centred to the SE of Greenland. Heights persist over Iberia while a residual trough lingers over the Baltic States and Eastern Europe. Mild air with 850s of +4 covers most of the British Isles with only lightly negative uppers in the far north and north-east. From there, the second LP crosses through centre parts while a new LP deepens from the south west and moves first NE and then east crossing Wales by T+180. The British Isles is in a cyclonic flow at that time with tentative heights building into Scandinavia. Mild air persists for most but again the far north remains under negative uppers. Moving on and the LP clears away east but slows to the south of Denmark as the next shallow LP follows it across the south of Britain. Meanwhile, heights are building over Scandinavia and to the north and by T+240 most of northern and central Britain is north of the trough and under an E'ly flow while the trough extends from Northern Germany through the Low Countries to Southern Britain and north west towards Greenland. A sharp temperature gradient across the British Isles by this time with positive uppers confined to the far south west while 850s of below -8 are across most northern and north eastern parts and Shetland is basking in -12 uppers. February starts as a real battleground according to GEM with the south remaining mild under the trough and the north turning much colder. 12Z GFS OP - at T+120 not hugely different to GEM except in the immediate vicinity of the British Isles. GFS OP has three shallow areas of LP with once crossing out of eastern Scotland and two approaching from the west. The main Atlantic feature looks shallower than on GEM and perhaps more hint of height rises around Iceland. Mild air covers all the British Isles by this time with +4 uppers over the south west. From there, a series of shallow LP cross the British Isles with the last clearing into the North Sea by T+180 with a ridge upstream from the HP which has eased west towards the Azores. Weak heights also extend south from Iceland and a NNE'ly covers the north of the British Isles with more of a NNW'ly component further south. The milder air mass has been replaced by 850s of zero to -4 by T+180 with uppers of -4 to -8 further north. Moving on, the LP which has come up from lower latitudes extends a lobe of energy east across southern Britain. An attempt to build a wedge of heights from Iceland south fails and by T+240 the Atlantic trough sits to the west with a new LP coming out of the eastern seaboard and a residual trough and some very cold air over Scandinavia. Strangely, the 850s profile ends very similar to GEM with positive uppers over the south west and much of Ireland but with -8 uppers over eastern England and much of Scotland. GFS OP ends less favourable than GEM but I note the colder air mass over Scandinavia and perhaps more heights over Greenland which was the theme of last evening - mid-Atlantic ridge in far FI? 12Z Parallel - we have a Parallel run tonight which is nice. At T+120 less sign of disruption over the UK than on GFS OP or GEM with the lobes of energy ejected more to the NE so the LP is close to the Hebrides at this theme but the core Atlantic trough also seems closer and hints of further secondary disturbances in the flow to the south west. Mild air with positive uppers for most of the British Isles at this time. From there an unsettled couple of days with small areas of LP crossing southern Britain bringing further rain but by T+180 a clean break in the trough with a wedge of heights upstream and a N'ly over the British Isles. Uppers of -4 to -8 over much of the British Isles but colder air still moving south through Scotland. The N'ly is transient but the heights sink south first as a ridge and then move into Europe as a new HP while the next Atlantic trough is positively aligned to the northwest and by T+240 a flow of SW'ly TM air has been re-established with positive 850s for the whole of the British Isles. Basically, Parallel ends very poor for cold fans with the SW'ly pattern re-establishing thanks to the infusion of heights into Europe from the north west. 12Z ECM - a very different Atlantic profile than Parallel at T+120. Heights to the east and north east of Iceland have forced the Atlantic trough to align negatively and any lobes of energy are sent more ESE across the British Isles rather the NE as on Parallel. The trough now extends across the British Isles and phases with the residual trough over Scandinavia. Milder air has reached most of the British Isles but it remains cold with -8 uppers to the far north east. From there, weak heights to the north but they have the effect of aligning the trough negatively so LP are taking a more southerly track crossing the British Isles with the Iberian HP relaxing a smidgen further south. Slack pressure over Scandinavia as well. Milder air has been pushed back to the west with -8 uppers over the furthest eastern counties at T+192. From there, the trough remains close to the south west of the British Isles and by T+240 a new area of LP is approaching Cornwall on an ESE trajectory with a notable nose of HP into Scandinavia by this time. Milder air has pushed back into southern and western areas but it remains cold to the north and east if you are looking for your snowfields (!) ECM joins GEM and GFS OP in positing a battleground at T+240 and we all know how marginal these can be. Parallel is alone in keeping it mild for all. Looking further ahead, OP and Parallel at T+312 and T+384 respectively. The curious thing with far FI output is how often it drags you in - I'd have bet my money (and very nice money it is too) on the OP going cold and Parallel staying mild but the reverse happens. OP snatches mild from what looked an inevitable cold set up while Parallel creates a wintry nirvana (with poor 850s admittedly) from nothing. Control look similar to Parallel but is if anything even more spectacular for coldies by the end of its run. Conclusion: - Parallel is the one model keeping it mildest for longest (Control not too different) but the other models are all sniffing around changes within the T+240 window so a shorter lived milder interlude of 3-7 days. GEM tonight is the most favourable T+240 for coldies but both GFS OP and ECM are suggesting synoptic changes which could head down a much colder evolution. In the short term, milder air marches back in during Tuesday and it may even feel a little spring-like by Thursday but it could well be a false dawn - let's hope.

Evening all A lot of talk of weekend snow but it won't stick around as milder air marches back in midweek with daytime maxima in the south likely to be well into double figures. From there, hints upstream developments might shift the mild or very mild pattern to a more unsettled and cooler pattern towards the end of the month. As to whether February produces the goods for winter fans, that remains to be seen. Don asked me yesterday if I thought we would see a cold February - I think we'll see an extended cold spell in February but an entire cold month looks improbable. If we get 10-14 days of well below average temperatures, we'll be doing well. That's nothing to do with anything - that's how winter operates in the UK. For now, let's see what tonight's offerings provide - a sumptuous banquet or thin gruel? 12Z GEM: T+120 takes us to Wednesday next week (January 27th). A mild SW'ly air flow covers most of the British isles with HP over western and south-western Iberia, a trough in mid-Atlantic and a residual LP near Iceland as well as another LP far to the east over the Baltic States. Mild air with positive uppers covers all but the far north of the British Isles. From there, small lobes of energy ejected from the core of the Atlantic trough cross the British Isles to the north but a new LP developing to the south of the main trough deepens and re-aligns the trough as it swings NE while a new powerful storm emerges out of North America. Heights are suppressed further south over Iberia and North Africa. Mild or very mild air over most of Britain but colder air in the far north by T+180 with a weak push of heights to the north west. That push of heights from the north west towards the northern North Sea causes the trough to disrupt close to the British Isle but the trough persists to the west and by T+240 it looks as though any wedge of heights is giving way to a new push from the Atlantic. It remains mild over most parts with any cooler air restricted to the far north. Not much for coldies from the GEM run in all honesty with the Atlantic firmly in charge at this time. 12Z GFS OP - on then to the American model. At T+120 not too different to GEM. The tiniest wedge of heights near Iceland but basically the Atlantic is in charge with the mild regime further supported by HP over Iberia. A chain of secondary LP are developing in the circulation of the Atlantic LP as the colder and warmer airmasses interact. The wedge of heights to the north west is significant as it causes successive LP systems to head east across the centre of the British Isles. By T+180 yet another active LP is approaching south-west Ireland with a shallow trough over Scandinavia. Mild air persists over the south but further air colder air remains and in the far north the milder air never really arrives. From there, the evolution gets a little messier and more interesting - the next Atlantic LP crosses the British isles and pulls down a brief PM interlude but he big storm coming from the lower latitudes begins to fill as it moves NE allowing weak heights to build to the north so by T+240 a slack pressure pattern exists over the British Isles. Colder air has pushed back with uppers below -4 for most but milder air again approaching slowly from the south west. Certainly a more interesting if less clear cut evolution from GFS OP suggesting a slowing Atlantic and opportunities for amplification. No Parallel again tonight so Control steps in - as you might expect, very similar to the OP at T+120. Moving on and a couple of LP disrupt and move east across the British Isles but at T+180 a new deep LP is well to the west of Ireland with some early hints of heights building over Scandinavia. The first LP moves NE and then stalls to the north west of the British isles by T+240 while a new strong LP from lower latitudes moves towards the British Isles. 850s slightly negative over the British Isles suggesting average temperatures at this time. Like the OP, Control ends interesting if inconclusive. 12Z ECM - no real surprises at T+120 with a flow of long-fetch SW'lies between an HP over south-west Iberia and an Atlantic trough. The trough is generating secondary features to its southern and eastern flank. From there, the ECM evolution diverges from some of the others - one LP crosses the British isles with another taking a big chunk of the trough's energy and moving east across southern Britain at T+192 with a NE'ly following to the north and west and a weak ridge from Iceland south while a shallow trough is upstream of that and a new LP emerges from lower latitudes. Colder air has displaced the milder air in the north and west but it remains mild to the south and east. By T+240, a complex trough sits over the British isles with one LP centre to the south-west and a second over Norway leaving a cyclonic flow for most parts. Heights extend north west from the Azores and are over the far NE of Scandinavia. Cold air with uppers below -4 covers all parts. ECM ends cold and also interesting so could we be looking at a brief mild interlude of 3-5 days rather than, as seemed likely yesterday evening, a 10-14 day mild spell? Too early to say but with GFS and ECM sniffing for change, GEM looks a little on its own this evening. Looking further ahead, the T+312 and T+384 directions of travel from OP and Control. So how do you want your -12 uppers, via a Greenland HP or a Scandinavian HP? The net effect is the same but hugely different with OP keeping the PV over Northern Russia and Control bringing the PV back to its usual home. Conclusion: plenty of ifs, buts and maybes about the output this evening. The milder spell may be shorter lived than seemed likely with the Atlantic trough disrupting toward the British Isles after which opportunities for amplification develop (it would seem). I'm not sure where this is going but it's going to be interesting finding out.

Evening all After all the drama with Christoph which even in lowland East London produced an impressive squall line late in the evening and, after a fine but breezy day day, has produced more rain this evening, we go back to the medium and longer term prospects. Both GEM and JMA teased yesterday evening with a mild spell quickly cut short but GFS in particular was solid on an Atlantic-influenced scenario in the medium term while ECM's well-documented T+216 and T+240 tantrums frustrate in extremis. A milder spell next week looks certain especially for the southern and western half of Britain but as we head into February, are there genuine signs of a new pattern change to put the cold fans back into the game? 12Z GEM: T+120 takes us to Tuesday January 26th. By then, a ridge of HP is crossing from west to east with the remnants of Christoph over Norway and an LP over eastern Europe. Upstream, a weak ridge extends SE from heights over Greenland but a large positively-aligned trough dominates mid-Atlantic. SW'ly winds are crossing the British Isles but uppers remain below -4 for most parts though milder air is inexorably closing in from the south west. From here, the LP throws lobes of energy towards the British Isles but these disrupt over central parts and slide east toward Denmark. Heights persist over Iberia, Greenland and to the far north-east with a new LP developing in mid-Atlantic as part of the complex trough. Milder air has crossed all parts of the British Isles by T+180 with positive uppers as a ridge again moves west to east across southern areas. Not much change to the overall pattern from T+180 to T+240 - the long fetch SW'ly persists with heights anchored over or close to Iberia. Atlantic systems move round the top of this HP system and down into Scandinavia so we get an occasional PM incursion. Just a hint of heights coming down from the north at T+240. Mostly mild or very mild throughout with just a slight cooling in the PM airflow. Desperate stuff for cold fans from GEM after last evening's promise. 12Z GFS OP - the OP has been mild for the last few days. It's different from GEM at T+120 with a clear phasing of the Atlantic and residual post-Christoph troughs with a new storm over the Baltic States. A new lobe of trough energy extends east into Ireland suppressing the attempted ridge to the south. Milder air with positive uppers is into southern and western areas while the north and east remains cold with uppers below -4. Onwards and the pattern becomes established with heights over Iberia and mild TM air moving across Europe. Small LP break off from the main mid-Atlantic trough and move east across the British Isles as heights try to form over Scandinavia. The controlling Atlantic LP is further north on GFS than GEM but extends south allowing new LP to form in its circulation as the colder and warmer airmasses meet. It is mild or very mild across the British Isles by T+180 with +8 uppers close by to southern parts. From there, changes start occurring - the heights over Iberia are broken down by T+192 as a new HP comes out of North America in advance of a major LP also moving off the eastern seaboard. As heights relax to the south, the original Atlantic trough can move east and south across the British Isles into NW Europe as the HP re-positions to the Azores and re-orients the ridge to the north-west. A cyclonic flow covers the British Isles by T+240 and pushed the mild air to the south with negative uppers across all parts. OP certainly cuts the mild spell short by moving the trough down and allowing the Iberian HP to relax west and north. With no Parallel tonight, I'm moving to Control for my third chart fix. As you might expect, very similar to OP at T+120. On to T+180 and differences remain subtle to be honest. The Atlantic LP is shallower on Control than OP and there's a defined secondary LP crossing just to the north of Scotland at this time. Generally mild for most parts with uppers around or just above zero for all parts. From there, the evolution is similar to OP with a new Atlantic LP from lower latitudes forcing a slight re-orientation of the HP away from Iberia and allowing the original trough to move east just to the north of the British Isles. Colder air is moving back over the British Isles by T+240 from the west. Both OP and Control have this synoptic change - it's hardly a Pattern change, more a subtle shift - by T+240. 12Z ECM: I suspect, like GEM, this will be firmly in the mild camp. Indeed, the T+120 looks very close to the GEM with the milder air flow already moving in across the British Isles from the south west. By T+192 not much has changed. Small secondary LP have crossed the British Isles but mild or very mild TM air flows round the top of the HP over Iberia. Indeed, there is +16 air approaching from the south west which would seem more appropriate to late spring than late January. However, our new "friend", the lower latitude LP shows up on ECM and that starts to push the trough east across the British Isles and by T+240 there's a run of fresh to strong W@ly winds across southern parts as the HP has relaxed slightly west. Cooler air with uppers of just below zero has covered the British Isles by T+240. Moving further ahead, GFS OP and Control at T+312 and T+384 respectively: Control drops the PV into the north Atlantic at T+384 but OP is more interesting in that the PV comes back over but relaxes a notch further west in far FI and that facilitates a ridge across the Pole by far FI. All this suggests no strong signal to this observer at this stage. Conclusion: The mild team have clearly won this round of the winter war - it will turn milder by the middle of next week and it doesn't look as though there's a quick and obvious way back to cold for 7-10 days. Rainfall totals have eased a little as well so it won't be too bad most of the time. GFS and ECM however hint at changes to the pattern fairly quickly with the Iberian HP relaxing and re-orienting as a new HP/LP combination emerge out of North America. This will cause the Atlantic trough to start heading east and perhaps south east into north-west Europe by T+240 bringing a new period of stormy and unsettled weather. OP then teases with some amplification as explained above while Control gains a surge of Atlantic energy as the PV moves south. As is so often the case, cold fans are going to have to wait for teleconnection changes or SSW changes to manifest themselves perhaps as we move into February.