stodge

Afternoon all Not much to add to what has already been said. The morning ECM 00Z OP certainly looked a chilly run especially for the north with milder incursions further south so not a huge change from what we've seen. The GFS 06Z OP certainly was a chilly offering - the jet heading south putting us on the cold side of the trough so secondary LP systems crossing the south means more rain and snow to northern hills and especially Scottish mountains. FI goes off on a bit of a tangent so we'll see. Control, it has to be said, keeps the jet that bit further north - the key, as I said yesterday, is the extent to which the Azores HP ridges into Europe. If said HP is held back in the Atlantic and the LP can move ESE into Europe supported by a build of pressure into Eurasia the trough becomes negatively aligned and we stay on the colder side. If the HP heads into Europe, the alignment goes positive and TM air spreads across the British Isles and into Europe. It looks a chilly and unsettled week to come though rain amounts don't look that great which I find surprising given the synoptics.

Indeed, not a hint of Wave 1 warming in the next two weeks.. The PV cannot continue at such levels ad infinitum - the question is whether the decline will be gradual well into April or even May or whether we will see a sudden and intense Final Warming which might not only open the door for some late cold but set up strong northern blocking for late spring and early summer.

The ECM 12Z OP is remarkably unsurprising in content. Plenty of PM air especially for northern parts but milder incursions further south. Continuing unsettled with more rain to come for most as we end February. The GFS 12Z OP and to an extent Control show, for the first time, a possible way out of the Atlantic rut as we head into March. The key is stopping the Azores HP ridging into Europe which keeps the trough aligned positively (as it is now). As the jet edges south and the LP systems head more ESE into Europe once across the British Isles, the HP is forced to ridge further west and north-west in the Atlantic and eventually (in FI so just eye candy for now) one such HP cell ridges far enough north for an undercutting NE and E'ly flow to impact the south. 850s drop to -12 in far FI so that might be good enough for wintry precipitation to both higher and lower ground if other factors work. It's always good to see OP and Control heading in the same direction and there are plenty of colder options in the GEFS. The key remains whether we can get some form of vortex displacement in March but it's all very early days and tiny steps.

Certainly looking chilly next week but the HP builds in at the end of the month and it may be back to the usual "sine wave" but interesting to see the LP slide SE into Europe albeit to the east of us rather than seeing Europe covered in a huge HP area.

Morning all Echoing much of what has already been said, the "sine wave" pattern of ridges and troughs will see out this month and take us into spring. The signal for HP to build in across southern Britain also seems to be fading as the dominant PV keeps on developing vigorous LP areas across the North Atlantic and keeping the Azores HP (for all its many attempts at ridging NE) as a bit part player with the ridges rapidly collapsing SE until the next cell attempts to build. The 00Z CFS Daily breaks us out of this pattern in mid march with the PV being displaced to Siberia and pressure building first into Scandinavia and then into Greenland for 7-10 days of an easterly dominated pattern before a brief Atlantic return and then as April beckons the PV looks much weaker. Well, maybe but I'd like to see more of a hint of warming in the 10 HPA and I'm just not seeing that at present. Yes, as spring comes, the PV will weaken but unless there's a dramatic final warming just round the corner I just can't see why the displacement should happen. In any case this isn't even in FI but beyond that so it's not to be relied on but this pattern will inevitably end and perhaps we are seeing just some hints at what may follow (or we may not).

Evening all A diverse and divergent set of output this evening in the medium to longer term. As the AO comes off its stratospheric (pardon the pun) levels, there seems a greater sense of uncertainty. Will we see a break in the strongly Atlantic-driven pattern and how will that break manifest? One option clearly is repeated builds of pressure from the SW ending with an MLB either over southern Britain or just to the SE over Europe. It's perfectly possible though the HP cells are rapidly flattened by the all-powerful jet, at least in the short term. As we move further into March and the TPV begins to weaken, will we see the HP signal develop further? Another option is we keep in the current pattern with strong LP system dominant and HP only influencing as transient features - again, it's possible but eventually the Atlantic will amplify and we'll get a large storm slowdown somewhere enabling pressure to rise in front of it. That leads to the third scenario -- amplification. This winter has seen so many of the usual signals and teleconnections suppressed or weakened (perhaps by the IOD) but nothing lasts forever and in time amplification will return to the northern hemisphere possibly as spring allows the TPV to weaken and slacken its grip. As the latter happens, the question will be whether the cards will fall right for UK fans of cold. They don't usually - they may not this time. I see no serious change until mid-March in all honesty - it may be the HP will periodically settle conditions down especially for southern areas but the residual strength in the TPV (no sign of any warming yet) will prevent a serious MLB build let alone any ridging into Scandinavia so the HP flattens across Europe until the next LP comes in. I do think we will see amplification in a month or so which will make for some interesting synoptics but how the cards will drop remains to be seen.

To this observer, the real danger seems to be as the LP crosses to the north of Scotland on Sunday night and into Monday. The winds expected through the Central Belt look very strong into the early hours of Monday.

Well, a slightly more interesting 12Z OP from GFS. The SPV (or TV or PV or whatever people are calling it) ends up directly over the Pole thus allowing a hint of amplification in mid-Atlantic and negatively tilting the trough so a chilly start to March but it's one option. Control keeps more energy over NW Greenland so it all flattens again after a chilly snap.

Thank you, my friend. How soon we forget some things. I'd forgotten how strongly the SPV responded to the SSW of January 2019 and it recorded a record wind speed in March let alone February. I wonder if the fall away via the FW will be similar this season but perhaps a little earlier with an FW in early April - we'll see.

No hint of any warming as we move into March with 10 HPA temperatures still at or below -68c at the core. I suspect, contrary to what I thought earlier, March will be a continuation of February in terms of it being a broadly westerly regime with little or no HLB. Cold Easter anyone?

Evening all While I gladly acknowledge Amy Butler's wisdom in all this, the TPV at the moment puts us in uncharted waters. The question for me is whether it will effectively spin itself out in a strong early final warming or gradually dissipate over a long period. IF we get a rapid and powerful final warming in March I would expect an extended period of northern blocking through April and May. If the dissipation is longer and slower I'd expect more "typical" weather patterns (which would still mean HLB to the north as that's not atypical of spring). Some of the CFS longer range charts continue to play with the idea of a much weakened and distorted TPV decamping to Siberia and beyond in mid March - well, perhaps but that's a very long way off.

I don't disagree and of course it's all in far FI anyway but the GFS 12Z OP shows a possible way out of the current pattern. The TPV has shifted from its normal home and is further west over Canada allowing blocking to the NE to become possible. The other key factor is a part of the Atlantic trough splits and heads SE ending up around the south of Iberia and North Africa. It's not quite a Genoa Low but it provides some support and forces the next Azores HP ridge to go more NE than ENE which in turn supports the MLB over the British Isles and perhaps further NE.

Up to a point but if we can get enough amplification for the Azores Hp to ridge NE into Scandinavia, that works well. There are subtle differences with the 06Z OP in terms of the Atlantic profile - is there enough to hold the HLB in place? I suspect not but it's interesting to see the signal again.

Afternoon all Colour me none the wiser once again - the 12Z GFS OP is unstintingly disturbed all next week and indeed well into the following week before the Azores HP attempts to ridge NE in FI. Control heads in a very different direction into FI with an intense mid-latitude HP over central Europe. That kind of variation suggests there's no strong signal as to how the coming period of intensely disturbed weather will end. 12Z GFS OP keeps the HP suppressed well to the SW and the trough has a slight negative tilt whereas UKMO is the more traditional "sine wave" with the HP a lot closer.

Morning all The GFS 06Z is in deep FI but in the short term the broad picture is quite clear - a midweek push of HP gives us 3-4 calm days especially in the south and east before the Atlantic takes over with a vengeance next week. It's going to be hard to give detailed predictions for the timing and impact of secondary LP at this time but they look the most potent aspect as the main monster LP churns away to the north and north west. Rapid cyclogenesis in mid-Atlantic could well create "bomb" type storms which would pass from SW to NE across the country bringing spells of very strong (if not damaging) winds, heavy rain and snow for highest elevations. So how does this end? Eventually, the Atlantic will lose its speed, perhaps quite rapidly and the rapid amplification could well encourage a new mid-latitude HP to develop close to the British Isles. As the Atlantic slows and amplifies, the trough will dig south and that will further encourage anticyclonic development. Is it going to work in our favour and allow a change of air source? Maybe, maybe not - a relaxing weakening TPV shifting west into northern Canada would encourage a build of HP over Scandinavia and it may be we end up with a mid-latitude HP oscillating between Scandinavia and the British isles (with always that hint/hope of retrogression to Greenland that so rarely comes off). For now, batten down the hatches for next week as it's going to be wild especially (but not exclusively) for western coastal areas.

Afternoon all Not much to add - the charts moving toward mid month are increasingly mobile varying from unsettled to downright stormy. The jet is moving at speed across southern Britain so plenty of weather on offer, none of it lasting very long. Prospects for snow on Scottish hills and mountains look reasonable with PM incursions more frequent but further south it's fast moving rain, fast moving wind and hopefully noting else fast moving such as garden furniture, roofs and the like. Not sure where strat developments are taking us - the 06Z Control is interesting but not reliable given what has happened so far this winter. The OP suggests another round of warming at the end of next week but it's hard to see the TPV breaking down from that.

Once again, interesting to see the GFS 12Z OP taking the jet just along the Channel coast so the possibility of extended periods of PM air for northern Britain and snowfall for higher ground. The ECM 12Z OP ends with a monster LP centred over (I think) western Norway - the MSLP would threaten the record for Norway which is 938 MB set in February 1907. Curiously, the record high MSLP for Norway is 1061 MB also set in 1907 (January). I have to say the winds associated with that monster would be country-wide and serious for the UK (fortunately the woodshed in the far SW should remain intact)

Afternoon all Nothing at all for fans of deep cold and prolonged wintry weather in the current output for much of February and indeed into March contrary to my first thoughts and hopes. We do see an intriguing change in the jet stream as it moves further south to be moving across southern Britain which would mean more frequent colder PM incursions into northern Britain and the likelihood of some considerable snowfall for Scottish mountains. Lower down and further south just rain and wind for most. The Azores HP cells push up from the SW but cannot progress north because of the strength of the jet fuelled by the TPV so collapse across southern Britain into the continent. I'm not enthused by the strat either - warmings simply push the TPV back into its usual home where it currently looks fixed into March. The interest will be if we can get periods of negative alignment in the trough to bring in some colder PM air but as the HP heads east the tilt turns back positive and TM air returns.

I agree those looking for cold to mid February are going to be disappointed. Those looking at the end of the month - well, perhaps but a setback or two in the past 24 hours especially with regard to strat warming. I do think March will surprise on the cold side - particularly around mid month as the TPV relents but it's very early days.

Evening all Well, I'm none the wiser. A brief milder interlude over the weekend but next week still looking very much up for grabs. The build of HP midweek next week teases with a brief but quite potent N'ly before toppling but the next build, at least according to GFS OP, sets up a brief Scandinavian HP before the northern arm takes over and the Atlantic roars back for mid month. 12Z ECM OP ends very anticyclonic while GFS 12Z Control ends very zonal with a classic Bartlett. If you want some eye candy, the CFS monthly looks more than interesting for late Feb into early March but of course the usual caveats apply... On the less inspiring side, the strat split continues to look elusive but it does seem likely one warming will quickly be followed by another so weakening and displacement may be on the cards. I'm also less enthused looking at the GEFS - only a couple I'd describe as cold but a good split between mild anticyclonic and mild Atlantic-dominated. I'm still not expecting anything cold before the end of February apart from the odd day here and there of PM air - obviously, cold that late doesn't work for some on here but it can still deliver snow as we all know. Plenty of time left...

Afternoon all Well, the GFS 06Z OP piqued interest yesterday and has done so again today. I'm still dubious of us finding a way out of the mild rut before the middle of February at the very earliest and I think late Feb - early March remains our best shot at something cold. Clearly, it's about HP positioning and orientation - do we get a small LP over Iberia for example which serves to keep the HP to the north or do we get a toppler as the northern arm of the jet proves too strong? The key to an evolution to something different would be to slow the Atlantic and get some amplification and that's going to be helped by a weakened or re-aligned TPV. IF the projected warmings can achieve the necessary de-stabilisation then we have a chance of something more than a mid-latitude HP just to the south or south-west of the British Isles and get that vital northward move to start advecting some colder air over us.

Evening all I've long been of the view mid-February and later are when the synoptic charts will become more interesting so no surprise that isn't reflected within the current reliable or even semi-reliable. I'm watching strat developments with the thought late February could be interesting but it's all speculation. In the immediate an unsettled and chillier week last week gives way to a more anticyclonic spell into February as the trough digs down to the Azores and throws the HP ridge in front of it over western Europe from Iberia to the southern British Isles. The 240s from the 12Z output across the models all tell a very similar tale. The interest from the extended GFS OP is the LP sets up down near the Azores which pushes the anticyclonic cell up over the British Isles - the 850s are nothing unusual but I do wonder if we could see a fair amount of fog and frost IF we get a clearer circulation. Control ends on quite a tantalising note with a much quieter Atlantic and perhaps a ridge stretching south from a large HP in the high Arctic.

Afternoon all As we await the all-important ECM 12Z run, I'm left with the impression the mostly benign start to February is being replaced by a more mobile and unsettled Atlantic profile. The 12Z OP 10 HPA strat chart continues to intrigue in FI but we'll see if that takes us anywhere in terms of a sting in the tail wintry spell for late February or early March.

Yes, next week;s 24-48 hour chillier NW'ly spell still present across the models and of course plenty of detail to firm up in the coming days. It does seem as though the HP-dominated benign spell will return for the start of February and the early part of the month looks between the more unsettled and active Atlantic and the HP regime to the south and south east so mild air for us all for most of the time. The signal for a break in that pattern towards the end of February remains and I suspect March in particular will be very different to this month and next month.

Evening all Obviously, it's been a very disappointing winter for most on here though today was glorious in the south if you like your winter days crisp and bright. Whether it was the strength of the IOD or some other factors a mild winter was called by most LRFs way back so we can't really be surprised. I'm cautiously optimistic March will be a wintry month this year and possibly April too and even in London snow can fall and settle in late March and early April. Given all snow in the UK is transient (apart from the odd Scottish crag), I'll take a couple of transient spring snowfalls. As an aside, I assume the Tropospheric Polar Vortex has existed for millennia - I also presume it has tended to the same locations or have there been periods in history when it was further west or stronger over Siberia?