stodge

Perhaps the rumours of the death of cold a shade premature:

The signal for raising Greenland heights has gone for now though again hints at the very end of 06Z OP FI. The 00Z GEFS have plenty of blocked and colder options depending on whether we see pressure rises to the west and intriguingly to the NE which has come back into favour over the weekend. Arguably the most interesting of the time synoptically with many evolutions on the table. Today for example there is snow over Normandy and strong winds over the north west coast of France - wouldn't have taken much for that to have affected southern counties.

Morning all A fine morning here in London after a weekend which was perhaps less of a washout than had been forecast. It's Day 20 of the 21 since the breakdown of the February cold spell and I'd like to say we were looking at an imminent pattern change but we aren't. After a chilly start to the week, it does look as though the south will have some milder weather during the week though talk of "spring like" conditions looks a little overdone. Moving on into Cheltenham week and what conditions will await the punters at Prestbury Park on Thursday March 16th: Starting with GEM 00Z at T+240: Very mobile typical March fare with plenty of PV activity and low heights to the NW and even the Azores HP suppressed so despite transient ridges of HP, a largely unsettled picture. ECM 00Z at the same time: Some differences though the broad theme is much the same. A more noticeable Eurasian HP is fading without influencing our weather and while the orientation of the Azores HP is interesting it's a bit of a "no man's land" or col over the south of the British Isles. GFS 00Z OP at the same time: Again, slight differences but not massive. The British Isles is in a cooler W'ly or WSW'ly flow with the LP track running NW-SE across the Faeroes and then down into the Baltic States. Unfortunately, any lingering hopes for heights over Greenland seem for now to have been dashed with the PV not heading for Siberia as seemed likely last week: Into furthest FI and the LP track changes dramatically as the trough sinks down across the British Isles and into Europe: Spring definitely on hold if this chart verifies with HP pressure to the SW and NE, the corridor for the Atlantic systems is straight down over the British Isles and into France. Very unsettled with plenty of rain and showers and perhaps snow on northern hills. The 00Z GEFS at T+240 have plenty of scatter as you would expect but the Greenland heights option appears to have been extinguished to be replaced by HP either just to the west or to the NE and clearly there's been a new signal. The spread reflects the difference between one cluster keeping LP in charge to the west and another slowing down the Atlantic and allowing heights to build near the British Isles but to the west and the NE so the OP evolution far from devoid of support and those of us hoping for some late cold still very much in the game this morning and perhaps the most interesting there are few members showing anything very spring-like.

Okay, I'll have a go. I think you're actually on the Silver Spirit, leaving Hamilton on March 30th arriving in Funchal on April 6th which would be about right for an Atlantic crossing - about 20mph across the ocean. Other thing to note is the gradual time difference which means you lose an hour every day as the clock re-adjusts as you move eastward. Both Bermuda and Funchal on Madeira are at roughly 33 degrees north. The first problem is we don't know what course the ship will take. I suspect it will stay close to the common line of latitude unless a storm or similar forces a course change. The second problem is we're dealing with weather patterns across 3000 miles of ocean so the air may be sourced from the north (cold) or the south (warm), the east or the west. The ship will have accurate and updated meteorological data - I don't. The average temperature for Bermuda in early April is around 20c and for Funchal 18c so we can probably reason the temperature over the ocean at that latitude should be 18-20c maximum by day and say 11-13c at night. It's likely the weather will be fair as you'll be influenced (typically) by the Azores HP which dominates the lower Atlantic latitudes but the exact positioning of said HP will be crucial to determine if you have a light W'ly or a light E'ly breeze. Silversea is one of the top end cruise lines so even if the weather is poor it will still be very comfortable. Anyone else got a view ?

Morning all So to Friday and well into the new month and let's see if the wintry interest of yesterday has continued with the overnight output. Starting with GEM and with T+240 taking us to Monday March 13th: GEM models quite an unsettled spell through next week leading to a brief N'ly at the end of next week. It is however brief and by Monday pressure is rising from the SW in a classic "toppler" situation whereas yesterday the ridge was angled north toward Greenland, today it's a more classic NE ridge though it has to be said no sign of a raging Atlantic behind it. ECM at the same time: ECM has watered everything down this morning - the midweek warm up for the south is weaker as is the N'ly next weekend and we end up here with HP in charge and fairly benign conditions. Could the HP move over the British Isles - possibly but I can't see it moving N or NE on that chart. GFS finally at the same time from the 00Z OP: The most impressive output of the morning for cold fans and it's not hard to see the big differences - the HP is much further north and the ridge is angled NW to link with Greenland heights. It is however quite close to the UK so the message here would be cold and dry with the real wintry weather over Scandinavia. The LP exiting Canada is set to move north keeping the WAA going to the west of Greenland and supporting the heights. We end up here: The heights "find a way" to retrogress N and then NE - the key player is or are very low heights over Europe which block the usual path of the HP into the Continent. Here's the NH view of the same: The WAA is now to the west of Iceland but it's a hugely amplified set up with ridging from the north of Siberia (about as HLB as it gets). Western and Northern Europe stays cold and someone will get snow out of that without a doubt. So we have some themes going forward from this morning - an unsettled immediate period, a possible brief warm up for the south midweek followed by a brief but potentially strong N'ly over next weekend and from there it all depends on where the HP sets up and its orientation. It could sit just to the SW and be oriented to allow the Atlantic over the top or it could ridge north and block out the milder air leaving us in a N or NE flow as heights shift North. The 00Z GEFS at T+240 are in two camps - those that make the Greenland HP an influence and those that don't and that's reflected in the spread: Plenty of interest ahead I would hope.

Afternoon all Another late runner for the day's update but it's a glorious day here in London with temperature at 11c so very decent for early March. How are we looking moving into mid month or just before: Starting with GEM 00Z OP at T+240, Sunday March 12th: A chart to please any cold weather fan in all honesty and it doesn't need much explanation. ECM 00Z OP at the same time: Not in the same place but perhaps not that far away. The LP coming off the CONUS could swing North and allow heights to rise in mid Atlantic or it might not. Otherwise, it's a benign chart with a WSW'ly flow covering most of the British Isles. On then to GFS and the 00Z OP at the same time: Very different with a strong active North Atlantic jet firing LP systems toward the British Isles. Further into FI, the outlook remains very mobile but with PM or returning PM air becoming more dominant, the accent is on cool/cold conditions with rain/showers (snow to altitude). The 06Z OP at T+234: Something quite different. Yes, it's a mobile pattern but weaker with heights rising in Greenland and note the PV lobe dropping into NW Russia. The onward evolution is more curious - lower heights over Europe and an HP building from the west over to Scandinavia leaving the British Isles in a weak, cool E'ly with rain/showers especially for southern counties. The 06Z GEFS tells the story: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240 The story is there are plenty of options ranging from very mild/warm through average to cool/cold on the table along with settled conditions or unsettled conditions. Those members building either a Greenland block or a mid-Atlantic block tend (not surprisingly) to be the coldest while those that don't tend to keep the milder Atlantic flow in charge. The other key element is the PV - the colder options lift the PV from NE Canada/Greenland while the milder members don't - again, no surprise. My view on the output is the colder scenario for mid March has taken a step forward again today with very encouraging GEM and GFS 06Z output but the GFS 00Z was strongly Atlantic biased and the ECM, as it has been for some days, has been neither fish nor fowl and perhaps more indicative of model uncertainty than anything else.

Morning all Pinch, punch, first of the month and if we are to be believed, it's spring and everyone goes from wanting feet of snow and ice days to wanting warm sunshine and azure blue skies. Mother Nature doesn't care and March doesn't usually sing the right tune but let's see where we are this morning: The output of Saturday March 11th starting with GEM 00Z OP: One of the big trends of recent days has been the signal to raise heights from the south as the jet shifts back north. GEM is quite anticyclonic and a hint of height rises in Scandinavia is replaced by the Azores HP shifting north. Plenty of energy to the north though and no sign of Greenland heights. ECM 00Z at the same time: A fairly non descript mobile Atlantic pattern with LPs passing SW-NE well to the north of the British Isles. Some returning PM air in the mix and I'd imagine we'd be looking at typical March fare of sunshine and some potent showers offering transient snow to altitude. Onto GFS and the 00Z OP at the same time: Not a million miles away from either GEM or ECM at this stage - a chilly NW'ly flow but with pressure rising from the SW ahead of a temporary ridge and the next frontal rain. Not much changes out to the end of the run with the NH view showing low heights over the Arctic and the PV over the Pole. Here's the 06Z OP at T+234 so the same time: A rather more potent LP passing east to the north of Scotland so a strong NW'ly flow with gales or severe gales and some squally wintry showers. The NH profile at the end of the 06Z couldn't be more different to the 00Z: Back to the 00Z and the GEFS are fascinating with a clear cluster angling for the Greenland HP block and this is reflected in the spread: To sum up, we haven't moved too far again today. The option of a Greenland based block remains firmly on the table even though the OP runs are looking more to a height rise from the south.

Morning all A gorgeous morning in deepest London and two weeks after the end of the last cold spell, it's nice to see some crisp chill late winter sunshine. As we move technically into spring, what does the future portend (as it were): Starting this morning with the model output for March 10th and I'll open the batting with GEM OP: A gentle northerly to end the output with pressure rising from the west but not as a link to heights to the north thanks to a couple of shallow shortwave features. Note the LP near the Azores. ECM 00Z at the same time: A very different evolution - ECM was keen to send the jet back north yesterday and has continued in that vein with the trough aligned SW-NE between heights to Greenland and the Azores. A slack gradient to the east of the British Isles. GFS 00Z OP at the same time: Again, something a little different but keeping the jet going back north allowing pressure to rise from the SW. An early taste of spring on that chart especially for the south. It's all very anticyclonic - a theme of this winter it seems and at the end of FI: A lobe of HP from Greenland sits over the British Isles so fine days and cool nights would be the theme. Note the PV has plunged into the Baltic States. T+240 on the 06Z OP: From there, the PV seems somehow to come back to Greenland. Fortunately for fans of cold the 06Z GEFS at T+240 have a number of cold options with Greenland HP a significant minority so in a sense very little has changed since yesterday even if the OP runs are not so promising: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240 All in all, the route to a colder evolution at the end of next week remains tenuously open but the form house seems to be the jet lifting back north at this time. We need the Atlantic to slow down to encourage HLB as there is a clear window of opportunity with the vortex being shunted further west.

The 00Z OP hinted at spring, the 06Z takes us back into winter: Note the displaced PV and the question is whether those heading for Cheltenham should be equipped for sun, wind, rain, snow, hail or all of it ?

Thank you, my friend. Plenty for me to consider and look through and a chance to improve my knowledge which is never a bad thing. The "Canadian Warming" scenario is one I've heard mention though they seem as rare as hen's teeth in all honesty. Unlike 2010 when the bulk of the cold conditions occurred in the first half of winter, 1946-47 was a late starter (around Jan 22 if memory serves until early March) but 1962-63 started just before Christmas 1962 and continued for most of January before easing in February. Can we then postulate that the Canadian Warming of late 1962 caused the split and/or displacement from which the tropospheric response was to set up the blocking HP scenario which kept Western Europe very cold but the SSW which triggered a displacement, broke that and ended the cold spell ? In the absence of any data, we could postulate a Canadian Warming in late 1946/early 1947 and the end of the spell coming as a result of either an SSW or an early final warming ? As Inheritus said, it seems we flirted with a Canadian Warming in November last year which, had other factors not intervened, could have led us to a very wintry year end and start to 2017. Off to do some research...

Morning all First, thanks to Nouska for updating my knowledge of the stratosphere which is all part of being on here. The stratosphere seems to be a complex multi-layered beast open to interpretation and misinterpretation it would seem. The 10HPA profile from March 2013 told another story but as seems to be clear, we need to split the vortex rather than displace it. I presume no one knows if there was a vortex split in winters as 1946-47 and 1962-63 or whether that was more about displacement. Back to the here and now and after a very wet night in London, let's see where life's great meteorological journey is going to be taking us next month (perhaps): We are at Day 13 of what I thought would be a 21-day minimum spell of Atlantic-dominated weather following the breakdown of the February cold spell and the subsequent major warming. Looking ahead to what would then be Day 23 (as it were) - Thursday March 9th: Starting with GEM 00Z OP: The theme throughout the GEM output is mobile with a push of heights from the south which doesn't succeed and heights over Greenland which serve only to keep the LPs on a more direct west-east track. It's looking like a wet start to March and snow to higher elevations can't be ruled out at times. ECM 00Z at the same time: Some subtle differences and signs perhaps of the jet swinging back north but the Atlantic isn't exactly firing on all cylinders and a view of the same chart from the NH perspective tells a different story: Strong heights over the Pole and more than a hint of those coming toward us. The evolution from there might be of interest. GFS 00Z OP at the same time: GFS has hinted at height rises from the south over its last few outputs so it's to be taken seriously. The trough is digging south into the Atlantic and a more amplified picture generally suggesting (to me) further FI could look quite spring like. Well, it gets there in the end, sort of, but it's a bit of a struggle. Looking at the NH view of those last two charts: The core of the PV has shifted more to Siberia but there's enough residual energy at the far end of FI to prevent height rises over Greenland but a weak Atlantic and weaker jet allows for the Azores HP to make its move and build toward the UK. Note the big HP over Hudson's Bay. At this stage I'd say the picture moving into March isn't clear. The form horse might be for height rises from the south and that is suggested especially by GFS but all models show a weakening Atlantic and the possibility of height rises to the north certainly hasn't disappeared. My honest view at this stage is that a gentle move into spring looks more likely than a final cold flourish but that's far from settled. Looking at the GEFS, though, there are some colder solutions in the mix at T+240 and certainly further out the idea of northern blocking is far from dead.

Morning all A rare opportunity to have a Sunday peruse of the charts but a shortened version of my usual methinks. GEM 00Z at T+240, Wednesday March 8th: Not much sign of an immediate pattern change it would seem. Indeed, signs of the jet returning north as pressure builds from the south. Heights over Greenland but of no influence at this point it would seem. ECM 00Z at the same time: A very different profile over Scandinavia with a hint of rising heights we often see on this ECM chart but the Atlantic looks to be in charge albeit perhaps slowing, GFS 00Z OP at the same time: Again, we see a slowing Atlantic and pressure rises from both north and south. The NH view of the same chart is enlightening with a significantly displaced PV: However, in furthest FI, a strong Aleutian ridge builds sending the PV back over our side of the globe but possibly toward Scandinavia or NW Russia. Have to say my hopes of a significant pattern change from a Greenland HP appear to be waning although the GEFS still have plenty of options and plenty of cold options on the table at T+240.

I'm not a professional forecaster - just a muddled amateur. What I think you're saying is that wave 1 warmings probably won't do the UK much good in terms of changing the tropospheric pattern so we need the mysterious (well, to me) wave 2 I often hear mentioned. The fact remains I see a "response" to each wave 1 which seems to be to re-consolidate the vortex over NE Canada/Greenland but why is the vortex there ? Why doesn't the PV settle over the Bering Strait as an example ? If you're telling me it's because that's how the planet works, fine. It also seems that what I see on a 10 HPA chart might not be reflective of what's happening at other levels of the stratosphere. I was interested in the March 2013 profile because even though it was a very cold spell for western Europe, it took place with a strong cold stratosphere still in existence and the positioning of the coldest areas looked to be being repeated this year. I still have much to understand it would seem.

Interesting contribution and I've snipped only for ease of reading for others. I see two issues and I wonder if these happened during other spells of predominantly snow free winters in the UK: - first, the warmings seem to come disproportionately from the Siberian side and that has the initial response of throwing the PV back to NE Canada/Greenland. We would need a significant Canadian warming to displace the PV to Siberia. Second, even when vortex displacement occurs, it isn't a "clean" lift leaving enough residual energy over Canada/Greenland to help the LP factory going and prevent the formation of HLB. So the process is warming leading to vortex consolidation over NE Canada/Greenland leading to a messy secondary displacement to Siberia leading to a new warming sending the energy back to Canada/Greenland and the cycle repeats and the best the British Isles can hope for is either a brief N'ly regime or a Scandinavian HP which inevitably sinks as the PV displaces back to Siberia and the northern arm fires up. Later in the winter/spring the PV is weaker and there is more opportunity for it to be further displaced west into Canada giving Greenland HLB a chance so a cold March is always more likely than a cold December on that basis. Exceptional winters (which this hasn't been) need a break in the cycle either via a Canadian warming or a clean displacement to Siberia.

Morning all After the perturbation of Doris yesterday, something a deal calmer today. Even in lowland East London, we lost a fence slat in the big squall around 8.30am and we had quite a few hours of strong gusts until well into the afternoon. Enough of the past and present and time to muse on the future looking ahead into March as we try to establish if this winter has any "bang" left or whether it will whimper quietly into an early spring. It's been 10 days since the end of the last cold spell and I predicted at that time a 21-day period of milder Atlantic-dominated weather before the major warming (on going as we speak) provided a window of tropospheric opportunity for a pattern change. Theoretically, the medium range of the model outputs should be showing that change so let's see if I'm on the money or heading for the café for a double helping of humble pie with a side order of egg on face: Let's start with GEM and the 00Z OP: Not sure what to make of this in all honesty. Some signs of pressure rises over Greenland but nothing very significant and a deep but small LP going nowhere slowly in mid-Atlantic. Ridging from the Azores offering the chance of height rises in Scandinavia via a shallow ridge. All a bit messy. ECM 00Z OP at the same time: Not a million miles away from the GEM. The first obvious point is the southerly tracking jet which would keep the weather unsettled at best. Heights are more to the north of the British Isles than over Greenland and aren't strong at this time and there remains a notable PV presence to the far north. The Azores HP is much more suppressed to the south and you'd think the LP would more likely more SE into Europe than NE into Scandinavia. Interesting. GFS 00Z OP at the same time: Once again, we have the deep mid-Atlantic LP but there are definite heights over Greenland and the jet looks to be keeping to the south. We have a more organised trough over Scandinavia with a lobe of very cold air which could track SE and graze the far NE of Scotland. Switching to the NH view of things, the chart for the same time as follows: Moving on into further FI and we end with this: Am I looking at a west-based negative NAO ? Perhaps. I am seeing a southerly-tracking jet and plenty of heights over the Pole and to the NE. An interesting evolution and one to keep an eye on. As far as the GEFS is concerned at T+240, there are a lot of cold options on the table and very little spread suggesting the OP outcome may not be wholly implausible. At T+384, it's interesting to note the spread in mid-Atlantic is affected by a couple of members building a mid-Atlantic ridge so again the spread suggests the OP is there with the majority at this stage. Looking at the 10 HPA temperature profile, it's interesting to note the "third warming" has been downgraded considerably this morning and this is, I think, excellent news for cold fans. The likely warming would have had the effect of re-consolidating the PV back over Canada/Greenland. Without that, the weakened PV begins to wander and while I've been putting this together, the 06Z has rolled out and the T+384 chart from the NH perspective demonstrates this: A very good chart for pattern change fans. The PV is lifting out to Scandinavia and the angle of the LP is shifting more NW-SE so the heights can build as pressure drops over Scandinavia and the possibility of a cold NE'ly flow remains very much on the table. All in all, using the dreaded "P" word, there is much potential for a pattern change into March. The weakened PV is eased further west allowing for heights to build to the NW or N of the British Isles and with the jet heading south, the chance of an early spring cold outbreak before mid March is clearly there. As always, the British Isles needs a touch or more of good fortune but at this early stage, the signs are encouraging and there'll be plenty of chart interest, I think, once we get past the end of this month.

Morning all Apologies for the lack of report yesterday - a busy day. Plenty of weather happening at the moment as Doris moves in - good luck to those in Scotland seeing some snow and I hope the strong winds further south don't cause too many problems but it's the first notable storm for a while. This was well forecast in concept if not detail a week or so ago. We're midway, as I reckon it, between the end of the early February cold spell and what I hope will be an intriguing pattern change going into March. Earlier in the week, there were clear signs the models were sniffing something (aren't we all ?) into next month so let's see where we are looking ahead to March 5th or thereabouts: I'm going to take the Northern Hemisphere view for a change this morning so starting with GEM: No sign of a pattern change there it has to be said. The PV continues very strong between NE Canada and Greenland and a broad SW'ly flow over the British Isles is maintained. There is a strong Eurasian HP but poorly orientated (North-South rather than West-East) so of no use to western Europe. The Azores HP remains suppressed so an unsettled mobile regime looks to dominate. ECM at the same time: Similar but different would be my view. The British Isles remains in a SW'ly flow with the PV still well in place but the Eurasian HP is much better positioned and aligned but still too far away to have any influence at this time. GFS 00Z OP at the same time: Something very different here and not wholly out of tune with some of its evolutions over the past week or so. The PV is that bit further west into Canada and this has allowed heights to rise to the north of the British Isles with the jet displaced further south. The LP systems are further south yet it's still a broadly WSW'ly flow albeit very unsettled with rain or showers. Unfortunately, the PV simply dumb-belles round in situ and the Greenland heights are killed off albeit with the jet still in a more southerly position into furthest FI. The Control at the same time is very different and goes on to deliver the pattern change in a very good run for fans of cold: Looking at the GEFS at T+240 there are plenty of cold solutions in the mix. The spread is not on the Greenland heights but on the strength of the Atlantic LP systems. If the trough is aligned more to the SE than the E the chance exists for the Greenland ridging to become more influential so there's plenty of scope for change at this stage. The differences in the two Trop evolutions are evident in the way they are forecasting the 10HPA stratospheric temperatures. Here's the GFS 00Z 10 HPA T+384: And the equivalent PRMSL chart: And the same for the Control at the same time: Very different. The OP maintains the PV, albeit weakened and the next warming sends it back over to NE Canada/Greenland starting the next 10-14 day tropospheric lag. With no warming on the Control, the PV meanders around allowing the tropospheric response in the form of height rises over Greenland and the resulting trough into Scandinavia. All in all, perhaps a step back as it would have been ice to have seen the GFS OP go strongly on a pattern change but it's still there very strongly in the GEFS. The other models aren't sniffing it so strongly as yet but it's only just coming into range. The warming occurring now is going to have the usual 10-14 day lag so it could be March 9th before we see the full manifestation of the pattern change or it may be nothing will happen at all.

Morning all After yesterday's exceptional warmth in the south east (18c recorded at a number of locations), it's back to more traditional mild temperatures at 13-14c for the next couple of days - still well above the 9-10c which is the normal London maximum for late February. The weekend may or not see a N'ly blast of dubious severity (quite likely northern hills will see some snow and perhaps some lower ground in the far north but for the rest of us a short chillier burst) before a reset to more normal Atlantic conditions next week. Today is Day 7 of the 21- day milder Atlantic dominated spell forecasted last week as a direct result of the second major warming of the stratosphere which is shortly under way. Let's have a look at the medium term taking us to the end of next week - Friday March 3rd. GEM 00Z at T+240: On first look, a strongly Atlantic dominated chart but not quite as clear cut with a strong Gulf of Genoa LP providing the opportunity for the Azores HP to ridge into Scandinavia - there's a little spoiler in the way but that may or may not be relevant so we could see a new pressure rise. The northern arm of the jet appears strong however and absolutely no sign at this stage of any height rises in Greenland. ECM at the same time: A more defined Atlantic profile and the Azores HP more suppressed. A mild SW'ly flow and generally pleasant conditions for much of the British Isles. A more confused pressure set up over Scandinavia - hints of a ridge but no more. The jet may be weaker to the north but you can't really say there's much evidence of blocking. GFS 00Z at the same time: And the 06Z OP at the same time: A very different evolution from GEM and ECM in all honesty. We get the HP building over the UK and then sinking SE in the face of the strong northern arm of the jet. It's a repetition of the pattern from earlier in the month up to a point. A fairly non descript E'ly on both charts for the south. Switching to the Northern Hemisphere view for the end of the OP run, here's the 06Z: And the 00Z OP; As similar as two completely dissimilar things in a pod (as someone once said). The 00Z OP evolution is actually similar to yesterday's though with the core of HP more to the NE of the UK than Greenland but the vortex is pushed over Canada allowing for height rises to the north of the British Isles. The 06Z is entirely different and maintains a very strong PV. Finally, the chart everyone else loves to ignore - the 10 HPA temperature. Here it is for the 00Z OP at the end of the run: Not dissimilar to yesterday with the tropospheric outcome we've already seen. Here's the 06Z OP: It's different - not very different but different and perhaps this is the key to the tropospheric evolution. The question for me remains whether the weaker third warming scheduled for 6-8 March will either displace the PV further to the Canadian side or re-consolidate it in the Canada/Greenland area. The 2013 evolution I showed yesterday is closer to the 00Z than the 06Z and that explains the tropospheric scenario. I just wonder if the 06Z OP is playing a more traditional response to the Siberian warming. Just glancing at the 00Z GEFS and plenty of support for raiding heights in the Greenland area so we'll see where that goes in the coming days.

Morning all I deliberately haven't looked at any model output since Friday morning - two reasons, one I have a life and second, I refer you to the previous reason. 12c already here in my part of London and it could well be the warmest day of the year so far but perhaps already the warmest day of the 21-day Atlantic spell which is now at Day 6. Looking ahead and after some unanimity last week, the medium term looks much more variable after what may be a brief 24-36 hour N'ly blast at the end of the week: Starting with the 00Z GEM this morning at T+240: From an unpromising position, GEM conjures a weak MLB to the NE of the British Isles. It's not really a Scandinavian HP as the one from earlier in the month and there looks too much energy to the north to stop it sinking. A small cut off feature off Biscay helps prop it up in the short term and I note the Atlantic trough digging well to the south. ECM at the same time: Very slack flow and an archetypal "haven't got a scooby doo" chart. The possibility of a height rise over Scandinavia and the British Isles can't be ruled out and with the Atlantic moribund you'd think there was plenty of opportunity for that. One of charts that makes you wonder where the evolution would go next. GFS 00Z OP at the same time: Perhaps a half way house of sorts between GEM and ECM. Again, as the lobe of PV energy exits Scandinavia, we see pressure rise and more than a hint of it on this chart and perhaps something more sustainable than GEM with a lack of energy to the north. The Atlantic seems moribund here as well. From here of course the GFS "goes off on one" as some might say and by March 7th, Day 21 we are at: Something very different and potentially much colder than we have currently with the hint of some colder air feeding in from the east and the Atlantic well displaced to the south and west. The NH view at the same time shows the weakened PV displaced well over Canada: On a more cautionary note the 10 HPA st the same time: I say "cautionary" because the PV won't be finished off by the second warming about to start and the third warming from the Siberian side for early next month is now looking weaker. Comparing the forecast 10 HPA with the equivalent actual from 2013 I'm interested in the positioning and the intensity - it was a colder, more organised PV back then and the resulting tropospheric picture was: Some similarities in the synoptic evolution but it was a few days later we got that really cold feed of air from the east. MY view at the moment is that this March will be a watered down version of 2013 - less cold and possibly drier but it will still be cold and the possibility of snow has far from disappeared. To conclude, very early days but I do think we have a possibility of a significant pattern change soon after the beginning of March. The options of an MLB over the British Isles or perhaps some HLB ridging SE from Greenland are both on the table - it may even be the HP will set up to the south and continue our early spring weather but I think that's the least likely option at this time. The ongoing stratospheric developments remain of interest - oddly enough, we don't want a third strong warming if we want cold. Enjoy today's warmth - it may be as good as it gets for a while.

Afternoon all A delayed report on the morning model output and it's a beautiful day here in London and whether you want to call it spring-like, Caribbean or just pleasant depends on your perspective but it's a world away from this time last week when we were watching snow flurries. It shows how the transition from winter to spring can be rapid but to be fair, that transition often comes with a sting in the tail. Looking at the mid term outlook for the end of the month - Feb 27th to be precise - and starting with the GEM 00Z output: Perhaps not as benign as it may first appear - a WSW'ly flow of modified PM air from a large LP just off SE Greenland. The attempt to ridge into Scandinavia will come to nothing even though heights are rising as the trough exits east. Note also the wintry flow over the Balkans with plenty of late snow. ECM 00Z at the same time: A milder airflow for the British Isles but a stiff breeze especially to windward coasts. The HP is centered over Germany but the slightly unusual orientation over Finland/NW Russia is already showing signs of being swept away by the strong SW'ly. Note how far that Atlantic trough is digging - almost to the Azores. GFS 00Z at the same time: The secondary LP in advance of the main feature quickly flattens the flow and the HP has no northern ridging. A lot of similarities with ECM in terms of the trough digging down. The 06Z OP at the same time does something rather different with that secondary feature: This allows the opportunity for a transient raise of heights over Scandinavia. The 00Z output hinted strongly at a pattern change at the very end of FI: The PV eases west into Canada, the jet slows and amplifies and pressure rises in the vicinity of the British Isles with a possible ridge to Scandinavia. The 06Z however maintains the mobile theme: The NH overview of the 00Z and 06Z tell the story: It may simply be a question of timing - the movement of the PV on the 06Z is gradually NW into Canada so the possibility of a Greenland height rise three or four days later can't be discarded and that would fit with my timing of March 7th onward. Finally, my favourite chart and indications of another assault from the Siberian side into early March:

Morning all With the mild/very mild regime now firmly established, it's easy to forget how cold it was just a few days ago. The current synoptic set up of HP to the south and LP to the north is the default for most times in the UK and with he HP in charge at present, it's a largely benign scene. This morning's GEM 00Z OP output at T+240 continues in a similar vein: A stiff WSW'ly breeze in evidence but nothing terribly threatening about that chart. ECM at the same time: A flicker of interest perhaps ? The hint of height rises to the NE was mentioned yesterday and with a solid Italian low to prop up the MLB and a hint of a ridge from the north, who knows ? The last block came from the east but in the past cold Scandinavian blocks have set up from HP areas tracking NE from Iberia. In this instance, the jet is just too strong and were there a T+264 chart I suspect it would show a flat picture. For the British Isles, a brisk but fairly benign SW'ly and fair for most of the south and east with a likelihood of drizzle for the north and west, GFS OP: Very different although it's a benign outlook for the British Isles under a ridge of HP. Scandinavia is awash with low heights as the last of the series of troughs which will affect us earlier in the week exists and the jet re-adjusts back to the north. The Northern Hemisphere view at the same time with the PV centred to the north of Greenland. However, more interest at the far edge of FI: We get to this interesting point as the PV shifts to interior Canada and the jet weakens. An HP over the British Isles joins with the mid-Atlantic ridge and is able to begin ridging north into Greenland as the PV splits between lobes over Canada and Siberia. This is Day 18 of the current milder interlude so perhaps a N'ly by day 21 ? We'll see - it's an evolution we've seen before. but the GEFS are, as you'd expect, all over the place at this far range so it's one possibility among very many. Finally, my favourite chart of the moment: The big warming next week isn't the final warming I would conjecture. Indeed, the PV starts to get colder again into early March. It's akin to a boxer against the ropes having been pounded for the best part of the round but still able to throw a punch. I still think some form of tropospheric response in terms of an amplification is likely in early March but it may again only be brief before the PV tries to reset. Again, a long way off but a very different profile to both 2016 and 2013 so not quite sure where this will take us for March. I've seen suggestions it will be drier and warmer - could be - I wouldn't call it at this stage though it's entirely possible if we get an amplified regime, the block will be favourable for S or SW winds - this morning's OP evolution isn't but that's one OP run in FI.

Morning all Day 2 of what I think will be a 21-day milder spell of Atlantic-dominated weather and certainly too early to see more than the faintest hints of the next change in the pattern. Looking out at the medium term from this morning's 00Z outputs and starting with ECM: The storm hinted at in yesterday morning's output has continued but as a more consolidated LP moving east into Scandinavia and drawing down a chilly NW'ly which although offering only a glancing blow would, you would imagine, bring snow to the Scottish mountains and possibly some higher elevations further south. Pressure is rising behind but only weakly while the next LP is in a very different place so an interesting evolution going forward. GEM at the same time and as we often see with the Canadian model, the only thing better than a deep LP is a deeper LP. A strong storm well to the north of the British Isles and a brisk WSW'ly of returning PM air so not terribly warm and perhaps snow to higher elevation in any showers. Interesting to see if the trough would swing east in later evolution. GFS OP at the same time and as I noted yesterday this model seems keen to have everything happen that bit quicker. The storm has already passed to the east (more ESE'ly track than ECM) and pressure has risen nicely behind it leaving the British Isles finer after a possibly chilly start. The LP to the west seem to be gathering - here's the NH perspective of the same chart: The PV in its usual place but not perhaps as strong as some modelling in recent days has suggested and indeed by the very end of FI: Well, are we looking at the beginning of something here ? The PV is now over Hudson Bay and the Azores HP displaced back into the Atlantic encouraging a lowering of heights over Europe and the hint of a height rise over Greenland. All very speculative at the moment but it's the possible direction a tropospheric response to next week's big warming might produce. Finally for today, my favourite chart at the moment - the 10HPA view of the stratosphere: Fragmented and warming up nicely as has been shown in lots of recent GFS output. To recap, an initially benign start to the three weeks before a slow but gradual transition to colder, more unsettled conditions by the end of next week and the hint early into March of a possible change to something more wintry. To be emphasised though, very early days and huge numbers of hoops to jump through. The chances of those in Scotland seeing snow before month end look good (especially to elevation) while rain and strong winds become more of a feature in the forecasts from this time next week.

Morning all As the current cold spell finally ends and we move into the warmer pre-spring period, what are the models telling us for the future this morning ? I won't bother with the T+144 output as that's telling a consistent story of a benign weekend with the Azores HP moving NE toward but not quite over the British Isles. While the core of the HP moves towards us, the ridge isn't orientated in the same way so the airflow is a bit more W'ly than SW'ly with quite strong winds to the NE as a small LP passes to the North of Scotland. Moving on to the T+240 point and starting with GEM this morning: Strongly mobile but note the trough digging down almost to the Azores so not flat by any stretch and it wouldn't be far fetched to see that ridge building into Scandinavia becoming a more pronounced feature but the jet is too strong to the north. Something a bit different from ECM and this was hinted at yesterday. As we often see in late winter, the boundary between very cold residual winter air and the emerging warm air can be quite stark and encourage cyclogenesis. This feature would bring strong winds and heavy rain for most but the Scottish hills and some other higher ground would see snow. The Azores HP is suppressed with a different (more N-S rather than W-E orientation). GFS: Close to ECM I would argue and perhaps a shade quicker. The following LP (currently developing off the east coast of Greenland) takes an even more SE'ly direction crashing through the British Isles into Europe but the attempt to build heights to the NE behind it is quickly eroded and FI ends with the PV still established over the Pole and N Greenland leaving the British Isles in a SW'ly flow. It would be a 24-36 hour cold snap and again snow for elevations would be likely (and perhaps even a transient covering to lower ground depending on a number of other factors). The forecast 10 HPA profile after the next round of warming (which is about a week away) is interesting: Comparing with early March 2013 which the profile was as follows: 2016: All very different and it may mean something or nothing. To bring in some other charts to help: Another view of the 10 HPA showing the huge variation in temperature this winter. The temperature has fallen back with the ending of the first warming last month. And here's the 70 HPA chart. I'm left with the view for all our observations, the stratosphere has behaved in a fairly average way in terms of temperature so far. The huge difference between the 10 HPA forecast profile for early March and what happened in that exceptional month is making me question the likelihood of a cold month but the pieces of the puzzle aren't in place yet

Morning all Back to the output after a busy weekend which saw falling snow but no settling snow in lowland East London. I said last week my view was we would move into a 21-day milder spell of weather from Tuesday (after six days of below average temperatures in London) as we had, as is often the case, a pre-spring warm up in mid to late February before early March sees a pattern change to something colder again. Where are we this morning ? Starting with the situation next weekend and UKMO opens with a benign offering as the Azores HP ridges from the south of SW albeit with an interesting orientation toward the British Isles. ECM at the same time: Note the absence of the Iberian LP on the ECM output. GFS 00Z OP at the same time: A bit of a halfway house - conditions settling from the SW though quite breezy over the far north of Scotland. GEM 00Z OP at the same time: So the models all pretty much in the same place with UKMO if anything on a slight limb this morning with the small Iberian LP. Moving on.. GEM at T+240: ECM: GFS offers something different: This may just be a question of timing but note how the LP systems are further south over Scandinavia indicative of a stronger dig of the PV in that area and that leaves the British Isles in a cooler W or WNW'ly flow with some quite cold air not far away from Shetland. Switching to the Northern Hemisphere view, here's the same time: The PV has cleared Canada but is sitting to the north of Russia/Scandinavia closer to the Pole with enough residual energy back over Greenland to prevent heights. Further into FI and a lobe of energy sheers off and heads south sending the trough down right over the British Isles so colder unsettled conditions would return: Not entirely unsupported by the GEFS but a strong cluster wants to keep the PV over Canada/Greenland by the end of the month. We've talked about the next warming due in 10 days or so - the 10HPA profile enters March looking like this: If the next warming is the one that really shreds the PV - fine - I'm not surprised to see no immediate tropospheric response and as Ian F suggested the other day, maybe it won't have an impact but it's too early to make that call. However, as that's outside the range of most publicly-available modelling (bar CFS), we won't know for a week or so but I've seen little to change my overall view though GFS OP's traditional FI tease this morning might not be wholly improbable. We're done with cold for now but we're not done with cold - I think it unlikely we'll see anything before the very end of the month and I maintain three weeks in the new pre-spring pattern before the impact of the next warming (and the traditional lag) offers the next opportunity for something more amplified. I also think a prolonged N'ly outbreak is the form horse rather than anything from the East and while lowland snow options will be limited, for those with altitude and those further north, there's plenty of time for significant snow through March and nothing I've seen so far suggests the possibility and even the probability of a renewed wintry outbreak early next month isn't on the table.

Afternoon all Just back from lunch with my Dad - nice warm pub, table by the fire and good food. Saw falling snow but nothing settling. Good luck to those with altitude who have had some settling snowfall.

Afternoon all As anticipated, we are set to move into a milder spell of period governed by a weak atlantic and rising heights over Europe keeping the British Isles in a broadly SW'ly pattern. This process starts from the middle of next week and in my view is going to last at least three weeks taking us through the rest of February into March. The re-location of the PV over to Canada has provided the opportunity for HLB to develop from the Siberian side supported (from the east) by a lobe of PV further over Siberia. Unfortunately, the next move of the PV is back toward Siberia over the Pole and that causes the Scandinavian HP to sink. IF the PV had re-strengthened over Canada, we'd have seen a more typical "battleground" situation (with all the possibilities) but as I argued the other day, this is an atypical "breakdown". You'd normally expect a fired-up Atlantic to push up against the block and ease it back to the east but the PV's renewed move (presumably based on weakening via warming) back to Siberia cuts off vital support to the Scandinavian HP and so it sinks. You might expect from such a move to see heights rise over Greenland as the PV exits but the displacement is far from clean or complete and indeed enough residual energy exists over North Greenland and NE Canada to prevent heights so we see a height rise over Europe instead and while the Atlantic remains subdued none of that helps a synoptic pattern leading to cold. The renewed burst of warming (again from the Siberian side) in FI: Unfortunately, this has the predictable response of sending the PV back over to Canada/Greenland. Had the warming come from the Canadian side, we'd have seen the PV head for Siberia and the chance of Greenland height rises would have increased but as it is the PV goes "home": We end February with what looks like a strong PV though that may be an illusion of sorts. Given the usual 10-14 day response to the initial warming, assuming the warming hits on or about the 22nd, we're looking at March 4th-8th for the tropospheric response which might be another attempt to build a Scandinavian ridge so that's three weeks overall of milder conditions from Tuesday next week. None of this is unusual - winters often have a spell of cold in early February which blows out followed by a warmer almost pre-spring interlude before a sudden reversion to colder conditions and this might be as the PV weakens and is displaced to a more favourable location for advantageous HLB for the British Isles. I'm NOT suggesting a 2013-style scenario but I do think early March could see a notable pattern change from something quite benign to something rather less so. The path to very cold starts from very mild has always been my motto and we may well have some above average values in the next fortnight or so. What changes this ? We need a clean lift of the PV out of NE Canada/Greenland to Scandinavia. Without that, pressure cannot rise across Greenland. To be honest, most of us coldies would sell our souls (and probably those for our nearest and dearest as well) for this chart to verify. The key is the lack of residual PV energy over NE Canada and especially Greenland which allows for heights and at the same time the trough drops beautifully into Scandinavia opening the door to a very cold N'ly. I'd like to say it was the form horse - in all honesty, at this time, I can't.