stodge

Evening all All remains on course with the trough dropping spectacularly SE to the west of Ireland ending up over Biscay and ushering in a prolonged spell of E'ly or NE'ly winds lasting quite possibly to the end of the month. Variations on a theme = some models have stronger influence from heights to the north and north west while others keep shallow areas of LP closer to southern Britain so a glorious Scottish holiday for some - Harris and Lewis will be delightful - but a more non-descript spell for others with plenty of haar for eastern coasts and a risk of rain or showers for southern areas. GFS teases in far FI with the traditional early May N'ly (Buchan anyone?) but a fairly weak area though this could in turn begin the journey to the summer synoptic pattern - we'll see.

A lot of support for a prolonged spell of E'ly winds as we move to the last third of the month. Plenty of northern blocking. None of this unusual I should add.

Evening all Signs of a slight change in the pattern later next week as heights continue to fall in Europe in response to the traditional seasonal northern blocking in Scandinavia and elsewhere often in association with the final warming of the PV (very sudden this year). T+156 chart from UKM, T+168 from ECM and GEM and T+156 from GFS all from the 12Z It's LP to the NW and SE and heights to the SW and NE - while that puts the British Isles in a col to some extent, the lower heights over Europe are dominating and pulling in an E or ENE flow over southern and central parts. Again, far from unusual for the time of year and the pattern can take a little shifting if heights persist to the north - GFS offers a warmer route in FI as a deep LP stalls to the south west and draws up more of a SE'ly flow.

Evening all Easter in the balance I thought last evening - THIS evening, well - looking at the T+168 charts: An Easter of two halves from UKM with a warm and fine Good Friday and Saturday but colder air is approaching from the east suggesting the second half of Easter very different - fine but potentially chilly especially in the south and east with the north and west hanging on to warmer conditions. Nothing so dramatic from GEM - still settled but not as warm to start and not as cold to end. GFS suggesting the colder push is going to pass just to the south of the British Isles but it's on a knife edge. We await ECM....

Evening all Having looked at the 12Z suite, Easter is certainly a way from resolution. Yes, ECM at T+240 tonight offers something very pleasant but GFS OP at the same time has the HP over Scandinavia and -4 850s over the country so fine but chilly. The T+168 charts from UKMO, GEM, ECM, JMA and GFS show the divergences in the evolution The fundamental seems to me whether heights will rise first from the SW or the NE - UKMO looks the outlier but it's never a forecaster to ignore. Note how both UKM and GFS keep the Atlantic LP further to the west - it's the push in of the positively aligned trough which encourages the Azores HP to ridge NE towards southern Britain. Beyond that, the GFS OP and Control runs don't scream warm and settled past Easter but it's too early to be too confident as we are still far from clear about next week.

Evening all After this weekend's chilly and wet spell, we see the deep Atlantic LP disrupting well to the west and hints of a S'ly or SE'ly developing which would be pleasant but GFS in particular and some of the other output are playing with heights over Scandinavia and the competition between warmer and colder airmasses which of course characterises spring very much in evidence. No strength in the Atlantic so the possibility for blocking to the north (far from unusual at this time of the year) very much in evidence and those looking for warmth must be hoping the orientation is more SE than NE but that's far from clear. In truth, Easter still very much to be resolved - the Good Friday afternoon (T+216) charts from ECM, GEM, JMA and GFS OP. Have to say it looks more settled than not for most at this time.

Real April showers today (as you might expect). Three or four heavy downpours with thunder and lightning observed mid-afternoon.

Indeed, ECM joins the pack suggesting a chilly and unsettled run up to Easter with the jet just to the south of the British Isles and Atlantic LP crossing southern England. By T+240 negative 850s over most of the British Isles: Cornwall milder but much of northern and eastern Britain chilly under -8 uppers.

Indeed and we know convective activity can rapidly lower temperatures so hail and sleet becomes likely with snow in the heaviest showers. Tonight's 12Z models have backed off a secondary N'ly early next week in favour of a NW'ly as a small LP moves SE into Denmark and north Germany. From there, GEM goes very unsettled with the jet just to the south of the British Isles and frequent LP incursions producing spells of rain and presumably snow for northern hills and mountains. As I said yesterday, this is looking a very different April from 2020 or 2021. GFS OP finally relents in far FI by ending a strong North American storm to southern Greenland thus allowing heights to build NE from the Azores into Scandinavia but that's all conjecture. ECM is also looking chilly and unsettled well into next week.

Evening all My take from the 12z suite this evening is the extension of the colder spell into early next week. This seems to be down to the HP cell first moving south, then intensifying back north prolonging the N'ly airflow. UKM at T+144 suggests a return of the N'ly airflow on Monday. Not all models say this but there's certainly been a 24 hour extension of the cold from some of the output. Even when the colder spell breaks down, the milder incursion is fitful at best with a renewed N'ly plunge for the second weekend in April being forecasted. Further into FI, the GFS goes very unsettled (a theme of recent days) with residual northern blocking keeping the jet closer to southern Britain and spells of wet and windy conditions - quite unlike the last couple of Aprils it has to be said.

Evening all It may not be what some had hoped but certainly 3-5 days of cold weather with the chance of snow for those with sufficient altitude and good fortune. As the HP slides south the westerlies return but plenty of options from there into the latter part of next week with no strong return of heights it would seem and probably an unsettled spell or two offering transient colder PM slots and alternating spells of rain and drier, brighter weather into mid month. The question for later April and into May is or will be the extent of northern blocking - it's the main time of year and how it sets up will be significant.

Evening all I left the forum last evening being told GFS was right and all the other models were wrong and the shortwave developing to the NW would halt the push of cold air SW into the British Isles. And yet... UKM, GEM and ECM have stuck to their guns and GFS has now fallen into line. Some form of LP will develop over or just to the east of the British isles before easing away as pressure builds down from the NW but with the core of heights staying to the west, the colder air remains in place albeit with some moderation past next weekend and into the following week. As for temperatures and the possibilities of snow - the former will be much lower than recent experience and as for the latter the further north and the higher up the better your chance if we get some convection. I do think we'll see the return of night frosts and these could be quite sharp in some places. I also note the GFS 12Z starting to show the wind reversal at 10 HPA in FI - not huge by any means but a clear reversal.

Evening all To be fair, the GFS has been pointing to the changes in the 10 HPA temperature and zonal winds for a while but no one seemed to be looking or everyone was looking at the earlier forecasts of a more robust PV and a gradual decline into April and even May. @Mike Poole has put up his usual thorough analysis and I'm with him - the GFS makes so much more of the feature to the north west than all the other models which move to a "clean" NE'ly incursion and it's a delight to see the colder 850s marching SW towards us. Snow? I'm not expecting any in lowland East London but as always further north and higher up could yet a spring surprise. There's little doubt it will be very much colder next week with 18-20c being replaced by 8-10c (if we're lucky). The comment about hail and sleet in the showers is hugely valid - we could easily see transient snow to lower ground in the heaviest showers. GFS does evolve a very unsettled spell into mid April with the jet well to the south and LP passing close to or over southern Britain. Other models keep the cold air for 4-5 days. One other thought - is the suddenness and severity of this final warming going to lead to a prolonged period of northern blocking into April and early May? That's not unusual in and of itself but it may well be we see a prolonged period of north or east winds in the middle of spring this year.

Evening all Still plenty of uncertainty with the end of next week in mind. As others have pointed out, do we get a "clean" evolution to a NE'ly as suggested by ECM and GEM and to an extent UKMO or will it all get complicated by shortwaves, small troughs or whatever as GFS offers? One thing on which we can probably all agree next week won't be as fine, warm and sunny as this week.

Evening all I'm going to disagree with a few of the more recent posters - there's been a significant shift toward the colder outcomes on tonight's 12Z suite compared to last evening's. GEM is a thing of beauty if you want spring cold at T+168: JMA is decent and ECM just about gets there. UKM is much slower and may not get there - the profile of the LP to the south is very different from GEM for example. GFS OP has a brief cold interlude but rapidly becomes very unsettled and wet with the jet tracking just to the south of the British Isles. The main message is this benign spell of fine and warm weather isn't going to last and the next phase of spring is going to be more "interesting" in weather terms.

You say that and I'm sure it's valid but this has been an extraordinary collapse in zonal wind speeds in a very short period. A prolonged and strong warming has been the cause but it wasn't so long ago forecasters were speculating about a much more gradual end to the PV season with the vortex still powerful into April. In a season which has seen very little warming, we get all our warmings at once (so to speak) at the end of the season. Whether this has impacts through the summer I have no clue but I suspect it will play a role of sorts in April and May.

Evening all Have to say the jury still very much out on the severity and longevity of any Arctic plunge at the end of next week. Some of the 12z models aren't interested - the GFS OP would usher in a very unsettled, wet and cool spell with LP tracking across the south of Britain. There seems little appetite for full-blooded retrogression in the other models with a slack trough forming in mid Atlantic but it's hardly a west-based NAO either. I do note the zonal wind speeds collapsing so the initial thought is it's all going to happen slowly if it happens at all.

Evening all UKM and GEM show the HP orienting NW-SE bringing a more SE'ly flow over the British Isles but with time the core of HP tries to migrate west to sit more to the north of Scotland. Both JMA and to an extent ECM take the HP further west which opens the door to a N'ly blast - JMA's N'ly is especially potent Just for fun at this stage - GFS wants little to do with a blocked pattern re-asserting the Atlantic in far FI - this usually means there's no strong signal at this stage.

UKM keener to keep the HP influence for longer than other models and indeed shifts the core north rather than south which looks the outsider but you hever know... Beyond that, as the zonal winds relax, we finally get to move the PV off its perch and a change in the pattern as heights shift back west into the Atlantic and the trough drops down into Scandinavia. We may well see, and this is far from unusual, an early April with heights to the north and west and the trough well down to the east of us which means NE winds as LP moves ESE across Northern and Eastern Europe.

The key is as the zonal winds decrease, the opportunities for amplification increase. One of the big trends looking beyond the end of the month is to drop the trough into Scandinavia and pull heights west into mid-Atlantic. I'm not talking classic retrogression but this allows LP to swing south to the east of the British Isles introducing spells of NE winds from Scandinavia during April.

Evening all Not much comment on the 12Zs so far - presumably we are all waiting for ECM to show its hand. What do you mean, it already has? T+144 from ECM, GEM, UKM, GFS and JMA to name but five Variations on a theme but some subtle differences in location and orientation of the HP. GEM and JMA keep the core of heights in the North Sea or over eastern Britain while GFS has the centre over southern Sweden and Norway. Unfortunately, the orientation is slipping NW-SE allowing more of a SE'ly flow over the British Isles as heights fall to the south west. Plenty of options from there into further FI - GFS offers the scenario of the core of the PV moving to Scandinavia and the HP shifting west into mid Atlantic opening the door for a late N'ly.

This is the Easter snow set up I remember from 2008 - covering even in East London:

Well, now... -7 850s late in March - a nice cold wet day but for the hills of Wales?

Morning all As @Cambrian wisely opines, very early days but are we looking at winter's last hurrah or spring's first surprise ? Hardly the first Day 10 chart in any winter to tease and tantalise. It looks as though the push of HP next weekend from the south west is enough, combined with lower heights over Iberia and France, to allow a significant rise of pressure from the north east and that's quite a chilly little bit of air coming our way. The GFS 00Z T+240 10 HPA wind profile is interesting - after weeks of very strong zonal winds, clear signs of a fall off which would also encourage heights: The entire GFS 00Z run in FI is eye candy for fans of cold weather as the weakened PV finally pulls further west over Canada leaving again the opportunity for heights to build to our north east, then north and eventually over Greenland. However, at this time it's just nice to look at - if it's still here in a week's time and is at T+72, well, some will still say it'll downgrade, won't they?

Afternoon all I don't have the knowledge of the SPV others bring to this so just my observations off the models. Unfortunately, the PV remains too powerful and the zonal wind too strong to allow proper amplification into Scandinavia in the short term so we missed an early March cold wave as the HLB has become an MLB (the cold wave has gone south to affect, unfortunately, the Ukraine). The medium to longer term modelling continues to show strong heights to the east and we go into the second half of the month increasing signs of this amplification building slowly westward towards the Baltic. That means LP systems coming in from the west aren't able to move through to the east of the British Isles and either swing strongly north or disrupt over or just to the west of the British Isles. As the zonal wind speed decreases and the PV comes under continued Wave 1 warming (something strangely absent in the depth of this past winter), the opportunities for this amplification westward continue and I'm now increasingly of the view we will see strong northern blocking in April (nothing unusual in that of course) centred over Scandinavia and a prolonged period of winds sourced from the east. The other interesting development is or are the consequent draining of heights from Europe - part of which is the trough disruption mentioned above which leaves energy to move SE into Europe and even link with instability moving up from North Africa to create a weak but general LP area over much of Europe to support the heights to the north and east. Moving this on into real speculation, I just wonder if this spell of northern blocking is setting us up for a classic "European monsoon" in May/June with frequent incursions of warm but thundery and unstable air from the south.