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I think we need to be cautious of comparisons heading through Spring and towards Summer between 2007 and 2017. There are some similarities for sure in a few respects, but also subtle and important differences 1) In 2007 at this time we were progressing quickly into a moderate La Nina event with global atmospheric angular momentum falling significantly into the summer. In mid late Spring 2017 we are firmly in neutral ENSO conditions with a slight bias towards official El Nino conditions developing from later this summer http://ggweather.com/enso/oni.htm 2) QBO Easterly (negative) downwelling phase much more progressed in 2007 than 2017 2007 hPa JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 10 -226 -318 -326 -338 -368 -208 -15 50 107 111 180 213 12 -253 -313 -318 -336 -353 -371 -142 -15 60 109 172 226 15 -266 -296 -317 -321 -320 -330 -329 -245 -70 42 115 192 20 -231 -226 -250 -278 -304 -318 -324 -333 -343 -319 02 125 25 -89 -69 -115 -233 -285 -292 -324 -332 -339 -331 -296 -28 30 54 53 14 -147 -253 -297 -313 -316 -321 -316 -320 -265 35 82 90 80 22 -184 -262 -293 -288 -298 -289 -290 -306 40 97 107 111 90 -71 -204 -242 -260 -265 -263 -262 -278 45 107 111 109 120 49 -126 -171 -212 -221 -218 -230 -249 50 96 111 103 128 92 -39 -100 -151 -162 -175 -204 -200 60 55 91 78 114 109 56 -13 -40 -33 -51 -98 -100 70 41 34 55 91 99 79 21 -08 12 28 04 -30 80 33 -09 37 26 69 51 16 13 21 16 22 -33 90 35 -17 17 -17 35 -10 -11 -39 -20 -80 15 -115 100 08 -20 -10 -29 00 -60 -61 -106 -117 -204 -61 -210 2017 hPa JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 10 2 10 -162 12 76 75 -40 15 112 123 73 20 142 159 131 25 161 169 145 30 171 177 153 35 169 185 155 40 165 170 158 45 155 166 141 50 132 145 107 60 77 94 28 70 15 36 10 80 -22 21 11 90 -55 -21 -1 100 -150 -80 -38 3) Taking 1) and 2) together, progressively tanking -ve GLAMM and QBO teleconnected strongly with (at the time) record low arctic sea ice to favour anomalous arctic heights and a southerly tracking jet in 2007. The risk of those synoptics happening again this year cannot of course be completely ruled out in times that are more and more unprecedented year on year in terms of looking at previous analogues, but suffice to say residual +QBO at the surface *probably* lasting well into the summer should align well with relative angular momentum propped up by the expected ENSO state in the Pacific (quite unlike 2007) to produce at least some periods of Western European ridging (fine warm summer conditions) rather than any predominating higher latitude blocking and UK/European trough. In that regard, nothing untoward should be read into the present attempts by the models to programme northern blocking into the new month. It should be expected that negative zonal winds across the polar field in conjunction with the final warming of the stratosphere should produce at least one or two phases of HLB at this time of year, but without the wider background ingredients in place such as were present in summers like 2007, little more at this time should be read into trying to extrapolate these months ahead. 4) Of the here and now: Both total and relative angular momentum have responded to tropical activity passage through the Pacific with westerly winds added to the global circulation Tropical convection patters are the engine of future pattern changes it is true, but as applies in winter and any other time of year, this is not a stand alone phenomenon and it is always wiser to look at the whole atmospheric circulation budget which includes the extra tropics and reflects total global wind-flow. This is measured and reflected by the Global Wind Oscillation (GWO) The amount of total "westerlyness" in the global circulation determines the predominance of downstream amplified ridges when angular momentum is higher under these conditions The atmosphere is in not too different a place to where it was in February. This was the last time we saw a notable spike in angular momentum tendency and which coincided with attempts to build higher latitude blocks early in that month. This time, the FW of the stratosphere has augmented that process and the tropical signal in the Pacific has been a little more durable. Accordingly, the GWO has mirrored the phase progression seen in February but with a marginally stronger and slightly slower amplitude orbit into the Nino type Phases 5,6,7. We should expect angular momentum to start falling back as the current tropical wave fades from the eastern Pacific. Caution though should be taken in terms of how the models programme the mid and higher latitudes over the coming first half of May period because there is a highly likely absolute floor limit to the fall-back of AAM in terms of the evolving ENSO background. In this respect, another litmus test of where the atmospheric/ocean circulation is jiving is the Southern Oscillation Index (SOI). In association with tropical and extra tropical signals, whilst still officially neutral this has been tanking negatively once again with El Nino type westerlies being injected into the global circulation and rossby waves transferring polewards from the tropics. Looking further ahead, if we take into account the periodicity of the MJO (up to 60 days) and the general ENSO trends in the Pacific, then it is not unrealistic to expect another eastward progressing MJO wave as we usher in official summer In the absence of the -QBO wave prematurely downwelling as occurred in Summer 2007, and no La Nina descent signal in the Pacific expected to allow angular momentum to fall too far, then the effects of the seasonal stratospheric break-up should be able to diffuse in a way to favour at least some summertime mid-latitude ridging with phases of migrating Atlantic troughs re-setting the pattern, rather than heights displaced to the west and north and a downstream trough over UK,/W Europe and into Scandinavia. So what will be key to watch will be how far the return tide mark of angular momentum is through May as the tropical progression fades and then renews. If this is higher, or at least no lower than seen early March following the previous wave, then this will bode more favourably as one important ingredient for a decent opening to summer.

It was 168hrs and beyond mate.Trust nothing beyond 120 would be my advise, we may have seen a couple of cool outlier solutions but i wouldnt be suprised if we end up with huge Northern blocking at the ecm/ gfs ops suggest..

Morning, not posted in a while. After the unseasonably cold snap this week, although I like cold and snow in winter when it hangs around, it seems a waste of a potent northerly in late April with the strong sun and longer days, though it did bring some dramatic convective skies, hail and even thundersnow for some. But I like many others are probably hunting for a nice warm up. Having spent 10 days on Easter hols recently in Spain with blue skies, temps in the low to mid 20s, getting some colour and vitamin D, it's been a bit of a shock. The GFS was offering the low 20s for the middle of next week, but seems to have shifted temps downwards on the last few runs. The reason is the orientation of the high which seems to have shifted north and west on last few runs, so we get more of a cool easterly or northeasterly flow rather than light and variable winds. So temperatures not hitting 20s, rather mid to high teens at best. But should be pleasant out the breeze in the sun. Yesterday's 12z run for 1500hrs next Wednesday: Same time but from this morning's run, the high further north and west:

I don't think that's true, even the met office updates in the last few days have been painting a summery picture through the first half of May and still is.

Timelapse of today's weather

Our problems mostly come from quite early on as the Atlantic system which moves in this weekend disrupts and sinks south east through the UK creating a cut off area of low pressure somewhere across central Europe, this prevents the Azores ridge from building strongly through most of Europe and instead we end up with heights further west and not as warm. So that south easterly predicted quite strongly a couple of days back with warm air and high heights have been replaced by cooler easterlies, possibly north easterly which will bring cloud into Eastern areas. That said the position of this Euro low and depth will have an impact on the high that develop. a weaker cut off low will certainly result in warmer conditions which is something the GFS this afternoon tries and results in a couple of days approaching the 20C mark.

The Gfs 12z looks a lot clearer and sunnier than the 6z next week and becoming pleasantly warm, especially sheltered from the occasionally fresh to strong Easterly breeze..so..an anticyclonic spell looks to be on the way after BH Monday.

Indeed. But, if you live in either NE England or E Scotland, 'haar haar' might be an apter response. However, that said, don't 'fret' it!

A lot of snow lay all day inland probably above about six hundred feet.Hills over a thousand feet got a fair plastering. Cawdor hills which we can see from home are pretty white Currently 0c inland but 2c here

What a shame from a couple of nights ago! It was looking so warm and settled, now it looks like a nagging easterly will peg back temperatures. I remember early June last year was horrific here with persistent easterly winds and temps in the low teens. Anything but that again!!

The Ecm 12z eventually goes for full blown retrogression with significant height rises around Greenland and lowering heights to the NE..this would be an exciting prospect in winter but in May I would rather see something much warmer from southern europe but at least next week becomes more settled and hopefully we will see some strong sunshine to help offset the cool Easterly flow.

Decent cell cruised to the east of Bournemouth about 15mins ago..

North ten minutes ago North five minutes ago South East West Developing cells in every direction. Getting increasingly dark here... Edit - the wind has just got up as well and getting even darker. And as I type we got hail.

Aye, not just in winter. Whilst the runs so far today have been a disappointment in comparison to yesterday..The latest update from Exeter is only delaying the good weather by an extra day or two with a significant improvement from later next week with high pressure, increasing amounts of sunshine and warmth which continues into the extended outlook too.

Aye a dreadful 6z with temps really struggling, still time for a switch back karl but lets face it, for our grotty climate what can go wrong will go wrong..

A cool breezy and cloudy Gfs 6z next week with even some rain around, high pressure gets sucked NW and the run ends with another chilly Northerly as a result of retrogression.

Morning all As I've said in my In Depth analysis (shameless plug), there's a good deal of agreement across models this morning. As I said yesterday, the source of the air flow would be crucial and the idea of an E'ly or SE'ly sourced from warmer regions has been diluted somewhat in favour of a more ENE'ly flow from west Russia which will obviously be cooler. There are more differences in the orientation and position of the trough than the heights which look remarkably similar into next week.

Northernlights you've just ruined my day!! The Voice of Doom lol - you keep the cold up there, you hear me?

I think it's best not to have knee jerk reactions to the 00z output as a day is a long time in model watching and the 12z could be a different story. Today's MO update will be interesting as to whether it sticks with the summery outlook or not..I hope we see a warm / very warm early-mid May.

The detail for the upcoming weekend is still a long way from being nailed on as it would appear to be the interval before a major pattern change. This morning's gfs starts with the familiar picture of the weak ridge of the next two days giving way as the upper trough dominates the eastern Atlantic by 12z on Saturday resulting in this surface analysis which shows lows forming on the associated front lying to the west of Ireland. As can be seen the task of cutting off the cold northerly is complete and temps are back to normal. From here it starts getting a tad complicated. The main trough in the Atlantic is reinforced by more cold air being ejected SE from the Canadian vortex/lobe (last throw of the dice). This results in a 'tongue' of the trough stretching east over the UK. On the surface this results in the aforementioned front swinging on it's axis and tracking north east across the UK But at the same time a new low has formed in the circulation of the main trough and is over Lyme Regis by 00z on Tuesday bringing some more wet weather to the south, albeit one wouldn't expect a huge amount of rain from all of this. It is at this point that the major pattern change gets under way with pressure building rapidly in the vicinity of the UK and the rough shunted further south in the western Atlantic. As ever it's a question of where the surface high sets up shop and the gfs this morning has it way north of the UK thus an easterly flow with temps around normal This morning's GEFS anomaly is broadly supportive of this scenario

Well what a great day to be a weather enthusiast today Some brilliant sky scapes:

Edmonton has fallen by 0.2c and now stands at +2.4c = 3.6c below normal...probably will end up now with 2 months in row being 3c below normal.

They also have access to a lot more data than we do, so I don't think you can call it 'absolutely crazy'. I still think that locally it could get warm midweek, particularly further west.

MO have been promising summery warmth for the early part of May for some time now. Even ensembles is showing dryer and above average temps following Bank holidays washout. I think more runs are needed for next week.

Sorry frosty but a warm spell for next week has never had any consistent model output, models have swung back and forth between cooler easterlies and warm southeasterlies for days, i keep a close eye on GFS ensembles and even when OP's were showing the possibility of mid 20's C a decent number of ensemble runs didn't, there has just never been any conclusive evidence of a very warm spell next week, i feel too many posters get carried away with warmth and let it cloud their judgement.

Didn't see the forecast so i assume he was forecasting a very warm week next week which is absolutely crazy with even the UKMO runs never going for it and many other runs the day before showing cooler easterlies.

Big flash and crack of very loud thunder just now to my south! I'm out of the no storms club, plus my first spark of 2017. So happy! Edit, so that cell has passed south, but there is another huge cell to the north and another massive cell directly to the west. I think we may get the north cell to come over as its blowing this way...

Significant points with the EPS this morning • Weakening of the Canadian lobe as the high pressure builds adjacent to the UK and surges north west. Thus cutting off the energy feed into the Atlantic. • Simultaneously intensifying the Russian arm and tracking it west. • Thus with the surface high cell over Iceland by day ten and the low pressure WSW of Ireland around 25W an easterly component over the UK veering south east over the eastern Atlantic. • Ergo weather continuing dry but temps hovering around the average • Moving into the 10-15 period the pattern continues to develop with high pressure in the southern Greenland area and the cut off low pressure way to south with the Atlantic becoming very much an inactive zone. The key here may well be the trough to the east edging ever closer which may just put the UK back into a cooler northerly. • Still much to be resolved and the next two or three days should be quite interesting

9.4 to the 25th 1.7 above the 61 to 90 average 1.2 above the 81 to 10 average _________________________________________________ Current high this month 10.0 to the 4th

Slight differences in jet stream orientation in the N. Atlantic having big impacts on the location and movement with time of the big ridge next week. This is an occasion where we could do with a little of the northern jet steam arm remaining in place to keep lower heights between Greenland and Iceland and so allow the ridge across the UK to remain largely independent of the blocking highs across the Arctic. This year is displaying a propensity for extensive high-latitude blocking which would be if some concern for the summer season except that it's still only April and a big shake-up is fairly common by late May to set the stage for June and much or all of July. The other day I mentioned some similarities in the overall global picture to 2007 - this was not the same as saying that the summer will be extremely wet as some inferred; rather that there is an increased chance of an unusually wet outcome. Research since that summer has identified unusual Indonesian rainfall patterns as a key contributing factor to what could otherwise have been a reasonable summer with plenty of warmth on offer. Hopefully we'll avoid that this year. Another big question is whether Arctic blocking continues or not, and in what configuration. I have yet to find convincing evidence either way with respect to whether low Arctic sea ice extent or area encourages such blocking; the low-ice summer of 2012 was very blocked for example, but 2016 was not. There is a tricky-to-resolve interplay between altered jet stream patterns and increased heat and moisture availability to low pressure systems. Given the Arctic blocking being modelled for May 2017, it sure does appear likely that low sea ice extent and/or area will be a present factor for the summer, and quite likely record low. Fascinating times ahead - if a bit worrying from a broader climate perspective.

Spot the difference

HAHA yes but I'm not writing it off, just saying the 00z looks cooler than yesterday's runs regarding next week.

Morning all Very much like the bleak midwinter here in London with a cold N or NE'ly wind and doubtless close to a ground frost outside the capital. I saw a shower of rain and soft hail yesterday afternoon in SW London and I suspect those with altitude have seen something more wintry. This is a snap, however, not a spell and the trend to build HLB to the NE was very strong yesterday leaving the British Isles in a warm or potentially very warm SE'ly flow. Let's see where we are now with the model outlook to the early hours of Saturday May 6th: Starting with the 00Z GEM: The evolution through the Bank Holiday weekend and early next week is pretty well set with the trough splitting next Tuesday as heights rise strongly to the NE. Part of the trough recedes back into the Atlantic while a smaller element remains around the Low Countries helping to prop up the northern HP. That passes close to or just north of the British Isles by this time next week before receding into Greenland. Battle is then joined between the colder NE flow and the returning Atlantic trough and the latter prevails bringing more unsettled conditions back in from the SW. It's worth noting the very strong Greenland heights which may keep the jet running well to the south (the Azores HP is out of the picture) through the British Isles so once set in, it could be quite a prolonged unsettled spell. ECM 00Z at the same time: A number of similarities with GEM but some key differences. The position and orientation of the Atlantic trough is different - it is weaker and further south. This maintains a broad NE or E flow across the British Isles at T+240 though the risk of showers in the far SW in the strengthening E'ly breeze can't be ignored. There's little sign of a coherent Scandinavian trough but the possibility of disturbances in the flow to the NE is another factor. The jet is very weak and held a long way south. It would however be a fine and dry outlook especially for NW Scotland. GFS 00Z OP at the same time: As is often the case, GFS goes a different route. Initially it's much the same as you might expect but GFS has hinted for the past few days at low heights penetrating further into Europe next week so while the HP builds strongly to the NE before retrogressing NW in tune with the other models, the development of the trough is very different. Rather than holding the trough in the Atlantic, GFS OP brings it into western Europe and specifically over France with a change to a cooler and more unstable ENE flow across southern Britain with a heightened risk of rain or showers especially in the south, SW and the Channel Islands. Scotland would stay mainly dry, warm in the west, cooler with haar to the east coast. Further into FI and the pattern remains broadly unchanged with strong HLB and the jet sent a long way south. A chance of the jet moving back at the very end of the run with LP approaching the south of Britain from both east and west accentuating the chance of rain or showers. Looking at the 00Z GEFS at T+240 and it's hard not to be surprised by the lack of disagreement. The OP is strongly representative of the suite and the location and orientation of the HP around Iceland now seems to be the favourite option. Needless to say, there are more options further into FI but while the Control goes for a more Atlantic-based breakdown, a number of the members develop a strong Scandinavian trough or LP and a return of cold N'ly winds around or just before the middle of May. To conclude, more agreement than I've seen for a while. The ending of the cold spell presages a more unsettled weekend with the trough attempting to move in as heights build strongly to the NE. This brings in a warm but brisk SE'ly wind and the likelihood of rain or showers for southern and south western areas. The heights win out into next week but the trough moves across the south on Bank Holiday Monday bringing a potentially disappointing day before conditions improve from the north and the whole of the British Isles enjoys a few days of dry and warm weather albeit with sea fog or haar a threat for eastern coastal areas. Further into next week and with LP close to the south on some evolutions, rain or showers for southern counties are quite possible while the best weather will always be to the far NW - that trip to the Western Isles you've always promised yourself, a good time to take it !!

Yeah Frosty, best to not have any knee jerk reactions........

Hopefully another day of interesting convective skies today across England - especially towards the SE - where there will be greatest instability beneath departing upper trough Here's my storm forecast for today: Storm & Convective Forecast Issued 2017-04-26 09:23:12 Valid: 26/04/2017 06z to 27/04/2017 06z STORM FORECAST - WEDS 26TH APRIL 2017 Synopsis Upper trough will continue to push SE into mainland northern Europe today, the back edge of the trough influencing eastern England, while heights rise off the Atlantic across northern and western Britain. At the surface, an area of low pressure will drop SE from the Norwegian Sea toward the North Sea by midnight, associated frontal system ahead of the low will bring cloud and rain to Scotland, mostly dry EIRE + Wales, with an unstable and showery Nly flow across England. ... ENGLAND ... Cold air aloft towards SE UK (500mb temps AOB -35C) in association with departing upper trough will create steepest lapse rates here and the strongest likelihood of thunderstorms as diurnal heating increases instability by and through the afternoon. Isolated lightning from heavier showers can't be ruled out anywhere across England though. Any storms will be weak, given dry polar airmass and lack of warmth, but will produce small hail or graupel locally and perhaps gusty winds too. Issued by: Nick Finnis

That Jay Wynne will have some egg on his face after his forecast was last night, looks a good deal cooler for next week going by what I've seen this morning.

Where did next weeks warm spell go? The Ecm 00z for example looks much cooler than last evenings 12z.

Tonight's Ecm 12z ensemble mean will give those of us looking for an early taste of summery weather during early may a warm glow..it's looking increasingly anticyclonic next week and hopefully beyond.

Well the skies at the allotment this evening have been a delight! Light rain now but nowhere near enough. Can't explain those lines in the raincloud over the houses, not very clear on camera but beautiful.

Still piling into the Northern Cairngorms.

Looks as though the mountain snow will survive for a few days yet with night time temperatures falling to freezing up there.Notice too that the projected heat for next week is getting watered down. Northerly and easterly winds are always more likely in spring With the experience on the farm for the last few years that the seasons are running two months late then I think we could still get a cool May. Currently overcast and 3c

The ecm has the front approaching Cornwall Sunday morning and slowly tracking north east in the next 24 hours petering out as it goes. Probably the main section of the rain moving east over France. Then comes the pattern change and it too is centering the high cell to the north with the easterly component. But just to complicate matters it swings the high/trough on it's axis so ending with HP to the NW and LP to the SW. So certainly a dry scenario with temps around average but the door is ajar to various possibilities as we lose the Canadian lobe.

Snowing hard in Malton at the moment, but not settling, about 4C so probably wont. Tried to get a picture, but too dull with just a phone camera.

Evening Summer 1976 I have to be honest, I'm sort of thinking the same as well

Its the time of year when the atlantic traditionally settles into its spring slumber, and the outlook certainly looks non-atlantic dominated, a northerly followed by a slack cyclonic airstream over the bank holiday weekend (rather unfortunate timing - as the lengthy settled period looks like breaking down just in time for the weekend with rain for many), followed by an easterly to greet May, possibly becoming more of a northeasterly in time... with signs high pressure will retrogress to the NW, and low pressure settles to the SW (but far from certain). We could see more of a southerly feed next week which would pull in some very warm uppers for the time of year, nothing too unusual though with perhaps the NW the best spot for dry sunny conditions (again quite par for the course in May - when the east can often be plagued by sea fret and haar and low cloud with warmest conditions in the NW). The main headline is for a continuation of the lengthy dry spell bar a shortlived unsettled blip over the weekend.

Surprised the chart hasn't been posted yet! Heatwave potential if it sticks in that spot (which it doesn't on this run) - I'm talking maxes 25C-28C. But a chance the high will drift NW with time.

The Ecm 12z also shows a marked improvement next week as high pressure builds in and temperatures respond, soaring into the 20's celsius..what a beauty!

indeed. we will be back to the boring monotonous tripe soon enough,which some people seem to enjoy. Next month could have some nice summer like weather which people crave,but i would not be so smug if i were them. Never trust that type of weather in may,it could be a distant memory by june/july.

What a fantastic day weather wise,everything in one day,how the heck anybody who's interested in weather could complain about today is beyond me. Travelled over 450miles with work,north to south then return,so much more interesting and enjoyable than what's to come over the next few months.

I wouldn't discount the cold Northerly option, it's been showing up quite a bit in various operational runs, there's been at least some members going for it in every GFS ensemble set I've looked at over recent days. The winters that panned out as similar to this in terms of snow in the Scottish Ski Areas were 2012 and 1998, in both cases the best conditions of the season came in late April onwards into May in the Northern Cairngorms. I'd say it's almost the form horse here, if it goes the other way and we do get a high pressure dominated April into May, I'll certainly be hoping it pans out like 2003 and not 2007 thereafter! Just to illustrate the point, some photos looking down / up Coire Cas on CairnGorm in mid March, then mid May 2012: