Model Output Discussion - Spring Has Sprung

[WYorksWeather]

Tonight we seem to not have a great outlook in the short to medium term.

After we get the current cool cyclonic period out of the way over the weekend (unfortunately a pretty dreadful one for most), into early next week we have a warmer pattern developing for Tuesday and Wednesday, but nothing particularly impressive. Raw maxes of 17C on Tuesday and 20C on Wednesday, perhaps in practice 18-19C and 21-22C. Exact figures probably dependent on timing of cloud and rain.

Wednesday possibly a new warmest day of the year, but nothing out of the ordinary for the start of May. 

 

However, further into May we have a significant pattern change on the GFS tonight. In the extended range, the 12z at around day 12-14 sets up a high over and to the east of the UK. It's not the strongest, but especially eastern areas you would think stay mostly dry under that.

The temperatures are nothing spectacular to be fair as the core of the resulting heat plume is away to our south, but a number of days with very pleasant afternoon temperatures in a row.

Of course, this is a long way off.

In terms of the ensembles, the GFS still isn't that interested, but it has mostly erased the cooldown after the initial warmup around the middle of next week, and a bit of a signal to follow the GFS OP later on to a lesser extent, so I guess already an improvement on what was showing 2-3 days ago.

Summary

Still a long way from any sort of heatwave or anything particularly notable, but the pattern on the GFS 12z OP would be pleasant enough. Certainly a welcome improvement.

From a personal perspective, I'll be paying close attention to forecasts for May Day and the following week (commencing 6th) as I've booked it off work.

[WYorksWeather]

Bit of a late night update - did the ECM 12z follow the GFS 12z with a warmer spell in FI? The control (OP doesn't run far enough) says no - the whole pattern is a few hundred miles to the west, and we're actually stuck under cool and cyclonic northerlies.

To be fair, the control was amongst the coldest runs. One pattern that we do notice though is that the downward trend in temperatures after the warmup early next week has been downgraded to more of a return to average, similar to the GFS 12z ensemble. Still no sign of anything particularly warm though on the mean, but still looks a fair bit warmer than of late overall.

Next is the GFS 18z. Ensemble isn't out and I'm not waiting up for it, but does it follow the 12z?

The answer, much as with the ECM, is no. The pattern is not as far west as the ECM, but the high is over and to the south of the UK, which is badly positioned for any real warmth. Nothing overly cold, and should be largely dry, but I'd hesitate to call it warm.

All in all, not the most inspiring late night update after the earlier optimism. I imagine the models will still go back and forth a bit around May Day and beyond as we still have a fair way to go.

[northwestsnow]

Excellent EC 00z this morning ..

Bit of a tightrope at times though in fairness..

 

Edited April 27 by northwestsnow

[northwestsnow]

Good news.

EC mean a LOT less aggressive with the southerly tracking jet this morning

Yesterday 12z mean day 10

00z day 9 mean

[WYorksWeather]

The GFS 00z ensemble has now fully eliminated the cooldown in the mean - temperatures now looking consistently near or above average.

Looking at precipitation it seems like we'll struggle to keep things entirely dry though - a fair few precipitation spikes. But certainly nothing there screaming extremely wet pattern - the mean rainfall is pretty low which suggests it'll be dominated by infrequent showers rather than heavy frontal rainfall.

 

Sea level pressure tells the same story as well - mostly on the rise after this weekend's dip.

All in all - not too bad. It's also interesting how the number of warm outlier runs is beginning to increase again - an odd run taking the temperatures above 25C, like P20 of the GFS, with a broad area of high pressure over the UK and centred to our south east.

Also looking at the dam lines a very strong high for the time of year - the 584 line into the SE of the UK.

By the end of the run some very hot air just to our south as well, so the pattern may have continued beyond the end of the run.

The first heatwave run of the year - taking into account a usual under-read of 1C or so many areas would surpass the Met Office heatwave thresholds with this.

Again, only one option and a very long way away, highly unlikely to verify. But as many of us have been saying we need to be on the lookout for these very warm outliers and see whether they gather any further ensemble support. Most of the time they do fall away again but sometimes they keep gathering momentum...

[Scorcher]

Finally some promising signs this morning.

Things are certainly trending in the right direction with more warm runs appearing- it's been a while since there was any prospect of anything very warm developing at all.

I would snap your hand off if you offered me a week of sunshine right now, even if it was only in the mid teens.

[drm]

 northwestsnow yes good trends from both the ECM and Gfs this morning for pressure to rise steadily, long may they continue we deserve a dry spell after the last 8months, no doubt it won't be a smooth journey. 

[minus10]

Although some way off i think the gefs mean pressure for 9th May looks promising this morning...

 

..high in a better position to allow more of a warm up and importantly drier conditions..

...allowing the heat to build further south too ..

..together with the ecm0z op..

..as others have stated good signs as far as they can be this morning...has to be better than what we are enduring now...a distinctly chilly drizzly 6 deg here this morning...

 

[northwestsnow]

 Scorcher

Yes indeed , the North west has endured horrendous weather since October ..

It's the talking point in taxis,workplaces and households for a good while.

Really hoping things improve  

[Summer8906]

9 hours ago, WYorksWeather said:

The answer, much as with the ECM, is no. The pattern is not as far west as the ECM, but the high is over and to the south of the UK, which is badly positioned for any real warmth. Nothing overly cold, and should be largely dry, but I'd hesitate to call it warm.

Given what we've had to put up with for most of the past 10 months, I think that pattern alone is quite good enough!

Plenty of time for intense warmth later: frequent dry and bright weather is arguably all we need now, whatever the temperature.

Even if the first half of May has a mean max of 15C, that will actually feel relatively warm given it's been in the 10-13 range for about six months now. Would certainly prefer dry, bright and coolish than mild but dull and wet cyclonic SW-lies, at any rate. Thankfully it looks like only one SW-ly day in the near future: Monday.

Edited April 27 by Summer8906

[Scorcher]

 northwestsnow The GFS 06Z is continuing the positive progress as well. Warm air stuck over the UK into the weekend and an easterly flow which is always good for NW England at this time of year.

This chart for next Saturday has come out of nowhere. It would be a shock to the system (a very pleasant one) for most in this area, given we haven't reached 20C yet.

 

Not hugely deep in FI either- only a week away!

Edited April 27 by Scorcher

[WYorksWeather]

 Scorcher This morning's UKV has come even more out of nowhere - a sudden heat spike to 25C as early as next Wednesday!

[Scorcher]

 WYorksWeather There was always the potential for it to happen though with such warm air close by/over the UK. Still on a knife edge though given pressure isn't very high- especially further south.

Anyone who has booked a trip to France/Northern Spain for the end of next week might be getting a bit wet...

[Rain All Night]

On 26/04/2024 at 15:05, Rain All Night said:

0z deterministic runs, out to Fri 3 May (day 7)

I'll take the developments from 1st May onwards without complaint - from the Met Office app forecast, it looks as though even down here in the far south we will see improved temperatures along with the inevitable showers. Should be nice for those further north who may stay dry?

0z ensemble means, out to Sat 11 May (day 15)

Through the first five days of May, we will see upper-level high pressure retrogress gracefully through the UK, teasing us with warmer air before leaving us once again at the mercy of cooler pressure patterns, which currently seem to be favoured by the ensembles right through the first third of May.

0z deterministic runs, out to Sat 4 May (day 7) - bank holiday Saturday

Possible brief warmth on the bank holiday weekend, but plenty of ways for it to go wrong?

0z/6z ensemble means, out to Sun 12 May (day 15)

Perhaps some anticyclonic activity over the UK around 9th May? Otherwise, not much to report.

[Addicks Fan 1981]

 Rain All Night I reckon we will have a very interesting may indeed but I do envisage a negative AO/NAO month of may ahead as well down primarily to the final warming of the stratosphere prior coming into the summer months as @WYorksWeather and @Mike Poolehave said.   

At the same time i do also envisgae a zonal winds recovery, also believe the east QBO has reached its peak and will start trending less in an easterly vein as may and the summer progress.    

Things to keep our eyes on I'd say.    

[northwestsnow]

EC 12z even better than the 00z !!

A few snapshots..

[Bats32]

 northwestsnow Omega block in the right place this time!

[Scorcher]

 Penrith Snow I don't think I'll be needing my heating after tomorrow thanks...

Famous last words looking at the output now.

[northwestsnow]

 Scorcher 

I'm still nervous that it will pan out in our favour,I think after the almost relentless let downs of winter I've kinda developed a semi permanent ' if it can go wrong it will ' mindset,I'm sure it's not just me .

That said I'm hoping for the best ,I'm semi retiring next month at the grand old age of 51 and I'd love to see a long warm spell to usher in my 2 day working weeks !

 

[Scorcher]

 northwestsnow I think whatever happens, the warmer air is nailed on now. How warm it will be at the surface and whether it will be completely dry in this area is still open to question I think.

The ECM is less favourable in the short term with the warmest air initially missing us but it's very good in the latter stages of the run- we would probably see 4 or 5 consecutive days in the low 20s in NW England.

Edited April 27 by Scorcher

[northwestsnow]

 Scorcher

yep ill gladly sacrifice a ' less good ' mid term for an extended dry warm spell longer term,god knows we are due a dry spell.

[northwestsnow]

Mean is fine.

Probably not a heatwave but will be pleasant in any sunshine ..west is probably best ,actually south west will probs be best.

Either way, at long last a change is on the way ...

[Mike Poole]

ECM clusters in the extended now showing something much more promising.

The majority cluster 1 (23 members) looks very good, and cluster 3 holds promise with a tweak or two also.  No guarantees yet, but I agree with the view of others that a change might be beginning to show, plenty can go wrong, let’s hope we can count this down to a settled warm spell in mid May.

[Addicks Fan 1981]

 Mike Poole i tell you this the sooner we have our zonal winds recovery the better, have also noticed further afield that the la niña development has been delayed by the new CFS members.   @Gavin Palways said on his videos to look out for the members in blue as they are the modern members if you like.    

Hope also we do get the WWB as @summer blizzardhas mentioned as that's an important thing in my eyes to look out for.   

[SunnyG]

 northwestsnow It will go wrong. I'm 100% sure that it will be downgraded as we get closer to the 5th May.

Edited April 27 by SunnyG