Model output discussion 9th April onwards

[mushymanrob]

Troughing looks like becoming dominant around the end of the month and into May, so we should see some rain which is needed badly. Weve only had 1.7mm here in Derby this month!

On the minus side, its looking like remaining cool with temps below average.

 

[summer blizzard]

GFS making more of the trough in around 8 days for those who want rain. 

[Frigid]

Gfs ensembles still going for a colder period in the latter stages of the month, also looking more unsettled. As for now, temperatures will probably be average but feeling pleasant under clear skies. 

[Scorcher]

Interesting to see that the models have backed away from anything particularly cool in the reliable time frame. With 850 hPa temps remaining around the 0C mark at this time of year you can easily get temperatures into the mid teens with the strong sun now- as we've witnessed over the past couple of days. It's been 17C here yesterday and today with the 850 hPa temps not far above 0C.

I'm really not too concerned about any notable cold over the next week or so.

[Guest]

3 hours ago, summer blizzard said:

GFS making more of the trough in around 8 days for those who want rain. 

Not here it doesn’t, apart from an outside risk of a shower tomorrow afternoon the GFS Ops is completely dry here until we’ll into May! 

[Frosty.]

Well.. this would be a pleasant early May from the Gfs 12z operational wouldn’t it?!....  

[Earthshine]

4 minutes ago, Jon Snow said:

Well.. this would be a pleasant early May from the Gfs 12z operational wouldn’t it?!....  

Better!  Want to see more days with temperatures above 20C.  I don't care if it rains a bit more, just want some proper warmth!

[I remember Atlantic 252]

34 minutes ago, Jon Snow said:

Well.. this would be a pleasant early May from the Gfs 12z operational wouldn’t it?!....  

Depends where, for my location that screams cold with lingering most of the day north sea mist, temps stuck around 9 degrees with cold wind, areas W of Pennines, NW Scotland, Wales and SW England over 20 degrees in unbroken sun, luckily it's at 384

[Mike Poole]

My thoughts on the current setup.  First let us look up - we are heading towards the final warming in the stratosphere:

Days away and it doesn’t look like anything spectacular, so it would probably not influence any changes down here at all.  Most of winter and all of spring we’ve had little driving forces on our weather in the UK, very unusual, some similarities with summer conditions for all that time.  

So it would be a bit weird if that changed now, and the op model output is suggesting that it won’t - position of the highs more important than position of the lows, maybe.  Not much from the Atlantic, but high pressures still able to reach high latitudes.  There’s no polar vortex to drive major changes, but there are still influences.  AAM now forecast to remain neutral rather than decline, and then increase as per CFS:

I think, with little driving the weather the pressure patterns can move about and could undoubtedly throw up some really cold solutions for the UK from a northerly still.  But this does have to end at some point, because if nothing else is driving the weather, sea surface temperatures might well do, here’s the latest:

I can’t access the archives because of the meteociel fire to check back, but from my memory of looking at them, temperatures are really  increasing within the area highlighted in green over the last months.  With so little driving our weather at the moment, SSTs now may influence the early part of summer, I think, in encouraging the Azores ridge.  

Probably take hold on 17th May when we’re allowed back indoors

All the best, folks,

Mike

 

[stodge]

Evening all

Tonight's T+240 charts from GFS OP, ECM, GEM and JMA respectively.

As you'd expect variations on a theme at this distance. Northern blocking in evidence but is it easing a bit to the west and allowing the trough to move over the British Isles - both ECM and JMA seem to be suggesting this.

GFS OP and GEM keep heights much closer and the result is more settled in the north and west with LP to the south and south west keeping southern and western areas more prone to rain and showers. As others have said, some backing away from the colder options of a couple of days ago but nothing in this output suggests late spring warmth either. GFS OP is perhaps the most interesting in that it alone has clearly broken down the Greenland heights and while I'm not suggesting Atlantic zonality, the heights are pushed towards the British Isles but until and unless the LP shifts from around the Azores it makes little difference.

Far from an atypical late April pattern as we've said.

[Mike Poole]

ECM clusters:

Just 1 until T240 so that tells us nothing- we all know it is anticyclonic up til then , here’s the last one T264-T360:

But none of them look like realistic evolutions to me, at that range.  Is it possible that the models are trying to predict things beyond their use-by date?  Heaven forbid.  As a modeller, I also have a phobia of models - of them being used for the wrong reasons, the covid crisis gives many examples of that.  Very many.  ECM clusters - pinch of salt!

 

[damianslaw]

A cold front moved through in the last hour or two and gave blue skies... how weak a front! There was a bit of precipitation on the radar over SW Scotland that simply fizzled into nothingness.

In the near-term a very sluggish pattern, no movement in the atlantic, high pressure circling around on low spin in a washing machine. Little variance day to day, bits of cloud, plenty of sunshine, average temps by day, frost risk at night.

Into the last week of April, both ECM and GFS continue to push heights to our NW, allowing a chilly northerly flow and a shallow trough to develop which might deliver the first appreciable rainfall for many of the month. All a bit messy, but the theme for the last week is for something more unsettled than during much of the month, and quite cool.

Start of May too far off to call, but many will be wanting a good Bank Holiday, given the current indoor restrictions. 

[mb018538]

Anyone looking for some rain? Many areas may reach the end of the month without seeing any rain, or 1mm or less. 

Going by the 00z ECM Op run - a fall in pressure doesn't correspond to lots of ppn, as the low pressure system that forms manages to miss the UK, taking an unusual north to south track from below Iceland to the west of Biscay due to a slow moving and blocked pattern:



GFS Atlantic jet profile highlights this weak jet well:

[minus10]

Which way will it go next ?

On the threshold ?

[Methuselah]

Nothing too alarming on this morning's GES temperature ensembles -- and, a sudden emergence of scatter, circa Day 10, always gets me interested:

     

[Methuselah]

Up tp Day 5, and this morning's GFS looks okay:

    

[mushymanrob]

Well the 8-14 day chart continues the evolution of the 6-10 dayer, and is consistent in suggesting pressure will drop over the UK later next week onwards. I wouldnt like to say where the surface lows will be, but the upper flow is still in the North of the UK.

Broadly speaking, to me this suggests itll get slowly unsettled with showers becoming more frequent and longer spells of rain are likely. But with temperatures below average.

 

[Methuselah]

Indeed, the trusty 06Z also points toward a more unsettled picture developing. But, as rainfall is what's most-needed, that's no bad thing?

    

[Alexis]

"Anyone looking for some rain? Many areas may reach the end of the month without seeing any rain, or 1mm or less."

Pretty much the only rain we've had this month has been snow!

[MATTWOLVES 3]

16 hours ago, Mr Frost said:

 

Indeed - some beefy showers starting to flag up for tomorrow (late morning through mid afternoon) 

As you say...risk around the Bournemouth area but more especially SW England, SW Wales and parts of Ireland - temperatures expected to hit 15/16/17C in parts of those regions.

UKV snapshots below:

Tomorrow 13:00 (zoom in on the areas listed above on both charts below)

 

15:00 - absolute humdinger of a shower just off St David’s Whitesands bay. (If my geography is correct!)

 

Could all completely vanish on the next run but interesting to see/discuss!

Also as you say...barely any rainfall on the latest ECM and GFS run!

Total accumulated rainfall from start to finish on the ECM - really pathetic amounts! (Not that I am complaining)

Same again for the GFS run!

 

All subject to change of course but absolutely nothing to get excited about if you are a big rain lover or in need of a decent amount! 

Most of us had enough rainfall during Winter. 

 

It can all sod off until September - unless it’s solely coming from convective weather/thunderstorms. 

All the best to you all!

David hope your doing OK mate..your forecasts and summaries are getting top notch...keep it up,also many others on here both new and old giving some great insight into our weather conditions..keep it up...makes for a very satisfying read

Shorter term folks it looks rather spiffing if you ask me...plenty of sunshine for tomorrow and into the weekend. I would imagine in favoured spots perhaps a 16 or 17c,and in light winds this should feel very pleasant! I have a feeling a few of you will be knocking the froff off a few cold ones

I think I will be taking the gym out on the Garden so it resembles Venice Beach..California

It does look to turn colder next week with temps dropping back a tad below average,but not much in the way of any rainfall! It's most definitely turning out to be a strange month for April! 

Enjoy folks.

[minus10]

44 minutes ago, Alexis said:

"Anyone looking for some rain? Many areas may reach the end of the month without seeing any rain, or 1mm or less."

Pretty much the only rain we've had this month has been snow!

Yes , I am, preferably at night or as thunderstorms with it warming up and no frosts. Yes i know , wishful thinking. However could happen if the end of the gfs6z run is to be believed ...

 

[Frosty.]

Dare we dream to hope for a bit of warmth from the south on the 6z?...and the good news is it’s only two and a half weeks away!...what could possibly go wrong!
 

[summer blizzard]

In the medium term it does look like our settled spell is slowly coming to an end but the models are struggling to decide where to take the pattern. We see by about day 6 that a slacker more cyclonic flow develops (GFS makes more of the low than the Euro) before another breif interlude of settled weather. After that and the hints are that blocking will be somewhere to the north and east and that it may produce a much more cyclonic, wet pattern for the UK (as has been the theme for a few runs) but equally if the low backs west it may produce a warmer one.

[Allseasons-Si]

Afternoon all

the latest 12z ICON is pure filth,....in winter

go away and come back next winter cos you are not welcome anymore,everyone blow this further

 

[Allseasons-Si]

The UKMO at 144 and the gfs at 168,....GO AWAY

I want to book some time off work for some fine warm weather,...when,...next Christmas