GezM
  • GezM
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Friday, May 17, 2024 10:42:19 AM
I was trying to make sense of the divergent ECM and GFS models this morning. I ended up taking a look at the average charts. I know you have to treat these carefully because they don't truly represent the different possible outcomes but longer term on the 0z charts they are not hugely different. At 192 hrs, i.e. beginning of the bank holiday weekend, they both show high pressure to the south east of the UK and low pressure to the north west, over Iceland and Greenland.

By 240 hrs, the anticyclone moves away and another one builds near the Azores. Meanwhile pressure remains lower to the north/north east of the UK and we move into a north westerly airflow. Through this time pressure remains reasonably high over the UK itself.

This would imply warm and fairly dry, then perhaps a cold front coming through, followed by cooler and fairly dry.

Time will tell if this is how it pans out!



 
Living in St Albans, Herts (116m asl)
Working at Luton Airport, Beds (160m asl)
DEW
  • DEW
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Saturday, May 18, 2024 7:31:43 AM
WX temps - a very warm area around the S Baltic in week 1, as before, with cooler weather on either side. The difference this morning is that the warmer weather is now forecast to spread to all of western continental Europe in week 2. Britain stays near norm; N Scandinavia and W Russia cool. There is a very dry area over the Baltic in week 1, moving N-wards in week 2, followed by a wide band of rain starting in S Britain and C Europe week 1, to N Britain and N Europe week 2.

GFS Op - the synoptics start with HP over N Britain and LP over France but from Tue 21st the HP moves to Scandinavia while continental LP links to that near Iceland with a mostly shallow trough persisting across Britain. At first this trough mostly affects S Britain but with HP declining over Norway and rising over Germany, affecting the N from about Wed 29th (quite focused 995mb Donegal Sun 2nd)

ECM - unlike GFS, the trough does not persist with pressure rising over Britain resulting in a ridge lying along the Channel and shallow LP (1000mb) near or S of Iceland by Mon 27th.

GEFS - not unlike yesterday. In the S and SW, temps a little above then a little below norm then back again from Mon 27th with the usual variation then setting in; small amount of rain in most runs on many days. In Scotland, N and E England, dry until a major rain event Mon 27th, then again frequent small amounts of rain; temps declining slowly to norm by the same date and staying there.
War does not determine who is right, only who is left - Bertrand Russell

Chichester 12m asl
Saint Snow
Saturday, May 18, 2024 3:24:32 PM
Originally Posted by: Saint Snow 

Fair bit of divergence in the models this morning. The Atlantic remains active but there's a fair bit of high pressure around - I know this is stating the obvious, but it's the relative locations of each that causes the different outcomes.

GFS is by far the worst. It starts to build pressure from the SW before spinning some weird low formed over central Europe NW'wards over us, then brings in a trough to sit to our west, which first spawns a spin-off that moves over us, before the main trough joins it. Miserable throughout FI with high pressure kept to our NE and SW.

GEM not much better at first, as it also has that little Euro-low, this time moving NNW'wards to centre over the eastern part of England. But GEM then ridges the AH quite strongly over the southern UK at least as we move into FI

ECM the pick of the models for a dry evolution - although not very warm. Yes, the same Euro-low bothers us in the first half of next week, but ECM then migrates the AH first to the west of the UK, then centres it over northern Scotland before inflating it to cover all of the UK. It does then retrogress it a bit back northwards, but almost all the UK (barring the far South, perhaps) remains under the influence of the high with an easterly drift.

 




Meh.

Both ECM and GEM worse than yesterday, taking high pressure settling just to our north rather off the menu. GFS not as bad as it was but still not good.

Martin
Home: St Helens (26m asl) Work: Manchester (75m asl)
A TWO addict since 14/12/01
"How can wealth persuade poverty to use its political freedom to keep wealth in power? Here lies the whole art of Conservative politics."
Aneurin Bevan
DEW
  • DEW
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Sunday, May 19, 2024 7:04:25 AM
WX temps; week 1 still with the warm area in S Baltic, cooler either side; in week 2 this gets warmer still and milder air moves N over France to affect (esp W) Britain and only the far NE (i.e N Finland and N Russia) stay cold. Main area of Pptn is continental W Europe, Britain on the edge of this and looking wet for S England in week 2. Dry for Scandinavia and northern N Sea, and also Spain.

GFS Op - LP for continent, HP ridge on SW-NE axis near/over Scotland, the latter weakening at times as troughs cross it (Wed 22nd 1005mb moving N over N Sea, Sun 26th 1010mb moving SE near Cornwall, Mon 3rd more general LP from France affecting S England)

ECM - similar to GFS but ridge of HP less established (LP Wed 22nd moves across Scotland; that on Sun 26th hangs around the NW for a day or two before filling)

GEFS - in the S, temp near norm at first, becoming warmer around the beginning of June and rain from time to time in various ens members; in the N temp declining to norm by 23rd, rain event at that time and smaller amounts thereafter (but dry in far NE)
War does not determine who is right, only who is left - Bertrand Russell

Chichester 12m asl
Saint Snow
Sunday, May 19, 2024 6:51:44 PM
GFS continues to be a horror show.

It keeps the theme of spawning a very active low over Central Europe, then sending it northwards up the North Sea to give all the UK a soaking as we go through this week. The AH ridges quite far northwards - but to the west of the UK.

By the end of the week, it's planted a fat trough to the west of Ireland where it sits for days in end, spinning fronts over the UK from the SW.

It then inches the trough eastwards to sit over the UK through FI.

ECM and GEM both have the same initial evolution - but with stronger ridging of the AH. As the fat Atlantic trough moves in, they both split the ridged AH and place the northerly lobe to our NE - both then show the trough moving towards then over the UK (GEM has it less active in terms of fronts than the other two)

Not very encouraging over the next 10-14 days.

 

Martin
Home: St Helens (26m asl) Work: Manchester (75m asl)
A TWO addict since 14/12/01
"How can wealth persuade poverty to use its political freedom to keep wealth in power? Here lies the whole art of Conservative politics."
Aneurin Bevan
DEW
  • DEW
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Monday, May 20, 2024 7:04:57 AM
WX temps repeat yesterday's forecast: week 1 still with the warm area in S Baltic, cooler either side; in week 2 this gets warmer still and milder air moves N over France to affect  Britain and only far NE Europe (i.e N Finland and N Russia) stays cold. Main area of pptn is continental W Europe with Britain on the edge of this in week 1, but new for week 2 is a large and intense area of rain on the Atlantic affecting Ireland and NW Scotland. Dry for Scandinavia (but not now including northern N Sea) and also Spain.

GFS Op - pressure tends to be high over Scotland and low over France until Wed 29th but areas of LP develop and interrupt this pattern; 1005mb moving N up the E coast Wed 22nd; 990mb Rockall Sun 26th; 1015mb S England Tue 28th. After the 29th LP comes in from the Atlantic, at its deepest 990mb off SW Ireland, but persisting off W Britain to Wed 5th, while at the same time HP moves from N Norway to Germany.

ECM - not unlike GFS but the LP Wed 22nd is deeper and hangs around over Scotland for a couple of days before HP re-asserts itself. Of the other LPs, that on the 26th stays near Iceland and that on the 28th is delayed for a day, to the 29th.

GEFS - the spell of rain previously noted for the 22nd/23rd for the N is now more widespread, especially heavy in the E. Beyond that, temps are near norm, perhaps a little cooler briefly around Sat 25th, and, less certainly, somewhat warmer and sustained around Fri 31st; small amounts of rain in various runs at various times.

These reviews will be suspended until Wed 29th as I'm away - over to you, Saint.
War does not determine who is right, only who is left - Bertrand Russell

Chichester 12m asl
Saint Snow
Monday, May 20, 2024 8:07:26 AM
Originally Posted by: DEW 


These reviews will be suspended until Wed 29th as I'm away



Hope you have a nice break, David. 👍


Originally Posted by: DEW 


over to you, Saint.



🤣

I think not! My random posts are just ad hoc ramblings, lacking the deeper and more meteorological analysis you bring. They're as much to help me get a grasp of the output! 😊

 

Martin
Home: St Helens (26m asl) Work: Manchester (75m asl)
A TWO addict since 14/12/01
"How can wealth persuade poverty to use its political freedom to keep wealth in power? Here lies the whole art of Conservative politics."
Aneurin Bevan
Rob K
Monday, May 20, 2024 11:28:27 AM
I'm struggling to know what to expect at the moment. Initially this week was looking quite nice, then yesterday the BBC week ahead forecast looked fairly disastrous, with rain moving in by Thursday.

This morning I check the models and ARPEGE keeps most of the country dry apart from a few showers, with the band of rain mostly kept out in the North Sea to the east. 

GFS looks somewhat wetter this week but settles things down after the weekend.

ECM also not too bad but potentially a rather threatening little centre of low pressure hanging around over the south next week.

UKMO looks the worst of the bunch by a mile.
Yateley, NE Hampshire, 73m asl
"But who wants to be foretold the weather? It is bad enough when it comes, without our having the misery of knowing about it beforehand." — Jerome K. Jerome
GezM
  • GezM
  • Advanced Member
Monday, May 20, 2024 11:50:38 AM
I'm sure many of us will be planning outdoor activities this Bank Holiday weekend so that is my key focus. Unfortunately, looking at the GFS and ECM rainfall charts it is looking quite unsettled across the whole of the UK. Showery in general and with more prolonged rain for a while in western parts on Saturday. 

Not really looking like a wash out though and I daresay that some fortunate areas will dodge much of the rain. 
Living in St Albans, Herts (116m asl)
Working at Luton Airport, Beds (160m asl)
Jiries
Tuesday, May 21, 2024 7:41:03 AM
Originally Posted by: GezM 

I'm sure many of us will be planning outdoor activities this Bank Holiday weekend so that is my key focus. Unfortunately, looking at the GFS and ECM rainfall charts it is looking quite unsettled across the whole of the UK. Showery in general and with more prolonged rain for a while in western parts on Saturday. 

Not really looking like a wash out though and I daresay that some fortunate areas will dodge much of the rain. 



They are all so unreliable both models and forecasts so best to check out from the window and if good then plan it for the day, if bad forget it just stay at home instead.  We went out to Albury Hall last BH weekend because we saw nice azure blue skies and few clouds despite horrible wet BH weekend forecasts/models showing.  We now go out when we see good weather from the window nowcasts.  
Saint Snow
Tuesday, May 21, 2024 10:48:16 AM
All models continue to be firmed-up on the evolution of a low from Central Europe moving NNW'wards up the North Sea/East Coast of the UK through this week.

After that, some subtle changes to how things develop (from what was showing yesterday). There's still the fat Atlantic trough moving in - but each of GFS, ECM and GEM show higher pressure to our SW and NE extending more influence over the UK, so the dire period of weather that GFS especially had been forecasting is reined in somewhat - indeed, ECM and GEM particularly have some nice charts with high pressure dominant over the UK at times.

None are showing a prolonged dry spell but, after a soaking for many over the coming few days, it's looking like a mix of a settled couple of days followed by a day or two of crap, then settled again, then repeat.

 

Martin
Home: St Helens (26m asl) Work: Manchester (75m asl)
A TWO addict since 14/12/01
"How can wealth persuade poverty to use its political freedom to keep wealth in power? Here lies the whole art of Conservative politics."
Aneurin Bevan
GezM
  • GezM
  • Advanced Member
Tuesday, May 21, 2024 11:58:07 AM
For heat lovers, I noticed that the London GEFS at 0z is showing the first 30C temperatures of the year (so I believe) occurring in early June. It is an outlier at the moment so I'm not expecting it to happen.  
Living in St Albans, Herts (116m asl)
Working at Luton Airport, Beds (160m asl)
Brian Gaze
Tuesday, May 21, 2024 12:07:58 PM
Originally Posted by: GezM 

For heat lovers, I noticed that the London GEFS at 0z is showing the first 30C temperatures of the year (so I believe) occurring in early June. It is an outlier at the moment so I'm not expecting it to happen.  



We've had about 15 GEFS runs so far showing temperatures in the London area ~30C. 

https://www.theweatheroutlook.com/tracker/tmp2m?lat=51.5&lon=0&location=London&frange=a 

This morning's went up to ~33C.

UserPostedImage
Brian Gaze
Berkhamsted
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Jiries
Tuesday, May 21, 2024 1:07:59 PM
Originally Posted by: Brian Gaze 

We've had about 15 GEFS runs so far showing temperatures in the London area ~30C. 

https://www.theweatheroutlook.com/tracker/tmp2m?lat=51.5&lon=0&location=London&frange=a 

This morning's went up to ~33C.

UserPostedImage


We very well overdue for that so hope sooner than later to see those lovely warm to hot temps.  
Zubzero
Tuesday, May 21, 2024 2:31:50 PM
Originally Posted by: Brian Gaze 

We've had about 15 GEFS runs so far showing temperatures in the London area ~30C. 

https://www.theweatheroutlook.com/tracker/tmp2m?lat=51.5&lon=0&location=London&frange=a 

This morning's went up to ~33C.

UserPostedImage



https://www.meteociel.fr/modeles/gfs/royaume-uni/temperatures-2m-hd/252h.htm 

What a difference 6 hours make. No doubt be completely different in another few hours.
cultman1
Tuesday, May 21, 2024 6:56:30 PM
I think this change of fortune for heat lovers may be wishful thinking. The Met Office projections into June don't seem to share the confidence of  GEFS but who knows? 
Matty H
Wednesday, May 22, 2024 6:47:28 AM
Next weeks MetO longer ranger text forecast is painted as largely settled across large areas, particularly the south west. 

Not according to the operational GFS and ECM it isn’t. 
GezM
  • GezM
  • Advanced Member
Wednesday, May 22, 2024 8:13:55 AM
Originally Posted by: Matty H 

Next weeks MetO longer ranger text forecast is painted as largely settled across large areas, particularly the south west. 

Not according to the operational GFS and ECM it isn’t. 



Indeed. GFS paints a particularly poor picture with no sign of anything more settled coming our way. Pretty much the whole of the rest of Europe is looking warm to hot , even Scandinavia, while the UK and Northern France are cool and wetter.  
Living in St Albans, Herts (116m asl)
Working at Luton Airport, Beds (160m asl)
Jiries
Wednesday, May 22, 2024 12:00:44 PM
Originally Posted by: Matty H 

Next weeks MetO longer ranger text forecast is painted as largely settled across large areas, particularly the south west. 

Not according to the operational GFS and ECM it isn’t. 



Let hope they are completely right and we well over due for settled weather and overdue for a warm to hot spell as well as none was found over Spring season.
Matty H
Wednesday, May 22, 2024 6:46:42 PM
ECM op is closer to the text forecast for next week than the GFS op which continues to be absolute litter

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