model discussion Model output discussion 11th July onwards

[Frosty.]

The longer term ECMWF 0z ensemble mean indicates polar maritime / perhaps even arctic maritime once the main trough transfers further to the NE?…..you just have to follow the isobars back to their original source to see that (albeit modified by the Atlantic) BUT…it certainly looks like an increasingly unsettled outlook beyond this weeks relatively quiet / benign conditions!  

 

Edited October 12, 2021 by jon snow

[carinthian]

38 minutes ago, Kentspur said:

The trouble is all that early relatively cold air that Eastern Europe has built up is now going to be blasted away if this occurs its not a good sign. +16 850HPA in late October is tragic for the Baltics/Poland etc. Goodbye cold pool. Tell me ECM day 10 was an outlier?

 Yes , that would be sad.  We have our first snowflakes of the season down in the village this morning. Unfortunately the trend in the models indicating a warm up over Europe with a elongated trough development to the West of the British Isles. Never a good sign for those of us looking for something colder. The promise shown in the models a week of a a ago  of a possible colder continent flow melts away.

C

Edited October 12, 2021 by carinthian

[carinthian]

Latest GFS op run confirms my worst fears from my propective. Deep trough out to the west of British Isles with cold sinking into Mid- North Atlantic and warmth pumped into Central Europe. Lets hope in the longer term the trough migrates much further eastwards for us many on the look out coldies.

 C

[johnholmes]

The latest 500 mb anomaly outputs with comments on how useful or not and a comment on the hype already developing in this thread for winter! I don't suppose I will be popular but as with any of us I am entitled to make comment using the models.

Tuesday 12 October

Ec=overall is trough dominated for  uk, at 10-20W with ridging over Greenland, then trough-ridge-trough for n America and far w trough quite marked off west coast, flattish over pacific

Noaa=it has dropped  any ridging in uk area, this has happened slowly over last 2-3 days. It does seem to be ‘following’ ec rather than the more usual other way round. It was not very good in predicting the ridging we have had when ec was. This makes using Noaa less definite at the moment. Not sure if this is a brief decrease in confidence in it or something more lasting?

Anyway much as ec in uk area, some indication of very slt +ve over Iberia, ridging over Greenland much less marked compared to ec, it shows just w of Greenland with marked +ve anomaly. (This is probably partly/largely due to it being where the main vortex usually is). Further west similar to ec

 

So it looks like a more changeable period is developing for the uk 6-10 and 8-14 probably similar, so maybe 2 weeks, but how unsettled not clear just yet, although the 500 flow on both (s of w) is quite strong which suggests fairly unsettled for many.

As to the comments using synoptic chart s for beyond T+240 and suggestions of these effects for an early winter. I do despair of some folk year on year trying to make the models shows what most want, cold and snow.

ECMWF/GFS DAY 8-10 MEAN 500MB HEIGHT COMPARISON

WWW.METEO.PSU.EDU

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

 

 

[Downburst]

The latest ECM 46 day 500 Anomaly looking ahead as we move in Autumn proper. Signs of higher than normal pressure over NE North America is the main theme and of course NE Pacific Trough. Through over us perhaps to end the month.

Skipping into the unreliable and next month, it is noted that this ties in with the Long Range ECM and Met Office seasonal forecast at this time I believe. 

And Surface for that period is showing a signal for higher pressure NW Atlantic and signs also of drier than average there. I believe we keep seeing this signal for that area. Not certain at all if this will impact us, a west based +NAO?

[johnholmes]

Well the second line of rain/showers on the radar has just gone through here, briefly close on very heavy I thought, checked the Davis and it suggests 20.8 mm/hr at 1254, total 2.4 mm

[Frosty.]

Looking at the GEFS 6z there’s certainly potential for a cold shot next week according to the mean plus this small sample from the perturbations…either polar or possibly arctic maritime?…for sure, it becomes very unsettled for a time next week before easing to more of a north-south or northwest-southeast split longer term?  

 

[Ali1977]

Next Wed still looking pretty chilly, maybe down to single figure maximums in Scotland. Nothing unusual at all though.

If day 8 was the furthest you could see on the GFS you’d think a decent cold shot was on the way looking at this chart with heights pumping into Greenland , but sadly it flattens out and becomes a standard damp autumn type set up!! 

 

Day 10 here.

 

If Siberian and particularly Scandinavian snow cover helps potential blocking scenarios further into winter , we are doing pretty well here to start the 3rd week of Oct. I know it’s only 1 piece of a large puzzle but along with an E QBO and coming out of a solar minimum it could help.  

Edited October 12, 2021 by Ali1977

[Ali1977]

Now what is more noteworthy is the mean for next week, this is a pretty potent spell with snow on northern hills (mainly Scottish) . There must be some good ones in the Ens.

Watch this space, this isn’t deep FI.

 

-12/14c uppers into Shetland mid October is pretty unusual , surely. It’s a cherry picked ens member of course!! 

Edited October 12, 2021 by Ali1977

[Frosty.]

The GEM 12z again trends very unsettled next week and as with the 0z is going for a colder polar maritime flow later with a chance of wintry precipitation across some northern hills & mountains?! …ok I realise that anything cold as such in October wouldn’t usually amount to a hill of beans but at least it shows winter is coming!!!  

Edited October 12, 2021 by jon snow

[Cambrian]

Today’s 12z UKMO charts show a firming up of the trough development at 120h compared with yesterday’s 12z for the same time, with extension from northern Scandinavia, through a secondary low through The Faroe Islands, continuing southwest out to meet the mid-Atlantic low. Yesterday’s chart had the pressure about 12mb higher over the Faroe Islands. 
Today / Yesterday 

 

 

Likewise, today’s 144h chart has upgraded the development compared to yesterday at 168h, with the pressure down to 980mb for the Atlantic low (995mb yesterday). 

 

 

It all fits well with the 12z GFS op for 144h. and with the general direction of the 0z ECM op too, so a broad consensus at that stage for an evolution leading to a very good chance of a colder spell next week.
GFS / ECM
 
 

There’s less cold air amassing to the east of Greenland on the GFS compared with the ECM, which makes a difference with the subsequent projections for the extension of the trough in the following few days, but all three models look to be setting up well for a more unsettled chillier spell.

[Ali1977]

Aberdeen’s 850 ens for next week are really pretty cold, even for the winter months.

A few crazy warm ones are really changing the mean but there are plenty around -5c to -7c , so surface temps pretty low there.

 

Edited October 12, 2021 by Ali1977

[Frosty.]

4 minutes ago, Ali1977 said:

Aberdeen’s 850 ens for next week are really pretty cold, even for the winter months.

A few crazy warm ones are really changing the mean but there are plenty around -5c to -7c , so surface temps pretty low there.

 

Yes indeed, just looked through the GEFS 12z and there are some stunning cold members in there with snow down to sea level on some of them..some real arctic shots affecting Scotland in particular in just over a weeks time!  

[carinthian]

7 hours ago, carinthian said:

Latest GFS op run confirms my worst fears from my propective. Deep trough out to the west of British Isles with cold sinking into Mid- North Atlantic and warmth pumped into Central Europe. Lets hope in the longer term the trough migrates much further eastwards for us many on the look out coldies.

 C

UKMO extended throws up some standard Mid - Seasonal conditions with mild fodder for most and a bit more unsettled for the British Isles. The question going forward is will the Atlantic trough transfer far enough eastwards to tap into some much colder polar airmass ? or will pressure rise again back again into the UK ?  Based on the general run of conditions attained for much of this year, the latter must be form horse.

[Ali1977]

ECM following the GFS with a colder period next week. 
 

I can’t seem to upload the images sorry

Edited October 12, 2021 by Ali1977

[Cambrian]

 

ECMWF still going for a brief colder spell on the 12z operational run, not as sustained as on the previous runs, the trough squeezed out by a toppler. It will be interesting to see the mean later.

168h / 192h with an extended trough and a mid-Atlantic high reaching up to Greenland. 

 

It topples down towards us by 216h….

 

bringing us back into a pleasant looking high with a mild southwesterly airflow by 240h. That could be a very decent day on the 22nd!

[Frosty.]

There’s a stronger suggestion from tonight’s ECMWF 12z ensemble mean longer term for a cold plunge later next week than there was on the 0z mean!…although next week is generally all about unsettled wet and windy, there could be a few wintry surprises too?!   

Edited October 12, 2021 by jon snow

[Don]

4 hours ago, Ali1977 said:

If Siberian and particularly Scandinavian snow cover helps potential blocking scenarios further into winter , we are doing pretty well here to start the 3rd week of Oct. I know it’s only 1 piece of a large puzzle but along with an E QBO and coming out of a solar minimum it could help.  

My only concern is will that snow cover last?

[kumquat]

There comes a point where Autumn has to start. I think it's here:

GFS:

ECM:

[mb018538]

Potentially looking very mild to go along with the unsettled weather next week:







22c showing in East Anglia on Wednesday afternoon on the ECM run:

 

[sheikhy]

Not too bad ecm this morning!!western aread take the brunt of any rainfaill throughout next week apart from monday when a heavier band if rain pushes through very quickly across the uk!!defo more unsettled but eastern and central areas escaping the worst of the rain on this ecm 00z run?!!!

[Frosty.]

There’s something about the ECM and day 10 I usually like, and this is no exception, turning arctic in the far north!   

[mb018538]

15 minutes ago, sheikhy said:

Not too bad ecm this morning!!western aread take the brunt of any rainfaill throughout next week apart from monday when a heavier band if rain pushes through very quickly across the uk!!defo more unsettled but eastern and central areas escaping the worst of the rain on this ecm 00z run?!!!

You'd be right there @sheikhy. Totals as high as 100mm over western hills, and as low as 9mm over East Anglia. East nearly always drier in these set ups of course.

[Methuselah]

51 minutes ago, mb018538 said:

Potentially looking very mild to go along with the unsettled weather next week:







22c showing in East Anglia on Wednesday afternoon on the ECM run:

 

Ah, my second favourite weather; after snowy of course! I can live with these temps:

   

Edited October 13, 2021 by Ed Stone

[Frosty.]

The longer term ECMWF 0z ensemble mean still suggests a colder flow from the NW / N later next week for a time as the trough pushes away across Scandinavia and there’s a hint of mid Atlantic ridging?, indeed beyond day 10 could see an improvement for the u k according to this unless another Atlantic low pops up to fill the void?…anyway to me it’s interesting as we nudge deeper into autumn, now mid autumn already!