Model Output Discussions 06z 04/11/16

[Ali1977]

Great ENS mean at 240, especially up near Greenland.

Low pressure back over the Med , but don't think a Scandi high is looking likely on this run.

 

Edited November 21, 2016 by Ali1977

[Frosty.]

Another upgrade from the Ecm 12z ensemble mean, the op wasn't too shabby either!

The building blocks to upstream deeper cold are being put in place!

[SMU]

As mentioned Debilt ENS significantly colder with the day 8-10 Op @ freezing @ the control around -2 Maxima day 10...

[Man With Beard]

1 hour ago, Frosty. said:

Much better looking Ecm 12z compared to last night, especially the day 10 chart, it ticks the right boxes.

This is the dream ... the easterly cold pool dot reaching the UK. Has it really been 25 years since this successfully happened (Feb 09 was sort of one iirc)? It never usually gets past about T144.

Well some of us sniffed a Scandi High this morning - far from a done deal but amazing how tiny alignment changes with heights to the east can transform the wider pattern.

[feb1991blizzard]

2 minutes ago, Steve Murr said:

As mentioned Debilt ENS significantly colder with the day 8-10 Op @ freezing @ the control around -2 Maxima day 10...

Key now Steve is that the ext don't follow some recent GEFS (and suspect ECM eps) runs where the pattern flattens on the mean at the end and the jet looks t start limbering up, if the extended can stay like that or preferably lower even more then we could be in business.

Edited November 21, 2016 by feb1991blizzard

[Ali1977]

5 minutes ago, Steve Murr said:

As mentioned Debilt ENS significantly colder with the day 8-10 Op @ freezing @ the control around -2 Maxima day 10...

This is a really big update - fingers crossed it holds and shows the same this time tomorrow, or colder obviously 

The mean seems to shoot up at day 10 but the 2 main models Op/Ctl are singing off the same song sheet.

Edited November 21, 2016 by Ali1977

[bluearmy]

6 minutes ago, Ali1977 said:

This is a really big update - fingers crossed it holds and shows the same this time tomorrow, or colder obviously 

The mean seems to shoot up at day 10 but the 2 main models Op/Ctl are singing off the same song sheet.

Maybe temps but not pattern, especially  so to our west where a toppling ridge delivers a very cold few days before settling into a euro high.

the eps generally flatter in the Atlantic later on which turns the mean flow wsw and as weakish high anomoly appears in the med, its unsatisfactory for coldies - unsettled looking under a low anomoly stretching sw/ne across us and mild in the south, cool in the north. 

[london-snow]

43 minutes ago, ANYWEATHER said:

 A Post ,Short and Sweet, what a Treat!!!

Don't get ahead of yourself and lead the garden path party. Many more runs and hurdles to overcome..

Edited November 21, 2016 by london-snow

[weatherguy]

At this time of the year you could still get pretty hefty convection off relatively high upper temps, and providing we have a continental "dry" flow you don't need uppers below -1c or so for snow to fall. 

That isn't to say that such details are particularly relevant at this timeframe however! 

Edited November 21, 2016 by weatherguy

[bluearmy]

Incidentally, not sure what affect it has in Steve's theory but assuming that the models can't have the next week too far wrong, it's increasingly looking impossible for November to return a sub -1 AO. Probably between -0.5 -and -0.8

 

[Ali1977]

8 minutes ago, bluearmy said:

Maybe temps but not pattern, especially  so to our west where a toppling ridge delivers a very cold few days before settling into a euro high.

the eps generally flatter in the Atlantic later on which turns the mean flow wsw and as weakish high anomoly appears in the med, its unsatisfactory for coldies - unsettled looking under a low anomoly stretching sw/ne across us and mild in the south, cool in the north. 

That doesn't really sound like this picture, just shows how means beyond a few days are really skewed !!

[feb1991blizzard]

3 minutes ago, Ali1977 said:

That doesn't really sound like this picture, just shows how means beyond a few days are really skewed !!

Hes on about the end of the EPS though, the GEFS mean looks a lot better at 240 but flattens out before 384. EPS go up to 360 remember.

[Ali1977]

1 minute ago, feb1991blizzard said:

Hes on about the end of the EPS though, the GEFS mean looks a lot better at 240 but flattens out before 384. EPS go up to 360 remember.

Ahhh, fair one....That's FI though, so hopefully wrong!! 

[knocker]

The anomalies this evening are all cooking with gas.

Very good conformity in the 5-10 range Troughs in the SW United States and the eastern seaboard with the Azores HP ridging NW into the strong Canadian positive anomaly. A weak trough Iceland  running south towards our old friend the cut off low over Iberia and the HP centred over Denmark as it has been forced east. A rough guide to the surface analysis possibly would be a dry easterly component veering south west as more unsettled weather moves in from the Atlantic. Temps around average but fair bit of latitudinal and diurnal variability

Moving into the extended period they are all more or less still on the same page. Upstream not much has changed and the one difference is that NOAA and the GEFS to keep a little ridging mid Atlantic whereas the EPS is quite flat although at the end of the day essentially a westerly upper flow. Downstream things have simplified a touch with a general negative anomaly and some suggestion of a trough Temps around average.

 

[winterof79]

An Easterly component with frontal snow a possibility from any advance from the West.

GEFS looking better

Edited November 21, 2016 by winterof79

[feb1991blizzard]

2 minutes ago, Ali1977 said:

Ahhh, fair one....That's FI though, so hopefully wrong!! 

They look horrendous at the end in graph form.

Although bizarrely, the point at which the temps get sig above freezing is the point where a few snow spikes show!!

[Cheshire Freeze]

2 minutes ago, feb1991blizzard said:

They look horrendous at the end in graph form.

Although bizarrely, the point at which the temps get sig above freezing is the point where a few snow spikes show!!

Ties in well with the period that I think Ian mentioned the Metoffice were seeing a potentially more mobile spell??

[northwestsnow]

Well fwiw i feel the ecm ens have shifted in favour this evening so for now im not going to concern myself with ext ens when there is so much volatilty !

 

Edited November 21, 2016 by northwestsnow

[ArHu3]

10 minutes ago, feb1991blizzard said:

They look horrendous at the end in graph form.

Although bizarrely, the point at which the temps get sig above freezing is the point where a few snow spikes show!!

someone here must be able to explain that, but here often snow falls at the end of a cold spell, so much that I associate them so closely together I couldn't believe what happened in 12-13 (snow and cold that kept on coming)  (could it be the wind changing from east to north to west which bring us snow...)

Edited November 21, 2016 by ArHu3

[feb1991blizzard]

2 minutes ago, CreweCold said:

Ties in well with the period that I think Ian mentioned the Metoffice were seeing a potentially more mobile spell??

possibly, lets hope that a) the general prognosis for the next month hasn't changed too much plus b) that is re-affirmed by tonight's dose of the 46.  Ive got my doubts now though I have to  admit.

[nick sussex]

This evenings outputs are the first to drop that low south from Greenland and disrupt it to the west of the UK so it could be that the lower resolution ensembles are slow to pick up on this.

We often see this when the ops take a different route, we should know in the morning whether this is one dodgy op run followed by a backtrack or whether they're on to something. Given a choice I'd rather the ECM trend verified, that at least has a chance of delivering some cold conditions within T240hrs and a chance of some snow. I'd like to see a full swing to a Scandi high and take my chances with that rather than hoping a lot more has to go right down the line.

 

[feb1991blizzard]

1 minute ago, ArHu3 said:

someone here must be able to explain that, but here often snow falls at the end of a cold spell, so much that I associate them so closely together I couldn't believe what happened in 12-13 (snow and cold that kept on coming)

Its probably as the atlantic blasts back through after a period of blocking, because your further East, you probably are on the right side of the battleground more often than us, we probably could be getting rain as your getting snow.

[Seasonality]

Proper cold in Central Europe on the 12z ecm. Deep cold 850s from 168h onwards leading to a maximum temperature of -4 forecast for Warsaw on yr.no Lovely cold and not even December! 

Edited November 21, 2016 by Seasonality

[sorepaw1]

 

In the shorter term this Sunday night coming looks cold with early frost forming -6.oC for central and southern England possibly colder further north in the Glen's and rural areas of Northern England 

It will help to get the soil temps down.

Edited November 21, 2016 by sorepaw1
To add further information

[ArHu3]

16 minutes ago, Seasonality said:

Proper cold in Central Europe on the 12z ecm. Deep cold 850s from 168h onwards leading to a maximum temperature of -4 forecast for Warsaw on yr.no Lovely cold and not even December! 

I wonder why the Netherlands is always excluded, everyone gets cold but there is always a warm spike above the Netherlands exclusively (seriously this happens a lot in the models in the last third of runs, they disappear around +120h)

Edited November 21, 2016 by ArHu3