Model output discussion - deep cold inbound?

[Day_9]

18 minutes ago, Snowman31 said:

Icon better and further south.. 

some ridiculous slider potential out to our west on that chart

[johnholmes]

Wednesday 3 rd ECMWF and 500 mb anomaly charts

Looking at the 2 ECMWF outputs first, the sequence from Tue 9 to Sat 13th is one of increasing 500 mb heights from the w/sw and 850 mb temperatures also increasing, from -5/-10 to 0 to -5(this only in the far n). The upper trough out of Scandinavia lying wsw over the uk changes to a flow over the uk from the wnw into a shallow trough over Europe.

On the colour 850 charts that run from today out to Sat 13 th and, as the above it shows a lowering of temperatures as the easterly flow at 850 mb develops. But from this weekend it already increases the 850 temperatures to T+72 before lowering them to put most of the country by T+192 (Thursday) in the range -5 to -10. It then warms out the 850’s slightly to nearer -5 for most, still with an 850 flow from se but with indications of a more w’ly and less cold 850 pushing in from the atlantic.

There are a whole variety of charts available from this site for anyone interested

Now to the 500 anomaly charts

Ec-gfs and at 0932 they are not yet available on the site I use, so to Noaa. The very large +ve area (> 390 DM) is kept and the actual contour high is shifted to closer to the +ve height anomaly. Beneath it is the main vortex, displaced and lying w-e with a slack just s of w flow into the uk. In the extreme west the trough-ridge pattern is kept along with the two closed upper lows.

The overall flow seems to me not to suggest deep cold is going to be other than a few days rather than any prolonged period, nor does the 8-14 seem to suggest any different.

To sum up, a colder spell returning to all the uk over the weekend, probably lasting to later next week before somewhat less cold air returns from the Atlantic. Beyond that I do not go, nor do these charts (anomaly) give any real guidance on snow potential. The 850’s in the first paragraph, if used with any skew-t outputs over a similar range will give some indication.

These are ECMWF 500 and surface charts on this link

http://www2.wetter3.de/Fax/00_ECMWF_ENS_p0_500hPa+144_240.gif

and another link into ECMWF charts

Numerical Weather Prediction Maps | MeteoCentre.com

METEOCENTRE.COM

 

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

 

 

[chris55]

Just caught up on the 00z runs.

Looking excellent. 

UKMO 144 my chart of the day so far.

[kold weather]

Very close call for the south-east again on the 06z, that Iberian low may just about be far enough east but right on the cusp there...

Otherwise looking solid for the rest of the country again.

 

Edited February 3, 2021 by kold weather

[sheikhy]

Up to 90 hours and looking fantastic!the most consistent its been for sometime lol!!

[Notty]

Eastern counties could be happy next Sunday

Edited February 3, 2021 by Notty
Typo

[That ECM]

Stronger heights to the north. 

[chris55]

6z at 96

It actually clears the low south a little quicker initially, cold air feeding in Sunday.

 

Edited February 3, 2021 by chris55

[sheikhy]

Omg its looks a beautyyyyyy at 102 hours

[kold weather]

Literally the 06z is far NW as the low can go at 90hrs if we want the whole country involved.

Any further NW and the SE gets rain on Sunday. However as it stands, decent snowfall as per the UKV for the SE section of the country.

Still, looks like we are all ok on the 06z.

[Radiating Dendrite]

3 minutes ago, kold weather said:

Very close call for the south-east again on the 06z, that Iberian low may just about be far enough east but right on the cusp there...

Otherwise looking solid for the rest of the country again.

 

I think we will just be on the right side.

Given these lows always seem to adjust southwards, even a 25 / 50 mile adjustment will be enough given how close this is now.

If we do not get at least some snow from such a setup, then frankly we may as well just all give up in the South!

[topo]

Looks like a historic snowstorm for Northern Germany and Netherlands...

[throwoff]

It’s getting closer, not long ago we were +240 chart hunting now it’s +100

This couldn’t actually happen.

 

[Malarky]

Deep cold pool slightly closer to us on this run, stronger heights to the north, and deeper low in the atlantic?

[Lampostwatcher]

Gfs6z so far 

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[Battleground Snow]

1 minute ago, That ECM said:

Stronger heights to the north. 

Good Spot, was just marking that up, I think this has to be a good thing in terms of longevity for the cold spell. All models are increasing it from run to run

[Ice Day]

So I would say that at 114 it's pretty wonderful nationwide and even a cheeky little upgrade for the southeast.

   

[TSNWK]

3 minutes ago, kold weather said:

Literally the 06z is far NW as the low can go at 90hrs if we want the whole country involved.

Any further NW and the SE gets rain on Sunday. However as it stands, decent snowfall as per the UKV for the SE section of the country.

Still, looks like we are all ok on the 06z.

Hello.. what did the low do between 90 on 06z and 96 on 00z. Did it trend closer to south east or further.  Tia

[FENDER.]

Wonderful charts, lets hope everyone gets A GOOD DUMPING with  a nation wide event

[Purga]

Lovely to see pretty much all of the UK under 0C mean 2M temps week 2

Very good ECM ENS for extended cold

ICON 06z run an upgrade if anything on the 0z up to 120h

And 06z less marginal for the SE on Sunday

0z                                                                  06z

 

[kold weather]

2 minutes ago, Radiating Dendrite said:

I think we will just be on the right side.

Given these lows always seem to adjust southwards, even a 25 / 50 mile adjustment will be enough given how close this is now.

If we do not get at least some snow from such a setup, then frankly we may as well just all give up in the South!

I think on balance thats probably right, though nearly all the lows recently have come in north of where expected, so maybe something just to keep note of.

Lots of snowfall for the east on this run, I'm still fairly onfident we will see somewhat widespread 30-50cms in the NE.

Further south, looks better for the SE than yesterday. Further west though the cold air still struggles to move in due a very weak ridging wedge between the two lows which pretty much prevents the colder air digging down too far to the SW until either one of the lows moves aside, which should happen somepoint Tuesday.

[frosty ground]

The 06z Run is colder than the 0z run

[sheikhy]

We are on the verge of booming set of 12z runs!!it can actually still upgrade from here by the way!!

[chris55]

Atlantic a bit further south at 144 on the 06z compared to the 00z, a cleaner undercut meaning cold air a little further west and south.

 

[Catacol]

2 hours ago, DCee said:

But the ECM has moved towards the GFS and the GFS has stuck with the initial cold for midlands north. So I'm right in my initial analysis thankyou.

Your tenacity is impressive - but your post a few pages back about a trend away from an easterly and mild SW taking over makes it a difficult position to hold. It also runs counter to the broad shape of ECM monthly ensemble means for next week and the Met monthly, produced using Glosea. And the idea that ECM has trended towards GFS is a bit dubious - I'm not seeing anything in this 144h prediction for the start of week that suggests a trend towards a stalling low and resultant mild SW

What would be true to say is that the most recent anomaly predictor does see a slight increase in pressure over central Europe

and it would be possible to argue that the trough could struggle to clear through - but the angle of that negative anomaly over Scandy makes it an outside bet. More likely we get low pressure arcing in along the south and simply slowing down upon exit - and in truth that means more snowy nirvana for lucky spots.

I think next week is going to be a good week for those who like white (though that isn't a promise necessarily of a nationwide event) and mild south westerlies are increasingly unlikely.

Moving beyond next week the ECM anomalies are all over the place. No consistency. MetO text guide based on Glosea for once though is our friend.

 

Edited February 3, 2021 by Catacol