Model Output Discussion - Christmas and New Year

[alexisj9]

2 hours ago, Harsh Climate said:

Back edge snow anybody?  Maybe a suprise covering for some sunday morning. 

So not just the euro 4 now, interesting.

[Blessed Weather]

Can we stay on-topic and keep to model output discussion in here. There have been too many posts today that are moans and/or opinions with no substantiation and they are continually derailing the thread as people are responding instead of ignoring or reporting them. I'm afraid further such posts are now disappearing. Thank you.

[Tim Bland]

I hate to say it guys but the mean of the ensembles is now near average by the end. I mentioned yesterday that there were some milder runs appearing and these are increasing run on run. Not saying the mean is rights but a relaxation of the cold into Jan looks more likely today. Let’s hope IF it happens it’s just temporary before the effects of the SSW 

[ItNeverSnowsInWindsor]

Well the trend on the GEFs isn’t looking too clever! Hope it’s onto a wrong signal!

[SMU]

ECM finds the wedge that GFS was trying to find

as mentioned for 24-48 hours surface Easterly the form horse

[Scott Ingham]

Just now, Tim Bland said:

I hate to say it guys but the mean of the ensembles is now near average by the end. I mentioned yesterday that there were some milder runs appearing and these are increasing run on run. Not saying the mean is rights but a relaxation of the cold into Jan looks more likely today. Let’s hope IF it happens it’s just temporary before the effects of the SSW 

Its temporary before the effects of the mountain torque event which wont be getting modelled correctly yet so id ignore them milder members for now. Keep on eye on the ensembles between the 3rd and 6th of january.

Im confident like catacol is that we wont have to wait for the ssw for things to "wax" again

[Weathizard]

1 minute ago, Tim Bland said:

I hate to say it guys but the mean of the ensembles is now near average by the end. I mentioned yesterday that there were some milder runs appearing and these are increasing run on run. Not saying the mean is rights but a relaxation of the cold into Jan looks more likely today. Let’s hope IF it happens it’s just temporary before the effects of the SSW 

GFS mean/long term ensembles when there is that much scatter are about as useful as a chocolate teapot. 
 

I don’t trust the GFS op out of high res, let alone the ensemble suites.

[Tim Bland]

3 minutes ago, Nick F said:

The time frames before then early Monday morning show band of snow moving in across NW England, Wales and the West Country, even to lower levels, so not strictly true. Could be a nice snowy treat to wake up to in the west Monday morning.

The trend for the low is to dive SE from SW to central S England towards northern France on most models, even UKV is trending that way, so the SE perhaps staying high and dry, though ppn is shown to move in off the North Sea during the evening over EA and SE - so one worth watching.

Yes, your right. Here is the total snow depth by Tues morning. Fair to say most people won’t need their sledges though ....

[Man With Beard]

Almost a "genoa low" there from ECM at D7 - a common precursor to a snow event in January

[Weathizard]

Bitter

[Mike Poole]

ECM T192 compared with GEM and GFS //:

All agree on the heights breaking through into scandi, but of the 3 ECM is a bit dicey as it is a bit far south.  

[Scott Ingham]

3 minutes ago, prolongedSnowLover said:

Well the trend on the GEFs isn’t looking too clever! Hope it’s onto a wrong signal!

Look at the cluster approaching minus 10 though after the 3rd.

It will stay cold when the mountain torque is factored in.

Ignore atm.

AAM is notoriously under modelled until 5 days away

[Tim Bland]

1 minute ago, Weathizard said:

GFS mean/long term ensembles when there is that much scatter are about as useful as a chocolate teapot. 
 

I don’t trust the GFS op out of high res, let alone the ensemble suites.

I agree to an extent but for a long time (up until yesterday) the ensembles were flat lining and steadfast. What concerns me is not the few milder members but the rate they are increasing. I’ve saved today’s so let’s see where we are tomorrow. Fingers crossed it’s good news..

[Kasim Awan]

6 minutes ago, Steve Murr said:

ECM finds the wedge that GFS was trying to find

as mentioned for 24-48 hours surface Easterly the form horse

192h continues development of the wedge southwards sustaining the decent easterly, over quite the inversion

ice days?

This all an effect of more energy going south and thus less erosion / pressure of the high to the north, keeping britain under an E flow. This is the favoured evolution.

 

Edited December 26, 2020 by Kasim Awan

[Allseasons-Si]

This isn't bad is it...

ECM 192,...THAT'S DARN COLD!!!

[Scott Ingham]

Just now, Allseasons-si said:

This isn't bad is it...

ECM 192,...THAT'S DARN COLD!!!

Backs up the few members on gfs approaching -10. 

Best uppers chart this year in that timeframe

[ICE COLD]

In January an easterly that will feel cold . When was the last time that happened? 

[Mike Poole]

1 minute ago, Scott Ingham said:

Backs up the few members on gfs approaching -10. 

Best uppers chart this year in that timeframe

Personally, I’d prefer the high a little further north than that run at the expense of a few degrees on the uppers.

[Tim Bland]

3 minutes ago, Allseasons-si said:

This isn't bad is it...

ECM 192,...THAT'S DARN COLD!!!

How is it still showing rain

[KTtom]

4 minutes ago, Weathizard said:

Bitter

I think there are plenty who will rip your arms off if you offer tonights ecm, those who will have another sleepless night tonight wondering if they will be flooded in the morning or have a day repairing the wind damage...cold, light winds and mostly dry will do most for week 1 2021

[Harsh Climate]

1 minute ago, ICE COLD said:

In January an easterly that will feel cold . When was the last time that happened? 

 

I think that would definately feed some snow showers in off the north sea, that lovely dry powdery type two  

[Kent Clipper]

ECM 216...impressive !

[Nick F]

-40C in northern Finland at the moment ...

... it will probably warm up there somewhat by the time 12z EC brings a NEly flow all the way from northern Scandinavia at t+168 ... but the flow will still probably feel raw at the surface.

 

[Kasim Awan]

Full loop of the jet from a nw to n to s to now ne to sw 240 will liven this place up

[IDO]

Just now, Kasim Awan said:

192h continues development of the wedge southwards sustaining the decent easterly, over quite the inversion

ice days?

This all an effect of more energy going south and thus less erosion / pressure of the high to the north, keeping britain under an E flow

 

Looking at the gefs this is def the theme but the variations cover a wide variation, from cold to less cold. This has been signposted as a tricky evolution for a couple of days but it appears all models are moving towards the ridge toppling over the UK around d9-10.

d9 ecm: 

The ecm op seems to be the best case scenario, very clean and I suspect as usual when it spots a new evolution it will be in the coldest cluster!