Model Output Discussion - Christmas and New Year

[Mike Poole]

GFS pub run T162 glorious pattern, T850s on their way:

This is not far away guys, on the .... cusp!

 

[chionomaniac]

I am looking at charts atm and putting them in categories: excellent, very good or good. Long may that continue.

last year it was: average, poor or very poor.

so far tonight we are a mix between good and very good

[Eskimo]

Can't believe something like this is just 6 or so days away and not 16!

Edited December 24, 2020 by Eskimo

[sheikhy]

Aaah lovely!!snow on monday and then sticks around forever!!!!what an 18z!!looks more amplified as well!

[DogToffee]

The models certainly give the impression of locked-in cold of some sort. I'm retaining a fair chunk of pessimism so that 3 degrees Celcius and sleet when it comes doesn't feel like a huge let-down.

I'm hoping for cold weather round here, anything more is an unexpected bonus in this part of the world. However, a couple of weeks of near-constant snow like in 2009 wouldn't go amiss if it comes to that. And this time I'm not trying to have a kitchen installed at the same time. Happy Christmas all!

[Ben Sainsbury]

I do wonder actually whether the models the next few days are more volatile than normal, due to the reduction in the number of observations taken on Christmas day in particular. An outside shot why this GFS run regarding the intensity of the low has been different to the rest?

[Allseasons-Si]

Watching for that Siberian express starting to show up thanks to more height's into Greenland,you can see it starting to re-curve round.

[Griff]

I won't confuse by posting GFSP mid run (now they're simultaneous) only to say evolution looked similar early doors and I spotted a -16 heading south from the Faroe Islands

[DogToffee]

2 minutes ago, Ben Sainsbury said:

I do wonder actually whether the models the next few days are more volatile than normal, due to the reduction in the number of observations taken on Christmas day in particular. An outside shot why this GFS run regarding the intensity of the low has been different to the rest?

Well it can't be due to a lack of obs from Christmas Day - not until later tomorrow at least!

[Griff]

4 minutes ago, Ben Sainsbury said:

I do wonder actually whether the models the next few days are more volatile than normal, due to the reduction in the number of observations taken on Christmas day in particular. An outside shot why this GFS run regarding the intensity of the low has been different to the rest?

@Mike Poole psychic! 

[Geordiesnow]

10 minutes ago, Scott Ingham said:

Not as good a run for snow its pulls in warmer air on its north west flank and melts the laying snow in the midlands so transient event this

I think any snowfall at lower levels will be transient regardless, as soon as the PPN stops and clears during the day, the temperatures will rise(around 3 or 4C) and that is why I been going on about the poor uppers in this aspect aswell as the fact it will be marginal for some. 

The GFS tries to pull in something colder and we do remain in a cold trough, be interesting whether the ECM/UKMO will trend towards more heights again around 144 hours  in the morning. Decent run though regardless. 

 

 

 

[Mike Poole]

Think this pub run has realised it is the last chance in Tier 2, done the scotch egg, done the 10 pints of cider, and we get this:

[Eagle Eye]

Merry Christmas Everybody

[Kasim Awan]

Strong surface inversion developing on 18z now. Some places getting ice days. 

Edited December 24, 2020 by Kasim Awan

[Griff]

Just wow  

[Kasim Awan]

FYI both GFS 18Z & ICON 18Z develop a slider early 28th. As I rank both these models pretty highly for modelling fronts this is a potential evolution which deserves monitoring.

The pivot on the GFS is a thing of beauty. Usual marginality applies.

Edited December 24, 2020 by Kasim Awan

[chionomaniac]

In situations like this I don’t look at surface conditions even up to 850HPa except just for fun. Main thing is always the 500hPa long wave pattern. So another good run. I can undoubtedly see the potential of a true cold arctic release of cold in every run..so close, but bizarrely never close enough. I’m convinced though, that it is only a matter of time. 

[Scott Ingham]

6 minutes ago, Geordiesnow said:

I think any snowfall at lower levels will be transient regardless, as soon as the PPN stops and clears during the day, the temperatures will rise(around 3 or 4C) and that is why I been going on about the poor uppers in this aspect aswell as the fact it will be marginal for some. 

The GFS tries to pull in something colder and we do remain in a cold trough, be interesting whether the ECM/UKMO will trend towards more heights again around 144 hours  in the morning. Decent run though regardless. 

 

 

 

I wouldn't go as negative as that. Where any snowfall has fallen and with dew points associated with this low I dont think transient.

If this run turns out as modelled i might agree based on moderation off the North Sea

[MATTWOLVES 3]

15 minutes ago, sheikhy said:

Aaah lovely!!snow on monday and then sticks around forever!!!!what an 18z!!looks more amplified as well!

Rrrrr shaky..you really sleigh me...get it

Lets get some snow in across the UK.. first the Midlands,then let the SE have a dose...hell let's get a repeat of 2010 when the entire UK was white over on the satellite pictures...spread the love.

Edit...I think @Sheldon Cooper is gerrin overly excited,he's said Merry Xmas a thousand times this evening....keep of the sherry mate...santa will be with you soon..

Edited December 24, 2020 by MATTWOLVES

[Allseasons-Si]

This is absolutely stunning,with -8's knocking on the door from the east.

228

[feb1991blizzard]

7 minutes ago, chionomaniac said:

I am looking at charts atm and putting them in categories: excellent, very good or good. Long may that continue.

last year it was: average, poor or very poor.

so far tonight we are a mix between good and very good

Take it you mean regarding what might happen further down the line, else what category would you put these in?

[booferking]

Remember folks if we wake up in the morning with raging south westerlies on the charts it will be a lack of data 

[Kasim Awan]

1 minute ago, Scott Ingham said:

I wouldn't go as negative as that. Where any snowfall has fallen and with dew points associated with this low I dont think transient.

If this run turns out as modelled i might agree based on moderation off the North Sea

What Geordie says is true only if the snow accumulation is too weak to develop a surface inversion.

Snowfall greater than forecast from an evap cooling surprise with amply decent coverage is a different story. This will set up an inversion and ultimately drive temps down from initial Met forecasts. This requiring a slack flow which we kind of have.

It's a possibility if the Midlands does well early next week.

 

[tight isobar]

Output tonight gonna put my pal mr singh.. right outta business... just wow @18z gfs

[Kasim Awan]

Ok so the GFS tonight appears to be a modified version of the ECM op. As an upshot it pulls down the entire pattern due to a weaker jet which I feel is more realistic given the apparently strong GLOSEA signal for higher pressure.