Model output discussion - Closing in on Christmas

[markw2680]

So there was a few on here way ott the other day about very cold and snow etc getting carried away about stuff 7 days away like it was gospel, yes things still look pretty decent especially around day 10 as usual, it’s all slowly getting watered down for Christmas now so will probably end up been a chilly breeze. Might seem downbeat but this is why you can’t take any computer model as gospel, it’s probably going to get colder but nothing dramatic I fear

[nick sussex]

21 minutes ago, TSNWK said:

Ok. Positive thoughts from me for considering.. if the latest issue is modelling a shortwave upstream of the USA leading to poorer outcome for coldies from the Euros but still looking ok from GFS can we on this occasion place more trust in GFS a US model that logic would dictate might be focused and accurate for that beck of the woods.   

Big 06z coming . 

The ECM is normally more right than wrong with these shortwaves over the USA.

However in the last week it did drop the ball on one op run . That was the one where it weakened that after being the first to show that developing into a stronger feature .

At this point I’d be more concerned about the UKMO which isn’t good upstream by day 6 . 

It should be resolved by tonight given the timeframes involved .

[That ECM]

10 minutes ago, Valleyboy said:

You are correct.  Temperatures will drop off this week, but only to December averages, thereafter we have rising temperatures with rain and wind.  It’s easy to see if people remove their cold bias, and rose tinted specs  

This would suggest not. What have you based this on?

[Skullzrulerz]

7 minutes ago, markw2680 said:

So there was a few on here way ott the other day about very cold and snow etc getting carried away about stuff 7 days away like it was gospel, yes things still look pretty decent especially around day 10 as usual, it’s all slowly getting watered down for Christmas now so will probably end up been a chilly breeze. Might seem downbeat but this is why you can’t take any computer model as gospel, it’s probably going to get colder but nothing dramatic I fear

Indeed it was actually so busy here I have to get up to speed with reading over 10 pages! 

Unfortunately most are going to be taken bit and now face "reality" it's now either downgraded by the UKMO/ECM or is still pushed away into the depths of Fantasy Dreams 

We seen to be looking at 10 day plus to find anything cold at all nationwide like we did just 3 days ago 

 

[Vikos]

That’s GFS and it’s delayeritis retardus

[bluearmy]

Ec mean and spreads days 8/10 look flatter than last run. The clusters do show a fair sized percentage of members with the Atlantic ridge extended across nw Europe - it’s around 50/50 with the trough dropping close to our east or across U.K.   hence the flatter look to the mean 

[northwestsnow]

4 minutes ago, bluearmy said:

Ec mean and spreads days 8/10 look flatter than last run. The clusters do show a fair sized percentage of members with the Atlantic ridge extended across nw Europe - it’s around 50/50 with the trough dropping close to our east or across U.K.   hence the flatter look to the mean 

I saw that in the mean...

Certainly trending the wrong way this morning Euro models wise  , there's always energy where we don't want it ...

Let's see where we are later   

On a brighter note a seasonal Christmas Eve locally with temps close to zero by 6pm !!Lovely.

 

Edited December 19, 2020 by northwestsnow

[Ice Day]

Well a bit of a jolt to the system this morning with the UKMO and ECM not looking as good as yesterdays runs, however, the GFS was another cracker and the GEFS are showing a likelihood of a lengthy cold period.  Whether it's cold enough to deliver lowland snow is yet to be decided.  

The SSW is also ticking down nicely, with the peak of the warming around 30 December.  This leads to a very bedraggled and almost split PV in early January.

  

These are the ups and downs of the rollercoaster that is the hunt for cold and snow in the UK.  Patience as always is needed with this 'hobby', but as far as I'm concerned the medium and long-term prospects are looking fantastic.  If it's all getting on your nerves, give yourselves a day or two away from the models, it always works wonders when fatigue kicks in!

Eyes down for the 6z

[BLAST FROM THE PAST]

1 minute ago, bluearmy said:

Ec mean and spreads days 8/10 look flatter than last run. The clusters do show a fair sized percentage of members with the Atlantic ridge extended across nw Europe - it’s around 50/50 with the trough dropping close to our east or across U.K.   hence the flatter look to the mean 

There’s still detail to resolve , the detail that is really up in air is the longevity...... I anticipate that as we get into Jan a ‘westerly’ regime will gather itself again.

Last night’s ECM didn’t have a GHP either but had the extension to our NE with trough to our S/SE.  That scenario still looks very much still there as per what you see in a good cluster of the ECM members?

 

BFTP

[northwestsnow]

Just now, BLAST FROM THE PAST said:

There’s still detail to resolve , the detail that is really up in air is the longevity...... I anticipate that as we get into Jan a ‘westerly’ regime will gather itself again.

Last night’s ECM didn’t have a GHP either but had the extension to our NE with trough to our S/SE.  That scenario still looks very much still there as per what you see in a good cluster of the ECM members?

 

BFTP

We need GEFS to be right.

EC will get flatter and flatter unless it pulls some Atlantic amplification out of the bag , sharpish.

[Alexis]

You'd think the models had decided against dropping a chunk of vortex over us reading the comments this morning! I'm assuming the southern contingent is just seeing that the easterly component is a bit delayed?

The GFS just moves the low over us and doesn't know what to do next, so just spins it in situ. Which isn't unusual for the GFS.

UKMO looks fine to me.

[johnholmes]

Sat 19 December 500 mb anomaly update

No ec-gfs for the second day, so just Noaa.

Its 6-10 seems to confirm the 8-14 day chart from 24 hours ago. The meridional pattern is converted during the 6-10 day period into a flatter flow in the UK area. It is still meridional in the far west (Pacific area) and into the east of n America. The 8-14 is a bit of both if you look at it. Overall there is no deep cold predicted by the NOAA charts, with  a Christmas ridge giving most places a dry cold couple of days. Isolated sleet/snow showers close to windward coasts for the north perhaps.

Beyond that and EC synoptic suggests a strong generally westerly and rather cold windy day or two turning into a very cold more northerly flow. GFS has this by 27 th December. Do the anomaly charts support this? I am not sure if they do or not. Maybe another 48 hours will make it clearer?

Anyway the NOAA chart is below for folk to decide along with the usual mayhem over each chart as the daily synoptic charts role out.

Enjoy.

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

 

 

[BLAST FROM THE PAST]

1 minute ago, northwestsnow said:

We need GEFS to be right.

EC will get flatter and flatter unless it pulls some Atlantic amplification out of the bag , sharpish.

I doubt it imo the Atlantic ridging and trough dropping down like a stone is strongly favoured,  the true GHP scenario though.....that’s the GFS for you.  I can’t see that being right.

 

BFTP

[chris55]

27 minutes ago, Valleyboy said:

You are correct.  Temperatures will drop off this week, but only to December averages, thereafter we have rising temperatures with rain and wind.  It’s easy to see if people remove their cold bias, and rose tinted specs  

Going from the available data, looks to be below average temperatures and drier conditions? Rather than rising temps with wind and rain? Maybe you need your specs on?

[northwestsnow]

1 minute ago, BLAST FROM THE PAST said:

I doubt it imo the Atlantic ridging and trough dropping down like a stone is strongly favoured,  the true GHP scenario though.....that’s the GFS for you.  I can’t see that being right.

 

BFTP

We will take a rain in check in another day or so...

[booferking]

Caution required Amplification looks to have failed first time so i wouldn't be putting much trust on 9 day charts, 3 days ago we were looking at the prospect of a Northerly over Christmas with chance of white Christmas snow showers up north that's quickly evaporated with the collapse of the high a i recurrent theme in previous years.

Edited December 19, 2020 by booferking

[Chesil View]

Talk about looking a gift horse in the mouth I thought I'd stumbled into a meeting of Model moaners and whingers (not  so ) anonymous. With all the wishing away going on I thought the ECM,GFS and UKMO must have all switched to a Carribbean sourced southwesterly overnight.

For heaven's sake guys get a grip. If I had offered you any of the last four GFS runs as a cert at the beginning of December you'd have pulled my arm off for them.

[swfc]

1 minute ago, Broadmayne blizzard said:

Talk about looking a gift horse in the mouth I thought I'd stumbled into a meeting of Model moaners and whingers (not  so ) anonymous. With all the wishing away going on I thought the ECM,GFS and UKMO must have all switched to a Carribbean sourced southwesterly overnight.

For heaven's sake guys get a grip. If I had offered you any of the last four GFS runs as a cert at the beginning of December you'd have pulled my arm off for them.

Haha. Yes gfs is now the forums fav to some mm. Think the fluctuations will continue for a good while till the situation over the pond is clear. 

[TSNWK]

Huge 06z now rolling.. if it trend to the euros then we move to trying for 3rd time lucky towards the new year has to be the safe call. If it maintains the theme since 18z Thursday ( 6 runs ) and we make this one lucky 7 then the ball is back in the euros court this afternoon.

love it. The drama!

[BLAST FROM THE PAST]

Early in run and GFS moves towards ECM and Icon at t84 with Lp coming across southern UK.

00z GFS t90

 

06z GFS at t84

 

GFS 06z t96

 

ECM T96

 

ECM t120

indeed GFS is earlier

 

BFTP

Edited December 19, 2020 by BLAST FROM THE PAST

[Methuselah]

The only fly-in-the-ointment I see, is the WAA into Scandinavia... when (if) the initial northerly hits, T+850s (especially in the east) mighn't be all that cold... But, hey, that's a nitpick!

    

Something is clearly a !

[Scott Ingham]

3 hours ago, Kentspur said:

Another very good set of GEFS This for London. Can't remember the last time I saw so many snow % opportunities albeit low atm

Lots of members starting to hit the -10 mark now on the ensembles. The ecm is highly disappointing this morning but i still firmly believe the GFS is better at working out upstream amplification in the states so ill wait to see the 12z and tomorrows oz before worrying about the lack of amplification on the ecm and ukmo

[TSNWK]

4 minutes ago, BLAST FROM THE PAST said:

Early in run and GFS moves towards ECM and Icon at t84 with Lp coming across southern UK.

00z GFS t90

 

06z GFS at t84

 

GFS 06z t96

Yep.. big change with little low over us and at such short range.. worry that on aspect it’s going with the euros.. but currently nothing of note has changed upstream

[BLAST FROM THE PAST]

Maybe my bet is back on...

 

cold air digging south quickly...come on Norwich

BFTP

 

Edited December 19, 2020 by BLAST FROM THE PAST

[chris55]

GFS 6z now developing Wednesdays low as per Icon/EC...almost a channel low..looks slightly cut off as well...

Thoughts on the possibilities of the cold undercutting the ppn on the northern edge? 
Possible I think