Winter Model Discussion 12Z 09/01/13> The hunt for cold ?

[Jason H]

Alex Deakin on the BBC website talking about the upcoming cold spell:

VIDEO:http://www.bbc.co.uk.../feeds/20964928

Excellent analysis there by Alex Deakin, another very good forecaster. Mentions the SSW and the potential for substantial snowfall next week. Wintry times ahead.

Edited January 9, 2013 by Jason H

[ChartViewer]

CMA120....Nick I Doubt the Queen(Sorry i meant alien queen hehe) is popping off this pod in China ...Awaiting the GFS18Z

CMA144...Much better.....with possible ridging into greenland in later frames

Edited January 9, 2013 by ChartViewer

[Bristawl Si]

Increasing risk of "snowfall" perhaps Significant snowfall music to people's ears

Full ECM ensembles

And Ian F used the word "bothersome" at the end of our regional forecast this evening for early part of next week.

Ian's been RIGHTLY cautious so far to veer from the "lots of uncertainty at this stage" stance but obviously the MetO are now starting to give serious thought to disruption next week.....i think...

Well that's my interpretation anyway, for what it's worth.

[weather eater]

I can understand the excitement Ian but I'm going to remain nervous until I see all 3 top models agreeing.

We had that yesterday Nick but they fell out with each other again this morning, handbags at five paces. Hardly surprising I guess given the MO message that we have record uncertainty about the uncertainty of model projections, otherwise known as Shannon Entropy. I suspect that sometime soon, if not already, somebody will be trotting out the phrase crucial 18z coming up, now while it will be great if it goes with the ECM, we are still not yet at the crucial stage.

[Bobby]

Where can i find the ECM precipitation charts?

Here: http://en.vedur.is/weather/forecasts/atlantic/#type=prec

Also here you can get snowfall maps as well as other ECM features you don't find elsewhere

http://www.wunderground.com/wundermap/ (click model data and select ECMWF)

Here's how I'd rate the current models for cold and snow

ECM: 9/10

ECM ensembes: 9/10

GFS op: 4/10

GFS ensembles: 7/10

UKMO: 8/10

NAEFS: 7/10

GEM: 8.5/10

JMA: 4/10

NOGAPS: 8/10

[Kentish Snowman in Yorks]

Increasing risk of "snowfall" perhaps Significant snowfall music to people's ears

Full ECM ensembles

Brilliant ECM ensembles. I know they are for Holland but we can't complain about those.

[Nick F]

Striking differences between GFS, UKMO and ECM at t+120, if the 12z ECM did come off, that low dropping down across the UK on Monday could bring some moderate snow across northern, central and eastern parts. 12z GFS (and UKMO) doesn't show this shortwave at all! Rather it has a cold nor'easterly with snow showers towards eastern coasts.

Be interesting what the t+120 fax shows later and if the 18z picks up on ECM's shortwave or not. There's quite a lot of support for this shortwave from the EC postage stamps.

[fergieweather]

Raw UKMO-GM snow accumulations for southern areas (just received) later Sat overnight into Sunday approximate 1-5cm (3-5cm for example Chilterns, Downs etc). We're not sure how much will settle, however, especially at lower levels. Stronger snow signal now in latest run, i.e., consistent with 00z GM too.

[Bobby]

Striking differences between GFS, UKMO and ECM at t+120, if the 12z ECM did come off, that low dropping down across the UK on Monday could bring some moderate snow across northern, central and eastern parts. 12z GFS (and UKMO) doesn't show this shortwave at all! Rather it has a cold nor'easterly with snow showers towards eastern coasts.

Be interesting what the t+120 fax shows later and if the 18z picks up on ECM's shortwave or not. There's quite a lot of support for this shortwave from the EC postage stamps.

GEM has it too though snow further West, yes lots of uncertainty, wouldn't like to be a forecaster now.

[thesnowman]

Yes - I really have no idea why posts asking for caution are being shot down. GFS is showing another highly possible scenario, it's almost as though people have forgotten it exists! With the failed December easterly it was GFS that reacted first.

I have to laugh and agree - the MODEL of greatest respect is GFS - the daddy bear of all models - BUT when Daddy scolds us - everyone runs to Mummy bear and baby bears because they make us feel warm and cosy... deep down we all know who is boss! so GFS return to Zonal - a 4 day cool blip - thats the facts as they stand, and don't be thinking daddy bear GFS will be changing his mind at 10pm tonight!

lets see if daddy bear is consistent... he has been in the past

[Timmytour]

The CMA ensembles have just come out and there's a lot of mild zonal runs in there.

Then again, they do belong to the 12z run from 22nd December!

[bluearmy]

Just to clarify for new readers, the model of greatest respect globally is ecm.

[Bristawl Si]

I have to laugh and agree - the MODEL of greatest respect is GFS - the daddy bear of all models - BUT when Daddy scolds us - everyone runs to Mummy bear and baby bears because they make us feel warm and cosy... deep down we all know who is boss! so GFS return to Zonal - a 4 day cool blip - thats the facts as they stand, and don't be thinking daddy bear GFS will be changing his mind at 10pm tonight!

lets see if daddy bear is consistent... he has been in the past

Not in UK MetO's eyes and they know as much as most in the UK!

[damianslaw]

Sticking to reliable timeframe which is Sunday -given the uncertainties from Monday onwards, turning much colder everywhere - the cold is already in place over the northern half of the country - we struggled to make 3 degrees today under fog..

The Fax charts show the sub 528 dam air touching the east anglian coast by friday evening, then hugging the east coast of the country on Saturday before sweeping westwards to cover the whole country on Sunday, any precipitation should by Sunday be of a very wintry flavour even on very low ground, but to early to speculate where the snow might fall. Dewpoints will be low thanks to cold dry air from the east which will increase the chances of rain turning quickly to snow in central/southern parts on Saturday especially if the precipitation is intense.. we saw snowfall under warmer uppers back in late October, this is by no means a marginal situation.

Looking into early next week, GFS is out on a limb at present, and I suspect the 18z will follow the UKMO and ECM output, the jet is forecasted to move on a southerly course, I can't see it ramping into gear to our NW, this goes against preety much all the other model ensemble output which continue to suggest heights building very strongly to the NW in reaction to the propogation of SSW, into the lower atmosphere. Interesting to note BBC are now making hints about the start of a possible very cold prolonged spell, even our local NW forecaster Diane who is a mild worshipper said early next week could deliver very low temperatures - she looked like she wanted to leave the country...

All eyes on the 18z and then how the models play with the shortwave feature progged to develop between Iceland and Norway, will this feature track south over the country or more on a SE track down the N Sea, the former is suggested by the ECM which would mean a spell of snow for many followed by a bitter easterly, the latter shown by UKMO suggests snow showers down the eastern side of the country possibly longer outbreaks of snow, with a NE flow behind - either way very cold weather would ensue, the complete opposite to GFS.

Have to say I'm so pleased we have lost the rainy dank dull mild southwesterlies, which up until the end of last week have made the last 3 weeks of model watching very painful and uninspiring.

[Weathizard]

I have to laugh and agree - the MODEL of greatest respect is GFS - the daddy bear of all models - BUT when Daddy scolds us - everyone runs to Mummy bear and baby bears because they make us feel warm and cosy... deep down we all know who is boss! so GFS return to Zonal - a 4 day cool blip - thats the facts as they stand, and don't be thinking daddy bear GFS will be changing his mind at 10pm tonight!

lets see if daddy bear is consistent... he has been in the past

If the GFS is the daddy bear the ECM is the wise old Grandad bear. GFS will switch in next 2 runs. I'd put money on it, let's hope the 18z does it.

[80sWeather]

Hi all,

I am a complete Newbie here and have been reading with great interest the various forums for the last 6 months. So I thought it was high time for me to join and express my appreciation for what has been a truly exciting time!!

I have learnt so much, but still much to learn. I don't quite understand the models and exactly what they all mean, but am slowly getting the jist thanks to all of you.

I live in Princetown, devon which is just short of 1,500 feet ASL so weather can be very interesting up here.

Anyway, I am watch with great interest tonight for what I have learnt is called the "pub run"!!

Thanks again all.

Ian

Hi Ian welcome to the MOD! All i can say is get the supplies in because if ECM verifies then you will need a jcb!!

[Robbie Garrett]

From the email I received this morning from the MetOffice. I am not sure what the right place is, but the ECMWF has probably got it just about right this evening... GFS and ECMWF are carbon copies in regards to this Warm Air Advection from the south towards Greenland at 48/72 hours. Differences might be the jet doesn't go over the block, but straight through the WAA stopping the ECMWF version of the run from collapsing at 120-168hours...

"For the transfer of warm air to Greenland to allow the block to set up.well that would need a strong push of cold air southwards over the eastern seaboard, but it would need to be just in the right place."

Edited January 9, 2013 by Robbie Garrett

[kate1]

I have to laugh and agree - the MODEL of greatest respect is GFS - the daddy bear of all models - BUT when Daddy scolds us - everyone runs to Mummy bear and baby bears because they make us feel warm and cosy... deep down we all know who is boss! so GFS return to Zonal - a 4 day cool blip - thats the facts as they stand, and don't be thinking daddy bear GFS will be changing his mind at 10pm tonight!

lets see if daddy bear is consistent... he has been in the past

I have to say I think Daddy Bear might let you down... And, that is a seriously disturbing analogy...

[Kentish Snowman in Yorks]

I have to laugh and agree - the MODEL of greatest respect is GFS - the daddy bear of all models - BUT when Daddy scolds us - everyone runs to Mummy bear and baby bears because they make us feel warm and cosy... deep down we all know who is boss! so GFS return to Zonal - a 4 day cool blip - thats the facts as they stand, and don't be thinking daddy bear GFS will be changing his mind at 10pm tonight!

lets see if daddy bear is consistent... he has been in the past

I think Daddy Bear needs to buck his ideas up!

[Ali1977]

-4 850s already in Scotland at t24

[Beast of Plympton]

Hi Ian welcome to the MOD! All i can say is get the supplies in because if ECM verifies then you will need a jcb!!

From my untrained eye, it looks like you may be right! We have 5 foot drifts in december 2010... The way I am reading that very cold uppers and easterly, am I on the right tracks??

How do the outputs compare to 2010?

[Downburst]

What ever about next week I think it's complex enough setup this weekend, I'm struggling to get a handle on it. Trying to get a picture for Sunday in particular. Fax and the TV forecast now coming into play. Better get ready for crazy posts about to come up!

[mackerel sky]

GFS picked this out a good week before the ECM came onboard, now mush on the control.So we are loving the ECM? Cherry picking. I And I expect this to be deleted. So thanks in advance. It is very difficult on the 12z to see this spell evaporate in the manner postulated. A nonsense in fact.

[Ian Brown]

I have to laugh and agree - the MODEL of greatest respect is GFS - the daddy bear of all models - BUT when Daddy scolds us - everyone runs to Mummy bear and baby bears because they make us feel warm and cosy... deep down we all know who is boss! so GFS return to Zonal - a 4 day cool blip - thats the facts as they stand, and don't be thinking daddy bear GFS will be changing his mind at 10pm tonight!

lets see if daddy bear is consistent... he has been in the past

We will have to see snowman, the inconsistency of the GFS 06Z and 12z, and the fact that the 12z OP, though not an outlier has little support amongst it's ensembles has to throw some doubt on the GFS right now. However, the ECM route to T144 is fraught with all manor of difficulties.

i think tomorrow morning we must have a better idea given the timeframes involved, and cold fans are approaching the final fence but we have a dogged opponent who usually finds a way to win in these situations.

[Mr Sleet]

I think Daddy Bear needs to buck his ideas up!

GFS was the highest verifying model around 11th December when it correctly predicted the return to mild conditions when the ECM and UKMO were going for continued cold.