Winter Model Discussion - Cold Hunting - 20th Dec

[johnholmes]

Generally got to be an upgrade - Cumbria near my IMBY - apologies for being self centred - looks "interesting" on the 27th

Blizzards down to 1200ft asl?

All is not lost.....

Ian

a day to stay in the pub I would think.

The Scottish ski areas look like getting more than they can probably cope with, snowfall totals with the wind probably even more of a problem?

maybe after all the 30mb suggestion of a cold spell for about 25 December may end up not far off the mark after all?

Certainly the anomaly charts have shown more flows from north of west than westerly in the last 3-4 days. Not reliable with their changing pattern but maybe?

Edited December 20, 2012 by johnholmes

[fergieweather]

This would shock the chief forecaster at the metoffice who composed todays anything but wintry update. It's still game on for a dig of cold air south next week into the new year, the fat lady won't be singing today anyway.

No - I can assure you it wouldn't. Potential (stress 'potential') for key broadscale pattern change has been hinted at into Jan but not in any formal sense - more importantly, the zonal train continues into the forseeable.

Edited December 20, 2012 by fergieweather

[LomondSnowstorm]

a day to stay in the pub I would think.

The Scottish ski areas look like getting more than they can probably cope with, snowfall totals with the wind probably even more of a problem?

Well considering the 50+mm of precipitation falling today and tomorrow is snow on the ski runs we'd be approaching January 2009 levels of snow, when Cairngorm was sitting with 2m and more snow than the big European and US resorts, although there wasn't much drifting then due to lack of wind. The only problem would be finding an opportunity to get up there since there's no sign of settled weather any time soon!

[bradymk]

Some cold short ensembles once again with the mean at the -4c mark. Transient north westerlies do look more likely now to me between xmas and new year with showers for the north and west, snow over higher ground. Shorter term, rain is relentess next few days, not good news with over 100mm accumalted in some places by beginning of next week. And as Ian has just said above, MetO now hinting at potential for colder weather and a pattern change mid jan which is encouraging. I wonder if this is because of data from there strat model.

[WhiteFox]

Surely, in order to achieve a SLP of 1060mb requires nothing more (or less) than a certain amount of air, in a column - in this case, a lot of air?

Correct. But cold air is more dense so you would need less cold air to have a surface pressure of 1060mb than you would warm air. I guess it explains why we don't see pressure readings of 1060mb in the summer!

[AWD]

From Ian Fergusson in the SW thread;

EA gauge at Parkend in Forest of Dean showing pretty much 50mm in 48hrs; widely 20-40mm across their gauge network for rest of region. Sat-Sun-Mon events clearly of key concern in a cumulative sense (especially as slower-response catchments such as Severn yet to show their hand from what's already fallen.).

Indications of a key pattern change into mid-Jan now being suggested - ie., to colder again - so interesting times ahead.

[Geordiesnow]

Indications of a key pattern change into mid-Jan now being suggested - ie., to colder again - so interesting times ahead.

Why look at Mid Jan when there is a good potential of a cold polar NW'ly setting up, yes admittedly it will more than likely to topple because of the lack of any WAA towards Greenland from the Atlantic but with such a strong PV coming down from the Arctic, it won't need to last long to perhaps get the -10hpa hitting the UK if it set ups correctly which may mean some areas could get some late xmas day snowfall even!

Whilst the set up for cold lovers is a bit more promising, the currect set up being projected is a massive concern for the storage of older thicker ice in the Arctic, those winds between Greenland and Svalbard are very strong, no doubt a lot of thick ice will head down into the East Greenland sea and melt away in the Atlantic.

[nick sussex]

Further to my little tease earlier in the thread! Another one of my paint jobs!

Just an outside chance here we could see the following develop from the UKMO 144hrs:

Red arrow, some energy digs more south off the eastern USA

Orange arrow, Azores high temporary ridges a little further nw.

Black arrow, low pressure forced more se.

As the energy digs south it shears enough away to split that energy heading east, this gives the Azores high a chance to ridge a bit further nw, this helps to deliver a bit more of a push se'wards on that low.

The northern flank of that low could produce some snow if that happens.

Edited December 20, 2012 by nick sussex

[peterf]

From Ian Fergusson in the SW thread;

EA gauge at Parkend in Forest of Dean showing pretty much 50mm in 48hrs; widely 20-40mm across their gauge network for rest of region. Sat-Sun-Mon events clearly of key concern in a cumulative sense (especially as slower-response catchments such as Severn yet to show their hand from what's already fallen.).

Indications of a key pattern change into mid-Jan now being suggested - ie., to colder again - so interesting times ahead.

got to feel for folks in the firing line regards their homes.just locked the poultry up for the night and i imagine i have another 2-3 hrs before at least 3ft of water floods the caravans and polytunnel.

nothing compared to those that worry about their homes though.

[The Eagle]

UKMO looks good for a Nw feed and snow showers for Christmas....small upgrades peeps, wouldn't take much to get that low over scanfi to be further SE brining down a northerly for the big day.

http://www.meteociel...=120&carte=1021

Doubtful that sufficient cold air has made it's way south for snow showers at 120hrs (maybe wintriness in showers) - it's a fleeting glance at a northwesterly.

Edited December 20, 2012 by The Eagle

[Iceaxecrampon]

a day to stay in the pub I would think.

The Scottish ski areas look like getting more than they can probably cope with, snowfall totals with the wind probably even more of a problem?

maybe after all the 30mb suggestion of a cold spell for about 25 December may end up not far off the mark after all?

Certainly the anomaly charts have shown more flows from north of west than westerly in the last 3-4 days. Not reliable with their changing pattern but maybe?

I dont know about that John....

Although Lakeland does have some fine hostelries.

Agree regarding Scotland - some Kilt whipping gusts projected there.

All eyes on the 18.

Ian

[bluearmy]

From Ian Fergusson in the SW thread;

Indications of a key pattern change into mid-Jan now being suggested - ie., to colder again - so interesting times ahead.

given that there is no ecm 30 day run since tuesday, i would have thought that the only thing that can have driven a change in longer range thinking can be activity in the strat and their concern that there could be a quick response to any warming due around the 8/10th jan. too early to predict something like that but it does happen on occasion that there is fast wave response to a SSW.

[fergieweather]

given that there is no ecm 30 day run since tuesday, i would have thought that the only thing that can have driven a change in longer range thinking can be activity in the strat and their concern that there could be a quick response to any warming due around the 8/10th jan. too early to predict something like that but it does happen on occasion that there is fast wave response to a SSW.

It's not a formal view from Exeter anyway - so don't read into it as thus! Merely that developments later into Jan are uncertain (clearly). Meanwhile, (their formal view - rightly, given the ensembles) is zonal train continuing in one shape or another into the forseeable MRF albeit with periodic NW influence chilling things down, but crucially, every potential for further heavy rain events / major cyclogenesis events to cause bother. So that's the focus for attention for the south & west (more wintry story for those ooop north).

[Frosty.]

The ukmo 12z looks good with cold air flooding south, ridging follows with frost but then another reload which is similar to the gfs 12z, the gem from this morning looked rather nice too, if that is a trend setter it looks like snow showers pushing south will be on the menu soon after xmas day.

[The Eagle]

ECM for Christmas Day

Cool, rain/hail showers on exposed coasts.

[SMU]

http://www.meteociel...H1-120.GIF?20-0

ECM is good at 120 for the NW & better on the UKMO...

Rain showers turning to sleet & snow flurries over scotland & the NW- maybe the cheshire gap-

at least its a bit more festive

S

Edited December 20, 2012 by Steve Murr

[karyo]

http://www.meteociel...H1-120.GIF?20-0

ECM is good at 120 for the NW & better on the UKMO...

Rain showers turning to sleet & snow flurries over scotland & the NW- maybe the cheshire gap-

at least its a bit more festive

S

The showers on the ECM will be of rain I'm afraid for Xmas day!

At 144-168 hours it looks miserable! http://www.meteociel.fr/modeles/ecmwf.php?ech=168&mode=1&map=0&archive=0

Karyo

Edited December 20, 2012 by karyo

[Cloud 10]

The showers on the ECM will be of rain I'm afraid for Xmas day!

At 144-168 hours it looks miserable! http://www.meteociel...map=0&archive=0

Karyo

[chris55]

A chance of a more wintry Christmas day showing in the models, more so on the GFS and UKMO. Shades of 2004 about it.

I remember Christmas day 2004 very well, with a heavy snow shower bringing a covering here into the evening. Quite a rare event from such a flow but does highlight the outside chance of a wintry shower getting a little further inland than we might expect from such a flow (if the 850s are cold enough)

[Chess01]

2004 was great here the only white christmas i remember . Imby we have had the best snow coming from nw or northely just like the 16th of december last year . I would expect more upgrades as we get closer

[karyo]

The less said about the 12z ECM the better!

The jet axis is unfavourable for cold and pressure over the continent is higher than the 0z which leads to milder weather. Still pretty wet though.

Karyo

[Bobby]

The showers on the ECM will be of rain I'm afraid for Xmas day!

At 144-168 hours it looks miserable! http://www.meteociel...map=0&archive=0

Karyo

Yes no snow with these uppers:

A rather stormy and wet ECM with snow mainly confined to Scottish mountains.

Signs in the ensembles and some OP runs though of a cold blast from the NW/N after Christmas with snow showers potential and maybe an undercutting low too with more widespread snow.

Edited December 20, 2012 by Bobby

[jimbo36]

Still not the greatest outlook from the models, no high level blocking in the outlook-

However things perhaps cold enough to turn Wintry over the NW & scotland over the festive period- it just depenbds how far east we get the upper trough-

Certainly worth a punt on a white Xmas for glasgow.

S

I hope not, i've been laying white xmas for glasgow and edinburgh on betfair, so hope next run brings back the mild

[Isolated Frost]

The less said about the 12z ECM the better!

The jet axis is unfavourable for cold and pressure over the continent is higher than the 0z which leads to milder weather. Still pretty wet though.

Karyo

Pretty cold for Scotland, with upper temps passing 0c for only a 24-36hr interlude in the 240hr run, and plenty of -4c and below incursions. On a W/NW flow with plentiful Am/Pm incursions, there is a lot of snow to be had on high ground, and at times on lower ground as well. Expect some sunshine to come of it as well under a more showery regime than the current one.

Just because there is not notable blocking around Greenland---Scandi, doesn't mean we can't have some cold and snowy weather, this time though, Scotland and the north mostly enjoy it, maybe that's why it's so glum around here!

[Mark Bayley]

A rather unsettled ECM, although not particularly mild from the Midlands north with temperatures generally around or slightly below the average. Milder further south during any interludes of warmer air, but noting notable. Could be a worse outlook, and there would be snow at times on northern hills and areas with a bit of elevation. Hopefully a change to something a little better during the first half of January, which there's certainly a sign for.

Edited December 20, 2012 by Mark Bayley