Winter Model Discussion - The Hunt For Cold -18z 17/12/12

[Robbie Garrett]

I shall post my first impression when I looked at the ensembles at 01:36 "Was - Woooah, **** me...." There is more support for a cold spell than I thought.

[legritter]

Just got woken up by v hvy rain on window ,yes things on modells are looking a bit better for cold past next wednesday could be interesting , this could start showing up on ECM TODAY .PERHAPS WE WILL GET SOMETHING NEW YEAR ,LATEST FAX WORRYING FOR FLOOD HIT AREAS .

[Dave Kightley]

Not a bad GFS run for Christmas week with Cold zonal flow and chilly esp in the North.. I suspect there would be Snow on the western Flank of the lows esp in the north. Later in the run pressure builds from the south and a mid atlantic ridge. Below average next week

[Dave Kightley]

Snow fest alert!!!!!!! Nice chart at 192 for countrywide snow.

[Dave Kightley]

U

[Dave Kightley]

Is this a undercut? Serious snow risk next weekend on this run! Boxing day towards the end the weekend looks rather chilly indeed

[Cal]

Is this a undercut? Serious snow risk next weekend on this run! Boxing day towards the end the weekend looks rather chilly indeed

Not quite... it's a secondary channel low, wouldn't get too excited re snow potential till <24/48hrs but as you say the risk is there and growing. 00hrs UKMO not too bad neither for temps to be slowly eroding away after Xmas day.

[Snowmad79]

Snow fest alert!!!!!!! Nice chart at 192 for countrywide snow.

LP passing and stalling to our east and a scandi trough. All we need now is for this output to make it into the reliable and for a bloody good Greenland High block to form and then it would be perfect.

The ball does start to roll at 120 so to speak and it's nice to see the jet negatively tilted, trending south again but I would really like a proper block to the NW to pop up out of FI just to be sure!

Edited December 20, 2012 by Snowmad79

[Dave Kightley]

Very good ens for Aberdeen.. The mean for Somerset is around -2/-3 for the end of the week.

[IDO]

So a Northerly (hopefully better than that easterly!) is being progged by GFS. IMBY not too much excitement for now, especially as the ensembles say its transient:

http://modeles.meteo...ndres&runpara=0

Need to get a lot nearer before snow chances are firmed up for southerners however further north promising for the wintry stuff. Mainly Scotland Tuesday till Friday, then more widespread chances:

http://cdn.nwstatic..../uksnowrisk.png

Week two surface mean temps highlight the cooler push:

http://wxmaps.org/pix/temp4.html

First time for some days that the mean has dropped to below average and NW Scotland has a sub-zero mean.

The GEFS mean also showing the brief (at the moment) northerly :

http://modeles.meteo...-21-1-180.png?0

Before the Azores High ridges back: http://modeles.meteo...-21-1-240.png?0 http://modeles.meteo...-21-1-300.png?0

The ECM has the northerly push to our west:

http://www.meteociel...1-192.GIF?20-12

Whilst UKMO has a more robust Azores High and the northerly is a toppler:

http://www.meteociel...44-21.GIF?20-06

No done deal yet but a little bit of interest for the holiday week. Hopefully upgrades rather than downgrades from here, the latter always being the punt from this type of setup.

Edited December 20, 2012 by i'm dreaming of...

[karlos1983]

ECM is having none of it!

[wolvesfan]

Morning all,

Better last couple of runs from the GFS,i for one wouldn't be too dissapointed to see a chart similar to this varify,

Ensembles showing good support,

Some might moan that its transient but i'll take any cold on offer at the moment.

ECM not dissimilar either.

[Blizzardo]

ECM is having none of it!

Its moved a little towards this solution but far from as extreme as GFS.

[bluearmy]

Ecm and gem op are not very good wrt the jet axis.

However, gefs look to support a cold trough and i will wait for the em ens before having a view.

ecm day 10 is fun if only for the way it splits the arctic high over canada and then appears to want to reunite the left overs near greenland beyond day 10 . Not to be taken seriously.

strat forecast continues to look good and warming is now consistently showing within ecm/ncep 10 day output. I wonder when exeter will decide to add a caveat to their 32 day forecasts?

[chris55]

GEFS mean not looking to bad towards the end of next week, although the projected pattern is precarious with small tweaks allowing the less cold air into the mix. One to keep an eye on. Scotland could certainly see some wintriness,

[Gibby]

Good morning. Here is this mornings report on the 00zs from this morning Thursday December 20th 2012.

All models show a very wet pre Christmas spell between now and Christmas and well beyond. They all show a series of active troughs from Southern latitudes moving SW to NE over the period with Saturday and Christmas Eve the next wet days likely after today. Temperatures will range from mild in the SW to nearer to normal for NE areas with some snow on the mountains today. Some drier interludes look likely probably Friday and later on Saturday the most likely time for these.

GFS shows a wet Christmas with Low pressure over the North of the UK eventually moving ut into the North Sea veering winds towards the West then NW as the general rain gives way to a spell of cooler and more showery weather. Towards the New Year very little changes in the very unsettled pattern with further Low pressure sweeping bands of rain followed by showers over the UK from the Atlantic. Then as we move into the first week of the New Year there remains very little significant change at the surface with winds remaining for the most part between South and West with the close proximity of Low pressure staying put.

The GFS Ensembles show an interesting dip in 850's post Christmas between the members with the likelihood of colder West or NW winds for a while before uppers return to near normal as the Atlantic brings somewhat milder air back later. Throughout the run there is copious rainfall shown, especially in the South.

The Jet stream shows a continuing sine wave pattern to the flow moving West to East close to the latitude of the UK or just to the South.

UKMO for midnight on Boxing Day shows a complex belt of Low pressure stretching from Norway to the NE Atlantic witha West to NW flow bringing further showers or longer spells of rain in temperatures close to normal, though this wouldn't proclude the risk of some wintry showers on Northern hills.

GEM today shows an unsettled picture too with winds between Christmas and New Year blowing from between SW and NW with squally showers or longer spells of rain with snow on Northern hills in the showers.

ECM shows a Westerly flow with further rain at times with the heaiest maybe transferring more towards Northern Britain with some drier spells in the South but this is basic straw clutching and the overall pattern from ECM for the period between Christmas and the New Year remains wet.

In Summary there is little to say this morning other than we are in for a protracted spell of very wet conditions. Flooding is bound to be an issue in various parts of the UK from time to time with disruption to travel as well from this. Temperatures will range from mild in the SW to rather cold in the NE at first before more normal values of temperatures affect all areas later in the period. Snowfall away from Northern hills and mountains looks highly unlikely in lowland Britain anywhen in this morning's output range.

[Weather-history]

Has anyone notice Wetterzentrale GEM and Meteociel GEM are different? I have noticed this a few times now. Any ideas why this is?

Just look at 180hrs charts.

[Summer Sun]

Has anyone notice Wetterzentrale GEM and Meteociel GEM are different? I have noticed this a few times now. Any ideas why this is?

Just look at 180hrs charts.

Yes big differences between the 2 of them

[Great Plum]

Has anyone notice Wetterzentrale GEM and Meteociel GEM are different? I have noticed this a few times now. Any ideas why this is?

Just look at 180hrs charts.

If I recall, I think one of them is the Control run...

[bradymk]

Yes big differences between the 2 of them

Yes i think the wetterzentrale one is the GEM control run because on meteociel you can also view the GEM ensembles and the wetterzentrale chart you just posted is identical to the GEM control on meteociel. So the GEM op is the one on meteociel.

[karlos1983]

Well I must admit, I expected it to be a little busier on here this morning after a positive GFS 00z, not quite the 18z, but still good.

@ +144

and at +192

I know it doesn't shout prolonged cold spell, but right now, i'll take it after recent disappointments. And I will probably benefit less than the majority with that setup,due to location, but hey I'm used to that and have a 4x4 so can drive where i want

Edited December 20, 2012 by karlos1983

[MisfitDog3]

I think the chopping and changing is taking it's toll! Interesting output again this morning but the strength of the Atlantic continues to give me concerns. I can't see the material to bring about a major change at the moment. I would normally say the next 48 hours will determine where we are going next week but I just don't see any settling down in the models just at the moment.

[No Balls Like Snow Balls]

IMO I think the models look good this morning for a potential cold spell from the North in between xmas and new year, certainly better than looking for a Easterly that never comes lol

[Methuselah]

Here's hoping for something snowy...otherwise there'll be more than a few 'displaced' headaches on here!

[The Northern Ramper]

Not bad consistency at 150 by the GFS between the 18z and 00z, certainly better than recent runs and although not identical (when are they at 150?) a clear pattern being picked up.