Wintry potential December 09

jenzz

ah lads - even the dogs getting excited now

jenzz

http://www.accuweather.com/ukie/bastardi-europe-blog.asp?partner=accuweather

Mr Bastardi seems to have the same idea of iceland & greenland for a week or so.................. But hes been saying this since June I think:D

Supercell

There is remarkable ensemble agreement about a cooling down.
My main concerns are 1) pressure too high 2) winds too northerly.
On the other hand, seas are still comparatively warm, if we get an unstable E or NE..there is rather huge wintry potential especially a few km inland.

Deep Easterly

Latest UKMO at 144hrs:


potentially frosty, contingent on cloud cover, with a major cold front between Norway and Iceland. How this effects us, if at all, looks dependent on how willing the Anticyclone is in moving to the NW.

Supercell

Severe frosts under clear skies in that. Zero precip anywhere.

200motels

I hope these long range forecasts are right.

Deep Easterly

Latest ECM (12z) at 192hrs:



Pretty similar to yesterday's run so far, but too painfully far out to be anyway nailed on

Trogdor

Threads merged

Supercell

Supercell wrote: »

There is remarkable ensemble agreement about a cooling down.
My main concerns are 1) pressure too high 2) winds too northerly.
On the other hand, seas are still comparatively warm, if we get an unstable E or NE..there is rather huge wintry potential especially a few km inland.

yeah while synoptically anythings possible...on balance I'm thinking this is too early should it occur.

The old rule of thumb applies,you'd want 4 or 5 days of the NE wind to be blowing for it to take affect and you'd want the surface at its source and en route to have gone frigid.
If after4 or 5 days , the easterly started to collapse,then it's all just hot air literally after that.

One to watch but I'd be more excited if it was after Xmas and Scandi and near Europe were sub zero.

Worth watching this for the moment...if it doesn't disappear that is.

patneve

I'd like to remind all that the proposed polar split (will it occur, i don't know) could be the most intense one seen in the last decade...Strangely enough, all the major models have been showing this evolution for quite some time (still isn't in the reliable time frame, though). The ECMWF 12Z run amazingly shows upper air temps for central europe and italy not seen in the last 10 years...! Not all is set in stone yet but I think that cold air will reach our shores with little precipitation. At this stage it is not certain where the HP will go, but I see it quite near our shores (between Iceland and Norway would be ideal:rolleyes:). However, very interesting model watching in the next few days:D

nacho libre

Deep Easterly wrote: »

Tonight's ECM 850's at 216hrs:



Would bring wintry showers to the east, but very very very very dry conditions to the western half which I would much prefer. Would help dry up some of the absolute saturation of ground as well!

screw that paddy1. what we really want is trough after active trough going from east to west. then a scenario ensuing whereby the altantic tries to win out but is gradually beaten back leaving some of us in frontal snow heaven for a while. well, you've got to have dreams in these gloomy times:P

ninebeanrows

Looks very plausible that we will be hit by a bitter cold spell on the run up to Christmas.

Cold winters always strike during periods of Economic strive and hardship, that is fact!

Hopefully things will play ball and throw us something special.

Things are still some distance away yet but looks good.

The cold pool to our east is very substantial.

This is one key factor that has been missing in the most recent attempted easterly blasts.

maquiladora

18Z GFS is fairly similar to the 12Z and the ECM and UKMO in the reliable timeframe, then when it goes deep into fantasy island it looks beautiful...

M.T. Cranium

There's a bit of a 1962-63 look to some of these charts for this early stage of the winter ... can report that it is very cold in the Canadian arctic, there's an area near 70 N 100 W that has thicknesses down below 474 dm and basically the whole of North America is now slipping into below-normal temps, a vast area of relative cold that won't last more than a week or two, so when part of it is carved off by rising jet stream latitudes (probably the western third) then this might push more of the bitterly cold air over the pole into western Siberia and Russia.

In my winter forecast, the best periods for cold are about 18-27 Dec and 6-23 Jan, not saying these will all be cold days but the index values I got from research showed colder than average for the UK and Ireland through those periods. It may try to warm up between these colder periods around New Years, but if that turns out to be a weak warmup against entrenched cold, it could turn into a snowstorm instead. I'm expecting it to be stormy and briefly mild there, but the indications are looking promising for snow cover to appear on several occasions this winter.

nacho libre

that fi chart is just too good to be true:(

pauldry

hate to be the scrooge of christmas present but that low over biscay will shift the high. it will be colder than forecast last week when it looked like a mild scenario but as for coldest in a decade i wouldnt be putting any hope on that. East of England yes. Ireland. No.

Also I know this is all too unpredictable to predict but this is my hunch. Ive been disappointed by lack of storms n snow events 87 times already in the last 2 years to change now!

maquiladora

nacho libre wrote: »

that fi chart is just too good to be true:(

The parallel GFS run is crazy in fi too.

pistolpetes11

I am trying hard not to get too excitied by all this but even this far out all the hype has me very very excitied , hopefully the Irish climate does not do it's usual and not deliver !

Thanks to all you guys for all the information and charts it truely fascinating ! And much Appreciated

Rougies

A couple of questions here for anyone feeling knowledgeable

Some opinions I've read here would suggest it would be too soon in the season for charts like these to deliver because of relatively warm landmasses at the moment (ie. Scandi/East Europe/West Russia) beneath the flow of cold air. I'm sure it would have some effect, but to any substantial degree?

A similar question, but this time regarding cold air over a warmer sea. I know the Irish Sea would be warmer earlier in the winter, but would that give more potential for convection and "lake effect snow" in the east of the country from cold easterlies?

Cornilius

It looks like ye guys are going to have some really exciting weather on the lead up to christmas which will make it extra special!unfortunately I am in Melbourne this year and next most probably so am really jealous hope ye guys get a real pasting! Its a miserable 18c and raining ere at the moment:(

patneve

GFS 00Z = very very good
GFS Parallel = even better

Night to all.:)

maquiladora

Parallel 0Z GFS run is fantastic. UKMO looks good, GEM looks good too. ECM looks good up to about 120ish hours. Could all be ruined in later runs but it's fun watching it coming together...

Rougies

Rougies wrote: »

A similar question, but this time regarding cold air over a warmer sea. I know the Irish Sea would be warmer earlier in the winter, but would that give more potential for convection and "lake effect snow" in the east of the country from cold easterlies?

If theres a sub zero dewpoint yes.
Air from the East especially with sub -8 850 temps usually delivers that.
You most definitely need it blowing over you for a few days though to take effect.
Sometimes you will have a front coming in from the east after a couple of days of the easterly/northeasterly behind which is the really cold blast of air.
This could be a dry front or it could be active.
If it's active,it would probably only deliver hill snow with rain or sleet on the coast.
After that you get the real stuff.

Thats just one option.
Other times it's just a slow advection westwards from the continent or scandi of the really cold sub zero dewpoint air.This would be very dry air but would cause convection over a warm irish sea.

Now the krux is this...
That air has to be heading this way and over us really for 3 or 4 days -so that means you need 6 days worth of it in the models in my opinion and experience before getting excited.
So when you see what are now post 120 charts appearing at +48 and drawing in cold without blips up to +120.
Then It's time to get excited.

I still think it's way too early though.Remember the continent has to go frigid first ...or all we'll have is an icy 4 to 6 c with rainy sleety showers.
At this time of the year that will take longer which is why what we are looking at is a big ask ie we need a week of this before it bites and thats *is* the big ask.

maquiladora

06 GFZ run is fun, would bring snow next Tuesday/Wednesday. :pac:





Deeper into fi it doesn't look as good on this run but there's not much point looking at those charts too seriously.

Redsunset

latest nearly reliable timeframe gfs run would bring a tear to a glass eye.

que sera,sera

maquiladora

redsunset wrote: »

latest nearly reliable timeframe gfs run would bring a tear to a glass eye.

que sera,sera

The parallel 06Z GFS run is very impressive too. I think I read somewhere that the parallel will be taking over from the current operational in about a week.

Redsunset

maquiladora wrote: »

The parallel 06Z GFS run is very impressive too. I think I read somewhere that the parallel will be taking over from the current operational in about a week.

Thats right i think it takes over from the 15th

roryc1

redsunset wrote: »

latest nearly reliable timeframe gfs run would bring a tear to a glass eye.

que sera,sera

I know a cool spell thats not at t240+, I this comes off we are really looking at some great snow potential :D
Just some eye candy for you all

http://charts.netweather.tv/gfsimages/gfs.20091208/06/180/prectypeuktopo.png

Wibbler

Is it time to board the rollercoaster?

Redsunset

Wibbler wrote: »

Is it time to board the rollercoaster?

Sure is.

hold on good and tight.

this could be one crazy ride