Winter Model Discussion - Cold Hunting -12Z 30/12/12

[UV-RAY]

Atlantic looks pretty dead on this run, strange run really though. As I said the other day strange runs and flipping models is always the sign of change in my experience

The pattern change will be upon us later this week, not too many seem interested in the dry weather after many of us have endured weeks of rain.

[swfc]

Make what you will of that ecm run but the last 24 hrs are showing to me that the change is being picked up.The variety of runs may confuse some folk but the change may occur earlier than anticipated

[Weathizard]

The pattern change will be upon us later this week, not too many seem interested in the dry weather after many of us have endured weeks of rain.

Don't get me wrong I'm very happy to see dry charts but this thread is the hunt for cold! Not much to discuss about the HP charts, mild and dry! Thank god for a bit of dry weather though, saturated here let alone in the SW!

[TEITS]

Easy to spot a route to cold, much harder to take a route that's beneficial to the UK.

Always possible as well that initially we are unlucky but aslong as the PV doesn't intensify and reorganise itself then other possibilities could arise. When we look back at the classic winters of 47, 63 the positioning of the blocking often fluctuated and sometimes this resulted in convective E,lys due to the blocking to our NE and other times the blocking backed W allowing Atlantic LPs to move in. infact even during the 63 winter some parts of the SW actually turned mild for a short period.

Im only mentioning this because I don't want members to think that if we are unlucky at first then its curtains for a cold spell. Based on what I have read in the Stratosphere thread it seems the potential for blocking could continue even into Feb.

Very exciting times ahead I feel.

[East_England_Stormchaser91]

Now thats more interesting ECM!! It seems I was almost right! Roll the frames a bit more and you would get that -12C cold pool heading our way! If only!

A Turkish import of cold, now that would be extraordinary!

[Zenarcher]

Model summary using the GFS, ECM, UKMO, JMA, NOGAPS and GEM.

Tuesday to Thursday - 24 to 72 hours - All the models agree within this time range and show clear and sunny conditions across England, Wales and Eastern Scotland on Tuesday, elsewhere will be cloudy but dry. Wednesday will be cloudy all over the UK with fog and mist being widespread as well. Thursday will continue to be cloudy and misty for the UK but the very far North of Scotland may see some sunshine. Gale force winds on Tuesday for all but on Wednesday and Thursday only gales in the North.

96 hours Friday - All the models agree on a large high pressure to stay over the UK we can expect this to bring further cloudy and misty weather to the UK.

120 hours Saturday - As the models showed yesterday high pressure still remains over the UK but it's showing signs of weakening and moving away this is something all the models show,

The Atlantic lows yesterday is where the question mark was at this very point, today we have a slightly better idea, all models place a low in a similar place just entering the Atlantic,

144 hours Sunday - This is where it start's getting interesting here all the models have picked up that perhaps the high pressure over the UK will return again although this time not as strong,

And all models also go for low to be at the South of Greenland although its deepness varies,

168 hours and beyond the changeable outlook - The GFS for most of the time keeps high pressure over the UK but eventually brings in the Atlantic weather, the ECM which for the last two runs have shown to be poor for those looking for blocked and cold weather is an improvement and weakens the Atlantic and builds high pressure to our North East, JMA builds high pressure up as well.

Overall - Some interesting changes today in the models they are clearly struggling with the changes at the moment. The ECM is a positive change from what it has been showing lately. Yes the GFS FI isn't too great today but what has it shown a lot over the last few days a blocked outlook which is a trend it has built up one run that disagree's is not end of story.

[Froze were the Days]

I think we're slowly going into a period of uncertainty - going into a period of High Pressure close to our shores and no active low heights close to us but can't help thinking through a majority of the models the cyclogenesis coming out of Canada even in the medium/long term looks far too active. We have seen FI runs with a Greenland HP becoming more extensive and then runs that show blocking to our north (and it has to be said from strange evolutions) and now the ECM 'wavering' with HP near to the east but the last day on the GFS op runs still shows active depressions 'building' in the west of the North Atlantic.

So overall happy we're going into a pattern change but still very unsure if we'll get to any synoptics that bring in any significant cold.

40% HP then back to zonal

40% HP close to the UK and remaining for some time.

20% HP eventually to a cold evolution.

Edited December 31, 2012 by Froze were the Days

[nick sussex]

Not a bad ECM in the later stages but its hard to read too much into this given the poor continuity shown by it in recent days.

Even if this run was to verify I can't see that much colder upper air making it to the UK given the lack of a suitable trigger and with still too much energy running to the north.

From where the ECM is at 240hrs you'd really need to see retrogression of the pattern and troughing dropping south to the east to really have a chance of much colder conditions with snow.

Overall some signs of a change but still alot of uncertainty as to where that will end up re any blocking. Personally I'd like to see the drama of an easterly saved for another time! I'd much rather see blocking to the north.

[legritter]

Come on gang we do have possible starting blocks , but caution at this stage required . its great to see this high pressure being modelled . as someone as pointed out we could slide into a cold spell sooner than the modells are currently predicting . i often employ different school of thoughts ,perhaps mother nature will balance the books a little . ok it might be on the dry side but many cold dryish winters after christmas new year do produce the white stuff . anyhow hears hoping that 2013 could turn out Magical .anyhow 2012 going out with one almighty downpour here now ,all the best gang .

[SMU]

Evening All-

HAPPY NEW YEAR TO EVERYONE & ALL YOUR FAMILIES.

We are now seeing the first green shoots developing in the models as a direct result of the stratosphere rapidly changing in temperature.

http://maidenerleghw...r.com/strat.php

we can see the ECM day 9 & day 10 zonal winds reversing at a significant rate of knotts- rather like the enterprise coming out of warp.

Its good to see the reversal of winds filtering down to the lower levels ~ 70 MB- which for me indicates that the SSW will be a good propergator.

The models are now responding - (especially the Euros tonight) with the jet decelerating at the same timeframe- the direct response for this will be high pressure systems starting to retrograde North as opposed to arcing East-

At it stands the green shoots are just that, cause for optimism out at day 10/11- but the timing does fit well with the projected warming & propergation I commented on in the strat thread.

The JMA is the best run tonight if your looking for the best potential to be had at day 12- however the ECM at day 10 gives the uk a chance of snow with a pocket of cold uppers crossing the UK.

Its going to be another 48 hours before perhaps we see a little stability in the outlooks - so probably not a lot of consistency until then.

However, cause for optimism tonight....

Steve

Edited December 31, 2012 by Steve Murr

[Bobby]

Not much change to yesterday's forecast, however with a slight shift to drier and cooler weather, but a lot of uncertainty going into the second week/middle of January.

Forecast based on latest model output:

Rain clearing the SE this evening with showers following on behind, especially in the NW and Scotland where they could be heavy with hail and turning wintry over higher ground. Drier elsewhere with a ground frost under clearing skies. Cool for all. As we head head through this week things will turn increasingly dry and mild/very mild as high pressure builds from the S, however with increasing amounts of cloud and occasional light rain and drizzle the further N and W you go, especially over hills. Best of any drier and brighter weather in the SE where winds will be also be lighter.

As we head into next week it looks high pressure will weaken increasing the risk of more unsettled and cooler weather from the Atlantic at times, especially in the N and W however the SE may remain largely dry. Towards the end of the week there is a possibility drier more anticyclonic weather will return with the N and W continuing to remain at most at risk from any Atlantic systems although rain probably not especially heavy.

Going into the middle of January greater uncertainty with increasingly unsettled weather possible with wind and rain at times, especially to N and W, however with drier and colder more anti-cyclonic weather also possible for all with frosts. Generally trending cooler.

Edited December 31, 2012 by Bobby

[on the coast]

Hi Steve. What do you think the chance of a cold spell happening this time around?

[Thundery wintry showers]

A bright and breezy New Year's Day lies in store for a large majority of the country, with some scattered showers in the west- I remember quite a few bright and breezy New Year's Days in the recent past.

The anticyclonic period starting on Wednesday will be grey and drizzly initially as a frontal system moves east introducing tropical maritime air. I also think Thursday may turn out rather grey for most of us and the GFS is suggesting an area of rain over SW Scotland and Cumbria- so not necessarily dry for all of us.

It's from Friday onwards that we are likely to see more of a continental influence come into southern areas in particular. Cloud amounts associated with any continental air remain very hard to pin down at this range, but the current GFS projections are suggesting variable amounts of cloud, so probably sunny on some days and cloudy on others. As others have noted, the cloudiest overall conditions are likely to be found in the NW.

Some of the longer-term outputs, notably this evening's ECMWF run, are bringing in a strengthening continental influence which would bring relatively cold dry weather and some long-term potential for an evolution to something snowy, but the signs at present are only tentative. The ECMWF ensemble mean still has high pressure centred to the south at T+216/240.

Edited December 31, 2012 by Thundery wintry showers

[nick sussex]

Some support for colder conditions into De Bilt:

http://www.knmi.nl/exp/pluim/Data/PLUIM_06260_NWT.png

Also the CPC maps in terms of overall trend are positive:

http://www.cpc.ncep.noaa.gov/products/predictions/610day/610day.03.gif

http://www.cpc.ncep.noaa.gov/products/predictions/814day/814day.03.gif

They expect the pattern to amplify in the eastern Pacific with ridge building into the western USA so thats another bit of good news.

And finally Happy New Year to all.

[Iceni]

Always possible as well that initially we are unlucky but aslong as the PV doesn't intensify and reorganise itself then other possibilities could arise. When we look back at the classic winters of 47, 63 the positioning of the blocking often fluctuated and sometimes this resulted in convective E,lys due to the blocking to our NE and other times the blocking backed W allowing Atlantic LPs to move in. infact even during the 63 winter some parts of the SW actually turned mild for a short period.

Im only mentioning this because I don't want members to think that if we are unlucky at first then its curtains for a cold spell. Based on what I have read in the Stratosphere thread it seems the potential for blocking could continue even into Feb.

Very exciting times ahead I feel.

The South turned mild on many occasions during the first months of 1963. There was a lot of snow, so it never melted away, but I remember being able to walk on top of the snow where quite a thick layer of rock hard ice had formed due to partial melts and refreezes. An odd sensation…

[SMU]

Hi Steve. What do you think the chance of a cold spell happening this time around?

8/10 in favour of SOMETHING below ave for 7 days

S

[Froze were the Days]

1/10 if it's a projected easterly and possibility of a short wave 'popping up' in the Norwegian Sea! let's try and forget about those episodes and look forward to a better 2013!!

Yes Happy New Year to all!!

Edited December 31, 2012 by Froze were the Days

[Weathizard]

When does the next EC32 dayer come out? Be interesting to read their take on potential.

[UV-RAY]

When does the next EC32 dayer come out? Be interesting to read their take on potential.

This coming Friday, though some say it's awful but that depends on what it's showing, having said that it handled the last cold blip pretty awful but so did everyone else. Edited December 31, 2012 by Seven of Nine

[lorenzo]

FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOUT AVERAGE, 3 OUT OF 5, WITH

FAIRLY GOOD MODEL AGREEMENT OFFSET BY FORECAST DIFFICULTIES ASSOCIATED WITH AN

EXPECTED TRANSITION TO A HIGHER AMPLITUDE FLOW PATTERN WITHIN THE 8-14 DAY

PERIOD.

Good to see NOAA scatching their heads too re Blocking

[bluearmy]

the ecm ens show the op run to be an outlier re uppers (no surprise). although there is a clear tendency to take the ridging further north, i dont see any way the cold can back west from se europe as there is hardly any appetite to take any energy into europe to our south. more likely, judging by the anomolys and spreads that something akin to the JMA op run where successive atlantic depressions take WAA further north and slowly back the ridge NNW. the pull back in low heights from west of greenland to east of greenland days 7 thru 10 is clear. also, at day 10, the canadian vortex sends a mean pulse of energy sw. i imagine this could be the trigger to dig the trough further south and send some WAA up in the greenland area to draw our ridge even further nw. if it doesnt dig south and heads into the atlantic unchecked, that would likely flatten the pattern somewhat. we would then probably need another amplification upstream to create a greeny ridge. so every chance of a weak continental flow as the ridge gets further north but a proper easterly looks very unlikely at the moment.

When does the next EC32 dayer come out? Be interesting to read their take on potential.

tomorrow morning

[Summer Sun]

When does the next EC32 dayer come out? Be interesting to read their take on potential.

Every Tuesday and Friday Matt Hugo usually tweets about it when its updated

[Iceaxecrampon]

Truly shocking for so called midwinter....

It was just fleeces required in Grizedale Forest today - swatting midges and swerving standing water on the roads coming back.

.....bonkers

Ian

[Frosty.]

Truly shocking for so called midwinter....

It was just fleeces required in Grizedale Forest today - swatting midges and swerving standing water on the roads coming back.

.....bonkers

Ian

LOL ian and you aint seen nothing yet, according to the models it's going to be turning much milder in the days ahead but thankfully much drier too, so lots more midges to swat in the next few weeks, and thats the forecast. Happy New Year to all on netweather looking forward to the big freeze later in the month, yes that's a ramp based purely on the strong stratospheric warming event which holds the key to whether this winter will be a damp squib or something to remember for years to come.

[Iceaxecrampon]

Cheers Frosty - and all on NWforum - I will raise a glass of 1664 to the Strat Warming