Winter Model Discussion - Cold Hunting - 20th Dec

[Robbie Garrett]

Interesting model runs, probably hiding the fact a major cold spell could be on the horizon! Maybe so far we've been lucky with the cold snap. I hope it doesn't but I can see the zonal train continuing into next year and possibly similar conditions to this year.

Taking into account some of the signals, a cold spell from Mid/late Jan 2013 to late March wouldn't surprise me, it most certainly can't be ruled out.

Not sure if the highways agency use the MetOffice or a European met organization like the national grid. I anticipate they have seen signals, understand the jets irregular pattern and it's ability to cause lots of precipitation at the moment.....

[Iceni]

keep the faith.the strat warming will save the day.7-10 jan!!!!

Yes but the stratosphere warms and then its effects take 4-6 weeks to filter down into the troposphere. That would take us to mid February.

[Panayiotis]

Just seen the ECM, it doesnt look as bad as the GFS and at 240hrs we have a nice HP, which should help bring despair to people who are witnessing flooding.

Edited December 23, 2012 by Panayiotis

[Barmada Casten]

so the trend continues for mild, wet weather for the foreseeable future. I have noticed a few people are clutching straws at a mid-jan cold event - this is highly unlikely guys - this may go down as one of the mildeest, wettest winters ever - an absolute hell for snow lovers.

How is everyone anyway???

Barmada Casten

[swfc]

pretty dire 0z.positives-rain amounts dropping off.Negatives-mild or mildish all the way

[Teesdale]

pretty dire 0z.positives-rain amounts dropping off.Negatives-mild or mildish all the way

Actually probably increasing for more NW areas as lows transfer to a more traditional location. Relief for the SW though.

[IDO]

I apologise for yesterday when I said the 12z was the worse possible GFS run for cold, and it can only get better. Sorry . The 0z this morning is indeed worse. At the end of FI:

http://cdn.nwstatic....384/npsh500.png

Not a great NH PV profile for any cold in the medium term.

One frame just to highlight the GFS: http://cdn.nwstatic....300/h500slp.png

At least the jet has pushed north on most of the run so the wet part of the zonal slow train is further north and the SW may be get some breathing space. The next 7 days totals: http://www.weatherwe...uktotpcp192.gif

This highlights the shift north of the very wet outlook .

The mean surface temps: http://wxmaps.org/pix/temp4.png

UK mostly average but of more concern is the profile for the Continent. High anomaly warmth right through to Eastern Europe . This is not great for any feed from the east and sums up this winter.

The Op is a warm outlier (later stages) but the mean remains above zero and the profile is still synoptically zonal: http://modeles.meteo...ndres&runpara=0

UKMO on 29th: http://www.meteociel...44-21.GIF?23-06

Zonal .

ECM, ditto: http://www.meteociel...1-144.GIF?23-12

It has an Arctic high for about 6 days and then pushes it into Siberia. Look at the Uppers in Germany (+12c): http://www.meteociel...0-168.GIF?23-12

At the moment the next 10 days+ is zonal and probably average to mild for the south, cooler further north, but very little snow on this run other than hills and mountains for Scotland, though the jet is probably modelled too far north on this run, so that may improve. Noted that the strat. still has potential :

http://cdn.nwstatic..../384/npst30.png

I am sure some decent charts will start to show up in FI soon. Please

Edited December 23, 2012 by i'm dreaming of...

[swfc]

ecm pretty pony too!!slight atlantic ridge but comes to nothing and back to square one

[mountain shadow]

The hunt for cold continues. Nothing on the 0z offer anything.

Flat and zonal.

[snow drift]

Good morning. I think that the New Forest, down here, should be renamed to the New Swamp. I have never seen so much water just Sat in fields and on roads.

Anyway, clearly not great runs if you are looking for cold. In fact they could be described as ugly as Bull Dog licking pooh of a stinging Nettle. However I thought I would post this chart for any Newbies who wonder why we look for blocking to our NW. Have a look at America. Illustrates Blocking and the plunge of cold air, as far down as North Florida.

Edited December 23, 2012 by snow drift

[Frosty.]

The models are so poor for cold at the moment that it's becoming almost impossible to find a chart worth posting, I only posted this because it gives a very brief potent shot of polar maritime, yes the models really are that awful. Don't let these rubbish charts spoil christmas, i'm sure things will look better in the new year as the strat warming feeds into the model output and increases the chances of major blocking.

[latitude]

This is all reminds me of last year. 9 weeks to go then its spring. 6 weeks to go and we can start talking about it.

[CRACKPOT]

Unfortunately, the models today and for the last few days have been churning out mild scenario after mild. This now matches a lot of the 'long' range projections of models such as the CFS which were apparently showing a cold winter back in November but that model and the majority of others are now showing this milder winter after recent updates - the charts only seem to be backing this up long into FI.

We need a SSW to give a big shunt into the model output and hopefully this will turn towards a colder scenario. This morning we have a dire output if looking for cold - we just got to get rid of some of this rain.

JK

[Duane S.]

This is all reminds me of last year. 9 weeks to go then its spring. 6 weeks to go and we can start talking about it.

Or... only 3 weeks since winter started.

And why on earth would we stop 'talking about it' (presuming you mean cold potential) on February the 3rd ? It's akin to giving up on any decent warmth from August 3rd onwards.

Too many on here are emotively driven from the day to day operational output. Although, I can't argue that they are not currently pretty awful, they are.That said deep FI on the GFS is currently the point when any real change is likely to happen anyway so whatever happens we have to get through a huge amount of poor weather first.

Have faith, the outlook will improve as we go on into January.

EDIT: Misread your post, you said 'start it' meaning start looking at spring, obviously not a coldie that's all, now I understand.

Edited December 23, 2012 by s4lancia

[Continental Climate]

Unfortunately, the models today and for the last few days have been churning out mild scenario after mild. This now matches a lot of the 'long' range projections of models such as the CFS which were apparently showing a cold winter back in November but that model and the majority of others are now showing this milder winter after recent updates - the charts only seem to be backing this up long into FI.

We need a SSW to give a big shunt into the model output and hopefully this will turn towards a colder scenario. This morning we have a dire output if looking for cold - we just got to get rid of some of this rain.

JK

I agree its so soggy out there but the models say 'NO' to any respite from the rain, and whats even more is its now warming up noticeably as well!! Anyway back to the models and a truly sickening chart for cold lovers here http://www.wetterzen...s/Rtavn1441.png!! Only at 144 as well, I trust that a hell of a lot more than some vague strat chart at 360!!

Edited December 23, 2012 by Continental Climate

[bluearmy]

If w get a strong warmng early jan (and it seems we will), accepted wisdom is that there is a lag period before the trop pattern changes to a HLB state. we can also get a sudden trop wave response to a warming which drives a quick neg AO pattern. If the existing trop pattern is receptive then we can get a fast cold pattern establishing followed by the sustained blocking several weeks later. The point is that if the trop is already looking good when a warming begins, we could easily go cold straight away and hardly notice any transition to less cold before the HLB takes hold and hopefully we find ourselves in the right place hemispherically.

I fear that this is not going to to be the case on this occasion. I think exeter's thoughts on post mid jan for any change to show could well have strong foundations. Lets just hope the trend for a mid lat high verfiies as its the best option given the saturated ground.

[Troubleatmill]

without a doubt the worst set of ensembles this winter, makes for abysmal reading, if we cant have cold then at leat some dry weather to let everything drain away, but the ensmbles paint an ominous picture this morning with mild 850 holding lots of moisture from the tropics

[Gibby]

Good morning. Here is the morning report on the 00z output from the big four, namely GFS, UKMO, GEM and ECM for today Sunday December 23rd 2012.

All models show the Christmas week to remain very unsettled and often windy with rain or showers at times. Today shows a respite in the rain with some sunshine in the Central swathe of the UK with continuing rain and sleet in the far NE and some light drizzly rain near the South Coast. Later today the front in the English Channel is shown to move North once more as a new wave runs NE along it bringing a return to rain and local flooding problems back to Southern Britain tonight. This will clear NE early tomorrow leaving in it's wake a West to SW flow with a further showery trough moving slowly East over the UK on Christmas Eve and Christmas Day with plenty of sometimes heavy showers in increasingly fresher and colder air with some wintry showers on far Northern hills. A NW flow is shown on Boxing Day with less showers and more in the way of sunshine. Later in Christmas week further unsettled is shown to advance in from the West with more rain at times in temperatures gradually moving upwards again as winds back more SW while becoming strong.

GFS then shows a mild and strong SW flow giving way to a cooler Westerly flow around the New Year as an active cold front moves East over the UK. Through FI the pattern starts quite zonal with further rain while later on the pattern sees a North/South split developing as High pressure moves in close to the South with dry if rather cloudy conditions developing here though still relatively mild while the far North staying mild and a little unsettled with these conditions shown to return to all areas by the end of FI.

The GFS Ensembles show nothing of interest for those looking for cold with almost a complete set of members going for a continuation of rather mild Atlantic based weather with rain at times and just brief slightly cooler spells. The operational was a milder outlier in the second half of the output.

The Jet Stream shows a continuation of the seemingly unrelenting flow across the Atlantic towards the UK with just undulating, wave like patterns drifting it somewhat North then South from day to day as disturbances pass by.

UKMO fro midnight on Saturday shows a deep depression just South of Iceland with a broad and mild SW flow affecting all areas. Rain will move NE on troughs over the UK, heaviest over the North and west with some welcome drier spells in the South and East.

GEM shows Low pressure closer in to the UK at the same time point maintaining more deeply unsettled and less mild conditions with further heavy rain and showers at times for all out until the end of its run.

ECM shows a very mobile pattern towards the end of its run with rain bands crossing East followed by showers as depressions run East just to the North of Scotland in temperatures which will stay close to normal or even a little above in the South at times.

In Summary the weather remains very unsettled with further rain at times over the coming two weeks. There are a few drier chinks of weather to come especially in the South with no cold weather likely anywhere through the period. The wettest weather may transfer to the NW later as something of a build of pressure to the South and SE carries the depressions and fronts further to the NW but this all looks rather tentative with the likely outcome seeing further substantial rainfall at times given the ground everywhere is so saturated. With high pressure down to the SE though ensures temperatures stay well up to or above normal at times.

[Bobby]

Well the 00z runs are about as bad as they can possibly get, so the upside is things can only improve from here.

There does seem to be a trend for pressure to ridge up from the south around day 10 (maybe giving a respite from the rain these places) on but the ensembles and NAEFS anomaly maps suggest it won't last long before it flattens and the Atlantic returns. That is if we do get a ridge which may not even get looking at the latest runs.

Edited December 23, 2012 by Bobby

[Timmytour]

The only thing i can think of to say positively about the latest runs is at least the mild aligned to the wind will provide a little drying out inbetween the periods of saturation

[phil nw.]

I can only agree with the theme of this mornings postings that the 00z runs continue with the Atlantic pattern with still plenty of rain in the offing over the next few days.

The modelling of the Greenland vortex and Azores high just locks the UK into the ongoing westerly pattern bringing some tropical maritime air north east and creating further bands of rain as it moves across the the country.

http://nwstatic.co.u...204f96b4c27f3d;

http://nwstatic.co.u...204f96b4c27f3d;

http://nwstatic.co.u...204f96b4c27f3d;

Looking at the mean outputs there`s no sign of any change for the next week or 10 days at least

http://modeles.meteo...-21-1-240.png?0

http://www.meteociel...1-240.GIF?23-12

with any signs of ridging in the Atlantic quickly flattened by the next approaching low.

Unfortunately not the seasonal outlook many of us were hoping for but until we see some upstream amplification in the jet profile any of the cold air to our north will have little chance of affecting the UK.

[Steve Edgefield]

Models this morning show some of the worst winter patterns for cold lovers. There are some excellent threads looking at the more techcnial aspects of modelling and where these may lead into the future. I always read these. However, what would be interesting and what I find is missing is an analysis of why we're in the pattern now against where we thought we would be.. I think GP and a few others do this from time to time but for me, this would give more credibility to the hugely complex subject of forecasting and may dissipate some of the blame culture that appears when things don't go as planned. I don't remember this zonal period that we're experiencing now being forecast to the extent that it is in terms of warmth and longevity. Why is that? What changed? What has led to the pressure buld to our south/south-east?

[Stour7]

Poor 18z....

Though a snippet of info.....Spoke to a guy in work today (customer). Anyway, he was discussing the flooding in the southwest and then went on to say this will continue over Christmas and into Jan. Now for the interesting bit......he said the highways agency have been given a heads up and told to stockpile grit for the middle of Jan as a potentially major cold spell may be on the cards.

No idea who he works for etc but seemed quite convincing that this is what he's been told and seems to tally with the potential warming event.

I have a customer who runs our local highways gritting depot, he said to me last week there's a high chance of a cold possibly snowy jan/feb, I asked how he knew this, he said it had come from a superior & that they were ready....

[Dorsetbred]

...., he said it had come from a superior & that they were ready....

Oh no you mean the BIG man himself has started viewing the models? Oh no, whatever next?

It is interesting to see the shift from what so early in the season was being "suggested" to the reality. The models are really hunkering down on the zonal stuff right now.

Edited December 23, 2012 by Dorsetbred

[cold snap]

Major straw clutching gem is the best run by a mile