Winter Model Discussion 18Z 19/2/13 onwards.

[be cause]

The most interesting weather may yet come out of the wild west ..

[SnowObsessor90]

Looking at it more of a spring perspective what do the overall longer trends suggest?, a continuation of this weeks more settled conditions with a possible warm up or a gradual decent to something more unsettled as the the 18z shows? or in reality is it neither with no clear trend?

Cheers

[winterof79]

Still undecided as yet.

http://www.wetterzen...chester_ens.png

The cold inches ever nearer on the ECM http://www.meteociel...0-192.GIF?25-12 as per the METO medium range for the N/E.

Some sort of incursion from the n/e looking like lining itself up http://modeles.meteociel.fr/modeles/navgem/runs/2013022500/navgemnh-0-180.png?25-06 but as is always the case,the models finding their way slowly.

Edited February 25, 2013 by winterof79

[Jason M]

Looking through this morning the form horse is a big fat west based -NAO. After a winter of frustration it just about sums things up.

ECM is running out at present though and looks decent upto 168. I think its worth just persevering for a couple more days yet as whilst the ensembles show largely what I said above there are still a few good uns in there.

Jason

[winterof79]

Low heights moving in to the Med http://www.meteociel.fr/modeles/ecmwf/runs/2013022500/ECH1-216.GIF?25-12

Spring looks like arriving later this year.

[bluearmy]

Ecm op manages to put the mean and spread from the 12z into the run. West scandi v low heights and iberian trough. Our weak looking ridge provides 'the filling'.

[bluearmy]

A few weeks ago and the current modelling is pretty good for snow. Still a chance if the balls all fall in the right place.

[Liam J]

The last few frames of the ECM are very messy looking but certainly not spring like with an easterly flow of sorts from Europe right across the Atlantic into the Eastern States! Some exceptional cold for the time of year not to far away over the continent.

http://www.meteociel.fr/modeles/ecmwf.php?ech=216&mode=1&map=0&archive=0 http://www.meteociel.fr/modeles/ecmwf.php?ech=216&mode=0&map=0&archive=0

[Frosty.]

And the award for best 00z run goes to ...the Ecm 00z, no contest really since the gfs 00z is a total flop with no sign of deeper cold returning and quite the opposite, a very mild FI trend. It looks very complex later this week, a bit this way or that way will make the difference between the gfs snooze fest or the ecm which this morning is keeping wintry hopes alive, a big improvement from the ecm yesterday.

[Weather-history]

I'm uploading March 2001 forecasts at the moment and ECM and GEM 0z op runs in their latter stage look March 2001ish

[bluearmy]

The hemispheric plot on ecm even more worrying for retailers hoping to sell some spring clothing. The utility companies rubbing their hands together. That nw canadian ridge again impressive. If that verifies, expect either the eastern states or nw europe to have a very cold march spell.

[nick sussex]

The dangling carrot continues this morning from the ECM!

Lots of unseasonable cold to the east, the key here is to get enough energy going into the Med, the low to the north clears ese and doesn't phase with energy to the sw, and then pressure starts to rise over the Arctic which adds a bit of southerly forcing on the pattern.

The GFS has a similar pattern but here you get an unfavourable phasing of energy from the n and south and not enough energy heading se.

In terms of the GEFS there has been quite a switch from yesterday evening with a new cluster of colder solutions and so perhaps a new trend developing.

We'll see what happens over future runs, my model endurance whilst waning has just enough left in the tank to see how this latest drama plays out!

[Timmytour]

I'm uploading March 2001 forecasts at the moment and ECM and GEM 0z op runs in their latter stage look March 2001ish

I'm already looking at next winter and wondering whether the holy grail of another 1947 or 1962/63 can be achieved.

This last winter was our best chance of 1947 I felt.... preceded as it was by a nice warm spring and a miserable summer reminiscent of 1946.

Now I'm looking at the prospect of a cold spring and thinking that could be similar to 1962 and there's some correlation in what the models are showing in the next couple of weeks.

Just got to hope the models stay consistent for the next nine months

Edited February 25, 2013 by Timmytour

[weather eater]

The GFS is extremely bullish at the moment with every run in the extended range ending the same way, the ECM far better for cold for at least some of us but frankly its performance in the modelling heights to our north has been woeful this winter, the GFS for all its faults has done better in that regard. Disappointed this morning I was not expecting much from the current synoptics but I was hoping for at least some cold nights but I've not seen anything lower than 0.5 and last night didn’t even make it below freezing, I will have much to say when winter ends and is analyzed.

[Gibby]

Good morning. Here is the report from the 00z output of GFS, UKMO, GEM and ECM for today Monday February 25th 2013.

All models show a straightforward pattern of weather between now and next weekend as the UK continues to lie under the influence of High pressure which is currently moving from Scandinavia to be centred over Northern Britain by midweek cutting off the cold NE flow that's been plaguing the South for many days now but maintaining the dry if rather chilly weather with large cloud amounts floating around. It then sits around or just North of the UK for the remainder of the week and then weakens in situ or slides SE over next weekend as pressure falls over the UK to bring Low pressure closer ot both the South and North of the UK with a very complex pattern of synoptics next week gradually resulting in an increased risk of rain and wind through week 2.

GFS then pulls away it's UK High away SE setting up a slack SE flow as pressure falls away to the SW and NW with a trough edging slowly East over the UK with rain for all with time. Through the rest of the period a Southerly then SW airflow develops with troughs swinging NE with rain and strong winds spreading to all areas by the end of the run with near average temperatures.

The GFS Ensembles show a milder spell slowly developing at the surface as High pressure relocates to the UK and eventually moves away allowing milder SE then Southerly winds to develop with a breakdown in the fine spell towards the end of the run. There is good clustering around this sort of evolution but there are other options too with rather colder results especially towards the North of the UK. The spread between members is rather greater again this morning though from the end of this week out to the end of the run.

The Jet Stream comprises of two arms currently, one riding over the UK over the North of the UK while the Southern arm continues to blow East across Southern Europe. The flow to the North weakens late in the week and weekend as the Southern arm keeps blowing strongly across the Azores and Southern Europe.

UKMO for the weekend shows High pressure centred over the UK with the chance of rather brighter skies in light winds. Things stay a little on the cold side with some night frosts but dry weather with some welcome sunshine by day.

GEM shows High pressure too over the UK with the trend to collapse it away SE as Low pressure to the North and SW take control. Outbreaks of rain would eventually develop with temperatures close to or a little below normal.

ECM shows a similar projected view with High pressure declining early next week following a dry and bright weekend. Pressure than falls with the chance of rain arriving from the SW increasing as we move into the midweek period coupled with a chilly SE wind.

In Summary the weather will stay fine and dry this week as the Scandinavian High centres on the UK late this week and weekend with light winds and temperatures near or a little below average. Thereafter pressure falls on all models with a trend to rather more unsettled weather through a variety of options shown, though the favourite option to win in my mind would be a gradual transition to a milder South and SW flow as the Jet Stream pulls further North over Europe and over the declined UK high that will of moved to SE Europe by then in a week to 10 days or so time.

[BLAST FROM THE PAST]

With such a subsided, well-capped flow and CUSC tops struggling even to 6000ft - well-handled by forecast ascents even some days prior - it never had the promise of anything more than moderate showers at most, with any accumulations over 1-2cm very much dependent on convergence/shower stream alignment. I recall one post fortelling of "20-30cm of snow", which was self-evidently a journey into the realms of Maddenology based on even cursory perusal of the ascents freely available.

What happened to the returning SW flow you and Matt were tweeting about Ian [tweets are so uninformative IMO as they are just one liners so one can't really grasp any depth from it]? Was that just what a model/mogreps was showing? If so is that model in tune with the others showing retrogression or a different outcome.

ECM pick of the bunch tonight and again like the UKMO did yesterday and IMO still does, show a prolonging of the cold set up. After this less cold blip lets see if an anticipated renewed cold surge attacks for early March taking the cold spell well into March with no breakdown...yet.

March to be a distinct month of two halves?

BFTP

[TEITS]

Have to laugh at the models because yesterday morning I was posting about mild S/SE,lys being shown and now the ECM is suggesting E,lys. I notice the cold runs have also reappeared on the GEFS after disappearing yesterday.

http://cdn.nwstatic.co.uk/ensimages/ens.20130225/00/t850Cambridgeshire.png

So really my view hasn't changed since a few days ago. We could see very mild weather in the medium range or very cold with heavy snow. Obviously this is a very vague interpretation of the output but in my opinion both are equally possible. Im not sure I have the stamina to follow this on every run!

[MR EXTREMES]

The dangling carrot continues this morning from the ECM!

Lots of unseasonable cold to the east, the key here is to get enough energy going into the Med, the low to the north clears ese and doesn't phase with energy to the sw, and then pressure starts to rise over the Arctic which adds a bit of southerly forcing on the pattern.

The GFS has a similar pattern but here you get an unfavourable phasing of energy from the n and south and not enough energy heading se.

In terms of the GEFS there has been quite a switch from yesterday evening with a new cluster of colder solutions and so perhaps a new trend developing.

We'll see what happens over future runs, my model endurance whilst waning has just enough left in the tank to see how this latest drama plays out!

oh please the models have been at it all winter I eat my hat if it happens I've lost all Faith in all the models in fi best just sticking to ukmo.

hopefully spring warmth is around the corner its time to remember how flip flop the big two models have been remember the snowfalls we had here so not totally disappointed but the models have been awful past hundred hours I for one won't hold much faith anything beyond.

gfs looks ok for a warm up but I'd be more inclined to think more of the same perhaps right through March.

[Frosty.]

The GFS is extremely bullish at the moment with every run in the extended range ending the same way,

As nick said though, the GEFS has flipped since last night with a new cluster of colder solutions so we may see more wintry looking gfs op runs soon. The Ecm cheered me up.

[mushymanrob]

gfs milder, ecm colder.... whats new? . the extremes of each model over the last 6-8 weeks has never been established, its highly likely that the mid-long range predictions of both models will not be totally correct either, and we actually get something in between.

until next week we are stuck with this dull, dry, cold which should slowly improve.

overall its just fairly normal late feb/early march weather.

Edited February 25, 2013 by mushymanrob

[weather eater]

As nick said though, the GEFS has flipped since last night with a new cluster of colder solutions so we may see more wintry looking gfs op runs soon. The Ecm cheered me up.

Morning frosty I don’t tend to follow the ensembles just the operational’s, If you view the GFS operational runs as an ensemble from about the last four days, they are all pointing the same way however, as usual it’s not an either or situation as both the ECM and the GFS could be wrong, defiantly a sitting on the fence time, its comfy, nice and wide at the moment.

On the subject of either or, this has been my bugbear all winter, analysis of the modelling has frequently tried to tie itself to the idea that if the GFS is rubbish and thus wrong, ergo the ECM is therefore correct, this is the main reason IMO that the ECM has lead the model thread up the garden path so many times this winter re heights over Greenland, and I can see it having one last go as we head into spring.

[karyo]

I'm uploading March 2001 forecasts at the moment and ECM and GEM 0z op runs in their latter stage look March 2001ish

March 2001 and 2006 were awesomely wintry!

Karyo

[No Balls Like Snow Balls]

There is good agreement that HP will dominate our weather up until T144/168 at the least.

After this there are small signs that it may become more unsettled with more of a W/NW flow

No really mild temps on the horizon.

[Purga]

The dangling carrot continues this morning from the ECM!

Lots of unseasonable cold to the east, the key here is to get enough energy going into the Med, the low to the north clears ese and doesn't phase with energy to the sw, and then pressure starts to rise over the Arctic which adds a bit of southerly forcing on the pattern.

The GFS has a similar pattern but here you get an unfavourable phasing of energy from the n and south and not enough energy heading se.

In terms of the GEFS there has been quite a switch from yesterday evening with a new cluster of colder solutions and so perhaps a new trend developing.

We'll see what happens over future runs, my model endurance whilst waning has just enough left in the tank to see how this latest drama plays out!

Fair comment but the milder solutions still look favoured.

[nick sussex]

Fair comment but the milder solutions still look favoured.

Yes that's still probably favoured but its quite a complex set up because you've got that energy heading se, and energy dropping south so its really where those two phase.

The milder solutions have the set up further west and phase that shortwave to the north with the UK on the mild side of that troughing, the ECM takes the shortwave east with more energy into the Med.

Its a delicate balance and for that reason I'm happy to give the models a few more runs to see whether we see eastwards and southwards corrections.

The key timeframe is around 144 to 168hrs because the GFS 00hrs run develops a shortwave south of Greenland which is the trouble maker, the ECM develops this runs it se then east and doesn't phase it.

As you can see the shortwave is still there, you need this to separate and clear away with the residual energy it stops southwards forcing on the pattern.

If you get this away earlier then the Atlantic low is forced more se with more energy heading into the Med, the juries still out here because of the uncertainty regarding these shortwaves.

Edited February 25, 2013 by nick sussex