Winter Model Discussion 18Z 3/2/13 onwards.

[Captain Shortwave]

As regards to ECM 12Z, anyone notice that very cool pool coming around and beneath the Scandi high?

Yeah and by t240 there is a very nice cold pool developing to our east with our name on it. Jason M said a few days back about the need for some cold uppers to move down the eastern flank of the high, That shortwave at T144 which drops into Russia will do the trick nicely.

Oh and add to that the Canadian Vortex is vacating the premises on a hopefully fortnightly stay in Siberia

Edited February 5, 2013 by Captain shortwave

[Severe Siberian icy blast]

Ok , so all the way out to 240 hrs and we see a very strong scandi high , low pressure trying to squeeze the block east but not able to , and shortwave features splitting from the low pressure over the uk , bringing snow events, very cold uppers creeping under the high out to Russia heading our way !

Cracking tonight

[Wayneywoo]

Guys,

If the ECM went further out like F F S (ha! filter changed those three letters to I'm not happy AND what did I put here to get changed to "I am quite sad?") to T+384, it looks like the Vortex is on its way across the pole. Stewart was hinting at this possibility with the Vortex heading over the pole towards our NE!

Crumbs....this could be a sensational memorable end to winter 12-13!

Edited February 5, 2013 by Wayneywoo

[manutdmatt1986]

Very nice ECM once again, Sundays Low ever so slightly further west than the UKMO with the very cold air wrapping back round at 144.

Ian F just said on Points West that today's snow showers for our region "could pale into insignificance come Sunday into Monday"

Met obviously seeing the snow risk as far West as the Westcountry (to include many other places I should think). This has the potential to be really good for many!!

So long as it actually gets far enough East to hit Kent this time! Always a thin line between dry, snow or cold rain in these situations. Going to be a fun few days ahead.

[Rocheydub]

LOLOL

feb 1991 at day 11 & 12

http://www.meteociel.fr/modeles/ecmwf/runs/2013020512/ECM1-240.GIF?05-0

i hope because day 10 has nothing of interest for us!!!

[Cheshire Freeze]

Crumbs....this could be a sensational memorable end to winter 12-13!

I have a distinct feeling winter may not end until sometime late March!

[SMU]

So ECM 240

http://www.meteociel.fr/modeles/ecmwf/runs/2013020512/ECM1-240.GIF?05-0

The advection is moving NNE west of England to rebuild & support the scandi high ( we saw this in feb 12 but struggled with low heights just over the SW coast of Norway - need top remember that )

Note the upper air cold pool of -17C swinging round the base-

now feb 1991- just lower presseure to the west supporting higher pressure to the east- so pro rate differenial wise we are the same

http://modeles.meteociel.fr/modeles/reana/1991/archives-1991-2-4-0-0.png

http://modeles.meteociel.fr/modeles/reana/1991/archives-1991-2-5-0-0.png look at the heights on this day-

552 DAM in 524 thickness air- = convective snow flurries building.

I would love the 216 & 240 ECM to land tonight-

1) VERY VERY cold at the surface of england overnight with snow cover

2) Substantial cold spell building from the east that potentially could hit the whole of the UK-

pity its miles away- however the fun is now within reach....

S

[Snowman.]

Refreshment of cold uppers towards the end of the run.

With possible undercut?

[Cheshire Freeze]

In an ideal world we'd juice out the easterly then retrogress that high to Greenland and drop a trough into Scandi just as the cold uppers to the east ran out. Greedy? You betcha! But it would be fun, no?

Edited February 5, 2013 by CreweCold

[mulzy]

Ok , so all the way out to 240 hrs and we see a very strong scandi high , low pressure trying to squeeze the block east but not able to , and shortwave features splitting from the low pressure over the uk , bringing snow events, very cold uppers creeping under the high out to Russia heading our way !

Cracking tonight

And not forgetting the Azores High backing west. Great run and that was achieved with the "winter killer" not too far away.

Edited February 5, 2013 by mulzy

[Tamara]

Very nice ECM once again, Sundays Low ever so slightly further west than the UKMO with the very cold air wrapping back round at 144.

Ian F just said on Points West that today's snow showers for our region "could pale into insignificance come Sunday into Monday"

Met obviously seeing the snow risk as far West as the Westcountry (to include many other places I should think). This has the potential to be really good for many!!

Your post actually gives perhaps an inkling of how far things have come in terms of the UKMET thoughts since the weekend. The model suggestions with snow threat and potential easterly to follow which the ECM has continuously flagged were considered the outlier solution and non consensus back then - and from their professional forecasting POV it was understandable. Now though, it is clear that a lot of consideration is being given to the weekend as all the models have fallen in line with the ECM.

I thought looking at the postage stamps from the ECM ensembles at the weekend at t168 (which at that time took us up to the coming weekend) that there might be some mileage in the ECM, as to me it appeared to have more support than appeared at face value wrt to the mean, and this inkling grew more and more each time the operational produced exactly the same trend suggestion.

Obviously the exact track and details for the weekend are still rather uncertain, but with the GFS falling properly into line with the sliding low on a similar path to the other two main models, that does give confidence that many places up and down the country have a chance of a snowfall

Edited February 5, 2013 by Tamara Road

[Severe Siberian icy blast]

So ECM 240

http://www.meteociel.fr/modeles/ecmwf/runs/2013020512/ECM1-240.GIF?05-0

The advection is moving NNE west of England to rebuild & support the scandi high ( we saw this in feb 12 but struggled with low heights just over the SW coast of Norway - need top remember that )

Note the upper air cold pool of -17C swinging round the base-

now feb 1991- just lower presseure to the west supporting higher pressure to the east- so pro rate differenial wise we are the same

http://modeles.meteociel.fr/modeles/reana/1991/archives-1991-2-4-0-0.png

http://modeles.meteociel.fr/modeles/reana/1991/archives-1991-2-5-0-0.png look at the heights on this day-

552 DAM in 524 thickness air- = convective snow flurries building.

I would love the 216 & 240 ECM to land tonight-

1) VERY VERY cold at the surface of england overnight with snow cover

2) Substantial cold spell building from the east that potentially could hit the whole of the UK-

pity its miles away- however the fun is now within reach....

S

Evening Steve ,

The orientation of the high on the last two charts look perfect for a severe cold spell from the east .However would the uppers we can see to our east keep there depth as they migrated there way toward to the uk?

I suppose with a very cold land mass as it moves toward Europe and as its such a vast area of land they can maintain there severity , depends on the angle they come at the uk , over the North Sea then they will weaken somewhat but if they come in a more southeast direction they may well be maintained .

Edited February 5, 2013 by Severe Siberian icy blast

[weatherguy]

I see after yet another epic ecm IB has disappeared into the distance for now.

See you in at least a few weeks sir if the ecm is to be believed and with its constant consistency who's not to say its wrong !

I've found Ian quite reasonable this winter, making lots of well rounded posts actually

Corking runs once again, but I'm not yet getting ahead of myself after what happened earlier this winter - bloody shortwaves!

Anyway, can we just take a moment to enjoy this lovely straight northerly that's happening more or less right now? Beautiful.

[lorenzo]

Nice run from the ECM. Notable Scandi high as mentioned. Just looked up Feb 91 and spotted a link to 30cm overnight snow and understand the excitement with that evolution, always nice to see -16 uppers on the approach run.

Looking at the ECM with respect to model bias, charts below, blues lowered heights, oranges raised heights, then you can see minimal bias at 120 hrs, then at 144 hrs a definite lowering of heights in this region vs verification.

Perhaps this can account for in part the evolution over this 24 hr period, might be looking at things under too much of a microscope here but the height suppression may help explain a little something, also looks like evidence to me of models underplaying heights in this region. At 120 you may see things appearing to power through, then 24 hrs later the block is reinforced.

That particular 12z was a great watch. Wonder what the postage stamps will tell us. Perhaps improved clustering this evening.

[weather eater]

Very good ECM run can't get up much excitement for post 120hrs because it will change, synoptics do not stand still they constantly evolve and this will change maybe like in Jan for the better, we shall see. I would like to see more in the way of heights building to our North and NW. Biggest plus for me is that GFS aside we are starting to get some really good cross model agreement, with NOGAPS and the UKMO very similar to the ECM, GEMs not a million miles away either, the JEM less so but only in its latter frames

[Tamara]

We can dream...Id love Feb 1991 again!!!!!....

GP posted a day or so ago about two easterly attempts. The one from the weekend and another one several days later.

[goosey007]

So guys going by sundays charts where is the rain/snow borderline likely to be? Going by the comments it looks as though the midlands/south east look like being in the fireing line, whilst south wales and the west country missing out with yet more rain......any clarification will be much appreciated!!

Edited February 5, 2013 by goosey007

[The Northern Ramper]

I see after yet another epic ecm IB has disappeared into the distance for now.

See you in at least a few weeks sir if the ecm is to be believed and with its constant consistency who's not to say its wrong !

Ian is a big fan of snow events and I am sure would love to see the ECM come off, not sure why people have such a downer on him for daring to suggest an opposing view to the rest. From what I have seen he has called it mild and cold this winter.

[cooling climate]

As regards to ECM 12Z, anyone notice that very cool pool coming around and beneath the Scandi high?

Lol either you do not read the posts in the thread or you have me on ignore.

In response to CH post the stratosphere profiles some three weeks or so ago gave a very strong

indication of heights to our north/northeast with the heights moving more towards Greenland later

on. I must admit that I did not expect such a long lull before the second phase started to kick in.

[chionomaniac]

Something in evidence tonight is the rare phenomenom of cold pool growth as it crosses from eastern Europe. This doesn't happen that often but in the right conditions the uppers increase in cold over the continent as they head in our direction.

So looking at the 850's on the ECM at T+192 over Europe they don't look too great:

A bit better by T+216

But building nicely by T+240 and this is both a cold continental cold pool growth as well as an Arctic feed.

I wonder what the ECM ensembles will be like tonight. We still have a good few weeks left before the mean zonal winds increase at the top of the strat filters down to the trop. For once we could have classic delayed indirect effects from the SSW as well as the direct effects seen earlier - it was always a matter of time, waiting until the Pacific block dissipated, which allowed the tropospheric vortex to take residence over there.

Edited February 5, 2013 by chionomaniac

[manutdmatt1986]

So guys going by sundays charts where is the rain/snow borderline likely to be? Going by the comments it looks as though the midlands/south east look like being in the fireing line, whilst south wales wales and the west country missing out with yet more rain......any clarification will be much appreciated!!

Looks to me like the front way stall just to the West of the extreme South East. Like it did in January. The details are bound to change before then though.

[chionomaniac]

Lol either you do not read the posts in the thread or you have me on ignore.

In response to CH post the stratosphere profiles some three weeks or so ago gave a very strong

indication of heights to our north/northeast with the heights moving more towards Greenland later

on. I must admit that I did not expect such a long lull before the second phase started to kick in.

Yes - I know, but we were stuffed by the tertiary warming that upset the apple cart somewhat. I wonder how many on here know how close we came without that!

[Roger J Smith]

Just a note on the retrogression of the Russian high, about 3-4 weeks ago there was a large cut-off high and surface 1060 mb high over the polar region north of the Bering Strait and Wrangel Island. That was squashed down about two weeks ago and split into the recent eastern NA cold wave high(s) and a stronger east Siberian high. Since then, have been watching the western flank of the Siberian high edging west and past 48h have seen key isobars making 10-15 deg progress around 65-70 N. This is the trend that the ECM and at times other models have picked up on and it only takes a slight acceleration from the pace that I've seen to get 1025-1030 leading edge isobars into Finland and even across towards northern Greenland. Some of the amplification of the Greenland high will probably come from developments in the Canadian arctic.

The short wave due to reach New England coast on Saturday is key at this time to possible developments around mid-week, if it heads towards south tip of Greenland it would be a strong sign for locked-in retrogression if much of it went west of Greenland but some is bound to miss to the east and that part could drag a bit of warmer air into the Jan Mayen sector where it could assist in height building. So I think everything is on track for a possible 4-5 week cold spell. My research model shows a rapid warming in mid-March and above normal temperatures in late March. But it shows mostly below normal through February and the first ten days of March. Can't rule out the odd day or two of Atlantic incursion given the fact that this pattern has not beaten the Atlantic entirely to the mat, but the refs may step in at some point and call it off, the way things are looking. Oh, and that Azores high should try to drift west through the period until it's pushed back east by strong progressive warming signals in early to mid March.

[Weather-history]

Lol either you do not read the posts in the thread or you have me on ignore.

In response to CH post the stratosphere profiles some three weeks or so ago gave a very strong

indication of heights to our north/northeast with the heights moving more towards Greenland later

on. I must admit that I did not expect such a long lull before the second phase started to kick in.

I went for a notable easterly during the back end of January in my forecast at the end of November, I maybe only 3 weeks out

[ANYWEATHER]

Ecm, shows the cold increasing by t+144 on its 12z run, compared to the 00z. Ecm is really not budging and I think it really is on the money, it would have changed its output by now if there was no certainty in its output and to be honest I would have thought by now it would have downgraded the cold output, but conversley the reverse!! Here is the two ecms 00z and 12z today.... The Gfs is walking behind the Ecm footprints....

Edited February 5, 2013 by ANYWEATHER