Winter Model Discussion 12Z 22/1/13 onwards.

[Rocheydub]

It`s looking more and more likely that we will start the new month in a colder north westerly pattern as shown in the ens outputs and if the Atlantic ridging shows it`s hand like in this run a potent northerly is quite possible.

Still too much of that Canadian vortex showing so the Greenland heights topple.Get rid of some of that and we are in a whole better position-this may come in time as the vortex continues to look fragmented.

And this^ ^ ^for all you newbies, is exactly what the models are showing... Keep your hats on!

[Snowman.]

Please explain so us not model readers aren't left guessing.

Kx

Note to self when the thread boring in summer learn to read models

The High in the atlantic and low to the east bring down some colder air.

High = Clockwise

Low = Anti-Clockwise

using this you can see that there are northerly winds flooding the country as bringing snow. but its late in the run so its far from accurate.

also someone asked what FI meant look at my signature and for more abbreviations here - http://forum.netweat...-abbreviations/

I actually liked the 12z got rid of that Canadian energy earlier on so the chances of a toppler are lower.

Edited January 26, 2013 by SN0WM4N

[Earth Wind and Snow]

Rather strange ending to this GFS run but the trends are still good for blocking in early Feb

[Grimsby Snow Lover]

Rather strange ending to this GFS run but the trends are still good for blocking in early Feb

Looks like a reload notherly type to me for what its worth

[Earth Wind and Snow]

Looks like a reload notherly type to me for what its worth

Yeah if the run continued for another few frames it would probably show a renewed northerly - be different again on next run but good signs now for another cold push in Feb

EWS

[Snowman.]

At least the trends are there will always be time for changes wonder if it was a outlier the Ensembles should be fun tonight!

Also got myself a avatar!

[bradymk]

Another cool 18z suite and colder than the impressive 12z suite. Mean getting close to -5c after the shortlived mild spell over the next few days. ECM Ens for London also impressive longer term http://www.meteo24.fr/fr/home/meteo-france-et-europe/passion-meteo/ensemble-de-previsions.html?eps=london Hoping we can keep the Jan CET below normal. Metoffice currently show CET at 2.9c which is impressive considering the very mild start. Lets hope we can get a below avg month from this January, seems a rare occurrence now.

Edited January 26, 2013 by bradythemole

[TEITS]

Rather late viewing the models this evening.

Very positive output tonight. When I seek a cold spell in the model output its all about momentum and whether this momentum is gaining strength towards cold. That is certainly the case this evening. I've just looked at the 18Z ensembles and randomly choose +300 and out of 20 ensembles only 4 are poor.

Still don't think we shall have to wait until +300 for the cold to return as this could earlier.

[Panayiotis]

At 300hrs and that is a beauty of an ensemble! With the Azores ridging north and low to our east, we have N/NW flow!

Looking at the whole ensembles for my area and there is a definite trend for colder conditions,some time to go but its looking good for another cold snap (spell?) to start from the second week of Feb!

Edited January 27, 2013 by Panayiotis

[london-snow]

Forgive me but i was under the understanding that our next shot would come from the north east?

Could well be a transfer of flow from nw~n~ne or am i barking up the wrong tree?

Edited January 27, 2013 by london-snow

[LomondSnowstorm]

At 300hrs and that is a beauty of an ensemble! With the Azores ridging north and low to our east, we have N/NW flow!

The evolution has a very similar look about to the last two cold spells over the winter, with low heights digging southeast into Europe and ridging in the mid Atlantic north-northeastwards. With the next stratospheric downwelling set to hit and some favourable tropospheric background signals (along with the general late winter PV weakening), the potential is there for another cold spell with perhaps more convincing blocking in place than the other two so far. Still very much a case of wait and see though, but it's positive that we're sniffing the scent of another cold shot just hours after a fortnight long cold spell.

[Panayiotis]

The evolution has a very similar look about to the last two cold spells over the winter, with low heights digging southeast into Europe and ridging in the mid Atlantic north-northeastwards. With the next stratospheric downwelling set to hit and some favourable tropospheric background signals (along with the general late winter PV weakening), the potential is there for another cold spell with perhaps more convincing blocking in place than the other two so far. Still very much a case of wait and see though, but it's positive that we're sniffing the scent of another cold shot just hours after a fortnight long cold spell.

Yes some favourable signals for another cold spell, I remember back in early Jan/late Dec when I thought to myself that we could be looking at a cold spell giving what the models were showing, and then on the 15th we were in the freezer! I have the same feeling now that I felt before so something maybe brewing! Edited January 27, 2013 by Panayiotis

[Cal]

Highly amplified over the next two weeks or so, little in the short term wrt to snow n cold, but, n a big but, things looking juicy teleconnectively from the 10th onwards.

[kumquat]

Significant height intrusion at 300z. Maybe..just maybe...

[Chris D]

I think all the models have been showing a highly amplified solution through this week (esp GFS)....some stormy weather likely in the west!

I think the weather continues to show great interest imo!!!!!

Some severe gales very likely in exposed W areas.

Edited January 27, 2013 by Chris D

[Ryan Dutch Weatherman]

Look at this CMA the Chinese weathermodel 12z is coming with a major blocking at 240 hours.

I think west Europe wil become for certain another colld outbreak from the Arctic..

Also current MJO fase is very good news for the wintry people , ist favour them.

Also the are strong signals for later in februari a trend for a Russia High moving west towards Norway.

I think we coulb be in for a long period of cold weather with lof of snow in februari en als a part even of march 2013 !

[Ryan Dutch Weatherman]

GFS 00z is stunnig en a smashing run , i told you before with the CMA 12z , but look at this !.

This is a big comeback of the artic flow en the snow flow !

[winterof79]

The projected mid spell is getting flattened out rather quickly http://www.wetterzen...chester_ens.png

Things looking interesting from next weekend GFS http://www.meteociel...&mode=0&carte=1

ECM http://www.meteociel...map=1&archive=0 and UKMO http://www.meteociel...=144&carte=1021.

GFS then continues its trend into FI.Our high migrates into the Atlantic and ridges north http://modeles.meteo...snh-0-192.png?0

With a rather pleasant outcome http://modeles.meteo...snh-0-360.png?0 Any one getting that feeling again?

Edited January 27, 2013 by winterof79

[tinybill]

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=204

morning all gfs is suggesting some major winter storms from feb 9 so don't out the snow gear away yet!!

[TEITS]

Excellent GEFS/GFS trend this morning. Check this out below using the mean.

PV at +192.

+240

+300

Note how it shrinks. This weakening is great to see and as a consequence you would expect blocking to develop to our N and that is exactly what happens. Clearly see this on the upper temps mean in my location.

http://cdn.nwstatic.co.uk/ensimages/ens.20130127/00/t850Cambridgeshire.png

[Gibby]

Good morning. Here is the A.M. Report on the 00z Output from GFS, UKMO, GEM and ECM for today Sunday January 27th 2013.

All models show a windy and unsettled week to come as the basic pattern of Low to thee North of the UK and High to the South is maintained. Some of the rainfall will be heavy and prolonged especially early in the week when severe gales are likely at times. Flooding could also be an issue as the recent snow melt combines with heavy rain through the week. There will be periods of more showery and cooler conditions like today and again on Wednesday and Thursday when the air might be cold enough for snow on Northern hills.

GFS then shows next weekend with the Azores High moving ever closer to the SW and with pressure having fallen over Europe as a whole a NW flow will set up dragging rather colder but drier conditions SE across the UK though the North and East may see further wintry showers at times, chiefly over the hills. This theme then continues into the middle of the following week when High pressure to the SW splits as a Low pressure divides the High into two bringing rain and wind back in to all areas late in the week to be followed by a quick return to cold and wintry conditions with snow at times, especially in the South as High pressure of sorts builds to the North sending the Jet flow well South of the UK again.

The GFS Ensembles show a trend to rather colder conditions to slowly develop again over the UK as we move through the period. It looks like the trend to develop a situation not unlike the recent cold spell is possible with a weak level of Northern blocking and coupled with a European cold air pool sending Low pressures on a more SE track with sleet and snow possibly becoming more of a feature of the UK by the second week if the path of these depression keep the UK on the cold side of the frontal activity.

The Jet Stream shows the flow blowing strongly across the Atlantic towards the UK for the oncoming 5-6 days before it ridges up in the Atlantic around the Anticyclone just to the SW by next weekend.

UKMO for midnight on Saturday shows Low pressure stretching from the Norwegian Sea to the Baltic with a colder North or NW flow developing over the UK ahead of a toppling ridge of High pressure in the day that follows. There would be wintry showers for many especially in the North and East with snowfall over the hills.

GEM shows a similar set up for Saturday as UKMO moving forward with rather cold zonality bringing spells of rain mixed with wintry showers, especially in the North as we move through to the runs end.

ECM too shows a similar trend, though on this run it keeps our friend the Azores High well in control at this stage keeping the cold and unstable air at arms length over nearby Europe in this time frame with any effects from this mostly felt in the North and East with a lot of benign NW winds and cloud cover likely further SW.

In Summary the trend is clear to see from all the models to aid the return of something rather colder as pressure falls over Southern Europe pulling the Jet South over Europe. The problem for the UK is getting the Azores High to drift far enough away to the SW to allow Low pressures to sink further West in their tracking SE movements encouraging the colder air over Europe into Britain as well as encouraging pressure rises to the North and NW to speed up the transformation to something more wintry such as GFS shows late in its operational. It could be a slow arduous track to a renewed cold spell and it may amount to nothing but there is a definitive trend shown throughout the morning output of the Atlantic winding down somewhat with time allowing more interesting synoptics for 'coldies' to develop.

[Frosty.]

It looks like Glacier Point has been tinkering with the Gfs 00z op run..this looks like his NEly blast evolving

As for the next week, it looks mildish and very unsettled with wet and windy spells for most of the week but turning colder from the north on fri/sat with wintry showers pushing south before the ridge to the west topples southeast, the southern half of the uk then has a fine spell with overnight frost and the far north has a strong and showery polar maritime flow for a while, the gfs 00z is then showing pressure rising across the whole of the uk before all the action later in the run that takes us to this chart, oh I wish we could take this run as gospel, it's setting up a big cold spell at the end.

[IDO]

The ECM and GFS to D10 are relatively similar re synoptics. A zonal flow pushed further north with time allowing heights to build close to the UK.

ECM T240: GFS T240:

So as the cyclonic westerly's pass east they draw some transient colder uppers through, so after early next week's milder interlude, we are in a seasonal flow of average Feb conditions. The ECM remains flatter than the GFS so any changes to prolonged cold still seems an age away (mid Feb?) on that run.

The ensembles from GFS: The mean shows average/above av. temps till around D10 and slightly below after, but nothing suggesting anything v.cold and just normal winter fare.

GFS in FI tries to ridge the east Atlantic but the first effort is a toppler. A reshot looks likely at the end of FI:

No sign of sustained cold from the op but there is sufficient "potential" for the pattern to develop. The next 3-5 days should tighten up on D10 onwards. In the interim we have a period of jet dominated changeable weather before it settles down (and possibly cooler), under Atlantic ridging.

Edited January 27, 2013 by i'm dreaming of...

[Cecil Hogmanay Melchett]

Verynice GFS FI this morning,ecm quite the opposite with a hideous profile to the north west.

Im not sure i can remember a winter in recent times with an almost constant PV in place over Greenland from Nov right through to Feb,really the weather gods must have it in for us as you can bet your bottom dollar there will be some great blocking up there come spring!

[bradymk]

Verynice GFS FI this morning,ecm quite the opposite with a hideous profile to the north west.

Im not sure i can remember a winter in recent times with an almost constant PV in place over Greenland from Nov right through to Feb,really the weather gods must have it in for us as you can bet your bottom dollar there will be some great blocking up there come spring!

ECM op doesnt fit in the ensembles and the temperature ens for de bilt are colder once again with the meam only just above zero now.