Winter Model Discussion - Cold Hunting -12Z 06/01/13

[Iceaxecrampon]

12Z

Weekend battleground at T+132?

Ian

[weatherguy]

At first I thought it was toppling, but at +168 there are signs of retrogression in my view, while the jet is heading south...Let's see how this pans out

[MR EXTREMES]

Think i have seen enough to call this a very very brief flirt from the east,that energy to the NW is going to do for us again IMO.

brief is 24hrs this is a few day event with cold surface temps and snowfall.

[Cheshire Freeze]

My ears are pricked...

Much better for future prospects on the 12z than the same period on the 6z

Edited January 7, 2013 by CreweCold

[Iceberg]

far too many people jumping the gun on this run. Out to T144 which is as far as we should realistically go, except for a bit of fun GFS 12Z takes most of the uk under cold 850's down to -8 and shows a possible snow event at the weekend.

Looks good to me.

[AWD]

UKMO not that bad at all:

Nothing sustained, but a lot more interesting than what's currently outside my window.

[MR EXTREMES]

energy shifting into southern greenland i think its pretty good to be honest im not in need of prozac and southerly tracking low heights possible.

[Dexter29]

If this potential cold snap at the weekend has nothing to do with SSW.

Then why did 2 TV BBC forecasters mention it in their forecasts as the reason for it turning colder this weekend?

Advising the public it's down to SSW.

[Weathizard]

So close, if that SW over iceland tracks SE rather than E like it seems to be, we could get a ridge into Greenland,

[fergieweather]

thank you Ian - surely some of modelling where we are seeing signs of fracturing of the tropospherical vortex are SSW related?

If so, then this would surely impact on the current cold spell progged and how and if it breaks down

Yes, for sure - but the broadscale (let alone mesoscale) set-up is a right mess in the ENS still, with some EC EPS members out past T+260 onwards showing a very wintry set-up; others a mild SW (!!) and this is symptomatic of the unreliability of where we are heading in terms of FI. The crucial point being stressed by Exeter is for folk (and newspapers!!) not to confuse the here-and-now MR set-up and chilling-off story with the (potentially far more profound) SSW impacts further into the month. This is a story yet to unfold.

Edited January 7, 2013 by fergieweather

[Stu_London]

far too many people jumping the gun on this run. Out to T144 which is as far as we should realistically go, except for a bit of fun GFS 12Z takes most of the uk under cold 850's down to -8 and shows a possible snow event at the weekend.

Looks good to me.

some sort of snow event for the the midlands looks likely on this run - probably not that severe but still time for changes

[Cumulonimbus Tower]

Looking at the bigger picture, there seems to be quite a lot of warm air being advected north in the mid Atlantic around the 168h mark on the GFS. Could this have the effect of blowing up a block, like a baloon, in the north-mid Atlantic/Greenland/Iceland further down the line?

Also, a bit on the dry side but one of the better looking METO charts at 120/144 i've seen of late!

Edited January 7, 2013 by Cumulonimbus Tower

[EML Network]

If this goes from Easterly to a Northerly...it's something I have seen modeled in several runs of late..this could turn out (after my initial worry) ...to be quite some run

[MR EXTREMES]

gfs is brillant for futher out love it happy tonight.

[Methuselah]

far too many people jumping the gun on this run. Out to T144 which is as far as we should realistically go, except for a bit of fun GFS 12Z takes most of the uk under cold 850's down to -8 and shows a possible snow event at the weekend.

Looks good to me.

Agreed, Ice...Especially when considering that, as IF has pointed-out above, whatever effect the current SSW eventually has, it isn't showing in the models just yet...My guess is that, when it does, it'll do so for the better!

[johnholmes]

Yes, for sure - but the broadscale (let alone mesoscale) set-up is a right mess in the ENS still, with some EC EPS members out past T+260 onwards showing a very wintry set-up; others a mild SW (!!) and this is symptomatic of the unreliability of where we are heading in terms of FI. The crucial point being stressed by Exeter is for folk (and newspapers!!) not to confuse the hear-and-now MR set-up and chilling-off story with the (potentially far more profound) SSW impacts further into the month. This is a story yet to unfold.

There is a chance Ian if you say it often enough some on here might actually take notice!

I may be wrong but my view is that the colder spell that comes and goes on the models towards mid/late this week into the weekend is partly as a result of the 30mb temperature spike that occurred 23 December. Picked up by the 500mb anomalies about 5 days ago suggesting about the same time frame. Still on course according to those ouputs for 12-15 start, and as the latest issue of the ECMWF-GFS this morning goes out to 10 days from now still around on the 17th and probably several days after that UNLESS all 3 of the major anomly issues change in the next 24 hours.

Edited January 7, 2013 by johnholmes

[Southender]

Nothing wrong with this? Looks good to me. Pesky PV lobe over Greenland nuked and further west. Greenie ridge building and trough dropping SE out of Norway.

Edited January 7, 2013 by Shrimper

[phil nw.]

A decent run for cold fans.Even at T96 hrs we can see the colder uppers heading this way.

The Greenland vortex starting to ease west again so becoming less of a problem as the main body of the vortex splits with some of it. heading towards Siberia and this has been the trend on the mean outputs.

Those height rises towards Iceland later and a northerly?

Edited January 7, 2013 by phil n.warks.

[Weathizard]

Reload alert!

Edited January 7, 2013 by Weathizard

[snowblizzard]

Just wanted to stress an important (indeed critical, for this thread) bit of guidance from our medium range folk at Exeter: Do NOT confuse current outlook for a return to the cooler conditions next few days with SSW effect. The latter has NOT yet shown it's hand in any NWP output in any reliable sense. They continue to expect this next key phase - with hugely uncertain outcome - to become a feature appearing from around 10d onwards, and NOT in the more near-term medium range. Current set-up into weekend / early next week etc is not related to SSW in their estimation - just bob-standard winter fare.

Yes, I think many are are becoming impatient!

It's going to take time for all these atmospheric changes to take effect.

We may be unlucky once again in the UK but I think we could be looking at a really special event come the second half of January!

[Cheshire Freeze]

Beautiful run into FI. Would bank this all day long.

EDIT: high sinks eventually but a great run upto that point.

Edited January 7, 2013 by CreweCold

[MR EXTREMES]

A decent run for cold fans.Even at T96 hrs we can see the colder uppers heading this way.

The Greenland vortex starting to ease west again so becoming less of a problem as the main body of the vortex splits with the some of it. heading towards Siberia and this has been the trend on the mean outputs.

Those height rises towards Iceland later and a northerly?

yes phil this has nothing to do with the ssw but the trend is cooling down with snowfall for some.

[Stu_London]

Heights end up going NW instead of NE on this run - much better for sustained cold.

Still FI so just eye candy at the moment - but might end up being one of the stellar runs I predicted earlier.

[london-snow]

Afternoon All.

Hope you all had a delightful Christmas & New Year.

I decided to take a break after the misery failings in December but am delighted to be back on the hunt for a cold end to winter 2012/2013.

After taking all today's output thus far and trying to make head to toe of where we go as far as the possible easterly it once again drawing back to December and we all know how that left us in the cold camp feeling..

It does always ring true that we are the end of the line for easterly's to come visit & when we do connect we have no cold air to tap into.

The way i would view this ' Possible Event ' is a bonus if it delivers but not the end of winter if it fails. It is once again a very fine margin between a cooling down or a cold to very cold pattern aka december 2012.

At least things should become a bit more seasonal.

[Timmytour]

Right now, you can see just what a lovely view there is from this rollercoaster.....