Winter Model Discussion 18Z 19/1/13 onwards.

[Frosty.]

I think that is true for both easterlies and northerlies frosty. A northerly can sustain so long as there is a strong block over greeland. Of course, they will topple without the block.

Easterlies, on the other hand, are more diffilcult to get in the first place, but they can also disappear fairly quickly without blocking in the right place.

Maybe we will get a proper Northerly in February if we get strong height rises in the greenland/iceland area, a few recent gfs op runs have shown good greenland high formation. I don't think anything like this run will verify in FI, it just looks typical default zonal dross in FI and I expect the outcome will be much better than this, a short spell of less cold and then another freeze.

Edited January 20, 2013 by Frosty039

[ANYWEATHER]

note trough disruptioñ on 12z compared to 06z,

[bluearmy]

Plenty of amplification in week 2 gefs again. Cant see this 'mobility' lasting very long if does indeed make it. Not too many amplified runs deliver cold uppers although surface temps look fairly chilly on around a third of the runs.

[Jonan92]

You should have a look at the ensembles of the GFS t384h... many of them show blocking in the Greenland area

[Catacol]

ECM needs to pull something out the bag tonight. The 00z run frankly was awful for longer term prospects, with the Siberian shard declining and shifting further east, and no end to atlantic energy from the displaced Canadian side. I'm out for the next 90mins or so... hoping for an about turn in medium term prospects when I return...

[BlueHedgehog074]

I wonder if there were ever any times during the 1947 and 1962/63 Winters' where it looked as though the Atlantic would try come back in within a close(ish) time-frame, but then kept getting pushed back, and back, and back with the possibility of blocking being under-estimated and the Atlantic being over done?

I mean, to be fair, the chances are the Atlantic will eventually smash away the chilly weather away from us, but I suppose it depends how quickly this will occur. The GEM 00Z, although not quite the most reliable model, seems to find a way to get the cold continuing just about with Lows going under the block...

An example next Sunday

(though even then the Lows do kinda go a little bit further North eventually, but it would probably stay cold/chilly for most).

Either, most of the other models have overdone the Atlantic influence with the possibility of the Lows out West being over-deepened, or that 00Z GEM Low undercutting idea with reasonable heights over Greenland could be the way to go. Even the 00Z ECMWF, at 168 hours (which I know will likely to change anyway), almost had a Low undercutting us to the South-West. Think it will obviously depend how powerful and flat the Jet-stream is, too, as this could wipe away blocking quickly if too flat and/or powerful with a risk of a more flatter pattern as well as how the Stratosphere warming events continue to behave and how it affects the Polar Vortex blobs to the North in future.

[Paul T]

Yes but behind it shows high pressure building northwards, with no height rises to the south and in Europe that chart doesnt seem as bad as you think.

in the next few frames It actually programmes that High to move to Europe, which is even worse for us!

[Jason M]

Ensemble 3 has a 1070 mb high over Greenland. :-)

[Catacol]

You should have a look at the ensembles of the GFS t384h... many of them show blocking in the Greenland area

I think 384z for GFS is cloud cuckoo land, never mind FI. T144 - 240 is medium range output in something like a useful range.

[weatherguy]

ECM needs to pull something out the bag tonight. The 00z run frankly was awful for longer term prospects, with the Siberian shard declining and shifting further east, and no end to atlantic energy from the displaced Canadian side. I'm out for the next 90mins or so... hoping for an about turn in medium term prospects when I return...

What about the continuation of the trend towards the possibility of an undercut rather than simply blasting away our block? Not over yet, promising run once more.

To illustrate my point:

12z

6z

Edited January 20, 2013 by weatherguy

[fourseasons]

Just watched the bbc national forecast and they said at the end to' not expect it to warm up this week' The models have suggested a possible breakdown towards the end of the week though they are not in complete agreement as to how and when this occurs.

Therefore, do the met office think that the breakdown may occur at the start of next week ? Interesting times...

Edited January 20, 2013 by fourseasons

[Jonan92]

I think 384z for GFS is cloud cuckoo land, never mind FI. T144 - 240 is medium range output in something like a useful range.

I know, but if you see that more than 50% of ensembles show heights rising to our west, it should mean something, maybe GFS is picking a background signal already

[Methuselah]

Ensemble 3 has a 1070 mb high over Greenland. :-)

When's the first meeting of Straw-Clutchers' Anonymous, then?

[bluearmy]

I know, but if you see that more than 50% of ensembles show heights rising to our west, it should mean something, maybe GFS is picking a background signal already

precisely. thats what they are for. not for individual analysis - but to see if there are any trends amongst them. the fact that so many are blocked indicates that mobility for week 2 is only a 50/50 call.

[Rollo]

Diagonal Red Line referred to the winter of 62-63 which I

I remember quite well and -at least a couple of times it appeared that the mild air would have an easy victory but the intense cold over the country repulsed it and the severe weather continued.Obviously the Synoptics are different this year but do not writes his spell of at your peril.

[cooling climate]

Plenty of amplification in week 2 gefs again. Cant see this 'mobility' lasting very long if does indeed make it. Not too many amplified runs deliver cold uppers although surface temps look fairly chilly on around a third of the runs.

As soon as it hits low res its swept aside. Will the ECM pick this up similar to what the op was

showing a couple of runs back.

Still small changes in the t72-120 time frame so the cold still in with a chance just.

[Mini tiger]

ERM ??

920 MB LOW !! Don't think I have ever seen one of them on a GFS chart

Would that bring snow all the way across the atlantic because its soooo cold ?

[Yarmy]

Before the ECM rolls, it's worth remembering what Matt Hugo said about the ECM 32 Dayer on the 18th Jan:

"The EC32 model does signal a milder interlude by late Jan before a renewed risk of northern blocking around Greenland and colder into Feb"

Something to look for in the ENS perhaps although a lifetime away.

[Tom D]

Cross-model agreement between GFS, UKMO and ECM at +120. GFS holds the low pressure off more at +144, but it would still be less cold. Confidence of a breakdown is increasing.

http://www.meteociel...M1-216.GIF?20-0

http://www.meteociel...H1-240.GIF?20-0

EDIT: Horrible. Horrible. Horrible. Is there anything positive we can get from these charts?

Edited January 20, 2013 by Tom D

[Jonan92]

ECM's run is awful in FI

[Mr Frost]

Cross-model agreement between GFS, UKMO and ECM at +120. GFS holds the low pressure off more at +144, but it would still be less cold. Confidence of a breakdown is increasing.

http://www.meteociel...M1-216.GIF?20-0

EDIT: Horrible. Horrible. Horrible. Is there anything possible we can get from these charts?

The only thing possible Tom is that the next run in the morning will show something completely different.

I would not get too upset about anything after 120+ just now.

[BurwellWeatherWatch]

ECM's run is awful in FI

what an insightful piece of analysis!

Yes - operationals coming together for something of a breakdown for next weekend, but that's about all we can say at the moment. May be mild, but more likely to be just less cold. For how long is the million dollar question. Operationals again flying around with all kinds of solutions. good to see some sort of tentative agreement around 120 even if it's not quite what we want. But wasn't the last time we had perfect agreement at 120 on December 6th...

[Jonan92]

what an insightful piece of analysis!

Well, this map doesn't show anything nice

Strong vortex and zonal

[TEITS]

Well very disappointing ECM. The most disappointing isn't just the break down of the cold spell but if we cast our minds back we had GP referring to a very cold blast from the NE and then we had the Strat thread suggesting the main potential from the SSW will be end of Jan. So combined with that we have the ECM showing this chart below.

Oh dear.

Im not for one minute having a pop here or dismissing the effects of the Stratosphere. However it does show that despite all these various technical forecasting methods, long or even medium range forecasting is impossible for the UK.

[IDO]

When a SSW was mentioned I was not expecting this:

I suppose it had to go somewhere! Wet and windy with average temps for the foreseeable. Hopefully it has not honed on a trend even though there was a mention by one of the experts that the two PV pieces were going to have a reunion. If that happens goodbye early Feb.