Winter Model Discussion 18Z 16/1/13 onwards.

[mcweather]

I know its FI but is that undercutting I see at 216?

[cooling climate]

Here in Hertfordshire I've seen 4 days at freezing or below and two at only +1 plus two falls of

snow with more to come that to me is a significant cold spell but like others have said it depends

on your location. Synoptically this cold spell has not looked that significant but as they say a

shallow high can do just as good a job as a full blown block.

The UKMO overly progressive this afternoon I think especially after viewing the GFS and ECM

which have delayed energy running east under greenland from earlier runs. Therefore I think it

would be wise to reserve judgement until tomorrow at least.

I see the ECM is carrying on from where it left off on the 0z run this morning in the latter stages.

Beast from the east on its way perhaps.

Edited January 19, 2013 by cooling climate

[SMU]

The ECM tonight a bit ropey past 144... but as said we can live in hope that we have a 48 hour window for it to change ....

The concern for the south I have tonight is will the WAA at 12pm tues be enough to push up well above freezing like the UKMo or will the ECM's slightly weaker gradient be enough to hold themilder dewpoints & air to the south....

S

Edited January 19, 2013 by Steve Murr

[Richie V]

Do I smell some hay clutching tonight!

[Summer Sun]

And t240 ends with this

Cold air pushing back into the east

[I remember Atlantic 252]

christ!

Now i didnt expect that!

Uppers crap, but not a bad ECMWF, maybe less cold 3 days, then cold again at 240, FI but just what model is showing

[David 'Minty' Hill]

Big low over the SW at t216

That would soon wash away any remaining snow!

Is that a sarcastic comment?? or has that low suddenly dragged loads of cold air with it?

[Paul T]

Do I smell some hay clutching tonight!

Possibley, but the only truely 'milder' part of the ECM is between 168 - 216. Not bad to be honest, not great, but not bad...

[johnholmes]

Essentially what the models are trying to do is come up with a feasible solution beyond say about T+144 to match what the 500mb charts are showing for the 6-15 day time period. That is blocking way north, a very deep and pretty cold vortex, much of it over the NE of Canada and northern areas of Greenland and another part over northern Russia, with a fairly strong flow west to east most of it south of this.

They will come up with various solutions as its not a very easy one to solve I would imagine. Just what will happen when the atmosphere either decides to do a change or is forced to do so by what has happened way above in the atmosphere is not easy to decide. In the post I made this morning the best bet would be some kind of blocking again through at least part of February, say about 60% at the moment?

Edited January 19, 2013 by johnholmes

[nick sussex]

Do I smell some hay clutching tonight!

Do I smell some hay clutching tonight!

Lol!

You might have said the same thing last week when some of the models ended the cold by today! The ECM could still go either way past 120hrs but if the UKMO is right then its game over.

[Summer Sun]

Is that a sarcastic comment?? or has that low suddenly dragged loads of cold air with it?

The uppers aren't all that cold so any precipitation will fall as rain hence why I said that would soon wash away any remaining snow.

All in FI though so no need to worry yet

[weather eater]

Certainly not a terrible run from the ECM, however, as we all know charts at 216hrs, 240hrs mean squat, I would prefer to see changes early that improve the mid range rather than rely on FI charts to come to fruition.

[TEITS]

Well the ECM is easy to sum up tonight.

Slower than the other models introducing milder temps with the exception of the GEM. However the potential for the cold spell to return fairly quickly from the E and still the slight chance it might not even turn milder although the NE/E would be more likely to remain cold.

As for our current cold spell and for my location its been excellent. So far 3 snowfalls which could be 4 tomorrow and my max temps haven't managed above freezing for several days now. The highlight so far was yesterday with 8hrs of non stop snowfall and max temps at 3pm of -3C!

I forgot to add no sign of a GH which appears to be absent this winter so far and was a key focal point of GPs winter forecast. If the cold spell does return after a brief milder spell then its more likely to come from the E.

Edited January 19, 2013 by THE EYE IN THE SKY

[Carlrg]

Matt Hugo posted on the strat thread that everything points to it turning milder (but not zonal) in the medium term. According to a couple of models including the BOM he may have hit the preverbial nail on the head.

http://www.meteociel...&mode=0&carte=0

http://www.meteociel...&mode=1&carte=0

http://www.meteociel...&mode=8&carte=0

Edited January 19, 2013 by Carlrg

[David 'Minty' Hill]

The uppers aren't all that cold so any precipitation will fall as rain hence why I said that would soon wash away any remaining snow.

All in FI though so no need to worry yet

Ohh i thought dam was like 500 purple colours where good maybe I dont read that chart right

[shaky]

The ECM tonight a bit ropey past 144... but as said we can live in hope that we have a 48 hour window for it to change ....

The concern for the south I have tonight is will the WAA at 12pm tues be enough to push up well above freezing like the UKMo or will the ECM's slightly weaker gradient be enough to hold themilder dewpoints & air to the south....

S

When you say south do you mean up to the midlands or up to the m4 etc!!

[mcweather]

I know its FI but is that undercutting I see at 216?

I'll answers my own question then shall I ?

http://www.wetterzen...cs/Recm2161.gif

http://www.wetterzen...cs/Recm2402.gif

yes it is , minus 12 uppers heading back west across the north sea.

pretty much in line with GP'S forecast then, with cold returning after a brief flirtation with milder / less cold weather

Edited January 19, 2013 by mcweather

[Froze were the Days]

It's the same old shape again at 216 on the ECM - low pressure close to our western shores linking back to a slice of PV near Greenland and somewhat bigger heights to the north east. It teases us at 240z but again will we see another half-hearted easterly come in before a depression to the west breaks it aside?

Edited January 19, 2013 by Froze were the Days

[shotski]

Would it be fair to say that any low pressure systems coming over the Atlantic already have a far lower

surface temp because of the dissplaced air from the recent ssw.

[cooling climate]

Well the 0z run was going down this route this morning and now the 12z ECM has taken it a step

further. If only the run went out to t268 and beyond we would almost certainly be looking at the

beast.

Now all we need to do is get rid of that three day milder blip and this would be turning into a very

prolonged and potent cold spell. Would tie in nicely with my predicted -1c CET from the middle of

Jan to middle of Feb.

[mcweather]

It's the same old shape again at 216 on the ECM - low pressure close to our western shores linking back to a slice of PV near Greenland and somewhat bigger heights to the north east. It teases us at 240z but again will we see another half-hearted easterly come in before a depression to the west breaks it aside?

Except that the block is being reinforced from the north and the east and would probably send that low darting southeastwards.

[J10]

Matt Hugo posted on the strat thread that everything points to it turning milder (but not zonal) in the medium term. According to a couple of models including the BOM he may have hit the preverbial nail on the head.

http://www.meteociel...&mode=0&carte=0

http://www.meteociel...&mode=1&carte=0

http://www.meteociel...&mode=8&carte=0

If you do quote someone, please quote their full comment.

Morning...

This signal for our +ve pressure anom to the N and NE of the UK at present day and in recent days does decline and disappear within a weeks time or thereabouts and this set of charts does show this;

http://wekuw.met.fu-...ll&lng=eng#fig2

The lobe of vorticity and ULL that has been sat over NE Canada has been persistent. Clearly it is producing a noteworthy amount of deep cold across E and NE Canada which is, without question, fueling the jet stream within the Central and W Atlantic, but clearly our block has so far won the battle. However, I do believe that change is on the way and within a weeks time, roughly, the block that we have now will decline and we will enter into a period of more mobile conditions and clearly this will make it somewhat milder.

What I am NOT suggesting here is zonality in any shape or form. I didn't comment on the EC32 day on Friday, but the latest update I believe is fascinating as it does show a more unsettled and milder interlude by late January. However, thereafter it is extremely bullish about bringing in 'Chino's Block' aka the Greenland high into the first half of Dec as the jet then ends up tracking south and we end up with a dominant wind direction during the first half of Feb (roughly) that is NE'ly.

I feel that this evolution is, without question, a clear and distinct possibility and this is where the EC32 will be put to the test now. Consistency in future updates is required, but given the usual consistent and correct info from Ed and this forum in particular, combined with the EC32 then I have a feeling that February will be far from mild, wet and windy!

Cheers, Matt

[Carlrg]

I know its deep into FI but the cold pool in Eastern Europe just throws in the towel and gives in at 186+ Its not fighting back.

http://www.meteociel...&mode=1&carte=0

If you do quote someone, please quote their full comment.

Trying to keep the spam down thats all. And i think i summed up the medium term quite well!

Edited January 19, 2013 by Carlrg

[SMU]

When you say south do you mean up to the midlands or up to the m4 etc!!

the UKMO would push milder air all the way up to the M4 Line-

The ECM may be weaker & focussed more on the E/NE areas for milder air...Post 72 the UKMO slides another small low across so you would then be safe to 120....

However that is quite different to the ECM...the models have followed a similar pattern over the last 4/5 days- especially the ECM & GFS- milder in the mid term with the atlantic pushing through-

then roll that timeframe through another 24 hours & the jet becomes amplified & sends more energy south-

I could quite happily have that for the rest of winter- but at some point it would likely break-

Maybe tomorrows 00z will show the same although im more interested in the WAA Tues-

At least monday night could prove very cold over the snow fields although it would warm up quick once the air was moving north-

S

Edited January 19, 2013 by Steve Murr

[Catacol]

pretty much in line with GP'S forecast then, with cold returning after a brief flirtation with milder / less cold weather

Big GP fan here, but actually I am a little concerned at the medium range output at present, in the context of what GP was expecting. His best guess was that the "milder" spell would be here about now.

The concern is that the Canadian vortex is holding its strength, and then when it does weaken it is emptying into the Atlantic with no obvious rise in pressure to the NW being picked up. GFS chart here shows the concern, with too much energy coming off the Canadian segment to allow much of a pressure rise, and loss of low heights to the south.

We might possibly end up with the same situation we had in December when heights then were expected to rise to the NW and didnt. Result? Lots and lots of cold rain, and a good deal of time required to shift the pattern on.

Saving grace is the MJO which looks set to move through 7 and this ought to signal height rises mid Atlantic at least as the composite here shows:

,

However the phase 8 composite is not so pretty:

and I am having trouble shaking off the experience of December and a certain amount of faith in mean anomalies and predicted composite matches has been lost. Disappointing lack of snowfall on Friday down here hasnt helped brighten my mood.

RJS long range forecast of cold in February still a beacon of light...

Edited January 19, 2013 by Catacol_Highlander