Model Output Discussion 29th December - Into mid-Winter.

[radiohead]

Just a shame that the pressure remains quite high and we get cut off from the deep cold air.

[Mucka]

1 minute ago, CreweCold said:

Yep as I said last night to Nick, get enough amplification initially and you stand a chance of some retrogression as continued signals suggest vortex movement away from the Canadian side. What we don't want a half a job Annie situation where we get a trapped Euro ridge. High risk!

Yeah but Winter is permanently high risk in the UK as far as any cold goes.

I'll take those loaded dice and press my bet thank you very much. 

[igloo]

and we could end up with the holy grail later on with a greenland HP the best charts theres been for the past 4 years 

[Harsh Climate]

Don't get me wrong excellent developments this evening and all we can hope for is potential at this early stage, but those saying the ECM between 168-216 are perfect and would dump heavy snow are mistaken, in my opinion it would be more a case of light flurries in the east.

 

If we are to get an easterly of this sort, a fresh injection of deeper cold with uppers -12+ is required if we are really going to get the heavy (lake effect type) snowfall.

[Jonan92]

OMG

 

Look at Greenland

[Tristrame]

11 minutes ago, Stozzy said:

192 snow showers piling into eastern areas and probably a fair way west in the wind 

How would there be showers with pressure at 1030mb + ?

That's  high pressure 

 

[Cheshire Freeze]

Someone call an ambulance, I'm overdosing on blocking 

[snowking]

3 minutes ago, Harsh Climate said:

Just a quick question.

If the ECM at 192 was to happen exactly as shown, wouldn't uppers of -8/-9 not be quite cold enough for the north sea snow machine t get into full force?? Obviously areas exposed to the strengthening easterly wind.

A very good question and one I've been wanting to make a point about for the last 24 hours or so

Ideally on the 500mb charts you want to see the shades of blue as blue as they can be to encourage greater convection. Do we have the thermal gradient to encourage convection given -8c 850mb temps - I would say likely so, but with the caveat I haven't checked the SST's in the North Sea for some time now.

But the more towards the greens and yellows that you get, the more likely any convection is to be 'capped' somewhat - by this, I mean the height to which those lovely towering cumulonimbus clouds can tower to is rather restricted, as if somebody puts a ceiling in to prevent them rising any further.

So in this scenario, the further South you head, the better.

Now of course that's all very broad brush and it would take closer scrutiny of Skew-T forecasts etc closer to the event to see how high/low this convective ceiling might be (I believe there is a NetWx guide for this somewhere)

But we ideally want to see those blues from our new best friend the Italian Low spread as far north and west as possible towards our shores.

 

[Guest]

Folks try and stay calm. the pain of December 2012 and that ECM still cuts deep. it is a stunning boombastic run but until its inside t72 i will not trust it.

[Purga]

Lovely ECM - poised for retrogression (Hint: Greenland High) and Arctic reload from the N / NE at 240hrs!

Edited January 10, 2017 by Purga

[TheWeatherWizard]

Just now, Tristrame said:

How would there be showers with pressure at 1030mb + ?

That's  high pressure 

 

very cold upper air temperatures with warmer than average SST's. should provide enough temperature gradient leading to convection?

[MR EXTREMES]

2 minutes ago, nick sussex said:

OMG the ECM might be heading towards a Greenland high. This must be MJO related given the re-newed signal there.

0 sunspots sustained as well for a period of time.

Atmosphere switching.

I believe northern blocking will dominate.

but ecm also likes to egg on greenland blocking.

Although I think might be worth waiting just after Thursday to get more clearer picture carefully watchING were low pressure finally ends up.

I'm optimistic though 

 

[Stozzy]

Where's the low pressure in the North Atlantic 

[tight isobar]

Getting greedy and probably foolish. .

However as the long fetch sets up shop via ecm..I cant keep my eyes of the deep cold out east 216 hrs..

Like a snakes head ready to strike...

And with the south western trajectory heading northern Spain. ..the encouragement is there!!!!!!

Edited January 10, 2017 by tight isobar

[Backtrack]

Worryingly though, the ECM is on its own

[Ali1977]

2 minutes ago, CreweCold said:

Someone call an ambulance, I'm overdosing on blocking 

That is some crazy chart although not majorly cold with the 850s, could this turn into something really special I wonder. Front loaded winter looking 100 percent wrong right now, next week its the Baltic back loaded winters beginning.

[Stozzy]

3 minutes ago, Tristrame said:

How would there be showers with pressure at 1030mb + ?

That's  high pressure 

 

Hight too the north , low too the south , strong cold easterlie wind over a warm North Sea . It's ripe for snow showers 

[weatherguy]

Oh my...Wonderful.

And height rises over Greenland to follow and reload the cold.

Nothing resolved yet given the discrepancy between GFS/ECM at such close range, but it's nice to see ECM sticking to its guns. 

[MR EXTREMES]

4 minutes ago, Tristrame said:

How would there be showers with pressure at 1030mb + ?

That's  high pressure 

 

He said from the east he's pretty much right tbh 

[pip22]

1 minute ago, Backtrack said:

Worryingly though, the ECM is on its own

Well. JMA sort of agreeing with ECM atm.

[January Snowstorm]

A truly astonishing ecm tonight.

It would certainly be as good as 2010.

Can it happen?? Maybe.......

[feb1991blizzard]

1 minute ago, snowking said:

A very good question and one I've been wanting to make a point about for the last 24 hours or so

Ideally on the 500mb charts you want to see the shades of blue as blue as they can be to encourage greater convection. Do we have the thermal gradient to encourage convection given -8c 850mb temps - I would say likely so, but with the caveat I haven't checked the SST's in the North Sea for some time now.

But the more towards the greens and yellows that you get, the more likely any convection is to be 'capped' somewhat - by this, I mean the height to which those lovely towering cumulonimbus clouds can tower to is rather restricted, as if somebody puts a ceiling in to prevent them rising any further.

So in this scenario, the further South you head, the better.

Now of course that's all very broad brush and it would take closer scrutiny of Skew-T forecasts etc closer to the event to see how high/low this convective ceiling might be (I believe there is a NetWx guide for this somewhere)

But we ideally want to see those blues from our new best friend the Italian Low spread as far north and west as possible towards our shores.

 

Yes, I always make this point, look at any of the previous great Easterlies with really heavy lake / sea effect snow, they all have one thing in common, very low heights, you can get away with surface pressure as high as 1025mb , as long as you have very low heights thus a very steep lapse rate.

[Frosty.]

Surely it's the Ecm trend that matters most right now, all coldies should be delighted with this trend which could improve further in the days ahead..hopefully! 10/10 for keeping coldies happy.

Quote

 

 

[Snowy L]

6 minutes ago, Tristrame said:

How would there be showers with pressure at 1030mb + ?

That's  high pressure 

 

Surely if the gradient is there you will get precipitation even at 1030hpa.

[geordiekev]

18 minutes ago, tight isobar said:

Its an amazing run for an impactual easterly. 

Height format accomplishment

Someone posted an archive chart a couple of weeks ago which looked very similar to this one from ecm. Just wondering what year it was from if anyone can remember.