Model Output Discussion 25/11/2012 12Z onwards

[Frosty.]

Yes there is potential but seeing as the last week or so has been given such a build up only to be talking about potential is in its self a downgrade.forecasting up to 2 days on the runs seems impossible at moment so 240hrs seems a lifetime away.

Yes I agree, FI appears to start from later in the week so it's all still to play for, one thing I can't see is any return to mild for more than a few days, and the much colder solution remains the favourite in my opinion, lets just hold our collective nerve and see what the 00z shows, no doubt some will be up all night in anticipation.

[Jayces]

The very latest breaking news from our correspondent based in Maine!

Dramatic developments re the upstream low which throws big doubts into the ECM upstream:

A STORM SYSTEM MOVING OFF THE MID ATLANTIC COAST DURING THE MID WEEK

PERIOD NOW APPEARS MOST LIKELY TO PASS WELL SOUTH AND EAST OF THE

AREA SPARING THE REGION FROM SIGNIFICANT PRECIPITATION. HOWEVER...AS

THE SYSTEM INTENSIFIES SOUTH AND EAST OF NOVA SCOTIA WEDNESDAY NIGHT

AN INVERTED TROUGH WILL EXTEND BACK FROM THE SYSTEM SUPPORTED BY

ADDITIONAL JET ENERGY COMING IN FROM THE GREAT LAKES. THIS INVERTED

TROUGH MAY SUPPORT A SMALL AREA OF LIGHT SNOW OR SNOW SHOWERS ALONG

THE DOWNEAST COAST WEDNESDAY NIGHT

Inverted in this case means negatively tilted, look at the timeline and what the ECM does between Wednesday and Thursday!

I take it that's good news?

Having no idea what any of the NOAA text means doesn't help ;-)

If I was to have a stab i'd say that they are suggesting the low being ejected from Canada (is it?) will travel NW and not E as per the GFS / UKMO and not as per the ECM?

[nick sussex]

Sorry nick, is this good or bad news, and what does it mean? thanks

Well if you look at the ECM operational run it takes that feature runs it east, it doesn't develop it, the GFS and UKMO both develop it.

So there are doubts about whether the ECM is handling that eastern USA pattern correctly, if thats not correct it does make a big difference to us in Europe.

I'm not saying the ECM has no chance of verifying, its an excellent model but all models go through good and bad patches, we can only hope its the latter.

[lorenzo]

the OP is an outlier in the speed of the evolution but many members do support what the 0z run showed this morning by T192 onwards.

Ian - was the OP outlier you cite above the basis of the ' game over for this period of cold' post earlier prior to it being noted as too speedy.

I am Not nit picking just wondering if there was anything else? I genuinely defer to your level of knowledge here, but fear there is a slight bias on the other side of the coin to Steve's cold bias and I am trying to find a way to see through it. FWIW the point regarding the ECM 00z mean is a good one. the bit in blue above indicates less confidence in earlier thoughts.

Nick - where on earth are these Aviation NOAA snippets from !!?

[snowice]

Irish met service have gone with the ECM for Saturday, but a note of caution "by no means certain"?

not over yet ECM in the morning will decide. so lets not panic!

Edited November 25, 2012 by snowice

[Duane S.]

... I would add that the CPC update today is this:

Notice the very strong heights retained at the pole, and substantially low pressure predictions over Europe. The ECM run at present has the Azores high regaining strength and a flat pattern dominating to the north, this within the context of collapsing polar heights. It just doesnt fit. Something is wrong there.

Quite agree, these charts have been rock solid and tomorrow's will be of even more interest as it will have the human touch. Combined with what Nick has posted ref. upstream events and that (if verified) completely nullifies the ECM evolution, anybody throwing in the towel now does so way too hastiliy!

[nick sussex]

Ian - was the OP outlier you cite above the basis of the ' game over for this period of cold' post earlier prior to it being noted as too speedy.

I am Not nit picking just wondering if there was anything else? I genuinely defer to your level of knowledge here, but fear there is a slight bias on the other side of the coin to Steve's cold bias and I am trying to find a way to see through it. FWIW the point regarding the ECM 00z mean is a good one. the bit in blue above indicates less confidence in earlier thoughts.

Nick - where on earth are these Aviation NOAA snippets from !!?

They're my new toy! Especially relevant when we're looking at upstream events.

Heres the link, its great you can choose from the USA states and they go into alot of detail:

http://www.nws.noaa....view/states.php

For some reason not all 50 states are there but you get general discussion aswell as aviation bits.

Lol I just had a brain meltdown Nova Scotia is in Canada so why was I looking for it on that link!

Edited November 25, 2012 by nick sussex

[in the vale]

So, we have the ECM suggesting PV reforming by 120 and swallows returning by 240. Or we don't, as per MO and to a large degree GFS. The bigger picture has not changed, December was always going to be a turning point for this winter, not winter as a whole. I remain confident that 12/13 winter will go down as a good'un, not 2010 or 62/63, but we'll all be pretty happy come spring. The short-term synoptics and the global patterns are rarely in agreement in situations such as this, but the longer term NH picture (as GP, JH, GP, Chio and many others study and helpfully report on for those bothered to read) remain strong for a colder than average winter. Witness the chopping & changing of all the major deterministic models - at any time of year this is a strong indicator that the meteorological physics engines are struggling with the signals presented to them. I would not (and haven't for the last 2 weeks) believed a single chart from any of them. Trust the bigger picture people, then you won't be downhearted every time lower slightly Greenie heights are shown or an unfavorable shortwave pops up. You - yes YOU - are very likely to get cold and snowed on this winter, enjoy it and smile when it does. Look at the models that produced it and learn for next year. Honestly, that's all we can do.

[Catacol]

That was yesterday's, they don't do it on Sundays- but your point remains.

Just noticed the date on the bottom. Interestingly on the cpc website it clearly says updated 25th November. Bit odd that...

[Methuselah]

At the end of the day, it won't be any particular model-run that decides what'll happen...It'll be the weather itself!

[Ian Brown]

Ian - was the OP outlier you cite above the basis of the ' game over for this period of cold' post earlier prior to it being noted as too speedy.

I am Not nit picking just wondering if there was anything else? I genuinely defer to your level of knowledge here, but fear there is a slight bias on the other side of the coin to Steve's cold bias and I am trying to find a way to see through it. FWIW the point regarding the ECM 00z mean is a good one. the bit in blue above indicates less confidence in earlier thoughts.

Nick - where on earth are these Aviation NOAA snippets from !!?

The game over refers to if the ECM - and all the minor models are correct - because there is no quick route back to cold if the jet barrels through at Northern latitude. Anyone in doubt about what a mild December means for the remaining winter months only needs to check back thru the CET figures since 1987.

What Nick has unearthed looks like good news, and bizarrely, I can recall a couple of times that the ECM has got it wrong pretty big and both were on Sunday 12z runs !

The 0z runs are massive - this is a likely all or nothing, but please don't tell me you want to get to the ECM at T216/T240 because of the 'potential' - we have sat through 20 odd years of charts like that.

[Eskimo]

Eyes down folks, our favourite run of the day (the GFS 18z) is trickling out. Will it be momentous, or just momentous crap?

[Isolated Frost]

+72, you can see why the UKMET is more conductive to an early cold incursion- no baltic shortwave, no e greenland shortwave, more pronounced waa up greenland-

in fact, all the three major models make the mean trough solution very similar

18z rolling out now, but I'd wait to the gefs to announce anything- the FAX is most vital tonight- if it supports the UKMO solution it is definitely 'game on'

[Paul]

Locking this one now, new thread in a second for the 18z.