Model Output Discussion - 8th - 14th January

[phil nw.]

(only part of the post is quoted)

To be fair though that only goes out to T+192, there are quite a few colder ensembles after this point, if can get to the FI position, it really augers well for cold transferring to the UK. It is disappointing the UKMO and GEM 12Hz) only go out to T+144.

It will be interesting to see the ECM this evening.

Yes it does but i was really confining my overview to the next 7 days and on that particular evolution-later possibilties certainly not ruled out as i suggested in my closing sentence.

[Stormyking]

Good start from the ECM so far by the looks of it, looks almost similar to this morning at the moment maybe slightly better at the moment.

[Matty M]

Comparing the 120hrs UKM & GFS to ECM - ECM is ravingly better at T120...........................................................

So tight at T144hrs, The troughing in Iceland is a bit worrying, we need a trigger over Denmark to let things flood SW

Edited January 8, 2012 by Matty M

[January Snowstorm]

ECM says no Easterly at 144hrs

Cut off low, but still too much energy over the top.

Where to from here is anyones guess as FI starts now

[Matty M]

It is a NO DICE from the ECM tonight, NO DICE

The Jet goes over the top and doesnt allow enough ridging south of the Arctic High.

[January Snowstorm]

168hrs and its the azores high thats more in the picture

Easterly no chance now, though at least cold is surrounding us and a 2nd bite of the cherry hopefully down the line.

By then of course the latter half of January is upon us

[SMU]

Pretty poor ECM so far tonight

http://www.meteociel...1-168.GIF?08-12

S

Edited January 8, 2012 by Steve Murr

[nick sussex]

From hero to zero in 12hrs! just as the GEM jumped ship so does the ECM and both deliver the worst outputs of the evening!

At this point I'd take the UKMO or GFS, which have now gone from also rans to Oscar winners!

Edited January 8, 2012 by nick sussex

[SP1986]

I think the ECM criticism is a little premature, I believe there is a 50-50 chance outcome. High pressure could well set up, feeding in a northeasterly air flow over UK, or the high will move eastwards quickly, displacing the arctic high. Even the low pressure cell to our southwest, could introduce an easterly of some kinds.

Steve you just posted the 0z chart (unless it hasn't loaded for me yet). I'm on 144 hours.

[Snowstorm1]

Pretty poor ECM so far tonight

http://www.meteociel...1-168.GIF?08-12

S

A few more bites of the cherry in this situation will be needed but to me so far GP looks to have things pretty much spot on with regards to his winter forecast

[Optimus Prime]

One of the biggest factors that determine snow is cold. If the easterly does end up being the result (Low chance from the factors I'm seeing) there is very litle cold pooling situated over the mild continental Europe;

Something along the lines of February 2005 would be the result.

[wolvesfan]

The only thing that is certain at the moment is the fact that nothing is certain,the mods flip floping back and forth with no cross model agreement for two consecutive runs.

It's going to be a few days before things become clearer.

[dixonoid]

Looks like some sort of easterly to me.

Edit: looked good before it updated, lol!

Edited January 8, 2012 by dixonoid

[03jtrickey]

Looks like some sort of easterly to me.

That was the 0Z run - it hasn't updated yet

[dixonoid]

That was the 0Z run - it hasn't updated yet

Sorry about that sure I saw 12z in the corner, a bit premature from me!!

[Matty M]

Well post 120.144hrs ECM is not pretty. Greenland becomes the new home of the PV

But lets look at things again, there are major differences at 120 between the 3 major outputs this evening.

Right the 12z ECM doesnt evolve things positively, but the 120hr chart with one or 2 tweaks could bring

an easterly later on.

[Jason T]

Over all much rather have the output we have now than of recent, Patients people patients..GP should be pretty pleased so far.

[Cheshire Freeze]

Well the ECM is amplified........on the wrong side of the hemisphere

[nick sussex]

One of the biggest factors that determine snow is cold. If the easterly does end up being the result (Low chance from the factors I'm seeing) there is very litle cold pooling situated over the mild continental Europe;

Something along the lines of February 2005 would be the result.

If a piece of the PV drops in to eastern Europe then the continent cools rapidly, the problem isn't the lack of cold it's the PV which spills too much energy eastwards. The easterly of 2005 was synoptically different.

I can tell you from experience we can go from 15c max to -2 max a few days later even here in sw France, if you can arrange to nuke that PV then any easterly would certainly be cold enough.

[January Snowstorm]

Well post 120.144hrs ECM is not pretty. Greenland becomes the new home of the PV

It's been there now Matty since Nov though I know what you mean

I think FI is definately 120hrs and all of the background signals show the opposite of what ECM shows

The law of averages alone would surely tell us we couldnt end up back at square one!! (Could we?)

[damianslaw]

I have always believed the change to colder conditions mid month would be courtesy of scandi troughing and developing heights to our NW these eventually merging with developing heights to our NE. GFS today would definately support such an evolution in synoptics as we head into the third week of January with the jet tracking on an increasingly NW-SE tilt. In this regard I did feel ECM's easterly to be a little suspect and if it did come off would be a shortlived affair thanks to the PV still ruling the roost to the NW.

The evolution to cold is a weakening of the PV, jet taking a NW-SE tilt, building arctic high to our NE forcing a major scandi trough event plunging deep into europe enabling strong mid atlantic ridge to develop towards greenland with this linking quickly with arctic high. Thereafter we are in a set up where undercutting and easterlies/northeasterlies can rule the roost with a definate n scandi high (not a sinker!).

The key trend over the past couple of days has been support for a weakening polar vortex a devloping arctic high and the jetstream taking a more NW-SE path, these are the first steps to the cold embedding itself as we head towards latter part of Jan.

[mountain shadow]

It's been there now Matty since Nov though I know what you mean

I think FI is definately 120hrs and all of the background signals show the opposite of what ECM shows

The law of averages alone would surely tell us we couldnt end up back at square one!! (Could we?)

Well the background signals might be good but the models are not thinking much of them. We must get the PV out of Greenland before any cold air has a chance of getting here. Odds are now against a mid month pattern change to cold and snow based on tonights runs.

[Optimus Prime]

I can tell you from experience we can go from 15c max to -2 max a few days later even here in sw France, if you can arrange to nuke that PV then any easterly would certainly be cold enough.

That simply WON'T happen in this set-up. The continent is mild which adds significant modification coupled with little in the way of deep cold pooling. It would be a non event for serious cold for most.

All the easterlys that brought sub zero maximum temperatures were from cold already embedded in the NW regions. The charts indicate well the lack of surface and atmospheric cold.

[SnowObsessor90]

I wonder what the odds are now of all the models suddenly flipping back to zonal over the next day or two with that theme continuing until there isn't much of winter left at some point in February because I certainly would not bet against it.

Edited January 8, 2012 by Anonymous21

[Cheshire Freeze]

That simply WON'T happen in this set-up. The continent is mild which adds significant modification coupled with little in the way of deep cold pooling. It would be a non event for serious cold for most.

All the easterlys that brought sub zero maximum temperatures were from cold already embedded in the NW regions. The charts indicate well the lack of surface and atmospheric cold.

Sometimes I feel like banging my head against a concrete post, it depends whether any flow has its origins from the arctic side of the jet- that's pretty much it. Current temperatures across the mainland at this current time has absolutely no bearing on whether deep cold reaches our shores.