Model Output Discussion 19th January 2014-18z onwards.

[nick sussex]

The ECM at 168hrs keeps a train of low heights connected to the PV chunk upstream, this is either going to be a damp squib or snow fest, theres now enough cold to the east for a good undercut, if you get the favourable low track then it could deliver a lot of snow, or just cold rain if the pattern is too far east, its actually quite an unusual set up.

 

Could go either way, high risk roulette!

[SMU]

JMA 192

 

sees another top drawer run-

 

http://www.meteociel.fr/modeles/jma/runs/2014012112/JN192-21.GIF?21-12

 

S

[Severe Siberian icy blast]

The ECM at 168hrs keeps a train of low heights connected to the PV chunk upstream, this is either going to be a damp squib or snow fest, theres now enough cold to the east for a good undercut, if you get the favourable low track then it could deliver a lot of snow, or just cold rain if the pattern is too far east, its actually quite an unusual set up. Could go either way, high risk roulette!

But the progressive nature between 144 and 168 looks a bit extreme to me to be honest , gets rid of that polar -AO in a flash. Anything just past 144 is just for fun

[Stuie]

JMA 192

 

sees another top drawer run-

 

http://www.meteociel.fr/modeles/jma/runs/2014012112/JN192-21.GIF?21-12

 

S

Yes Steve but there is just something very wrong image wise.

[Mucka]

JMA not so good as previous runs perhaps but still cold and probably some snow about for a while. Possible Easterly to follow, depends on how much forcing there is from the next Atlantic low.

 

 

ECM is exceptionally progressive through 144/168 but overall the support for any sort of strong Atlantic ridge Arctic high link up has largely gone missing this evening.

Edited January 21, 2014 by Mucka

[chionomaniac]

Iv actually been following the warming from the t384 and watched come forward , it starts around the 26th and carries on for about 5days fairly strong , now as we know the modelled -AO to develop next week is courtesy of minor warmings already happened , and the one to come is stronger than the last ones , although I'm sure if it excited you then we would of known about it ! But given the time of year , weakening westerly wavelengths and a natural moderating of the polar vortex , do you think we stand a good chance of having a dramatic flip in the models over the next 2 weeks ? Really keen to know your thoughts ed ? Thanks

I think it is too early and will be for a while yet to see any dramatic 'flip' in the models. But we are beginning to see the January pattern that I expected prior to winter. How strong any strat warming will be and how well it's effects will propagate are still an unknown quantity at this point, so I would suggest wait another week to see exactly where the strat is heading before getting too excited but it certainly looks like we are heading to that crossroads that I suggested for Feb on the winter forecast. Which path will we take?

 

My thoughts regarding Atlantic ridging is that this will eventually lead to reinforcing a Scandi block, rather than a Greenland block and that a 1991 type Feb cold pattern could emerge towards mid Feb. (Just musings out loud btw.) But a lot of modeling to get through before then.

[Weather-history]

+144 and then onto +168 doesn't make sense to me , it get's rid of a 1030 High over Greenland in a flash .....

You have to be careful with so called high pressures over the Greenland area. They are often not really there. A sign of a genuine Greenland high is oranges and yellows in the 500hpa charts.

[Man With Beard]

See, I knew the good old JMA would agree with something...

 

Nasty little freezing storm still there with the ECM.

But seems to disperse south without being that windy. Not sure how accurate that is!

Yes I'm absolutely baffled at how we get from T144 to T168!! I would genuinely be interested in an explanation from anyone who thinks they know!

[chionomaniac]

JMA 192

 

sees another top drawer run-

 

http://www.meteociel.fr/modeles/jma/runs/2014012112/JN192-21.GIF?21-12

 

S

JMA still bullish with the MJO forecast as well I note compared to the others, taking it into favourable phase 8 territory. (It was dated 19/1 yesterday and is 20/1 now - still waiting for an updated UKMO MJO forecast, though).

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

[Sky Full]

These similar looking charts all seem to indicate a change to colder conditions. Does similarity imply more accuracy perhaps? They all bring about an easterly or south easterly off the continent.....

GFS. 8 days out: http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=192&mode=0

ECM 8 days out: http://www.meteociel.fr/modeles/ecmwf.php

GEM 8 days out: http://www.meteociel.fr/modeles/geme_cartes.php?&ech=192&mode=0&carte=0

JMA 7 days out: http://www.meteociel.fr/modeles/jma.php

Surely they can't all be wrong, can they? Or maybe I'm wrong - wouldn't be the first or even the fifty-first time.....but you have to keep hoping don't you!

[bluearmy]

day 9 is more in keeping with the less than super spreads on the ecm ens from this morning (though perhaps a day progressive)

[Troubleatmill]

You have to be careful with so called high pressures over the Greenland area. They are often not really there. A sign of a genuine Greenland high is oranges and yellows in the 500hpa charts.

Yes, due to the high land and ice mass its often shows a false HP because the air is raised much higher, often why it looks like a forcefield to low pressures in Labrabor, they squeeze around it but seldom over it

[The PIT]

Well the block is still hanging there. I noticed the words the mild air will probably win has disappeared again from the forecasts. While the block remains there's always a chance. Okay abit of hope casting.

[Captain Shortwave]

Whilst everyone looks to the north west in horror, it's really over Siberia where things go wrong with the ECM wanting to transfer energy across the pole and in doing that recharges the Greenland/Canadian vortex and also puts pressure on the Scandi high. This is what you can see with the T144 and T168 charts

 

 

So basically we need that to do one on future output. The shortwaves going over the Atlantic ridge is not the end of the world as if you have heights solid to the north east then you have every chance of getting a decent easterly after it has past whilst keeping a mainly polar maritime sourced flow. 

The Siberian area for the PV is like a cat on a hot tin roof.

Edited January 21, 2014 by Captain shortwave

[IDO]

Some good consistency from the 0z with the power struggle between the Russian High (very strong on ECM) and the energy coming from the PV. The AH also a bit player at times. 

 

T240: 

 

It now looks like the initial Arctic High is transient and is being continually modelled to sink SE to reinforce the Russian High.

 

Multiple possible outcomes in such a scenario from D10-15, if it happens, but it looks unlikely we will get any sustained cold before the end of the month; cool zonality looks the call still and that means rain mainly for the south.

[nick sussex]

The Great Winter of 2013/2014 started on January 28th with low pressure sinking south and snow on the backedge, it ended on the 30th January as heights dropped to the north!

 

Well saves  a couple of trees from being cut down, you could put the highlights on a postage stamp!

 

Okay that was my bit of gallows humour, in terms of tonights output, good agreement on the overall NH pattern upto T144hrs, after that I still think there are several different outcomes possible.

[mulzy]

Just the natural ebbs and flows from the NWP, but the charts tonight are rather underwhelming from a wintry point of view (at least for most of lowland Britain).  Thank god this is a T+240 chart!

 

Edited January 21, 2014 by mulzy

[Liam J]

I'm sorry but something just looks wrong on the ECM 12z, what I don't know but I don't buy that overly progressive and rapid westerly attack & collapse of the heights. Maybe some sort of error? 

[Severe Siberian icy blast]

I would like to take a minute to highlight the ECM a minute where I think it looses the plot .

This is the 144 chart

Notice the high pressure the northeast has a core of 1040. Everything looking good going forward , yes a distinct vortex toward Canada ,but it looks poised to head toward a wintry pattern from there , but instead we go to this

we still have a very strong high but it's sinking , and the vortex is between the two pieces is rapidly joining forces again , yes we still have energy going southeast but it's game over from that point in my opinion , but it's far too progressive in the way it dictates the sinking of the high pressure .

[fergieweather]

Well the block is still hanging there. I noticed the words the mild air will probably win has disappeared again from the forecasts. While the block remains there's always a chance. Okay abit of hope casting.

There's no real talk of 'mild' in strict sense, but equally UKMO as of this morning weren't oarticularly keen on any pronounced easterly/pronounced cold solution from the mess early next week, so I imagine they'll stick with that notion albeit with a clear caveat continuing. Irrespective of that, the threat of very wet, disruptive conditions is starkly apparent and I can see another frenetic forecasting period looming... not least for my region. Interesting times indeed.

[SHM040519]

I'm sorry but something just looks wrong on the ECM 12z, what I don't know but I don't buy that overly progressive and rapid westerly attack & collapse of the heights. Maybe some sort of error? 

 

How the high can go in 24 hours, a 1030mb high amazes me! 

[Mucka]

Some over zealous moderation?

Posts have gone missing discussing the ECM evolution and its likelihood of verifying?

[nick sussex]

Theres two ways of looking at tonights outputs, if the models follow recent trends then they will pull the high further west and those low heights will be further west aswell.

 

This was the ECM  prediction for the 26th January on Sundays 12hrs run:

 

 

This is the prediction on tonights output:

 

 

Close upstream, big fail downstream.

 

 

 

 

[Man With Beard]

Another observation on the ECM. At T144 the low heights from the Atlantic have nearly phased (joined) with those over S Europe, looking like they will close the loop below Scandi High. But at T168, the hole has actually got bigger again! Surely the loop has to close after T144???

[tight isobar]

I'm sorry but something just looks wrong on the ECM 12z, what I don't know but I don't buy that overly progressive and rapid westerly attack & collapse of the heights. Maybe some sort of error?

fully agree its 12z evolution is odd to say the least in both energy track, and formation of divergence an odd run indeed.