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

[DAVID SNOW]

First complete vortex destruction forcecast at 1 hPa by the end of the run!!

 

Best strat chart of the season - though this is very, very high up!!

 

 

NH_HGT_1mb_384.gif

Again its @384 hours though and after that there would be only 20 odd days of winter left?

Last March IMHO was probably a 1 in a 100 year event

[ukpaul]

I think there is some erroneous use and assumptions regarding these charts. Yes, they show stratospheric warming. But even if this does verify (at that range, most likely not) it doesn't guarantee there will be a change to cold to our shores. Even if it does, there would be considerable lag to the point where the effects of this warming wouldn't be felt until pretty much the end of winter.

 The strat is much more likely to verify, given that this has been a theme now for quite a while it's not a matter of if but how.

 

(also, not posting 384h but 264h would show those who can't somehow find these charts themselves from saying that it's always at 384h. The warming is on target, the consequences are only now coming into range).

Edited January 21, 2014 by ukpaul

[Dancerwithwings]

The UKMO 144h is looking good Lets hope it follows the JMA and pulls in the very cold air from the East....

 

Frightening how similar these two look!

 

[MR EXTREMES]

II think that the negative tilt of the Atlantic low hitting the stronger Scandi block is far better in this run at T=132 - but not a lot in it otherwise..

I said about the neg tilt earlier as the uk fax show how very close to the low sliding under is to be perfectly honest I think its 50/50 that the alantic or low pressure pushes things futher east its so finely balanced considering the coldest air is just over the north sea incredibly close indeed.

[Paul]

Just as a reminder - model discussion requires at least some (in fact the majority) of your post to actually have something to do with the models. Please bear that in mind when posting, and if your post doesn't have this just post it elsewhere - there are many threads to get involved in

[bluearmy]

 

To wrap up: Rainfest AGAIN for most.  That is all. 

 if you insist. awaitying the ecm and jma with interest to see what strength we can pull in on this lee easterly (now we know that exeter see the more progressive option as the most likely, we should see a clearance between systems allowing a colder flow.). ideally, we want a further correction west on teh track of the low as that would keep us in colder uppers for the whole period.

[MR EXTREMES]

Well as Fergie has said,yet again,rainfall is the cheif concern for the reliable period.

After that,i guess your location and altitude will play a big part of what you are going to see falling out of the sky.

If your up north and have 200-300m altitude the outlook is potentially interesting,if you live in the south and have little altitude,than the outlook is probably extremely grim from a snow perspective...

I think to be fair we need to factor in wet bulb projections to so I think snow could be a bigger factor than some might think.

of coarse west northwest and northern areas are at risk im afraid its soggy for us in the south.

[Panayiotis]

People saying that the strat 'interest' is at 384hrs, but sorry thats wrong! The significant warming starts at 264hrs!

[Cecil Hogmanay Melchett]

http://www.wetterzentrale.de/pics/Rukm1441.html

Difficult to say but at face value there is potential in this chart with a genuine Arctic high and the high across Finland strecthing across the GIN into Eastern Greenland.

I know this set against one of the most intense robust Polar vortex in the history of mankind but at the very least a colder form of zonality is surely the least best option....

[Mucka]

One or two interesting ensemble runs showing up in the more reliable time-frame now the Op is starting to catch up with the stronger Arctic blocking than previously modelled but they still have some catching up to do.

 

 

GFS ensembles

 

NW England

 

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=236&y=40

http://www.meteociel.fr/cartes_obs/gens_display.php?x=235&y=40&run=12&runpara=0&type=3&ext=1

 

SE England

 

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=290&y=124

http://www.meteociel.fr/cartes_obs/gens_display.php?x=290&y=124&run=12&runpara=0&type=3&ext=1

Edited January 21, 2014 by Mucka

[chionomaniac]

People saying that the strat 'interest' is at 384hrs, but sorry thats wrong! The significant warming starts at 264hrs!

Actually for those who have tracked this warming from its inception at 1hPa it is now starting at day 6 on the latest GFS run. In a theoretical SSW case study, if this forecast was correct than it takes around 10 days for mean zonal reversal to occur at this level and then up to another 5-6 for reeversal at around 10 hPa. From then on in, depending on whether the vortex splits or displaces and whether propagation occurs, potential tropospheric affects will take anything from 6 days to 6 weeks to occur if at all.

 

So if we see a warming at T+384 at 1 hPa on a GFS run, and, if that is going to go on and lead to a SSW and then tropospheric disturbance it may take a full month from that very first sign. 

[nick sussex]

People saying that the strat 'interest' is at 384hrs, but sorry thats wrong! The significant warming starts at 264hrs!

The picture in your avatar is hilarious! That sums up the winter model watching looking for cold.

[bluearmy]

 

The picture in your avatar is hilarious! That sums up the winter model watching looking for cold.

 the irony being the chart is showing just what we need!!just an observation but trawling through all the gefs, there are a multitude of solutions but not one of them includes a decent greeny block (from the south). as arctic ridge encompassing n greenland is possible. therefore, we continue to have to look north and east for any chance of diverting the depressions on a track that might deliver something akin to proper winter. not dissimilar to this timwe last year. no greeny block was forthcoming although the west scandi shallow upper ridge delivered for us.

[nick sussex]

   the irony being the chart is showing just what we need!!just an observation but trawling through all the gefs, there are a multitude of solutions but not one of them includes a decent greeny block (from the south). as arctic ridge encompassing n greenland is possible. therefore, we continue to have to look north and east for any chance of diverting the depressions on a track that might deliver something akin to proper winter. not dissimilar to this timwe last year. no greeny block was forthcoming although the west scandi shallow upper ridge delivered for us.

This is an interesting change from NCEP, gone is the broad troughing to be replaced by something more amplified:

 

A RESILIENT LARGE SCALE FLOW PATTERN OVER NOAM AND VICINITYREMAINS AS AN ESTABLISHED PACIFIC STORM TRACK LIFTS UP TO ALASKAON THE WRN PERIPHERY OF AN AMPLIFIED AND WARMED MID-UPPER LEVELMEAN RIDGE CENTERED OVER FAR WRN NOAM.  THIS SCENARIO OFFERS ABOVENORMAL PREDICTABILITY.  THIS PATTERN IS REINFORCED FOR MUCH OF THEUPCOMING MEDIUM RANGE FORECAST PERIOD THIS WEEKEND INTO EARLY NEXTWEEK ALLOWING A SERIES OF HARDER TO DIAGNOSE IMPULSES ALOFT ANDSURFACE FRONTS/LOWS AND ASSOCIATED WINTER PCPN SWATHS/SUBSEQUENTARCTIC COLD SURGES TO DROP OVER THE RIDGE INTO AN AMPLIFIEDEAST-CENTRAL NOAM MID-UPPER LEVEL MEAN TROUGH POSITION.  WHILE THETIMING OF THESE COLD SURGES IS LESS UNCERTAIN...

[SMU]

http://www.meteociel.fr/modeles/ecmwf/runs/2014012112/ECH1-96.GIF?21-0

 

Solid start to the ECM- at 96 we see the energy moving SE over the UK at a more acute angle to the UKMO - so hopefully the residual energy going underneath will then support a faster route to cold from the East circa 144/168

 

S

[Panayiotis]

ECM looking good tonight, with the Arctic high moving south and linking with the heights over Scandi, which should reinforce the block over Scandi later on in the run:

Edited January 21, 2014 by Panayiotis

[pandit-scholar]

So far another good run from the ECM. A stronger Scandinavian block, very cold uppers not to far from the east and PV looking to leave Greenland at T +120.

Of course in the shorter term, we will have to endure a very wet stormy period.

Edited January 21, 2014 by pandit-scholar

[fergieweather]

Good broadscale agreement so far between EC DET and JMA....as of T+120

[shaky]

Good broadscale agreement so far between EC DET and JMA....as of T+120

interesting!!and looking at the ecmwf the cold pool is not too far of the east coast between 72 and 120 hours!!if it backs west a couple of hundred miles we could well see more disruption and battleground snow events!!bbrilliant stuff!!

[Severe Siberian icy blast]

Actually for those who have tracked this warming from its inception at 1hPa it is now starting at day 6 on the latest GFS run. In a theoretical SSW case study, if this forecast was correct than it takes around 10 days for mean zonal reversal to occur at this level and then up to another 5-6 for reeversal at around 10 hPa. From then on in, depending on whether the vortex splits or displaces and whether propagation occurs, potential tropospheric affects will take anything from 6 days to 6 weeks to occur if at all. So if we see a warming at T+384 at 1 hPa on a GFS run, and, if that is going to go on and lead to a SSW and then tropospheric disturbance it may take a full month from that very first sign.

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

[Man With Beard]

Something not right on this ECM run - a wedge of uppers over Finland stay around -2C in situ between T24 and T120, not much of south-westerly element in that region, surely they would cool down more than that being so far north? That's why it isn't cold to our north at T144.

[pandit-scholar]

It certainly understandable why the Meto is worried. Pretty good agreement at the moment that a deep low pressure system is heading our way by t +144.

Edited January 21, 2014 by pandit-scholar

[bluearmy]

 

Good broadscale agreement so far between EC DET and JMA....as of T+120

 funnily enough ecm 12z op today has the low exactly hwere the jma of yesterday put it. axis of the trough is les nw/se though. lets hope ecm sinks more south to keep the warmer core of the depression away

[Stuie]

Good broadscale agreement so far between EC DET and JMA....as of T+120

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!

[snowmadchrisuk]

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