Winter Model Discussion 18Z 19/1/13 onwards.

[NorthNorfolkWeather]

It is actually quite straight forward what is being modeled on the hemispheric scale.

We have had a large SSW that has displaced the PV to the Atlantic side with a large ridge based on the Pacific sector. Following this, the Atlantic PV has been cut in half leaving the two vortices seperated but still based towards the Atlantic sector. Further upper warming is destroying the stratospheric Canadian vortex but leaving the tropospheric vortex intact. The underlying upper Pacific ridge is maintained whilst the tropospheric Canadian vortex tries to join with its Siberian counterpart, thus removing the small wedge of increased strat and tropospheric heights keeping them apart.

Meanwhile, the Siberian stratospheric vortex (10 hPa) will slowly increase in strength and eventually make its way back to the pole (over the next 2-3 weeks). What occurs to the tropospheric vortex during this timeframe is unknown, however we know that its starting position is Atlantic based and that the tropospheric vortex is unlikely to regain full strength for a long time yet, and, as the upper Pacific ridge wanes so will the lower Pacific ridge, allowing heights to build elsewhere tropospherically at high latitudes. We don't know where yet.

And that post reinforces a comment I've made a few times, we live on a hemisphere, cold air moving South must be replaced by warm air moving North. If we're lucky we pick the air moving South orWest, unlucky, we get the air moving North or East

Edited January 20, 2013 by NorthNorfolkWeather

[Cloud 10]

LOL,not one comment on the 18z gfs tonight.

[keithlucky]

LOL,not one comment on the 18z gfs tonight.

Yes what model thread?

[Tim Bland]

GP has spoken and so the GFS has listened! Greenland high anyone.. I know it's in FI but nice to see

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=288&code=code&mode=0&mode3h=0&runpara=0&carte=1

Less than a week to thaw out and we can start talking snow again http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=312&mode=1

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=336&mode=2

Now THAT is a block http://www.meteociel.fr/modeles/gfse_cartes.php?ech=384&code=code&mode=0&mode3h=0&runpara=0&carte=1

Edited January 20, 2013 by Tim Bland

[bradymk]

Ok, quite a few GFS ensembles were showing heights to our NW in FI. GFS 18z now joins the party, im beginning to think this less cold period will be even shorter than i expected.

[Zenarcher]

LOL,not one comment on the 18z gfs tonight.

Well at least FI gives us something to talk about,

Edited January 20, 2013 by weathermaster

[Tom D]

LOL,not one comment on the 18z gfs tonight.

Not much to comment on before +192, much of the same if not worse than earlier for cold fans.

After +192 we see high pressure building over the Atlantic.

[Continental Climate]

LOL,not one comment on the 18z gfs tonight.

Ive got one word for it but i think a ban would happen soon after

[OldMetMan]

LOL,not one comment on the 18z gfs tonight.

Well, at T300 a stunning looking northerly blast with a strong mid-Atlantic ridge extending to Greenland. Not sure how it dreamed that one up!

[lorenzo]

LOL,not one comment on the 18z gfs tonight.

I didn't think we were commenting on any of the GFS runs at present... UKMO having slapped it down so hard in the last 2 weeks.

Anyhow, it's decided to stop it's zonal train in extreme FI land.

[snow mad]

and as if by magic she appears http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=384&mode=0&carte=1 long way off of course hopefully will be a new trend over the coming week

[Polar Maritime]

So.. we go from Zonal in FI to this from the N/E

Looks like GP's been fiddling with the models !

Edited January 20, 2013 by Polar Maritime

[lorenzo]

In all it's NH view nosebleed 1060mb glory, love it.

Thanks Pub run...

[keithlucky]

Where"s the breakdown on met latest fax chart?

[Tom D]

Where"s the breakdown on met latest fax chart?

It's slightly hard to compare because meteociel measures pressure in 5s, but clearly the 1020mb line is more expansive over the UK than shown in the raw UKMO. Perhaps there's something to indicate the high holding on at least for a short time longer than some of the modelled outcomes.

[chris55]

Well, if we have to make do with a broader set up like this in Feb then I "suppose" it'd do!

[bradymk]

Where"s the breakdown on met latest fax chart?

I would say that chart does suggest a breakdown in the following days from the NW. Already milder in the NW on that chart. It may stay cold at the surface for longer however but a breakdown looking likely but everything points to this being a temporary affair. I expect quite a few ensembles like the GFS op in 240+ timeframe. Edited January 20, 2013 by bradythemole

[Continental Climate]

In all it's NH view nosebleed 1060mb glory, love it.

Thanks Pub run...

A stunning chart there, beautiful in every way!! Very december 2010ish

[Severe Siberian icy blast]

The one thing the 18z can be good at is trend spotting , it's happened many times before, and this coincides perfectly with GP's and chiono's comments as if they've listened to them! Fi brings the greeny heights we have been looking for all winter . Lets see how long it takes for the rest of them to get to grip with what's round the corner .

Fascinating

[Jason M]

looking through the ensembles and its game, set & match to the vortex.

Opp has very strong support now out to day 5/6.

Jason

[chris55]

You can take the optiistic view that its a 'means to an end'. The blocks which sat in the wrong place for us late nov were responsible for driving the wave activity in the right locales to assist the SSW occuring and susequent split vortex. If the canadian vortex is to get to our east it has to bring a zonal period with it. Once there, we are hopefully able to build a decent greeny block in feb. if it stays where it is, there is no chance of a strong greeny block and the wedges of heights that have been deflecting the jet nw/se cannot continue forever. The question for me is how long the mobility survives. Looking at the recent week 2 gefs, i am taken by ian's comment that mogreps trends towards a 'warmish' block. Thats about the favouriite non zonal gefs pick. Now where would a mid lat block in feb be likely to head with no canadian/greenland vortex in place?

Shall we say around the 10th feb for the retrogression? Now theres a glass half full post!

Maybe the 5th!!!

The one thing the 18z can be good at is trend spotting , it's happened many times before, and this coincides perfectly with GP's and chiono's comments as if they've listened to them! Fi brings the greeny heights we have been looking for all winter . Lets see how long it takes for the rest of them to get to grip with what's round the corner .

Fascinating

You seen the 18z NAE SSIB!

[mike Meehan]

I had the impression that the forecaster on Country File this evening was hedging his bets towards the weekend and I can't say I blame him.

It does seem to me that the breakdown for Friday/Saturday is being brought on with indecent haste and I suspect the old lady won't wear it.

[Yarmy]

So FI starts at T72 but ends at T384 just in time for a monster Greenie High? All good fun, and the pressure is off about after a decent cold spell for many.

[Captain Shortwave]

looking through the ensembles and its game, set & match to the vortex.

Opp has very strong support now out to day 5/6.

Jason

Oh well it was good whilst it lasted. Great day for East Anglia today with the north East about to be battered tomorrow. Good innings for such a feeble wedge of high pressure. In the end I think what we will hope for is that the energy from the Canadian vortex to blast through us (maybe an Atlantic storm) followed by high rises behind it from the north Atlantic to Greenland. Certainly possible if we can zip the energy along.

[mike Meehan]

I would say that chart does suggest a breakdown in the following days from the NW. Already milder in the NW on that chart. It may stay cold at the surface for longer however but a breakdown looking likely but everything points to this being a temporary affair. I expect quite a few ensembles like the GFS op in 240+ timeframe.

I seem to recollect but I could be wrong after all this time, that the breakdown in '63 came from the NW - up there the temps were warmer and I got the idea that the attack was being made where there was the least resistance.