Model output discussion - 16th Nov onwards

[phil nw.]

don't be having a little wee on my fireworks there phil i'm trying to be optimistic! anyway, my point was, which actually agrees with your last point, it could well be a 'back end' winter. in fact, cohens study finds that in the siberian high scenario this is more likely. also some of the 'best' winters have been in the second half or even february (1947 or 1991 as a couple of examples). anyway, this winter seems unique (as they all are really) so we will have to wait and see. i've got a good feeling about this one though

Lol certainly wasn't my intention bobbydog and nothing wrong with optimism.

No i was really just saying from experience of chart watching over many years how ellusive the SH is.

When one does push far enough west though it is one of the most fascinating periods of weather modeling as that bitter cold creeps closer and closer to the UK.

Edited November 20, 2015 by phil nw.

[Nick F]

Hi Steve,

I'm sure there would be dsiruption and some undercut but looking across the output the forcing looks quite strong from deep trough development  S Greenland with jet powering up so UKMO looks to be underdoing that.

Agree. The jet looks too strong from most guidance to allow proper trough disruption with a cut-off low to develop across mainland Europe and pressure to build sufficiently across the UK to allow an easterly. Not that there'll be any deep cold air to tap into anyway, best source is from the north atm.

[The PIT]

3 day wonder but never mind then back to average to mild windy stuff which is the next best thing I suppose.

[Ali1977]

Interesting FI coming up...split vortex maybe?

[nick sussex]

Looking at the ECM postage stamps for T120hrs quite a mixed bag in terms of where low pressure is likely to drop se. Theres limited support for the UKMO but the more likely scenario is for the low to split rather than the UKMO which brings this se as a whole.Theres also a cluster of flatter solutions so still some uncertainty.

 

Its hard to see the PV backing down enough to get enough trough disruption further west and so it looks like a stalemate for a while with a lot of wind and rain and some cooler PM interludes.

 

There have been some westwards corrections this evening especially by the ECM but perhaps of more interest is what happens with the Siberian high and high pressure towards Svalbard.

 

The UKMO fax charts do seem to have gone with the UKMO raw output at T96 and T120hrs, perhaps MOGREPS is more supportive of the UKMO solution.

Edited November 20, 2015 by nick sussex

[bluearmy]

Welcome back to the winter pub run - you've been missed!

[Love Snow]

3 day wonder but never mind then back to average to mild windy stuff which is the next best thing I suppose.

Bit of a summer reversal three days of hotter weather then to cool and cloudy for a month "sigh"

[Cheshire Freeze]

Welcome back to the winter pub run - you've been missed!

 

Completely disintegrated vortex into FI. We've seen enough of these runs over the past week for us to reasonably assume that something could be brewing for December....could!

 

Beautiful end to the GFS 18z run

 

Edited November 20, 2015 by CreweCold

[Mucka]

ECM 12z London ensembles

 

Edited November 20, 2015 by Mucka

[blizzard81]

ECM 12z London ensembles

Nothing attached Mucka

[Ravelin]

Completely disintegrated vortex into FI. We've seen enough of these runs over the past week for us to reasonably assume that something could be brewing for December....could!

Has someone replaced the GFS with an imposter? I seem to remember the GFS's default position in the latter stages of the runs in winter was generally to ramp up the vortex, not shred it.

Edited November 20, 2015 by Ravelin

[radiohead]

A silver lining on tonight's GFS?

 

[Mucka]

Nothing attached Mucka

 

 

Sorry, edited now.

Was getting a weird glitch whereby I was copying the 12z but it was pasting the 00z,

Had to close my browser and reopen as reloading didn't work either?

 bizarre!

[Cheshire Freeze]

A silver lining on tonight's GFS?

 

 

The whole run is a silver lining. Uppercut, left hook and all kinds of assaults on the vortex. In all honesty with what we've seen output wise recently, the question is more when will it give up the ghost and surrender rather than if. Some say Mid December, some say late December. The 18z says ASAP guvnor.

[blizzard81]

ECM 12z London ensembles

 

Operational very top end of temps towards day 10. All in all, my gut says we are in for colder runs tomorrow.

[Mucka]

Operational very top end of temps towards day 10. All in all, my gut says we are in for colder runs tomorrow.

 

Hope you are right but it is noticeable that there is not one cold run among those members in FI.

Oops I dos ee one little trend setter. 

Edited November 20, 2015 by Mucka

[blizzard81]

Sorry, edited now.

Was getting a weird glitch whereby I was copying the 12z but it was pasting the 00z,

Had to close my browser and reopen as reloading didn't work either?

 bizarre!

Haha, no worries. I was just really eager to see them.

[Singularity]

So the GFS 18z det. has taken the Svalbard height rises and run away with them, as the polar vortex segment is displaced right down to the UK by +240 and the higher heights are then able to claim much of the high Arctic, settling down across Greenland just under a week later.

 

That's a bit bonkers yet not entirely unreasonable should the model have those Svalbard height rises in order. This is one reason why I tend to view increased heights there as a significant indicator that things could turn interesting in terms of some 'proper' cold winter weather.

 

Usual caveats apply - the pub run has awoken from its slumber.

[Polar Maritime]

A very interesting run showing from tonight's GFS, Certainly a good pattern to start Winter on with a cool/cold N/NW flow.

 

Edited November 20, 2015 by Polar Maritime

[Catacol]

Completely disintegrated vortex into FI. We've seen enough of these runs over the past week for us to reasonably assume that something could be brewing for December....could!

 

Beautiful end to the GFS 18z run

 

 

It does make you wonder how this kind of outcome can possibly pop out of the GFS "brain" when we see such a clear signal for the vortex to drop over into the Greenland / North Atlantic sector. Genuinely I cant see this outcome coming to pass.

[blizzard81]

I know it's the pub run but the control is similar to the op

[BLAST FROM THE PAST]

 know some have gone a touch despondent re short lived cold, well take hints from 18z and stormy remains but don't expect this colder regime to go,,,,loads of pM air to come and don't be surprised at more potency either especially end of month going into Dec.  Quite  a seasonal spell I fancy

 

BFTP

[Mucka]

Quite a timely post BFTP

 

GFS 00z has a robust Siberian high which forces the trough disrupt and dig South

 

 

We will need that Siberian high in place though for anything more than a snow on hills PM waft here and there.

[Cheshire Freeze]

Quite a timely post BFTP

 

GFS 00z has a robust Siberian high which forces the trough disrupt and dig South

 

 

We will need that Siberian high in place though for anything more than a snow on hills PM waft here and there.

 

That Siberian/Russian high pressure really is something. Interesting FI coming up...

 

 

Edit: Heading towards lift off...

 

Edited November 21, 2015 by CreweCold

[Midlands Ice Age]

That Siberian/Russian high pressure really is something. Interesting FI coming up...

 

 

Edit: Heading towards lift off...

 

 

Crewe cold..

 

That last chart is amazing, even for the pub run.

 

It seems to be on board with MO!!!!

 

It only needs a slight slowdown in the trough and it will be forced over us, instead of to the north.

 

Then all hell will be let loose.

 

MIA

Edited November 21, 2015 by Midlands Ice Age