Model Output Discussion 4th Dec.2013-12z onwards.

[IDO]

I really wouldn't take the pressure rise from the South around Christmas, hinted at in 12z output, at face value.

Even if it is on to something there is nothing to say exactly how that pressure rise will manifest itself, it may be further West or Further East and actually aid our chances of getting some blocking going.

It may well have even disappeared completely on tomorrows output.

 

 

Yes, but on the 12z there are about 50% ens at T240 showing some sort of transient ridge, so something has been picked up. Still just as many zonal charts and some interesting ones:

 

[Summer Sun]

After a fairly settled festive period (especially away from Scotland) the ensemble shows a return to more unsettled conditions with the PV starting to move east

 

 

Unsettled end to the year on the ensemble

 

 

Op run

 

Edited December 15, 2013 by Summer Sun

[nick sussex]

Dear Santa i'd like to order ensemble no 10 for Xmas! That's really the best of an underwhelming bunch in terms of some cold conditions for the day itself.

 

Overall I fear I may have to bring back my horror rating if the ECM agrees with the GFS!

[draztik]

Gav, the ensembles are still showing the Christmas period to be fairly unsettled... Esp the further North you go. The op and control do show more settled however, but the ensemble mean (at this stage) isn't buying it.

[Mucka]

Yes, but on the 12z there are about 50% ens at T240 showing some sort of transient ridge, so something has been picked up. Still just as many zonal charts and some interesting ones:

 

gens-14-1-240.png gens-17-1-240.png

 

Maybe, maybe not. We can't tell off just one run.

It isn't supported by GEM so we will see if ECM hints at anything similar - if not then it is case of seeing if GFS continues to develop it as a signal tomorrow and the Euros come on board. 

[Stuie]

I really hope Nick it churns this out again, big 45 mins coming up!

[Panayiotis]

Remember the ENS normally follow the OP unless the ECM sees the trend, there shouldnt be too much emphasis on that GFS 12z run!

[nick sussex]

I really hope Nick it churns this out again, big 45 mins coming up!

At worse we want to see last nights ECM at T240hrs, the 00hrs has an unfavourable profile over the Arctic, having said all this if the ECM could just give us GEFS no 10, at least that would bring a cold Xmas day after overnight snow has cleared the UK and would also give me a few flakes down here!

[Matty M]

Wow

 

ECMWF is extremely concerning

 

[Captain Shortwave]

Wow

 

ECMWF is extremely concerning

 

ECM would bring severe gales or even storm force winds to Northern Ireland and Western Scotland. Whilst the UKMO really doesn't want to develop that low and pretty much gives Gale force winds at worst.

 

Huge differences in the handling of that low at only 3/4 days out. GFS/GEM develop the low but with a weaker pressure gradient.

Edited December 15, 2013 by Captain shortwave

[Mucka]

Yup Northern Scotland would need to batten down the hatches if this verifies and gales through Northern England.

 

[Barry12]

Yup Northern Scotland would need to batten down the hatches if this verifies and gales through Northern England.

 

 

Wouldn't want to be on the shetland islands!!

[BlueHedgehog074]

Dear Santa i'd like to order ensemble no 10 for Xmas! That's really the best of an underwhelming bunch in terms of some cold conditions for the day itself.

 

Overall I fear I may have to bring back my horror rating if the ECM agrees with the GFS!

I'm guessing it's this one with that ridge of High Pressure to the West/North-West of the UK? Certainly a cool looking chart for the cold and snow fans. ;-)

 

 

(Overall, it looks like the models are continuing with a mobile Westerly theme with Low Pressure and its pal, the Polar Vortex, dominating to our North with a mixture of rain and showers for numerous areas (sometimes accompanied by strong winds). There could be the odd spot of sleet or wet snow over some Northern areas, probably most likely on high ground - especially on Thursday with those cool/cold polar Westerly winds):

 

 

Some days looks to be rather mild as well during periods where the Westerly winds turn more South-Westerly (or possibly Southerly). An example for Friday:

 

Edited December 15, 2013 by DiagonalRedLine

[Matty M]

Between 72 and 96hrs this storm tracks through a significant portion of Ireland and Scotland. 96hr chart makes it appear to miss out to sea but it hits hard.

 

Dare i say potential for most significant storm for a long time for parts of Ireland.

Edited December 15, 2013 by Matty M

[Mucka]

Wouldn't want to be on the shetland islands!!

 

Me neither, I have family there though. Still, they are used to a little wind up there. 

 

 

I think it fair to say BOM has a slightly different take on our Xmas day weather to this afternoons GFS.

 

Edited December 15, 2013 by Mucka

[Panayiotis]

Much better Arctic profile @168hrs for the ECM, those heights to the NE of Greenland should shift the upcoming low on a more southerly track, (right in to us!)

Edited December 15, 2013 by Panayiotis

[Mr Frost]

Between 72 and 96hrs this storm tracks through a significant portion of Ireland and Scotland. 96hr chart makes it appear to miss out to sea but it hits hard.

 

Dare i say potential for most significant storm for a long time for parts of Ireland.

Yes Matty, 3rd Winter storm in as many weeks IMBY.

Metoffice have issued early warnings.

At least it will be windy...

Issued at:

1146 on Sun 15 Dec 2013

Valid from:

0005 on Thu 19 Dec 2013

Valid to:

1200 on Thu 19 Dec 2013

Severe gale force winds are likely to affect parts of Northern Ireland, central and northern Scotland early on Thursday; gusts may exceed 80 mph locally. The wind will lead to large waves with some over-topping possible, and will be accompanied by heavy rain for a time. Squally wintry showers will follow into the afternoon and evening.

The public should be aware of disruption to travel from this combination of weather events.

A rapidly deepening area of low pressure will pass close to the NW of Scotland during Thursday morning. Although there is some uncertainty about the depth and exact track of this low, the high gusts, in combination with heavy rain, and some coastal flooding seems likely to bring disruption to travel.

In the wake of the main storm, (beyond the period of this warning), a regime of wintry showers will bring an increased risk of hill snowfall and icy roads.

Given the potential for a significant winter storm the public should continue to monitor the Met Office website for updates to this warning.

[TSNWK]

Much better Arctic profile @168hrs for the ECM, those heights to the NE of Greenland should shift the upcoming low on a more southerly track, (right in to us!)

Agree ECM 168 looked better up in the arctic, not so sure about 192 though, looks very Greenland vortexy Edited December 15, 2013 by TSNWK

[draztik]

ECM follows GEM and BOM in disagreeing with the idea of a settled Christmas offered up by GFS.

ecm 12z @ t240

Edited December 15, 2013 by draztik

[Captain Shortwave]

ECM is the best of a pretty bad bunch. At least it would deliver snow over the high ground of Western areas for Christmas day. GEM has a cyclonic south/south westerly with average temperatures and the GFS is mild and mostly dry.

Edited December 15, 2013 by Captain shortwave

[Mr Frost]

Fair to say the latest GFS run is out on its own with regards to a settled Christmas Day.

ECM below...

[Iceberg]

ECM has the Christmas low at sub 915mb (913mb on the higher res, but the public offering has it sub 915mb), its just that Meteo can't handle pressure that deep.....

Scary really.

[cooling climate]

Nothing remotely appealing about this afternoons and evenings runs from a coldies

point of view if you are looking for something far wintrier than transient hill snow at

best.

Only an eternal optimist could find something positive to say I'm afraid.

[Panayiotis]

Fair to say the latest GFS run is out on its own with regards to a settled Christmas Day.ECM below...

Yep, a cold, blustery and unsettled day for Christmas if the ECM verifies with showers becoming more wintry over high ground as the day goes on.

[Methuselah]

ECM has the Christmas low at sub 915mb (913mb on the higher res, but the public offering has it sub 915mb), its just that Meteo can't handle pressure that deep.....

Scary really.

Blimey. The one that sank the Braer was only 916mb!