Model Output Discussion

[londonsnow]

Great to see an improvement on the JMA/NOGAPS. In recent days the output from these has been relatively poor. At the moment the UKMO +144 is looking rather lonely. Having said this I would be much happier if the 0Z outputs trends towards the E,ly tomorrow morning.

P.S Keep an eye on the trough currently in the N Sea. This will swing SW into NE England/Humber/Lincs/E Anglia later tonight. Some could wake up to a decent covering.

believe you me, i've been following that trough v closely. it may even impact on london

[bluearmy]

the trend to less cold uppers on the 00z NAEFS is repeated on the 12z run. this has my attention, strangely in a positive fashion. the lower the uppers, the farther away we will be to the trough (and any frontal precip). the mean flow is looking more consistently se than east on this output. i think there is a big chance that should this pattern evolve as expected, it will be a lot less settled than it looked to be a few days ago. i dont want to make a silly prediction, but there could be a snowfest for the southern half of the uk on the horizon. the northeast can have the cnvective stuff off the north sea.

this is a 'glass half full' post to balance out my 'glass half empty post' earlier !!

[billy]

I may be wrong but it looks like tonights fax charts have followed the ukmo raw model

[damianslaw]

Not convinced with the UKMO evolution for the middle of next week, its being far too progressive. The block to the NE will prevent the trough getting much past the North Sea, I'm firmly expecting the UKMO to change tomorrow to show be a south easterly by Wednesday as we see signs of undercutting - very similiar to the synoptics we saw on the 13th and 14th, however, unlike then, the block will retrogress westwards as we see all energy in the jet transferring into the southern arm, it may be a tentative stutturing start mid-late next week with a bit of an atlantic/continent battle but the eventual winner will be the continent, in fact this is a much more interesting set up as it raises prospects of frontal snow as we see shortwaves develop only for them to be eventually squeezed out by the block to the north east. Its been a feature of much of this winter so far, hardly any fronts have managed to get into Scandanavia, they have simply had the energy squeezed out of them resulting in what has been a very dry winter so far, thank goodness after the torrential rain we saw in Nov, this winter has just been what we needed, we were staring at the prospects of further flood misery in Dec, this cold weather has certainly done us a favour.

Edited January 29, 2010 by damianslaw

[bluearmy]

I may be wrong but it looks like tonights fax charts have followed the ukmo raw model

not entirely as the shortwave off the nw of ireland is without a circulation. however, its far closer to ukmo raw than it is the ecm so we have to wait patiently for the 00z to see if they back up the general trend.

[Nick F]

I may be wrong but it looks like tonights fax charts have followed the ukmo raw model

It does indeed at t+120, though synoptically to the east of the UK there's not much in it between the fax and the UKMO + ECM op runs, with all 3 having a low centred over/near Denmark. However, over and to the west of the UK - fax and 12z UKMO op are progressive in bringing in Atlantic low pressure to the NW with UK under a SW'erly flow rather than the light and variable flow by ECM. So definitely more leaning towards UKMO for our patch of the woods.

[billy]

not entirely as the shortwave off the nw of ireland is without a circulation. however, its far closer to ukmo raw than it is the ecm so we have to wait patiently for the 00z to see if they back up the general trend.

Yep I see what you mean. Surely the ukmo cant have this right as its going against every other model tonight.

[BLAST FROM THE PAST]

Yep I see what you mean. Surely the ukmo cant have this right as its going against every other model tonight.

Written by Darren Brett...so don't worry they will change.

ECM is on the money, I have big confidence in that.

BFTP

[Duncan McAlister]

Looks like the 18z may be more like the ECM 12z than the GFS 12z - an earlier easterly but possibly less potent.

[Bobby]

GFS is looking more like the ECM at 144 with the atlantic undercutting...

Perhaps a big snow event for some.

[Cloud 10]

More jet energy going south on the 18z which bodes well for low pressure undercutting the block.

Sticks nicely to BFTP's script.

[Bobby]

This looking a tremendous run so far... easterly already raging by 156-162hrs.

[nick sussex]

I'm very surprised the UKMO have gone with their own model with tonights fax charts especially as theres no support in the ECM ensembles, their 144hrs output would bring milder air into the Netherlands which has absolutely no support in the ECM De Bilt ensembles suite so its bizarre that they've gone with their model earlier on.

The GFS 18hrs run is almost a carbon copy of the ECM, this indicates to me that the ECM signal for its output in the crucial time frame upto 144hrs is strong and the UKMO is on the wrong track here.

[Nick F]

More jet energy going south on the 18z which bodes well for low pressure undercutting the block.

Sticks nicely to BFTP's script.

You're better off using 300hPa wind charts for seeing where the jet streaks are in winter. 200hPa better for summer as the jet tends to be higher in altitude. Though it does roughly show the jet slamming into SW Europe.

yes, 18z trending very similar to ECM up to end of next week, often 18z seems to copy the evening ECM op offering anyway! Some very cold air at the surface next Friday, even in the south as we drag in a rather cold continental flow. Wouldn't take much of a shift for a major snow event for southern UK at least as Atlantic fronts try and push in from the SW up against the increasingly cold cP air.

[Ben_Cambs]

GFS 18z very good, brings the Easterly in around the 5th. At T+192, -12C Uppers next to the East coast

Edit: At T+216, -12C Uppers widely Amazing now, there seems to be some sort of reload at T+252, although it is in FI

Edited January 29, 2010 by Snowman0697

[Bobby]

Things are now trending nicely in the right direction I think. Still plenty of uncertainty though but I like the trend today.

[billy]

Written by Darren Brett...so don't worry they will change.

ECM is on the money, I have big confidence in that.

BFTP

Yeah ,but at least it will be mild . 18z is looking like a cracker of a run for cold . Similar to the ecm

[cooling climate]

This could be the coldest run so far from the operational GFS with incredible cold spreading

west into Scandinavia from Siberia.

[Duncan McAlister]

Looks like the 18z may be more like the ECM 12z than the GFS 12z - an earlier easterly but possibly less potent.

Erm, scrap that, pool of 492 dam heading towards N Scotland

[Ben_Cambs]

This could be the coldest run so far from the operational GFS with incredible cold spreading

west into Scandinavia from Siberia.

One massive deep cold pool it is. This run has been stunning. UKMO is on its own at the moment

-20C Uppers in Scotland on GFS in deep FI!

Edited January 29, 2010 by Snowman0697

[bluearmy]

gfs fi whilst technically plausible ...

watch the w atlantic in reverse

watch the -28c uppers heading west thru scandi ... WHAT!!!

it must friday night down the pub

[Cloud 10]

You're better off using 300hPa wind charts for seeing where the jet streaks are in winter. 200hPa better for summer as the jet tends to be higher in altitude. Though it does roughly show the jet slamming into SW Europe.

yes, 18z trending very similar to ECM up to end of next week, often 18z seems to copy the evening ECM op offering anyway! Some very cold air at the surface next Friday, even in the south as we drag in a rather cold continental flow. Wouldn't take much of a shift for a major snow event for southern UK at least as Atlantic fronts try and push in from the SW up against the increasingly cold cP air.

Thanks for that. the 300 charts do look more detailed.

[Tom D]

The op goes bonkers with cold uppers in FI! It's frightening! :D

These are some to save for future reference!

http://91.121.94.83/modeles/gfs/run/gfs-1-276.png?18

http://91.121.94.83/modeles/gfs/run/gfs-1-300.png?18

http://91.121.94.83/modeles/gfs/run/gfs-0-264.png?18

[Nick F]

Lol ... looks like Jan 1987 in the depths of FI with sub -15C T850s across the UK. Worth saving I suppose ...

How many consecutive GFS runs has that been showing a protracted easterly through FI??

[Altostratus]

The GFS has just produced one of the best runs in history. It just shows the potential of this event. With those huge blocking highs you'd expect something good to come out of this eventually.