Model Output Discussion

[Alex95]

Don't understand all the doom and gloom here, looks like a big upgrade for the shortwave and that is the important thing for next week, the early week stuff is boring fluff and always was, the shortwave was always the precursor to the massive blizzards and the shortwave is looking great here

Exactly what I was thinking, out to +108 hrs now and the frigid air is on its way, looks like a direct hit on this run The main thing is that the Greenland high will soon be in the 'very reliable' timeframe, and once we get one of those the ingredients for snow can come together more easily. This time tomorrow the time in which the Greenland high supposedly will start to develop will be not much further out than +72 hrs which will provide a much better standing point should it still be modelled.

Out to +120 since I wrote this post btw and blizzards knocking on the door of the NE

[Matty M]

What i would give for that pesky svalbardian shortwave to disappear altogether!!

http://www.wetterzentrale.de/pics/Rtavn1201.png

[mountain shadow]

I think this run will be better than the 06Z but it probably would do what the UKMO and sink the easterly pretty quick from that shortwave to the east of Greenland.

Who knows though but a better run so far in the medium term i feel.

The easterly has too 'sink' as the hig retrogresses to Greenland so I'm not sure what the problem is?

[glasgow-guy]

actually looking at the latest output they do score a direct hit to the UK but will need to wait longer i fear

[Rollo]

It certainly looks better than the 6z to me but I have always said that changes can and will occur right to the last minute,one thing seems clear we are getting our cold spell-now its just the snow we want.

[Geordiesnow]

The easterly for early next week is downgraded, resembling what the UKMO showed this morning though still a bit more pronounced than the ECM. It may still not be the last word, but I think expecting significant snowfalls from the Monday/Tuesday easterly was always stretching it. But I'm very interested in the positioning of this shortwave. Much further west on this run, which may well help to prolong the easterly flow on its northern flank.

Yep but to be fair only the GFS was going for a full on easterly earlier on whilst the ecm/ukmo were keen to have the high over us.

I'll take this run any day over the 06Z, not because of any IMBY reasons, it's because the cold and showery activity is much more widespread so perhaps more fun and games for more people.

[Thundery wintry showers]

I don't see a problem for cold/snow lovers on this run- the trajectory of the cold air is much further north on this run so it will have to engulf most of the country before the easterly flow runs out of steam. I expect the run to feature widespread snow showers between late on the 16th and midday on the 17th, and it shows that there is still considerable uncertainty. Although the three main models were in good agreement this morning the amount of ensemble scatter told a different story.

Edit: the precipitation charts indicate the ultimate of "thundery wintry showers" setups for east-coast areas lol!

Edited December 11, 2009 by Thundery wintry showers

[karyo]

Yep but to be fair only the GFS was going for a full on easterly earlier on whilst the ecm/ukmo were keen to have the high over us.

I'll take this run any day over the 06Z, not because of any IMBY reasons, it's because the cold and showery activity is much more widespread so perhaps more fun and games for more people.

Indeed, the pressure is lower and the easterly stronger so the snow showers should cross the country, unlike on the 6z!

Karyo

[Snowyowl9]

This is going to be the best synoptic cold spell since 2005/06 but colder.

http://91.121.93.17/pics/Rtavn1381.png

http://91.121.93.17/pics/Rtavn1382.png

[Matty M]

All the 12z is illustrative to me is that a continuing good synoptic pattern is developing but

the forecasting of that shortwave that develops over Svalbard is extremely poor at the moment

and its development has huge affects further down the line, a total lack of development would lead

to a steamingly cold easterly and the extremes of it there follow its strength and progress.

Very interesting and a forecasters absolute nightmare.

[weather eater]

What this run demonstrates to me is the futility of making pronouncements on a run and writing it off when it’s only in its early stages, out to 132hrs now and it’s starting to look a blinder. Better to wait and see how it develops, the forum won’t fall over if a post is not being made on the model thread every minute.

[Iceberg]

12Z GFS is a very very good run with much more snow next week for the timeframe it was always likely to be Wed/Thur/Fri.

This isn't getting put back, the whole country would get a nice covering from this.

I have to so though that none of the sites are doing well, so I rather fancy that the GFS ftp site is suffering issues atm(As they will all be getting from the same place).

[mountain shadow]

12z is an absolute stunning run. Problem is, I'm having to follow proceedings on TWO as terribly slow on here.

[Alex95]

The 6z and 12z aren't that different at +150, but everything is slightly further north. On the 12z however NE England (I'm using this example as I know the climate) would receive 3-6 inches from heavy snow showers / even blizzards, whilst on the 6z that finger of high pressure which is further south would prevent much snowfall, maybe a dusting on the ground.

[MKN]

at 156 most of the country is under -10s although probably woudnt b too much precip around

[Thunder_snows]

actually looking at the latest output they do score a direct hit to the UK but will need to wait longer i fear

yea it's looking that way ... alot more of the main pool of the air mass is being draged towards the uk, via the nth sea but the main extreme cold is not as expansive over eastern europe as the 06z but i does seem to be bringing in alot more -10's XD

[cooling climate]

That is what I Call an Easterly t144-150, excellent synoptics.

This is a belter of a run so far, something for everybody.

Edited December 11, 2009 by cooling climate

[MKN]

at 156 most of the country is under -10s although probably woudnt b too much precip around

[Cecil Hogmanay Melchett]

FANTASTIC 12Z gfs.Snow potential increases through next week and its cold and getting colder on that run.Just as

Tomasz said on bbc weather forecast earlier.

12Z IS AN UPGRADE!!!!!!!!!!!!!!

[Frosty.]

12Z GFS is a very very good run with much more snow next week for the timeframe it was always likely to be Wed/Thur/Fri.

This isn't getting put back, the whole country would get a nice covering from this.

I have to so though that none of the sites are doing well, so I rather fancy that the GFS ftp site is suffering issues atm(As they will all be getting from the same place).

I agree it's a very good run and better for the north than the 06z was although there will probably be a north and south shift on future runs as it's far from nailed yet but the meto update was very conservative when it came to forecasting snow and despite the 850's looking promising, it might ultimately end up the wrong side of marginal with sleet for low ground and snow restricted to above 800 feet.

[Duane S.]

This is a much better run than the 06z. Liking it a lot. No point speculating about it any further out than where I currently am at +150, very happy. Interesting little SW to the SW if you get what I mean

[mountain shadow]

http://209.197.11.95/c9s4a5k3/cds/gfsimages/gfs.20091211/12/144/h850t850eu.png?dopvhost=charts.netweather.tv&doppl=841a626ccf38162a&dopsig=34ebcd7c2cd70887a9a92e2e9024009f

All we need is UK MET and ECM to show the same, not to much too ask is it?

[MKN]

looks like a northerly following on, without any milder air to get through. All in all fantastic run, shows the massive effects small changes have even as early as 24 hours out though.

[Tim Bland]

12z is an absolute stunning run. Problem is, I'm having to follow proceedings on TWO as terribly slow on here.

Can't seem to get on TWO must be very heavy site traffic. They are Ramping big style over there. IMO next week is fairly nailed on now with sleety stuff on Mon / Tues (In East) and Snow showers from most areas to end the weeks. How heavy the showers are and if they merge to more prolinged snow is yet to be decided. IMO it won't be acurately forecastable until Tuesday at the earliest. Certainly charts to savour though!

[Geordiesnow]

The reason why i don't really want the easterly to sink is because the Northerly that might follow it is not guaranteed eand also the longer the easterly stays, the better obviously.

Will have to wait and see what the UKMO/ECM says before we start getting carried away though.