Model Output General Discussion

[Cal]

This is a fantastic chart for prolonged snow and if the low over france can make it sufficiently east then this cold spell is far from giving in :lol: .

http://91.121.94.83/modeles/gfs/run/gfsnh-0-150.png?18

Possibility of a decent scandi high?

http://91.121.94.83/modeles/gfs/run/gfsnh-0-162.png?18

Edited December 15, 2009 by Cal

[Optimus Prime]

Highest temperature on Sunday;

Lol obviously won't happen.

Edited December 15, 2009 by Optimus Prime

[Yeti]

Personally if we're looking for detail over this weekend then to be honest at the moment its a waste of time. Very diffcult to predict what disturbances will develop within this polar flow.

As for the breakdown thats being discussed. Again personally I feel its a waste of time but I do respect members if they want to look this far. I just can't be bothered at the moment due to the potential over the next few days plus the models will really struggle beyond +120.

Looks like the cold air is winning on this run?!

http://www.wetterzentrale.de/pics/Rtavn1501.png

There is less energy in the Atlantic so the GL HP can ridge S more; there is also more energy in the northern arm of the jet helping the low to dig down S:

http://www.wetterzentrale.de/pics/Rtavn16216.png

This in turn though would probably be the death sentence for the block...

[03jtrickey]

Just conjecture but looking at this chart here...

http://charts.netweather.tv/gfsimages/gfs.20091215/18/153/h850t850eu.png

If the low continued to move further south...

Easterly/Northeasterly reload potential?

Any thoughts?

[Guest]

I just hope someone has phoned The Fat Controller and told Thomas the Tank Engine and friends that their railway will be snowed in if this chart verifies:

"The Snowy Special" won't have a look in...

(apologies anyone who doesn't have wee boys...:lol:)

[eyeofthestorm]

Brilliant 18z for the longer term so far, heights beginning to rise over scandi by t144 possibly allowing an easterly re-load after the Northerly. Couldn't ask for more. :lol:

[bluearmy]

some encouraging developments to the north ..........

typical pub run or new trend ??

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=6&code=0&mode=0&carte=1

[TEITS]

Personally I feel some of these very low temp predictions by the GFS are perfectly plausible. The combination of clear skies, light winds, arctic airmass, lying snow can easily cause min temps to drop very low. Due to the short daylight hrs the temps struggle to rise very much which is why you see such low max temps. Happened in 1981 and no reason why it can't happen again!

[cyclonic happiness]

156+ is sucking another easterly /southeasterly into an already very cold low, this could be another "omg stop it, you are spoiling me" run!! :lol:

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=156&mode=0

[Snowyowl9]

I see alot don`t like UKMO T144 chart well I think it`s great,still in cold air and a secondary S-ly low to bring an east wind.

http://91.121.93.17/pics/Rukm1441.gif

As ECM goes as the best chart I`ve seen for that scenario today. :lol:

http://91.121.93.17/pics/Recm1681.gif

Still waiting for this cold air to reach this part an it`s early thursday morn when it will get cold enough for snow.

http://91.121.93.17/wz/pics/Rmgfs332.gif

All the less cold air coming from the north still from that high where the mild air went with.

http://91.121.93.17/pics/brack0.gif

This east wind is short lasting now only going to last a day or 2 now and it`s NE-ly,the SE east

will get the best out of this east flow now.

http://91.121.93.17/pics/Rtavn482.png

http://91.121.93.17/pics/Rtavn602.png

GFS back to form,it`s really going to be the NW-ly to deliver this time for the west.

http://91.121.93.17/pics/Rtavn1501.png

[cooling climate]

Could anyone tell me why Meteociel are still showing a operational run as well as the paralllel run.

I thought the parallel took over this afternoon or are they still running the operational for a few weeks

or so.

[Nick L]

Once again some ridiculous maximum temps on this run, take a look at this for Tues:

http://212.100.247.1...ba56bd7b8d32ba3;

http://212.100.247.1...ba56bd7b8d32ba3;

Madness!

Edit: Also looks like an insane minimum as well, -10c in the Midlands by 9pm. New GFS, same old crazy temperatures! :lol:

Edited December 15, 2009 by nick2702

[SMU]

Guys-

I cannot comment on the 18z's epicness- We all know its a show shopper out to 180-

Can I just say it WONT be at the top of the ensemble suite tonight...........

Will we get the ensemble mean below freezing for Xmas...

S

[cyclonic happiness]

Personally I feel some of these very low temp predictions by the GFS are perfectly plausible. The combination of clear skies, light winds, arctic airmass, lying snow can easily cause min temps to drop very low. Due to the short daylight hrs the temps struggle to rise very much which is why you see such low max temps. Happened in 1981 and no reason why it can't happen again!

I am hoping that we are getting into the period now known as "the synoptic shift", and that this will drastically alter our weather for years to come, perhaps we all have suspicions thus?

[Guest]

Personally I feel some of these very low temp predictions by the GFS are perfectly plausible. The combination of clear skies, light winds, arctic airmass, lying snow can easily cause min temps to drop very low. Due to the short daylight hrs the temps struggle to rise very much which is why you see such low max temps. Happened in 1981 and no reason why it can't happen again!

Aye, if there is snow over the Highlands in Scotland then I think -20C is on the cards. It would shock people how quickly the temp will just fall away. Maybe -15C in parts of England too. Snow cover at this time of year will make the temps plunge off a cliff like lemmings.

[Thundery wintry showers]

Personally I feel some of these very low temp predictions by the GFS are perfectly plausible. The combination of clear skies, light winds, arctic airmass, lying snow can easily cause min temps to drop very low. Due to the short daylight hrs the temps struggle to rise very much which is why you see such low max temps. Happened in 1981 and no reason why it can't happen again!

Aye, it was just those of the 12Z that I thought were OTT. If there was a widespread snow cover then the temperatures of the 18Z would indeed be quite plausible.

[nick sussex]

I think this run shows why its an impossible forecast for next week, so much depends on how the two lows interact here.

[cyclonic happiness]

Could anyone tell me why Meteociel are still showing a operational run as well as the paralllel run.

I thought the parallel took over this afternoon or are they still running the operational for a few weeks

or so.

i means that we look at their site for longer, making them feel a little more important :lol:

[Barb]

If someone offered me the 18z as reality I'd snap their arm off...

The cold just does not want to go away. Showing undercutting low and southern blizzard in FI.

[Thundery wintry showers]

I don't trust the GFS 18Z evolution after T+144 as it is at odds with what the other runs have showed from all of the models. Still, it does highlight another possible way in which we could hold onto the cold (and snowy!) regime through to Christmas- lows passing to the south and fizzling out of LP to our east leaving us in a sluggish easterly regime. The vast majority of the country would be in for a white Christmas.

[Cal]

White Xmas anyone :lol:?? Long shot but the signs are very encouraging, what a snowfest :lol: !

http://91.121.94.83/modeles/gfs/run/gfsnh-2-216.png?18

[SMU]

http://www.wetterzentrale.de/pics/Rtavn18017.png

I agree with TEITS- Uppers become irrelevent in this type of situation-

Slack air

Snow cover

Entrenched cold at the surface-

-13c in that frame-

& yes I doubt ive ever seen -15C in high res....

http://www.wetterzentrale.de/pics/Rmgfs1804.gif

Heres an interesting spin- we could have a white Xmas- that isnt a white xmas at the bookies-

It would be funny if Xmas day temps were say -5c & deep snow on the ground- but no snow falling!!!!!

S

Edited December 15, 2009 by Steve Murr

[Altostratus]

The 18Z is a thing of beauty. That really would be somethng special if that happened. It's nice to see this crop up in the models as it has been mentioned as a possibility my both myself and others. Probably unlikely, but the fact it is even showing up on the models is good news. Lots to enjoy before then anyhow.

[TEITS]

Aye, if there is snow over the Highlands in Scotland then I think -20C is on the cards. It would shock people how quickly the temp will just fall away. Maybe -15C in parts of England too. Snow cover at this time of year will make the temps plunge off a cliff like lemmings.

Indeed and what some are forgetting is the domino effect. If the day starts with very low temps the max temps struggle to rise due to the short daylight hrs. What then happens is the min temps drop even lower the following night and the next days max temps are even lower. This continues until there is a change in conditions.

Back to the 18Z and what can you say apart from stunning. However all this run indicates is the mild returning isn't a certainity!!

[Cal]

http://www.wetterzentrale.de/pics/Rtavn18017.png

I agree with TEITS- Uppers become irrelevent in this type of situation-

Slack air

Snow cover

Entrenched cold at the surface-

-13c in that frame-

& yes I doubt ive ever seen -15C in high res....

http://www.wetterzentrale.de/pics/Rmgfs1804.gif

Heres an interesting spin- we could have a white Xmas- that isnt a white xmas at the bookies-

It would be funny if Xmas day temps were say -5c & deep snow on the ground- but no snow falling!!!!!

S

Yes these are stunning runs Steve, it even carries on

http://91.121.94.83/modeles/gfs/run/gfsnh-0-324.png?18