Model Output Discussion: 12Z (22/11/12) And On...

[nick sussex]

There seems to be much less shortwave activity near Scandi here, this is good news and also the troughing is better orientated. The GFS sticks to its more amplified upstream pattern at 132hrs.

[Nick F]

GFS still not really having that low Sunday.

NAE shows possibly dangerous low approaching from south at 48hrs while GME has a strong depression moving northeastwards through UK.

I wonder is GFS missing this or what are peoples thoughts?

Reasonable run to run consistency from GFS to 120hrs.

Small differences in trough over UK and extent of Arctic High.

Difficult to say whether GFS is underdeveloping the weekend's low or whether ECM/UKMO/Exeter faxes are overdeveloping. The models often, for some reason, have difficulties in handling the developement of lows moving NE from just NW of Iberia. Remember the troublesome lows back in September from that direction. Tropical air from low latitiudes getting entrained into the developing low, plus strong jet alot - so potential that it could develop into quite a nasty little low, with storm force winds and very heavy rain.

Another low swings in towards the SW by early Monday - bringing yet more heavy rain early next week to the places where we least need it.

[ITSY]

look at those heights over Eastern Europe!! we need a NEly not an Ely with that set-up! never thought we'd be seeing a major easterly that drags in +8C uppers at the end of November! need slightly better orientation on that low

Edited November 22, 2012 by ITSY

[Matty M]

UKM trickling out.. Positions the trough much further south (over Iberia) at T120hrs...

[The Eagle]

Not the best 12z UKMO.

[Nick F]

I thought I had bad eyesight mate, it is there just 5mb or so les deep than NAE shows it but it is certainly there and about the same place as NAE shows it?

12z GFS definately shallower than the 06z GFS and the 00z UKMO and ECM, some 20mb or so less deep than this morning's ECM.

Edited November 22, 2012 by Nick F

[Matty M]

Not the best 12z UKMO.

No Arctic High never really gets its move on and the height falls over Greenland are worrying.

[Cheshire Freeze]

UKMO looking a bit dicey tonight. Heights look far too southerly for my liking.

Little low stopping connection to Arctic high.

How many times have we seen the UKMO be the party pooper over the years?!

Edited November 22, 2012 by CreweCold

[The Eagle]

No Arctic High never really gets its move on and the height falls over Greenland are worrying.

http://www.meteociel...44-21.GIF?22-17

Still shows a split vortex. But i'd guess high pressure will end up close.

GFS is good though.

Edited November 22, 2012 by The Eagle

[Matty M]

While the UKM is not ideal. The GFS @ 168hrs is getting tasy.

[Ian Ballinger]

Can't help but feel deflated today, lesson of the day, never get excited about what the charts are showing

[nick sussex]

Such differences between the UKMO and GFS, the UKMO stops the southwards push of the Arctic high in a frenzy of shortwaves!

No agreement with the troughing over Europe so basically its back to the drawing board, they do though agree on the upstream pattern!

[warrenb]

The UK Meto is fine, vortex split asunder, that high is going NE, and then the low to west undercuts, and bingo, retrogression later in December with southerly tracking lows.

[Geordiesnow]

Nope, not the best UKMO at all, that is probably the last thing we need in all honesty, yet another shortwave heading into Greenland which stops the Atlantic ridge in it tracks! That what stopped the October cold snap from lasting longer! Lets hope we don't have deja vu here.

GFS is good for maintaining the blocking though, but the models have appeared to of shifted the patterns eastwards somewhat and the link up of the Atlantic ridge and Arctic high is less successful.

[Cheshire Freeze]

Can't help but feel deflated today, lesson of the day, never get excited about what the charts are showing

Which was exactly my motto yesterday. At 168-192 hrs there's always time for dreaded shortwaves to be picked up and completely change the weather experienced in our little patch of the world, even if the generalset up is unaltered.

[Matty M]

Such differences between the UKMO and GFS, the UKMO stops the southwards push of the Arctic high in a frenzy of shortwaves!

No agreement with the troughing over Europe so basically its back to the drawing board, they do though agree on the upstream pattern!

What is the accuracy of the UKM @ 144hrs? I have a feeling (if i recall) it is one of the worst performers at that range?

GFS a corking beast from the east at 180hrs

Edited November 22, 2012 by Matty M

[Met4Cast]

Can't help but feel deflated today, lesson of the day, never get excited about what the charts are showing

Yeah, these charts are absolutely awful, eurgh, nothing but zonal

(To less experienced members, these charts are actually showing a very good alignment and cold heading towards the UK)

[Snowy Easterlies]

i thought people said that GFS has a better handle on heights to the northwest, so do we think UKMO has gone of on one ?

[The Eagle]

GFS is really good to 192hrs. Pitty UKMO throwing in a spanner. Other than that happy enough.

[No Balls Like Snow Balls]

FI is currently T96, none of the big 3 can agree where to place the LP. While the UKMO is clearly the worst of the 12Z for placement of the LP we cannot let it worry us to much as it is only 1 UKMO run that has done this.

Edited November 22, 2012 by No balls like Snow Balls

[Dexter29]

Can't help but feel deflated today, lesson of the day, never get excited about what the charts are showing

Absolutely, it happens during most projected cold spells, amazing charts like yesterday only to be replaced by not so good charts today.

Same old = Prozac bottle. Why do members do it to themselves, I have no idea.

Also last night there was talk of how a breakdown would happen at +240 and how it worried a few, that's now forgotten and now we are worried about there even being a strong enough block to even breakdown...

Tomorrow there will be something different to worry about I'm sure.

As the more experienced and knowledgable members say: just get the cold here first and see what happens

[snowmadchrisuk]

By +180 on the GFS we finally start to get the Cold uppers and starts to get very tasty ,but looking at the UKMO , FI must be less than 72 hours at the moment., this is often the case with upstream changes , But signals seem so strong for High pressure to our NW , I can only see upgrades as we get nearer the time... I have a feeling by this time next week we will be looking at breath taking charts as the Cold will have had time to work its way to the UK before then.

[swfc]

If the ukmo had run on another 24 hours wed be fine,why the panic?????Earlier it was ignore the oz and ecm and stick with the "rock solid"500mb charts!!!!lol.oh gfs looks ok by the way lol

[nick sussex]

What is the accuracy of the UKM @ 144hrs? I have a feeling (if i recall) it is one of the worst performers at that range?

GFS a corking beast from the east at 180hrs

It's not been great recently but its still a good model. In terms of the 144hrs we might get away with it those shortwaves might head into Scandi and with low heights over the Med the high cant sink.

It's not a disaster by any means, I think we have to accept that the models are having a hard time here!

We wait for the ECM but I wouldn't be surprised to see that come up with a different scenario!

[Cheshire Freeze]

i thought people said that GFS has a better handle on heights to the northwest, so do we think UKMO has gone of on one ?

The UKMO is a good model and seeing as the (relatively) poor evolution sets in before 144 hours I think it would be wise to dismiss it; this is the case even if the ECM sides with the GFS. I say this as I can recall a couple of times when the UKMO scuppered cold chances against the ECM and GFS and it was proved correct. Saying this I'm not so sure where we'd go from that UKMO 144 hrs chart; I think we would possibly get to our destination but it sure would be the (un)scenic route around procedings!