Model Output Discussion - 7th-13th November

[nick sussex]

Still no agreement between the GFS and UKMO regarding the amplitude of that eastern USA trough. The GFS 12hrs run is a little less progressive than the earlier 06hrs but still also much flatter aswell at 144hrs upstream in the USA.

Until this trough and upstream pattern gets sorted out then its hard to have too much confidence on the way forward.

[No Balls Like Snow Balls]

12z GFS shoots a cold pool into SE Europe so probably snow for those places. The UK starts to feed in air from Europe which helps in turn to bring in cooler nights again.S

lowly changing the pattern from the looks of the 12z to a HP dominated pattern.

GFS progging single figures away from coasts from Monday onwards for daytime temps, would be very noticeable after the mild we have had.

[Isolated Frost]

First class tickets to Venice... sorted! Pulse of cold air that would deliver a good hefty snowfall for eastern Italy.

[wimblettben]

I don't think anywhere will see 18c this week not even the centre of London, just using the GFS 2m temps, i only see 15c being reached maybe a 16c squeezed somewhere before a cool down again on Sunday and much noticeably cooler temps following on Monday.

Could go either way really.

Of course GFS can sometimes undercook temps so it is possible.

[phil nw.]

GFS 12z keeps the pattern pretty flat upstream so we get midlatitude blocking ,perhaps a cooler feel with some drift of the continent as time goes on.

Edited November 7, 2011 by phil n.warks.

[wimblettben]

Monday next week will certainly feel different to the end of this week going by the GFS.

[No Balls Like Snow Balls]

Monday next week will certainly feel different to the end of this week going by the GFS.

I really do believe that we will have seen the back of these mild temps from Monday next week and there will be nothing but a marked cool down from then on. Obviously it won't be good enough for some but after the unseasonably mild temps of late just a cool down feels like winning the lottery.

[Backtrack]

Monday next week will certainly feel different to the end of this week going by the GFS.

That's right at the end of the run. That chart isn't going to be accurate, it's just not possible to be very accurate 14 days out using the GFS as your only model.

It will certainly change, I guarantee it.

[kold weather]

Well the 12z keeps us in a cooler set-up but little to no retrogression of the upper high and towards the end the jet roars back to life.

Temperatures probably a little below average from 144hrs onwards, nothing too cold but certainly much colder then it has been.

[Cheshire Freeze]

I'm not too concerned with the possibility the ECM may not produce as good a run as the 00z as I think it was being progressive in bringing about te change. The important things to look out for is an amplified jet rather than the flatter version that the GFS produces.

FWIW just seen the UKMO 12z and on the face of it it doesn't look as good as the 00z......however when you look deeper pressure seems to be on the rise across Iceland/southern Greenland; now the crux- a powerful jet streak looks like leaving the NE Atlantic and it's whether enough energy can go underneath the fledgling height rises that will decide the pattern judging by the 144 hours chart. On the face of it the chart looks like a lost cause with a powerful low winding itself up to the west of Greenland but energy from this can soon dissipate IF the jet allows.

All in all quite a strange pattern that we have at the minute but one which looks like it could quite easily lead to cold further down the line.

Edited November 7, 2011 by CreweCold

[Gowon]

That's right at the end of the run. That chart isn't going to be accurate, it's just not possible to be very accurate 14 days out using the GFS as your only model.

It will certainly change, I guarantee it.

We won't have to wait that long, temps will be in single digits from Sunday onwards (for most of the country anyway) with frosty nights IF GFS verified.

[ITSY]

massive discrepancies still between the models - no idea what will happen. A couple of weeks ago I forecasted a continuation of average to mild weather for the duration of November, so i'm guna stick with that for the moment.

[Cheshire Freeze]

massive discrepancies still between the models - no idea what will happen. A couple of weeks ago I forecasted a continuation of average to mild weather for the duration of November, so i'm guna stick with that for the moment.

In all fairness the discrepencies are actually quite subtle and comes down to just a couple of factors which are intrinsicly interlinked. The ECM will shed some light this evening, if it continues where the 00z left off, even if not as good on the face of it, I'll most certainly be heading down the amplified route with a better chance of a quickish plunge into potential cold.

[chionomaniac]

In all fairness the discrepencies are actually quite subtle and comes down to just a couple of factors which are intrinsicly interlinked. The ECM will shed some light this evening, if it continues where the 00z left off, even if not as good on the face of it, I'll most certainly be heading down the amplified route with a better chance of a quickish plunge into potential cold.

So CC what do you think the ECM will bring this evening. My guess is a halfway house between the full retrogression to Greenland and none at all. A flirt then retreat!

c

[Cheshire Freeze]

So CC what do you think the ECM will bring this evening. My guess is a halfway house between the full retrogression to Greenland and none at all. A flirt then retreat!

c

Seems like a fair call at this juncture, I don't think we'll get a full on Greenland high until the last third of the month; what I do think we will see is attempts at the pattern that will ultimately implicate itself later in the month and into December. I think Steve M alluded to this a couple of days back too. That pretty much sumarises my thoughts at this moment in time.

For me I'm ~70% sure of a cold outbreak initiating around the closing stages of this month.

[Summer Sun]

High pressure builds strong to the east for the weekend and into next week

http://www.wetterzentrale.de/pics/Rtavn1261.png

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

http://www.wetterzentrale.de/pics/Rtavn1741.png

Rain fall should be low, temperatures around normal with frost and or fog possible at night depending on cloud cover

Deep FI

http://www.wetterzentrale.de/pics/Rtavn3601.png

http://www.wetterzentrale.de/pics/Rtavn3841.png

The last chart is no good if you want cold weather

:good:

[Snowstorm1]

Any info on ECM coming out at the moment Im waiting here in anticipation lol

[clark3r]

i def see a cooling trend to something near average in day time temps for the second half of the month! dont see any cold snap in the near future! will have to wait for the siberian swans to arrive before will look on the models for a cold snap lol!

[Cheshire Freeze]

RE ECM, initially it doesn't look as promising as the 00z but by 192 hours we aren't far off a cold spell IMO.

[chionomaniac]

Well it looks like the ECM is going with the cheeky flirt and withdraw idea!

[phil nw.]

Well up to T168 on ECM and it`s gone pretty much along the lines of GFS at that point.

http://176.31.229.228/modeles/gfs/run/gfsnh-0-168.png?12

A flatter pattern with a lot of mid latitude high pressure.

A more settled period ,mild this week but cooler surface temps. next week as we pick up a continental flow around the High.

[Cheshire Freeze]

Well it looks like the ECM is going with the cheeky flirt and withdraw idea!

Look at the NH view at 168-192 Chiono, vortex split??

[Snowstorm1]

This to me looks preety good? http://www.wetterzentrale.de/pics/Recm2161.gif

[Cheshire Freeze]

Don't see the dispondency........fantastic wave pattern setting up there......

[Liam J]

Don't see the dispondency........fantastic wave pattern setting up there......

So much potential on this chart, a nice big block over the Arctic ridging towards the UK with a trough setting up to the NE.