Model Output Discussion - 28th November - 4th December

[kold weather]

But, this doesn't mean we cant get a few decent cold snaps, We can get these with a cold PV can we not?

Yeah its more than possible, it does become hard for it to last any length of time but with the pattern becoming so zonal and with the PV placed quite decently for us we could well a pattern of re-loading weak NW/N airflows. Its not going to keep the coldies happy in the south but at least Scotland and N.England would have a chance in this pattern.

12z GFS moved the strong low on the 3rd a little further north now so not quite so severe.

[Cecil Hogmanay Melchett]

ukmo doesn't look half as good 1t 144h im afraid.

[Zakos]

Yeah its more than possible, it does become hard for it to last any length of time but with the pattern becoming so zonal and with the PV placed quite decently for us we could well a pattern of re-loading weak NW/N airflows. Its not going to keep the coldies happy in the south but at least Scotland and N.England would have a chance in this pattern.

12z GFS moved the strong low on the 3rd a little further north now so not quite so severe.

Thank you for your reply

Yes, I noticed there has been a slight downgrade from the GFS.

Agreed there is little scope for long lasting cold spells. Anything is better than the dreaded euro high earlier. There was no way that was going to deliver anything except inversion cold. At the very least some exciting weather these next few days! And with any luck, I and many others may see a bit of snow...

[swilliam]

ukmo doesn't look half as good 1t 144h im afraid.

No it does not deepen the low anything like as much - unfortunately the GFS has a habit of overdoing this.

[AWD]

No it does not deepen the low anything like as much - unfortunately the GFS has a habit of overdoing this.

and with a low like the UKMO suggests, it has no way near enough strength to pull down the colder uppers and deliver a pM shot like the GFS does afterwards! We all know what the GFS is like with deep LP systems too.

All eyes on the ECM tonight, will it back the GFS or UKMO?

[kold weather]

Whilst the GFS does overdo low pressure cells, conversly the UKMO is often quite abit too weak with these features as well. Given the 00z ECM developed a tight low pressure and given the pattern at the moment out there, I'd back the GFS LP as more likely....however that is not to say that a deeper low = stronger cold drag.

[Liam J]

GFS 12z has dropped the intensity of the deepening LP it has been consistently progging for Wednesday night, strange, I would expect it to back on the 18z but we shall see.

Expect changes even in the reliable time frame with such a volatile situation at the moment.

Edited November 28, 2011 by Liam J

[SuttonStorm]

Where are you viewing the 12z UKMO? It's still the 00z on Wetter and here on Netweather it hasn't updated for days?

SS

[AWD]

Where are you viewing the 12z UKMO? It's still the 00z on Wetter and here on Netweather it hasn't updated for days?

SS

Weather Online

[phil nw.]

Yes the UKMO at T144 has that Azores High closer to the UK and keeps the colder air further North than GFS.

The modelled Jet profile shows the main energy right over us which would suggest the main thrust of Polar air will likely remain further North in the UK and will be mixed out as secondary disturbances develop further South.

http://www.wetterzen.../Rtavn14414.png

Even with the UKMO outlook It will likely still be quite Wintry in the far North though, especially those with any height.

A much more NWesterly tilt suggested in the flow in the models in the next week-10 days which should continue to keep things quite chilly and keep the door open for further incusrsions of Pm air.Who knows if we can squeeze a little more amplification out of the setup this would pull colder air further south, albiet briefly.

Plenty of interest this week then with several fronts due to cross the UK with wind,rain and hill snow in Scotland.

http://www.wetterzen...ics/Rukm721.gif

Edited November 28, 2011 by phil n.warks.

[Harsh Climate]

Looking at that though, I expect a northerly to reload, probably on monday/tuesday.

[bluearmy]

2 cool days in the offing = friday and monday. nothing spectacular likely. note ian brown's thoughts on the way that shortwaves are likely to be picked up nearer the time to reduce the duration of any cold flow or more likely, prevent it from happening in the first place. i'm afraid that there is little to excite 'coldies' at the moment for at least a couple of weeks. the GEM NH plot this morning did seem to show a weaker p/v profile over the arctic at T240. however, until we see all three models showing this and more importantly, NAEFS in deep FI, i expect plenty of frustration on here. take away the past couple of winters and this seems quite normal fare for winter model watching.

[shedhead]

2 cool days in the offing = friday and monday. nothing spectacular likely. note ian brown's thoughts on the way that shortwaves are likely to be picked up nearer the time to reduce the duration of any cold flow or more likely, prevent it from happening in the first place. i'm afraid that there is little to excite 'coldies' at the moment for at least a couple of weeks. the GEM NH plot this morning did seem to show a weaker p/v profile over the arctic at T240. however, until we see all three models showing this and more importantly, NAEFS in deep FI, i expect plenty of frustration on here. take away the past couple of winters and this seems quite normal fare for winter model watching.

Agreed, can't help feeling the rise of exitement and anticipation in here is writing cheques the weather will ultimately be unable to cash. Yes it's going to get colder and yes one or two lucky members may not have to don hiking boots and dodgy looking kagools to see a bit of the white stuff, but in reality the models suggest wet, windy and even stormy weather looks far more likely than anything really wintry for 95% of us across the next week or so.

[chionomaniac]

2 cool days in the offing = friday and monday. nothing spectacular likely. note ian brown's thoughts on the way that shortwaves are likely to be picked up nearer the time to reduce the duration of any cold flow or more likely, prevent it from happening in the first place. i'm afraid that there is little to excite 'coldies' at the moment for at least a couple of weeks. the GEM NH plot this morning did seem to show a weaker p/v profile over the arctic at T240. however, until we see all three models showing this and more importantly, NAEFS in deep FI, i expect plenty of frustration on here. take away the past couple of winters and this seems quite normal fare for winter model watching.

Any GEM PV weakening is likely to be temporary or wrong.

Look at these strat PV positioning charts. The enhanced PV is right over northern Greenland from troposphere to stratopause.

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ec.php?alert=1&level=all&forecast=f240&lng=eng

[jonnybradley]

Any GEM PV weakening is likely to be temporary or wrong.

Look at these strat PV positioning charts. The enhanced PV is right over northern Greenland from troposphere to stratopause.

http://wekuw.met.fu-...st=f240&lng=eng

Sorry to keep asking questions....

What is the thinking on the PV, ie how long could it last and what would/could cause it to shift?

Again untrained eye but we seem to be caught in a new pattern with highs out to our south and the PV

[karyo]

Any GEM PV weakening is likely to be temporary or wrong.

Look at these strat PV positioning charts. The enhanced PV is right over northern Greenland from troposphere to stratopause.

http://wekuw.met.fu-...st=f240&lng=eng

The latest charts show a warming over South Europe and North Africa?

Karyo

[feb1991blizzard]

GFS 12 projecting snow down to low levels for Northern England, cant get the UKMO but if that shortwave digs south on the ECM next frame then it would be a good chart, we could be in business yet, not for a major dumping but certainly better than i had bargained for, still a wait and see situation though.

[January Snowstorm]

ECM answers the question of will it snow next Monday by saying "YES"

Quite a wintry run with deep deep cold just to our Northwest.

It looks a transient issue, but not bad at all

[Frosty.]

It's looking like turning colder in the coming days and very unsettled and windier with some proper rain for the south at last and not that spotty drizzle in the wind stuff, cold enough for snow in northern britain, mainly on hills from tues night, another major low likely to hit the uk late friday into saturday with gales and heavy rain, perhaps stormy on saturday? then colder with wintry showers and night frosts but nothing significant apart from northern high ground where it could be quite wintry next week.

Edited November 28, 2011 by Polar_ Low

[AWD]

ECM goes more with the GFS and a wintery start for the north next week, mainly high ground though as the colder uppers don't make as much inroads into the UK as they did on the GFS!

May not be a big freeze but at least it's something for some people! I still believe that the track of the LP at the weekend will determine what sort of pM shot we get afterwards!

Edited November 28, 2011 by Active Weather Dude

[Mark Neal.]

Might not be the best scenario for us down south, but i believe its pleasing news concerning the chance of snow next week,even if its albeit in the north. Hopefully the 18z will continue the theme, good to see the Ecm going with the Gfs. Pleasing and encouraging signs people. Things will change though but for the better or the worse, we will soon see.

[Summer Sun]

ECM so far tonight

http://www.wetterzen...cs/Recm1201.gif

http://www.wetterzen...cs/Recm1441.gif

http://hw.nwstatic.co.uk/ecmimages/20111128/12/ecm500.168.png

http://www.wetterzen...cs/Recm1921.gif

http://www.wetterzen...cs/Recm2161.gif

Edited November 28, 2011 by Gavin D

[I remember Atlantic 252]

ECM so far tonight

http://www.wetterzen...cs/Recm1201.gif

http://www.wetterzen...cs/Recm1441.gif

168h not working

http://www.wetterzen...cs/Recm1921.gif

http://www.wetterzen...cs/Recm2161.gif

use meteociel, shows NW wind snow/cold north, average/mild south

[Summer Sun]

use meteociel, shows NW wind snow/cold north, average/mild south

Thanks used NW's chart.

High pressure builds

http://www.wetterzentrale.de/pics/Recm2401.gif

[Frosty.]

I don't think there will be any blizzards next week apart from across the far north and scottish hills and mountains further south, the gfs and ecm 12z on the face of it, shows quite a potent cold snap for the north but snow does not penetrate south of the hills in the midlands so the south looks like remaining snowless for some time to come but at least it will become colder.