General Model Output Discussion

[cheeky_monkey]

Just looking at the latest models output may mean i have to delay my departure to Canada i have already moved my original flight from the 10th Jan to 15th Jan...it does really look like i may have to delay for another week possibly if the models are correct. GFS keeps it cold with further possible snow falls right through the run..which would make this the most prolonged cold spell since 1963.

Edited January 7, 2010 by cheeky_monkey

[Thundery wintry showers]

Interestingly Manchester recorded 21 days of falling sleet/snow during that month.

Looking at the statistics for various sites for February 1986 it appears that the easterly flow was generally less stable in central and northern districts than in the south- most likely a combination of lower upper air temperatures and longer sea track. I get the impression of a very dull dry month in the south, but with northern England and Scotland being sunny with light snow flurries in the west and snowy in the east. Durham had close to average precipitation in February 1986, almost all of it as snow, and sunshine was just a little below normal.

A close match to the upcoming setup is early January 1997 which saw generally easterly winds but the cold upper air generally moderated out. Dry cloudy weather was frequent but at times the flow was still unstable enough to give sunshine and showers. Eastern Scotland and north-east England maintained snow cover for a while inland, but it thawed near the coast, but in East Anglia and the southeast snow widely stuck around for 10-11 days. I think it will be a similar story here- turning warmer with a slow thaw in the northeast, especially near the coast, but remaining cold in the southeast. I think it will be mostly cloudy and dry next week with some light snowfalls in the southeast, and sleety showers near the east coast further north.

[snowmadchrisuk]

I think you are probably refering to the UKMO global model and their precipitation charts, this model is quite low in resolution, so won't pick out showers that feed inland. 06z NAE model, which is higher res, shows precip feeding inland to the midlands as early as tomorrow evening as a trough moves in off the N Sea on the developing easterly flow. GFS shows showers filtering inland to Midlands on Saturday.

Yes that is what I was referring to , I have seen the 6z NAE and that looks pretty good, we will have to wait for the 18z now as the 12z only goes out to +24 or it does on the charts I have access to. The 12z NAE does show a band of Snow moving SW during tomorrow morning but it seems a little to far North for some of the Midlands.

I see on the Weather online NAE they all go out to +48 .. looking very good from tomorrow onwards .. maybe a ppn upgrade to come from the 12z GFS then

[Neilsouth]

http://www.wetterzentrale.de/pics/Rtavn602.png

http://www.wetterzentrale.de/pics/Rtavn604.png

http://www.wetterzentrale.de/pics/Rtavn6017.png

Some parts could get a right pasting this weekend

[MKN]

http://www.wetterzentrale.de/pics/Rtavn602.png

http://www.wetterzentrale.de/pics/Rtavn604.png

http://www.wetterzentrale.de/pics/Rtavn6017.png

Some parts could get a right pasting this weekend

chris's reference to 1991 could be about right regarding sun/mon. Wouldnt think it would be to heavy but quite prolonged. Heavy for the east maybe.

[SizzlingHeat]

still only a very low amount of ppn being displayed on the GFS which is why i am thinking slightly maginal DP may end up in it all being freezing drizzle/snizzle?

[sandstorm2]

Quite a change in the GFS 1200 at+132 with the high wanting to move north and a twin centre low pressure system moving toward Southwest England there could be quite a bit of snow coming up next week.

SS2

[Hammer]

still only a very low amount of ppn being displayed on the GFS which is why i am thinking slightly maginal DP may end up in it all being freezing drizzle/snizzle?

As is mentioned several times, would not worry about the PPN, a few days away yet, it will upgrade nearer the time. Okay so it might not all be heavy but there will be some areas of heavy PPN.

[Neilsouth]

still only a very low amount of ppn being displayed on the GFS which is why i am thinking slightly maginal DP may end up in it all being freezing drizzle/snizzle?

Damn it as i said before stop worrying about precipitation rates displayed on gfs or the dewpoints , the airflow will be coming off a very cold continent and gfs cannot accuratly predict preciptation from the north sea.

[MKN]

Quite a change in the GFS 1200 at+132 with the high wanting to move north and a twin centre low pressure system moving toward Southwest England there could be quite a bit of snow coming up next week.

SS2

Quite alot of rain more likely if the precip ended up further north, id rather not chance that and stay dry until we get a shot at some colder air. Even if temps increase providing theres no rain snow would stay around for some time. especially if we get a top up over the weekend.

Yep by wednesday the snow in the south would be all but gone.

Edited January 7, 2010 by SnowTornado

[nick sussex]

The gfs here desperately tries to bring in milder air as it overblows those lows. Absolute garbage and won't verify, the likely outcome is a low heads se under the block, with pressure building west over the top of the low. To be honest i know longer take the gfs as a serious model and it's the same old story with this model.

[SizzlingHeat]

Damn it as i said before stop worrying about precipitation rates displayed on gfs or the dewpoints , the airflow will be coming off a very cold continent and gfs cannot accuratly predict preciptation from the north sea.

ok just dont go mental when sunday and monday is murky and cold with drizzly sleety rain/freezing rain

Temps of 0-2c with dewpoints of 0-1c and light ppn only going to be drizzle if not freezing drizzle. Its just over 2 days away, even the bbc weather only shows very light ppn on their overview. No idea where heavy snow is coming from, im sorry prove me if im wrong but when its drizzling on sunday then dont start moaning about why it never happened

lol with a username like sizzling heat he's bound to have a mild biase to his posts don't you think neil

i absolutely love the cold and snow and would like this to freeze us till the end of march but just expressing an opinion of how i see the charts and what i think the situation should be, dont want to be told im talking rubbish etc

[igloo]

Quite alot of rain more likely if the precip ended up further north, id rather not chance that and stay dry until we get a shot at some colder air. Even if temps increase providing theres no rain snow would stay around for some time. especially if we get a top up over the weekend.

Yep by wednesday the snow in the south would be all but gone.

yes i have to agree with you about rain unless you stay some 300m up on the hills but i will say this model tends to over power the lows some what and i wouldnt be surprised if it undercuts nearer the time

[derrylynne]

GFS in indicating a breakdown starting in about 5 days time. Ok there will be snow on the edge but looking at it we can expect the Atlantic to rush in then and turn it much warmer. Be interesting what the pub run says:-)

[mountain shadow]

ECM has the low about 300 miles further south over North East Spain.

http://209.197.11.111/c9s4a5k3/cds/gfsimages/gfs.20100107/12/156/h500slp.png?dopvhost=charts.netweather.tv&doppl=841a626ccf5c6e99cf0c6ec91ec96582cf0c6e01&dopsig=d566c579cf4dd12ace0d0828652cccd5

Makes a big big difference. ECM 12z again will be interesting as to whether it goes with this or not.

[mushymanrob]

The gfs here desperately tries to bring in milder air as it overblows those lows. Absolute garbage and won't verify, the likely outcome is a low heads se under the block, with pressure building west over the top of the low. To be honest i know longer take the gfs as a serious model and it's the same old story with this model.

whys that?... not being funny nick, but why isnt the 12z picking out a new trend? detail next week has been uncertain and the 12z just might have picked up on what may well happen. the fax @120 has the potential to throw troughs up from the atlantic in exactly the way the 12z runs with.

to my untrained eye, it looks plausable.

[snowmadchrisuk]

The gfs 12z is ending the cold spell by bringing the low pressure next week much further North , I would say this is possible but far from set in stone yet. All this cold air across the UK would make it's progress painfully Slow , also pressure is very High to the East still. I would in no way go for rain SUN/MON/TUE in the midlands, I agree its possible in the poster from Dorset's point of view but no way in the Midlands.

[derrylynne]

whys that?... not being funny nick, but why isnt the 12z picking out a new trend? detail next week has been uncertain and the 12z just might have picked up on what may well happen. the fax @120 has the potential to throw troughs up from the atlantic in exactly the way the 12z runs with.

to my untrained eye, it looks plausable.

The GFS has been good though at picking up trends. So it could be the GFS is onto something. Certainly to me looks like the end of this cold spell is in sight...

[The Weather Dragon]

GFS shows a perfectly plausible solution IMHO - all eyes on ECM

[mountain shadow]

The GFS has been good though at picking up trends. So it could be the GFS is onto something. Certainly to me looks like the end of this cold spell is in sight...

If I had a pound for everytime that has been said these last three weeks, I would be a rich man.

GFS has continually tried to end the spell, and has continually been wrong, until I see it on the ECM I'm ignoring it.

[nick sussex]

whys that?... not being funny nick, but why isnt the 12z picking out a new trend? detail next week has been uncertain and the 12z just might have picked up on what may well happen. the fax @120 has the potential to throw troughs up from the atlantic in exactly the way the 12z runs with.

to my untrained eye, it looks plausable.

It would be plausible if it was another major global model showing it, the gfs IMO is never to be trusted with European blocking, the ukmo disagrees with it at 144hrs by keeping the uk still cold at that point.

Edited January 7, 2010 by nick sussex

[Duane S.]

GFS in indicating a breakdown starting in about 5 days time. Ok there will be snow on the edge but looking at it we can expect the Atlantic to rush in then and turn it much warmer. Be interesting what the pub run says:-)

One thing I certainly DON'T expect is for the Atlantic to just 'rush in'. This cold is going to take some budging, the GFS has a far too simplistic view on how that is going to happen IMO.

Yes, next week COULD be the start of the end of our incredible cold spell BUT it will very likely be a slow process with a lot of snow for a lot of people before mild air eventually wins out. I still think things will become a lot clearer come sunday.

Edited January 7, 2010 by s4lancia

[Cecil Hogmanay Melchett]

It would be plausible if it was another major global model showing it, the gfs IMO is never to be trusted with european blocking, the ukmo disagrees with it at 144hrs by keeping the uk still cold at that point.

but not much longer after 144h nick.

The models are most definately going for a breakdown next week.

[Nick L]

If the GFS didn't keep flip-flopping between different scenarios in FI then more people would agree it could be onto something.

[sandstorm2]

The GFS 1200 brings the atlantic and mild weather with it in big style from about middle of next week to the end of the run, still think there will be quite a bit of snow for some areas before the rain arrives, of course all this takes place in FI.

SS2