Winter Model Discussion 18Z 16/1/13 onwards.

[LomondSnowstorm]

The GFS deepens the low to the west and has it further northeast on this run, creating an additional frontal snowfall risk for western and central Scotland and northwest England for Friday evening:

NAE clearly has this feature further south towards the south of Ireland:

[Anti-Mild]

Is there anybody there?

UKMO out to +72 and it's looking peachy. Lots of snow - looks like we may almost have an all-white satellite image again!

GFS out to +78 and it's basically identical to the 6z.

[Summer Sun]

UKMO at t72 is looking good for further snow

Amazingly GFS is almost identical

Some agreement for once

Edited January 17, 2013 by Gavin.

[Continental Climate]

snow and lots of it into the east http://www.meteociel.fr/ukmo/runs/2013011712/UN72-21.GIF?17-16!! The convection all down the eastern side of uk has not been mentioned but i think it could be significant, obviously people's attention is focused on the band!!

Like a morgue in here!! Come on people come out of your regional threads and see these delightful models,

[cowdog]

UKMO at t72 is looking good for further snow

Amazingly GFS is almost identical

Some agreement for once

The UKMO at 96 is interesting to say the least!

Is this possible? It seems odd they way it stretches the low in such a short time frame from T60.

Edited January 17, 2013 by cowdog

[Continental Climate]

T96 and the ukmo could start to get marginal for some http://www.meteociel.fr/ukmo/runs/2013011712/UN96-21.GIF?17-17!! Need it to be further south, which come the time im sure it will be

[Weather-history]

Amazing charts, you have a battle between two, in effect almost two Arctic continental airmasses! One coming from Europe and that low dragging intensely cold air off the North American continent into the Atlantic and right into Ireland, granted modified by the Atlantic somewhat but still incredible.

[tynevalleysnow]

Probably best charts I've ever seen. The fax showers a trough just off northeast england tomorrow before the front moves across uk. Could be a very snowy few days.

[Wayneywoo]

I personally think to have the atmosphere locked as it is now could give us the best possible. To have LP thrown at us from the Atlantic, coming up against the cold block over Scandi and being shoved south only to drop their snowy contents on us as they pass by. Long may it continue I say!

[Jezzer]

We're all getting very excited in the SE and London thread. The latest models are looking fantastic, potentially fresh reloads into next week too!!

[Snowly does it]

Monday looks marginal for the s, SE and EA unless some colder dew points are in play....

[bluearmy]

T96 and the ukmo could start to get marginal for some http://www.meteociel...96-21.GIF?17-17!! Need it to be further south, which come the time im sure it will be

not good for southern britain. superb for north midlands and northern england. this is a trend now for the trough to get to this latitiude despite what the ens show. i am not bothering with the ens in the pre day 5/6 timescale wrt to the ops recently. ukmo, ecm and gem ops have been excellent out to day 5 and 6. the ens can support or not. the ops have been on the mark.

[WhiteFox]

Amazing charts, you have a battle between two, in effect almost two Arctic continental airmasses! One coming from Europe and that low dragging intensely cold air off the North American continent into the Atlantic and right into Ireland, granted modified by the Atlantic somewhat but still incredible.

I was just thinking that. I can't recall seeing a chart with a deep Atlantic low like that which has the 0 degree isotherm so far south. In fact, there's only a fairly narrow band of >-4 air being pulled up ahead of the system!

As for the UKMO, it does look to have shifted Monday's system north slightly, but it's difficult to tell due to the jump in time, so comparison is not easy as the 0z had the system moving slightly north by t120 anyway (0z Tuesday). It'll change anyway I'm sure.

[Nick F]

The uncertainty continues beyond t+72, don't think we can really rely on synoptic detail much beyond Sunday.

We see another Atlantic trough disrupt on Monday to the W/SW, trouble is, the models tend to struggle with these disruptions. So really difficult to pinpoint the track of the slider lows early next week.

[patrickshere]

Monday looks marginal for the s, SE and EA unless some colder dew points are in play....

Laying snow will bring temps down though, and until snow is on the ground, models will struggle to accommodate for that. If there's 10cm of snow on the ground from Friday, I'm not sure I can see precipitation on Monday falling as anything but snow itself, unless somehow the Atlantic completely smashes through the block.

Edited January 17, 2013 by mituozo

[TEITS]

12Z UKMO/GFS show what a waste of time it is looking at the models after +72.

My advice is spend more time looking at the radar than the models over the next 24hrs.

http://www.meteociel...20-21.GIF?17-17

http://modeles.meteo...fs-0-120.png?12

Edited January 17, 2013 by THE EYE IN THE SKY

[Continental Climate]

development between 96 and 120 on the ukmo looks a bit strange http://www.meteociel.fr/ukmo/runs/2013011712/UN120-21.GIF?17-17!! I would have expected more of an undercut to occur but the trough by 120 just sits around near ireland, dont look right, anyway we shall see

[Snowly does it]

Laying snow will bring temps down though, and until snow is on the ground, models will struggle to accommodate for that. If there's 10cm of snow on the ground from Friday, I'm not sure I can see precipitation on Monday falling as anything but snow itself, unless somehow the Atlantic completely smashes through the block.

True enough, Norfolk certainly as a few cm already in place.

Cold air back in Tues/Weds with -10s knocking on EA door

[BLAST FROM THE PAST]

UKMO stilll shows a rapidly developing GHP/Arctic HP to our NNW into next week which I think is the right solution. The GFS showing HP to our E/ese is off the mark IMO. We should have a U or V shape with trough to our ESE and W. Having said that the UKMO has suddenly picked up at t144 THE BLOCK shifting towards our ESE...OK that definitely needs watching as it may break the cold down post that. Is the GFS onto something?

I don't buy it sinking

BFTP

Edited January 17, 2013 by BLAST FROM THE PAST

[Continental Climate]

12Z UKMO/GFS show what a waste of time it is looking at the models after +72.

My advice is spend more time looking at the radar than the models over the next 24hrs.

http://www.meteociel...20-21.GIF?17-17

http://modeles.meteo...fs-0-120.png?12

One disturbing similarity there is for both models to want to bring our old friend the azores high more into play, hope its a blip!!!

[bluearmy]

The uncertainty continues beyond t+72, don't think we can really rely on synoptic detail much beyond Sunday.

We see another Atlantic trough disrupt on Monday to the W/SW, trouble is, the models tend to struggle with these disruptions. So really difficult to pinpoint the track of the slider lows early next week.

whilst i agree with that sentiment in general nick, the ukmo, gem and ecm seem to have done very well with the placement of the troughing tomorrow since at least mondays 00z runs

[nick sussex]

A massive difference between the GFS and UKMO at T96hrs.

The UKMO separates the PV ejecting a piece se, the GFS pulls the low heights to the nw.

Thereafter the UKMO looks snowier but more risky if you don't separate the energy upstream, the GFS remains cold right through to 144hrs with no thaw for those south of the UKMO snow line but then looks like it will sink the high.

I'd put FI at T96hrs, best to not look further than that until the models come to agreement.

.

[Panayiotis]

UKMO showing a channel low, bringing in those cold uppers from Europe, with possible fresh snowfall, that low would no doubt produce snow across the south, still 144hrs away but remember the UKMO is the one which picked up on this snowy outlook earlier in the week, so possibly something to keep an eye on!

[Frosty.]

Either the gfs has lost the plot and is a stuck record as it's following a similar pattern to the 6z in bringing our freeze to a gradual conclusion or it has spotted something the other models haven't yet? either way it's continuing to snub the idea of a potent reload of cold from the northeast, I think it's tosh but time will tell. In the meantime, the very wintry spell continues until the middle of next week at the earliest, and in my opinion, it will still be going strong by the end of next week.

[Anti-Mild]

The GFS 12z has reverted to...........you guessed it - rampant zonality!!

About as predictable as FI is unpredictable!

I would say that FI is no further than +72 just now, so ignore all runs after this point, load up the radar, and get watching the lamp-posts!