Winter Model Discussion - 12/01/13 06z Onwards

[Mr.Plow]

Fantastic uppers of -12C approaching and heavy snow showers into Lincs/Wash area.

http://modeles.meteo.../gfs-0-78.png?6

How could I tell where the convection would form snow showers on that chart please?

I have seen people post charts with red convection dots, but can't find them now.

I am trying to work out when and if Norfolk may get snow showers rather than frontal snowfall.

[Jason M]

At 138 scandi heights fighting back. It's interesting to me that even where runs look poor at the moment the Atlantic just can't break through and clinch the deal. The 06 run looks like a ded cert quick sinker but we end up with a bizarre stalemate.

I'm still betting on scandi heights.

Whatever happens though we're looking at a great cold spell lasting for at least a week. When I recall the charts fom two weeks ago this is truly remarkable as we were looking at Spanish plumes and Bartletts.

Jason

[snow mad]

Trough about to disrupt! just goes to show the splitting vortex is our friend

[mcweather]

TROUGH DISRUPTION TO THE WEST AT 144

[Severe Siberian icy blast]

From what I've seen from the ECM and GFS is for milder conditions to set in from around Thursday onwards, this ties in basically with what GP said the other day. Then it's a case of how long before the next cold arrives.

Wel l he said coldest air between 15th-20th , then less cold between 20th-24th and a major cold outbreak from 28th

In the mean time , a very nice fi coming up

[WhiteFox]

I've noticed that the GFS has consistently shown Monday's snow to change to rain for a time to the south of London only to then turn back to snow. Does anyone know why this might be?

The GFS maintains a small warm sector on the system whereas the UKMO shows it as an occluded front with the warm air mixed out. Bascially, the extent and amount of snow is not yet nailed, but it's just about time to start using the hi-res models to try and determine what will happen rather than the GFS which models ppn poorly at 24 hours plus.

[chris55]

From what I've seen from the ECM and GFS is for milder conditions to set in from around Thursday onwards, this ties in basically with what GP said the other day. Then it's a case of how long before the next cold arrives.

Milder air never gets close on the 00z though,

[Cloud 10]

.....and then the jet comes up against an invisible wall,cold hangs on.

[EML Network]

where is thus run going ? that low Over Italy is moving our way all of a sudden, fighting against the Atlantic, it's shaping up for the Battle to and all battles ...I said this yesterday....as each day goes on..the cold is extended for another day on the GFS Operational....today we see the exact same thing happening again

Friday 12 noon the UK STILL under - 5 uppers

[ChartViewer]

All boils down to where the energy is going to go out of the Eastern seaboard in mid range whether we get prolonged cold or milder flatter pattern by next weekend......

T156 Jet profile 06z

Edited January 12, 2013 by ChartViewer

[WhiteFox]

Fi for me is between 72-108 hr mark.gfs starts to build pressure and an easterly to come in.the ecm and gfs are to a point heading the same way imo

It's the 6z and this is the first time it's shown the shortwave actually moving south so FI is probably more like 60 hours!

[bluearmy]

the 06z a good middle ground solution and once the atlantic comes up against the entrenched cold, i'd take little notice of the evolution thereafter. gfs op does not see the initial occlusion being as strong as nae. similarly, nae looks as though it doesnt see the second occlusion as strongly as gfs if we look northwest on T48 NAE

[bradymk]

Azores high ridging north eastwards come t156, cold lasting a lot longer than on the ECM. t162 sees an easterly flow across the south with still -6 uppers and -8 off the south east.

[BLAST FROM THE PAST]

From what I've seen from the ECM and GFS is for milder conditions to set in from around Thursday onwards, this ties in basically with what GP said the other day. Then it's a case of how long before the next cold arrives.

GFS hasn't got milder conditions setting in next Thursday? I think we will see less coldconditions occur as the Atlantic has a shot but I think the ECM has gone off on one again. GFS sort of began to follow but it doesn't totally back the cold away which I think is correct. And I don't think the ECM ties in with what GP has said.

BFTP

Edited January 12, 2013 by BLAST FROM THE PAST

[snowmadchrisuk]

Very windy in the Bristol channel this morning , My window won't stay open , i'm guessing that's something to do with the pressure/temp gradient currently evident. If we get the -10's across the country aka 6z , then i imagine features in that flow could pop up at very short notice. The PPN forecasts are currently changing wildly each model run , for example the Midlands were showing the Monday Front , and then another on Wednesday , this then changed to a feature from the North on Tuesday , and now it seems to have lost that as well and has Easterly with plenty of showers for Lincs/Wash and stalled front over SW . I don't think we have seen the last of the changes and timing of Monday's system is still very much open to question , if i had a choice though , I would rather see this come in later Monday rather than earlier.

[WhiteFox]

All boils down to where the energy is going to go out of the Eastern seaboard in mid range whether we get prolonged cold or milder flatter pattern by next weekend

In these situations I'd generally favour the Atlantic winning. The scandi high doesn't look strong enough to repel the strengthening jet. We get far more instances of the Atlantic breaking down a block from the east like this than we do seeing the block holding.

Far safer for energy to undercut than run directly into the block.

Not that I'm buying into the 6z at that range of course!

[stainesbloke]

There is always the possibility of that front stalling and intensifying over the SE. The MET O are keeping tight-lipped at the moment and are stating that confidence is 'low' about the quantities of snowfall, particularly for southern and southeastern parts. Anything from a few cm to a very disruptive event!

Yes, if that front stalls over the SE with those cold uppers moving in the ppn could well intensify for a few hours.

[johnholmes]

still trying to find time to do my final check on the 500mb checks-their prediction was pretty close to what we have and also to do an update on what they and any other links seem to be suggesting for further on than about 6 days from now; (that part=1-5/6 days seems fairly solid for cold on the synoptic models to me, give or take the odd wobble). Hopefully both will be available during today.

[weatherguy]

In these situations I'd generally favour the Atlantic winning. The scandi high doesn't look strong enough to repel the strengthening jet. We get far more instances of the Atlantic breaking down a block from the east like this than we do seeing the block holding.

Far safer for energy to undercut than run directly into the block.

Not that I'm buying into the 6z at that range of course!

Normally this would be the case yes, but due to the effects of the SSW in theory such a typically strong jet is less probable.

[UV-RAY]

still trying to find time to do my final check on the 500mb checks-their prediction was pretty close to what we have and also to do an update on what they and any other links seem to be suggesting for further on than about 6 days from now; (that part=1-5/6 days seems fairly solid for cold on the synoptic models to me, give or take the odd wobble). Hopefully both will be available during today.

GFS hasn't got milder conditions setting in next Thursday? I think we will see less coldconditions occur as the Atlantic has a shot but I think the ECM has gone off on one again. GFS sort of began to follow but it doesn't totally back the cold away which I think is correct. And I don't think the ECM ties in with what GP has said.

BFTP

Sorry I should have said less cold, as for the ECM it's a plausible solution but I would wait for this evenings run before drawing any conclusions and even then the way things are it will probably change again tomorrow. Edited January 12, 2013 by Sceptical Inquirer

[Cecil Hogmanay Melchett]

look at that pv over greenland,what gives?????

[bluearmy]

In these situations I'd generally favour the Atlantic winning. The scandi high doesn't look strong enough to repel the strengthening jet. We get far more instances of the Atlantic breaking down a block from the east like this than we do seeing the block holding.

Far safer for energy to undercut than run directly into the block.

Not that I'm buying into the 6z at that range of course!

you mean like the way the jet/depression runs into the weak scandi block tomorrow and heads sse !! will the jet be that strong come verfication ? i wouldnt bother over analysing post the point that the atlantic tries to get in. the entrenched cold will give the uk a 'continental type locale' at that point in time.

[Great Plum]

http://www.wetterzentrale.de/pics/Rtavn1742.png

-5 air or below across the vast majority of the uk for a week... Remarkable if it came off but a long way into FI...

[ChartViewer]

Didnt GP go for renewed Scandi height build and cold holding on until a brief milder spell around 24th before re load of cold?...This suggests it...

[WhiteFox]

Normally this would be the case yesterday's, but due to the effects of the SSW in theory such a typically strong jet is less probable.

Which is why I don't buy into anything the 6z shows after Tuesday tbh. It has performed poorly this week and given that the area where it has performed poorly is still the most important driver of the outlook at the moment I'll continue my scepticism...