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

[Captain Shortwave]

Ensembles keep the below average temps throughout the whole run, which is encouraging! However there is a lot of scatter for this weekend (more so than some days of next week surprisingly) and before this get resolved the further outlook remains uncertain.

What strikes me even more is the scatter that starts to occur by the 17th, FI is less than 48 hours!!! Uncertainty for sure.

[Panayiotis]

I don't see number 2 happening, the trends today have been for undercuts, and all model agree on this, none take energy over the block at the weekend. The uncertainty lies with shape/angle/extent of the Atlantic push and where the battle between the warm and cold air lies.

What strikes me even more is the scatter that starts to occur by the 17th, FI is less than 48 hours!!! Uncertainty for sure.

Yes both points I was trying to make.

[JAWebb]

Regarding this post:

Scenario 1 see's the Atlantic barrel straight into the UK after a little short lived fight from the block , not sure how long the route back to cold would be there after.

Scenario 2 see's the Atlantic run over the top of the block, I think if this happened it would be a long route back to cold.

Scenario 3 see's the undercut, and the cold weather is extended with snow opportunities for all.

All three totally plausible. Views as follows:

1. Atlantic will not barrel through this block and we are unlikely to see anything zonal powering the block away anytime before Monday. The evident Atlantic incursion is being pushed back day by day

2. Looking at all models as a mean this option has no evidence at present

3. Has backing from UKMO, ECM and GFS at varying degrees in the short term

At face value looks like there will be some sort of attempt at an Atlantic surge on Friday and Sat. Any fronts that do make it into the SW in the timeframe would deliver snow. How far those fronts can push East and cause disruption Into the spine of the country is anyone's guess.

No point in getting hooked on any model output post + 96 at the moment unfortunately.

Fascinating few days ahead.

Edited January 15, 2013 by JAWebb

[Matty M]

where does one get the prozac runs now show the snow line well east of Ire through weds/thurs but chance of short return during friday for a snow bast.

funny thing is,,,, liggle bit of change , dubling is under blizzard till March

[Wilxy]

UKMO still looking very cold this morning with lots of snow chances .

[joggs]

On phone at work n Very quiet in here, does this show in the gfs output?.

[Jonan92]

Has anyone noticed in the GFS the slowdown of the atlantic in the early hours of this run?

[The PIT]

A good battle coming up this weekend in the reliable time frame. Should get some Snow from that which will turn to rain in the west. GFS shows the cold air winning this battle and eventually forcing the Atlantic to undercut. So a very good run. All eyes on the ECM to see if that follows the same pattern.

[Radiating Dendrite]

00z is similar to the 18z, though the jet weaker and we have further undercut chances.

[KTtom]

Very surprised there's not more excitement with the Mets offering this morning... I would say pretty much perfect for a majour country-wide snow event this weekend, great orientation of the trough and the block going no-where..

+120

+144

[swfc]

cracking oz to be honest ,slider after slider.ecm not to shabby either

[That ECM]

With small changes making big differences people are prob unsure how to make a comment. For eg t144 would be good for the north with a wintry mix below about Birmingham. UKMO would move the line further south and GFS in between. Detail at this time is impossible but the good news is that the cold isn't going to be shoved away. The big three have an under cut at varying degrees.

[TobyT]

WOW some amazing charts this morning the block is not going anywhere fast UKMO is stunning for cold and widespread snow GFS is now coming on board

. After yesterdays 16cm covering up here in North Norfolk looks like things could get very interesting this weekend and for the foreseeable.

Edited January 15, 2013 by TobyT

[The PIT]

ECM Fi at T168 anybody?

[Gustywind]

The GFS is fine and very snowy, like the big bad wolf the Atlantic huffs and puffs but can't blow the uk cold house down. It first tries on fri/sat but undercuts the block bringing plenty of snow during the process. Then tries again with a stronger low at t108 which again fails this time stalling over the uk rather than undercutting which looks very odd. Again lots of snow particularly for the east and north. Finally heights raise towards Greenland and the whole low shifts south east dragging cold air back over most of the country. So in summary cold, cyclonic and with heaps of snow especially for the north.

[KTtom]

ECM Fi at T168 anybody?

Very similar to UKMO 24hrs earlier and if the UKMO went out a furthter 24hrs would probably look similar

[swfc]

ecm looks like a cracking run as the next low at 192 hrs looks to slide yet again.great 850s too so

[That ECM]

http://images.meteociel.fr/im/5550/ECF0-240_pel7.GIF. Hope you will allow me this chart of the day!!

[MR EXTREMES]

as i said yesterday the slider is no longer a slider and the ukmo is the only model that supports the amazing cold and snowy weekend.

but the bottom line is the alantic does not push right into europe but as i said yesterday the uk will become the parking space for low heights northern areas though will continue with the cold theme and some really wintry stuff and pretty cold at times with blizzard conditions.

from the midlands south there looks to be a very strong signal now for more flooding wont feel very mild but any snow chances have all but vanished except for the ukmo which is really holding its ground.

until friday though cold settled with heavy wiintry showers possible down the eastern side of the uk.

as you can see colder for northern england and scotland intresting weekend up there.

although this system has been put back another 12hrs by the ecm.

[Jason M]

We still need a correction on most of the models of another couple of hundred miles south. Whilst the charts this morning look at face value like snowmaggedon, in reality they would be a rainfest for many.

Can't post charts at the moment, but the ECM is a good example as for key parts of the run uppers would not support snow over much of England and Wales. Hard to tell with METO as we don't get the 850s. Yes, it can snow loads with uppers just below zero, but is usually doesn't :-)

For any lurkers here don't be fooled by the deep blues shown over us on the charts as people post this morning. They are not a good guide to temperature, especially when low pressure is over us.

Overall good charts in terms of trending, but no cigar for many this morning. A couple of hundred miles south though and we could get a full on easterly that actually delivers something of note.

Jason

Edited January 15, 2013 by Jason M

[swfc]

The outlook is looking good from a snow perspective on all models this morning which is rare in itself.the pressure may not be all that powerfull to the north east but this set up is great for the uk for most instead of the view.Ifind it very interesting and more edgy given the uncertainty with fronts pushing in and being repelled .Expect a further adjustment south regarding the extent of low pressure in the mid term ,"paul hudson"comment

Edited January 15, 2013 by swfc

[Timmytour]

A snapshot of a week away,,,,from four consecutive GFS runs. The 12z was a bit of a blip but hopefully there is a trend for cold uppers reinforcing to our north east. if this is a trend that can gather steam and quicken in its development, the Atlantic might well be kept at bay for longer and a real spell of chill with "the wrong type of snow" might develop

To continue the "moment in time" comparison..

Small slippage of the low over Northern Ireland...that was once over Iceland. More progress of the cold uppers from the North east

[MR EXTREMES]

We still need a correction on most of the models of another couple of hundred miles south. Whilst the charts this morning look at face value like snowmaggedon, in reality they would be a rainfest for many.

Can't post charts at the moment, but the ECM is a good example as for key parts of the run uppers would not support snow over much of England and Wales. Hard to tell with METO as we don't get the 850s. Yes, it can snow loads with uppers just below zero, but is usually doesn't :-)

For any lurkers here don't be fooled by the deep blues shown over us on the charts as people post this morning. They are not a good guide to temperature, especially when low pressure is over us.

Overall good charts in terms of trending, but no cigar for many this morning. A couple of hundred miles south though and we could get a full on easterly that actually delivers something of note.

Jason

agreed good post the ukmo would be the best uppers for the weekend if it showed them.

but the gfs is better towards the end of its run for renewed cold from the ne.

the ecm is even better in its later output with similar situation with a plunge from the ne aswell.

but the gem dont look good for weekend event unless your futher north but the bottom line is they all dont let the alantic any futher than the uk.

more runs needed but i did seem to think yesterday that the models were heading towards the evolution of low heights parking over the uk.

not terrible situation for all but not perfect for england and wales.

[swfc]

agreed good post the ukmo would be the best uppers for the weekend if it showed them.

but the gfs is better towards the end of its run for renewed cold from the ne.

the ecm is even better in its later output with similar situation with a plunge from the ne aswell.

but the gem dont look good for weekend event unless your futher north but the bottom line is they all dont let the alantic any futher than the uk.

more runs needed but i did seem to think yesterday that the models were heading towards the evolution of low heights parking over the uk.

not terrible situation for all but not perfect for england and wales.

good post.id have to concede that the 850s arnt great and maybe the surface cold is slightly mixed out but the set up synoptics wise is very knife edge and always capable of great snowfall

[BLAST FROM THE PAST]

The GFS has edged further again towards colder regime. The posters above are NOT picking up on the fact [MAYBE ON PURPOSE OR NOT] that the GFS further holds the Atlantic back and we see a further shift south overall of the jetstream again. Another small step by the GFS towards a colder outlook. ECM is similar to yesterdays but overall I'd say a further improvement. UKMO again is a stormer.

Re snow, I remember the great Jan 1985, I was still in Swansea back then, we had attacks from the SW. I can't post charts as at work BUT the first assault remained as rain below 300 meters but the second brought the goods big style. It may be the samne this time but overall IMO the outlook improvement continues.

BFTP

Edited January 15, 2013 by BLAST FROM THE PAST