Model Output Discussion 5/12/2012 18Z onwards - the one after THAT ECM

[SMU]

http://www.meteociel.fr/modeles/ecmwf/runs/2012120612/ECM1-168.GIF?06-0

Stunning chart-

Snow fluries anywhere- Sub zero maxima

-15c widespread overnight-

Wheres the moaners now!

[Matty M]

T144hr showing trough forming just west of Norway hopefully to propogate southwestwards!

[Stuie]

Wondered which way it was going until this point. Brr

[Matty M]

Yea 168hr ECM is bitter, if i get a little east flow out of it the very cold uppers will spark Lake Effect

[chris55]

fantastic 850's at 144, but winds seem northerly, screams cold and dry away from East coast, but still kinda FI for precip

Can we please step away from the cold and DRY analysis. Read Rob K s post a few pages back. Its not Kinda FI for ppn it's 100% FI.

[TAFKAP]

Anyone moaning at this needs a health check!!

Anyone moaning at that should be shot lol

[Matty M]

And to note. ECM so much better with the cold pool to our east than the GFS.

Significantly colder at upper level around 2-4c colder everywhere

[EML Network]

I hope I am wrong, but the closer we get to this cold spell, the more I am just not seeing where any precipitation is going to come from, I guess it's a long way off just yet, but you have to admit that there doesn't look to be very much in the way of it for the vast majority away from the East Coasts, it would be the ultimate disaster if we found ourselves under -8 uppers , but with naff all in the way of precipitation ...maybe I am worrying about nothing ??

[chris55]

Messy but cold, cold enough for snow and some ice days IMO.

[Matty M]

I hope I am wrong, but the closer we get to this cold spell, the more I am just not seeing where any precipitation is going to come from, I guess it's a long way off just yet, but you have to admit that there doesn't look to be very much in the way of it for the vast majority away from the East Coasts, it would be the ultimate disaster if we found ourselves under -8 uppers , but with naff all in the way of precipitation ...maybe I am worrying about nothing ??

Well between the 144hr and 168hr chart a frontal feature has crossed the UK from east to west.

[ITSY]

Exactly Steve.

Anyway, HELLO UK cold pool

[Nick L]

I hope I am wrong, but the closer we get to this cold spell, the more I am just not seeing where any precipitation is going to come from, I guess it's a long way off just yet, but you have to admit that there doesn't look to be very much in the way of it for the vast majority away from the East Coasts, it would be the ultimate disaster if we found ourselves under -8 uppers , but with naff all in the way of precipitation ...maybe I am worrying about nothing ??

You're worrying about nothing. Not going to repeat myself and others posts but please read the past few pages explaining why it's silly to worry about ppn at this stage.

[Catacol]

The ensembles are modelling low pressure to the South west which could result in exactly the scenario developing

on the 12z.

That needs a bit of clarification. The ensembles have to be interpreted as does all output. Take a closer look... This is ECM ensemble for Friday 14th:

That is a pretty clear signal for strong heights and undercut. SE flow bringing snow? Then look at Sat and Sun in succession:

The signal for low pressure over the atlantic is actually moving east to west, suggesting that many runs are calling for a stalling of the atlantic, not a progressive attack. Note also that the signal for heights to the north is very consistent indeed. What changes in the low res ensemble at 216 and 240 is the depth of low pressure over Europe and that gives an ensemble picture that looks like southerlies. Now... I'm not saying that this WONT happen, but I think the ensemble track from 168 to 240 when looked at in sequence is more significant in terms of the image of a stalled atlantic.

Ensembles are definitely the way to go, but a single ensemble snapshot can be deceptive.

[mountain shadow]

I hope I am wrong, but the closer we get to this cold spell, the more I am just not seeing where any precipitation is going to come from, I guess it's a long way off just yet, but you have to admit that there doesn't look to be very much in the way of it for the vast majority away from the East Coasts, it would be the ultimate disaster if we found ourselves under -8 uppers , but with naff all in the way of precipitation ...maybe I am worrying about nothing ??

Yes your worrying about nothing. It is unstable air, there will be features that cannot be picked out at this range.

[Frosty.]

This run could bring some thundery snow showers to n/e areas next week with drifting in the stronger winds from the ENE.

I can see a december 2010 esque pattern evolving, massive potential in the next few weeks plus.

We have severe frosts, drifting snow, freezing fog, high widchill and ice days in the next few week which takes us very close to christmas.

[I Cumbria Marra I]

Anyone moaning at that should be shot lol

Cold, sunny and snowless, yawn Edited December 6, 2012 by I Cumbria Marra I

[ITSY]

I hope I am wrong, but the closer we get to this cold spell, the more I am just not seeing where any precipitation is going to come from, I guess it's a long way off just yet, but you have to admit that there doesn't look to be very much in the way of it for the vast majority away from the East Coasts, it would be the ultimate disaster if we found ourselves under -8 uppers , but with naff all in the way of precipitation ...maybe I am worrying about nothing ??

PPN details in these scenarios will often crop up at 48hrs notice, often less. While we're looking at conditions after 96hrs I wouldn't worry too much

[Alex95]

The +192 chart sends that shortwave into Scotland - no winds for England, VERY cold night!

The ECM would give me 3/4 days of heavy snow, whilst the GFS would give 4/5 days. I'd bank either. I haven't studied the UKMO in as much detail, but that looks great as well.

[Matty M]

Well what happens between 168hr and 192hr is quite dramatic and very strange.

And not very positive for us! But still really cold.

[SupaSnowy]

I hope I am wrong, but the closer we get to this cold spell, the more I am just not seeing where any precipitation is going to come from, I guess it's a long way off just yet, but you have to admit that there doesn't look to be very much in the way of it for the vast majority away from the East Coasts, it would be the ultimate disaster if we found ourselves under -8 uppers , but with naff all in the way of precipitation ...maybe I am worrying about nothing ??

I think maybe worry a little to much, if this does happen most times snow will come not at first but later. Hopefully the closer it comes the models will show little features. East will always favor if its a eastley. Thats hope for a channel low.

[Tom D]

I hope I am wrong, but the closer we get to this cold spell, the more I am just not seeing where any precipitation is going to come from, I guess it's a long way off just yet, but you have to admit that there doesn't look to be very much in the way of it for the vast majority away from the East Coasts, it would be the ultimate disaster if we found ourselves under -8 uppers , but with naff all in the way of precipitation ...maybe I am worrying about nothing ??

This happens every time - you can't look at precipitation in detail with this setup beyond 24 hours, and I'm sure members will back me up here. I remember February 2010, with a mega Thames streamer when we got 18cm here - largely unforecast until the day.

[Ian Brown]

Odd looking T192, I assume it will bring back the Atlantic by T216.

[SMU]

the ECm at 192 over the UK shows the type of surface cold that breaks the -20c barrier.

-8c Uppers.

Snowcover ( where ? lots of places)

Dead still air-

-20c cold.....

The snow will come.

[TAFKAP]

Cold, sunny and snowless, yawn

Perhaps you'd prefer a bartlett set up?

[SMU]

Odd looking T192, I assume it will bring back the Atlantic by T216.

I would go for a SE blizzard at 216

S