Model output discussion - Post SSW - Will it turn cold?

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

-18c over parts on the NASA. 

Astronomically cold! 

 

[chionomaniac]

46 minutes ago, bluearmy said:

That old reverse psychology- took one for the team there !

where is @chionomaniac?  His salt has just doubled in value 

I'm here - been working and have also had to pick myself off the floor after checking the 12Z.

Best ever trop response that we have been able to track following a SSW, oh those of little faith lol.

I did think of buying all the snow shovels and salt in B&Q yesterday and then selling it back to them next weekend....

I have been convinced of an epic cold spell for a long time now (since before the split but my resolute belief was reinforced when I saw the residual Hudson Bay daughter vortex getting taken down).

It may have taken the best part of 10 years but finally we are seeing the makings of an epic spell when you take the strat vortex out of the equation. Even @TEITS may finally have to concede that there is something in this teleconnections Malarkey!

[Summer Sun]

ECM mean looks cold

[ZK099]

3 minutes ago, Mr snowman 2018 said:

Does anyone know what the snow depths will be like in Peterborough according to the 12z GFS or the 12z ECM ??

Don't worry about what the models say regarding snow depths. As others have said, they don't know the convection rates. If the ECM verifies you could expect well over a foot for Eastern areas and 10cm+ widely in the south/south east. This is ignoring any low pressure systems that head north from Iberia

[tight isobar]

Snow depth charts are an estimate @best -even 24 hrs out.

Ppn rate charts reasonable @that range(24hrs)...

As mentioned..covective decipher is way off the mark at this point..

And easterlys are fraught with consequence!!!

[Freezing-Point]

4 minutes ago, Summer Sun said:

ECM shows no more than 11cm for Kent area

What the models do know is that in this kind of setup the NE of England gets pasted.  Not as cold there but nice long sea track with intense showers. Thundersnow.

[kold weather]

10 minutes ago, Steve Murr said:

if ECM lands then 40-50cm widely over Kent 70-80 over the downs-

snow widespread elsewhere

East facing coasts - but streamers penetrating way inland also Ireland hit 30cm in an easterly the other year -

S

Basically if the 12z suite comes off the only analogs in the last few decades are Jan 87 and Feb 91 (Feb 09 isn't a bad one IF it *downgrades*) and that should give you an idea of possible snow levels.

[pandit-scholar]

With the ECM is on board, there is now cross model agreement for a memorable cold spell, certainly the coldest since December 2010, and even quite possibly, the coldest since 1991. Hopefully we will now have a consistent cross model agreement for the next few days. I still remember the "beast from the east" in December 2012 which never was, although this time things are different with the SSW.

 

Western Europe will be in for a hell of a shock, especially as we are the cusp of a meteorological spring with the daffodils starting to emerge out of the ground in our front garden. 

[bobbydog]

well, i've just caught up with the output. i looked apprehensively at the GFS and the ECM through my fingers...

i have to say i'm very disappointed.

 

 

 

that i didnt buy those snow tyres for my land rover!!!!!

[AWD]

12z EC Det a colder option in the long term, but a good turn towards cold in those ens in the medium term IMO;

0z ens for comparison;

Edited February 19, 2018 by AWD

[ZK099]

3 minutes ago, chionomaniac said:

I'm here - been working and have also had to pick myself off the floor after checking the 12Z.

Best ever trop response that we have been able to track following a SSW, oh those of little faith lol.

I did think of buying all the snow shovels and salt in B&Q yesterday and then selling it back to them next weekend....

I have been convinced of an epic cold spell for a long time now (since before the split but my resolute belief was reinforced when I saw the residual Hudson Bay daughter vortex getting taken down).

It may have taken the best part of 10 years but finally we are seeing the makings of an epic spell when you take the strat vortex out of the equation. Even @TEITS may finally have to concede that there is something in this teleconnections Malarkey!

Mass respect to you in terms of your forecasting of this cold spell. You and @Catacol kept the faith even when the models hadn't latched onto the SSW and provided exceptional insight about the background signals. You've called this one brilliantly. 

[BlueHedgehog074]

3 minutes ago, Summer Sun said:

ECM mean looks cold

Must admit, that is an impressive mean with a nice-looking Easterly flow. A little better than I thought it would be! 

[kold weather]

Also worth noting lapse rates are nearly 50C between S.north sea between SSTs and 500hpa temperatures. HUGE!

Also we will be in a mean cyclonic flow by that time as well as low thicknesses, it all scream massive snow showers, probably plenty of embedded troughs in such a flow.

Finally, the 500hpa temps are down to -42C by 28th Feb on the 12z ECM, thats firmly into polar low territory...that is how cold the flow is.

[sparky1972]

i hate to be the prophet of doom, but to be worrying about snow depth charts/predictions is futile, the cold is not even here yet, and there is still a chance that it wont, surely we have all got excited at cold/snowmaggen charts only for it to go wrong 24hrs out

[Catacol]

2 minutes ago, Mr snowman 2018 said:

Does anyone know what the snow depths will be like in Peterborough according to the 12z GFS or the 12z ECM ??

Wouldn’t waste time thinking about depths. At this stage it is far too early to assess degree of convective activity or any frontal snowfall. But model predictions of precipitation are genuinely a waste of time at a week’s range. They will bear no relation to reality other than to reflect the probability that the east will be hit harder than the west in the early stages. Those in the west will be looking to the back end of the week when frontal attacks from the SW are possible.

Its hard not to get carried away. I wonder how early the Met might contemplate issuing warnings - in all seriousness if we are looking at a week or more of very cold and snowy conditions then early warning would be wise. Having said that they won’t want to cry wolf either. very tricky call. 

Never seen model runs like this. Background signals suggest it could be a 10 day to 2 week event, off and on. Truly memorable.

[Radiating Dendrite]

22 minutes ago, Deep Snow please said:

Was just thinking that looking at it. Not all that severe snow wise.

All though a few perturbations give slightly deeper snowfall.

Going by past experience, almost certainly.

Guys - those snow charts are crap!

It was forecasting 20 inches in NW England for the last cold spell. They don't pick up shower activity very well.... only frontal. 

[terryall]

 

“well, i've just caught up with the output. i looked apprehensively at the GFS and the ECMthrough my fingers...

i have to say i'm very disappointed

that i didnt buy those snow tyres for my land rover!!!!!”

I’ve just bought some and glad I did!

[Anti-Mild]

If this is being modelled accurately, with convective snow off the North Sea I would fully expect to see level snow of 50cm+ somewhere in England - possibly Lincs or North Yorkshire, but everywhere is likely to see a fair bit of the white stuff.

[pandit-scholar]

4 minutes ago, Havaturkali said:

Gfs will be even more in this week.

What do you mean? Are you predicting the GFS to upgrade even more?? If so, you back this up with information as to the reasons why you think that. 

Edited February 19, 2018 by pandit-scholar

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

Bad news, the WMC is having none of it

[WalsallWeather123]

Widespread -16 uppers on CFS with snow showers

[SMU]

11 minutes ago, AWD said:

12z EC Det a colder option in the long term, but a good turn towards cold in those ens in the medium term IMO;

0z ens for comparison;

nice

Also the operational 1 day behind the mean for -10c line!

ignore that

op slower to bring in the cold !

Edited February 19, 2018 by Steve Murr

[Captain Shortwave]

Ensembles at day 6

       

 

Day 10

      

Similar trend, an easterly followed by a deep trough developing to our east as the poloar vortex swings over the top of the block to our north and allows heights to retrograde to the north west. The ECM suite probably the best of sustained cold, the GEFs trending to bring fronts up from the south/south west which could give snowfall for the south potentially.

Overall, a simply staggering set of model output, the deep cold predicted to land some time at the start of next week which sits around 6/7 days away. But the block which allows this to happen is already beginning to build so there is a real increasing chance of cold weather on a potentially epic scale. Looks like NE England could be the sweet spot having the perfect combinaition of lower heights than Scotland but a significantly larger sea track. But others should see showers push well inland on strong easterly winds with the chance of more prolonged snow developing from troughs or fronts pushing in off the continent.

We are very close to the best spell I have seen on this forum (Being here from 2012).

[Man With Beard]

20 minutes ago, Summer Sun said:

ECM mean looks cold

May look as if the cold is abating at D10 but I guess this will be the "mild" sector before the northerly. Think of it as Feb 1991 followed by Dec 2010 :0

[Nick L]

Lots of off topic posts being removed at the moment, please don't ruin the thread for others, thanks.