Winter Model Discussion 18Z 12/2/13 onwards.

[Barking_Mad]

What low temperatures are we looking at here. -5c to -10c ?

[phil nw.]

Hmmm, mainly light wintry showers as next week goes on, my experience of easterlies is those light wintry showers then become heavier and more prolonged and bring accumulations. It sounds like we are in for a prolonged cold spell, the snow showers mainly for the eastern half of the uk and then a risk of persistent snow spreading up from the south. What a difference a few days make, early this week the GEFS mean was showing persistent swly winds for the next 2 weeks, how things have changed.

It will interesting to view tonight`s fax`s Frosty with any possible attack from the south west around 7 days away.The T120 fax in particular may give a better idea of the placement of the surface high and the angle of approach of the low to the south west.

I hope something like this verifies for all coldies-a good way for Winter to go out on.

[bluearmy]

What low temperatures are we looking at here. -5c to -10c ?

would be struggling to get that low without snowcover and clear skies. nights are probably too short now. if we get snowcover, then those figures easily achievable, but only if we get clear skies.

[March Blizzard]

The nights are still plenty long enough to achieve -10C. Comfortably long.

[mushymanrob]

.as for the posters who say its getting late ,early to mid April 1908 delivered a lot of snow to low lying ground in southern britain ,MARCH 4th 1947 widespread snow and blizzards ,although this was on the back of well established cold .thanks again to regular posters for data etc ,only 6hrs till next ECM ,HOLD TIGHT .

...and march 1970, but late snow events (proper dumpings that dont melt immediately) whilst not impossible, are rare.

[West is Best]

My second post of the winter which is something of a record given that I used to post every five minutes. Blimey it was cold a couple of days ago in East Anglia brrrrr.

So I'm back on because this looks very cold again next week, starting late Tuesday. Models are consistently now pepping it up, and bringing it all forward as the significance and impact of the Scandinavian high starts to dominate the models. It really does look like a blistering cold spell ... again. Watch for further upgrades I'd suggest.

And those suggesting the nights are too long, well 1947 is often mentioned in this regard and with some justification. It can still be bitterly cold in March and April, let alone February. Brace yourselves for a bit of a humdinger by the look of it.

Edited February 15, 2013 by West is Best

[MR EXTREMES]

My second post of the winter which is something of a record given that I used to post every five minutes. Blimey it was cold a couple of days ago in East Anglia brrrrr.

So I'm back on because this looks very cold again next week, starting late Tuesday. Models are consistently now pepping it up, and bringing it all forward as the significance and impact of the Scandinavian high starts to dominate the models. It really does look like a blistering cold spell ... again. Watch for further upgrades I'd suggest.

And those suggesting the nights are too long, well 1947 is often mentioned in this regard and with some justification. It can still be bitterly cold in March and April, let alone February. Brace yourselves for a bit of a humdinger by the look of it.

indeed i put a post on here couple of days ago about march 1947 its also worth noting that 2011 was globally the coldiest march for over 100 years.

so anything is possible never thought 09/10 would be one of the coldiest with the right setup anything is possible.

intresting that someone mentioned feb 2008 remember that was the first really cold ne flow seen here on the southcoast for many years so it could be intresting end to feb.

http://en.wikipedia.org/wiki/Winter_of_1946%E2%80%931947_in_the_United_Kingdom

Edited February 15, 2013 by model rollercoaster

[bluearmy]

the question posed referred to possible night time temps under the current modelling. i stand by my comments that figures of the -10c ilk will be very tough to reach without snowcover and clear skies. of course there are the notorious frost hollows. not long to wait now.

[The PIT]

Well the GFS has now joined the party and caught up with the ECM. We've now got pretty good agreement well out in deep FI. So a bit of spring this weekend to lull the uneducated into security well us netweather folks sharpen up the snow shovel.

[Radiating Dendrite]

I don't want to put a downer on things, but surely comments like "buried under snow" and "sharpening the snow shovel" are a bit mis-leading.

There is still a long way to go with this and has been stated by some, it could end up chilly with a few wintry showers and that is it.

People may be best to get the de-icer out of the cupboard, but leave everything else in the shed for now!

[snowmadchrisuk]

actually, given the stronger blocking, i think we could see a rather more snowy period than the last two spells. the time of year not too helpful if we lose a continental flow at any point but there are plenty of signs that this period could see a really effective slider/undercutter into proper cold uppers. i read the extended metoffice forecast with interest as it seems to indicate march beginning with a block to the east/north slowly giving way to the atlantic (but with some battleground stuff along the way).

For those in the SW though if we lose the Continental feed at all as Low's approach it will just be yet more Rain down here.. Hoping there will be enough time for the Cold air to really get established across the whole country before any SW attack happens...

[nick sussex]

Its the same old story with these easterlies, always complicated and you're never quite sure what they'll deliver.

With slight changes in orientation of high effecting which areas are more favoured, you can make a case for several different scenarios playing out, you could be lucky and get a decent convective window followed by an Atlantic attack which then slides away ese.

Or a drier affair with little convection apart from the far se then an Atlantic attack which wins. Its really impossible at longer timeframes to forecast which airmass wins because the models have to juggle high to the north and the Atlantic trying to move in and invariably are clueless until much closer in.

Earlier on we still have some uncertainty with the track of the Norwegian shortwave aka CPDS Cold Pool Delivery System, the closer that gets to the se of the UK the closer the main cold pool will be to tap into.

The ECM postage stamps do show a variety of options re convection and then angle of Atlantic attack,I think the latter is very much likely to occur but its what the balance of power will be at that stage re the orientation of the block and how much energy gets diverted se towards Iberia which is the main uncertainty re longevity of the cold.

So certainly lots of interest going forward, snow does seem likely at some point so at least the tail end of winter does look like providing some fireworks.

Looking forward to tonight I'd like to see the ECM pull out one of its more sausage shaped highs with more trough disruption,and certainly we don't want to see the high slipping se'wards.

[snowhope]

Can snow penetrate right across the country in these setups or is it more likely an Eastern only event if it comes off?

[phil nw.]

I am closing this shortly folks and will start a new one ready for the 12`s.

I will give it a few minutes for anyone to finish off.

[snowking]

The NAEFS warning system (similar to the MOGREPS system utilised by the Met Office) showing the very low risk of snow showers into the east:

Even by Thursday, from the most recent output, the chance of more than 2cm of snow is 20-30% in eastern districts.

Without some shift in the 12z suite, we are not looking at anything particularly impressive from the east (though Steve's post highlights excellently what we need to see change to increase the convective potential)

SK

Edited February 15, 2013 by snowking

[phil nw.]

Ok now locking this-a new thread ready for you here