http://modeles.meteociel.fr/modeles/gfs/runs/2015010406/gfsnh-1-300.png?6

Look at the cold across the pond

http://www.weathercast.co.uk/services/ensemble-forecast.html

A gradual cool off mid month

GFS op and control showing the potential of a "bomb" to hit northern Scotland on Friday

I can't recall seeing -32 850s across the pole before let alone mainland USA!!  Cue Polar Vortex mass hysteria (again ) in the media, if this comes off!

Back in Great Britain, it will be interesting what this does to the jet.  Will it be a game changer for the worse or for the better?

David

Northallerton

People have been saying that over on NW too, but it's far from rare - there were -32C 850s in the models numerous times in both winter 2013/4 and winter 2012/3 over the Arctic Ocean and/or North America - I've not looked back further, but I know there were some -40s a few years back.

Thanks for that.

i too have seen it many of times, mainly across North America & Northeast Asia. What I have never seen is the white colouring, I believe this to be a new thing.

Indeed Beast looks like Scotland could suffer twice, first overnight on Thursday into Friday.

http://www.wetterzentrale.de/pics/Rtavn1201.gif

http://www.wetterzentrale.de/pics/Rtavn1209.gif

Then again on Saturday with an even deeper low (which looks like it could be 940 or below) affecting a greater portion of the North.

Early in the morning.

http://www.wetterzentrale.de/pics/Rtavn1441.gif

http://www.wetterzentrale.de/pics/Rtavn1449.gif

Then more of the eastern side by lunchtime.

http://www.wetterzentrale.de/pics/Rtavn1501.gif

http://www.wetterzentrale.de/pics/Rtavn1509.gif

Both WZ and Meteoceil had a dark purple as their lowest colour, leading to "black holes" for temperatures below that. Meteoceil has extended their colour scale to show colder temperatures than before - hence the white colouring.

just two words- cyclogenesis breeder

I was thinking I had not seen that white colouring before - in fact, that is probably what threw me.

I remember... I think the new white hole looks better :-) 

Looking at the ensembles little has changed tbh, only that the OP is in the mild cluster rather than the cold cluster which at this range is trivial, the EPS and GEFS show little or no change since yesterday.

GEFS 6z continue in a similar theme. Still looks like it will turn cooler or colder, but personally I'm not seeing the big freeze confidently forecast in this thread by one or two.

http://www.theweatheroutlook.com/twodata/datmdlout.aspx

I'm not aware of anyone "confidently" predicting a big freeze

To illustrate 384h GEFS, but tbh the pattern is good for any time period >300hr (it isn't just getting kicked back)

Scandi Easterly (polar continental): IIIII

Total: 5

Mid Atlantic high (Arctic): III

Total: 3

Mid Atlantic High (polar continental): I

Total: 1

UK based high/Cold southern blocking: IIIIIII

Total: 7

Icelandic vortex (zonal): IIIIII

Total: 6

Hope index = 5+3+1+7/5+3+1+7+6 = 68%

Actually a slight rise since yesterday, but the difference is trivial anyway for the overall picture.

What has changed is the number of zonal charts have gone up, but ALL of the charts showing southern blocking (Euro highs e.c.t.) are cold, in fact with the anticyclones slightly further north Many in the S block category would be scandis.

http://modeles.meteociel.fr/modeles/gfs/runs/2015010406/gfsnh-0-312.png?6

Makes no odds with that stuck in the middle

Read back through this thread.  One of our posters is very confident. Nothing wrong with that either, just pointing it out. 

In fact our snowiest and longest-lasting wintry spells coincide with cyclogenesis. There's always a delicate balance to these things and a supply of lows is required to "prop up" the block. Without a supply of lows to reinforce a block they invariably decline after a few days.

Of course at this range all we can look for is a broad change in the pattern anyway, something which going on today's ensembles still has decent odds of happening.

One thing, a few people were asking about how low the 850hpa can go, and how unusual -32C was in the pole/lower latitudes.

Put it this way, I saw -45C in the USA last year.

It depends. Are we confident of a normal arctic plunge into the States as is usual at this time of year? 

Are we confident of height rises to Greenland area that is an all the more rarer beast at this time of year?

To me, that chart looks implausible. Such cold leaking into the Atlantic can really only lead one way.....