Blocking High To Present Europe & North America With A Significant Cold Blast Late Week

Written by on October 21, 2012 in United Kingdom & Ireland with 1 Comment

Courtesy of Mark Vogan

Over the next 72 hours, very warm air will flood much of Europe and North America while a trough dropping over Greenland, supporting the lowest levels so far. This morning, is nothing to stiff at with Summit Camp currently reading -45C (-49F). Could reach near -50 to -55C (-58 to -67F) in the coming nights but changes of a massive scale are on the way for both sides of the Atlantic over the next 7 days. A complete flip is on the way.

Models are persistent now is flipping this pattern and although I may have been slow to shout about this cold, like i’ve kept saying, there was a lot of uncertainty with just as much chance of mild as cold to end the week. As it stands, I am confident that we will feel the bite of an arctic wind blowing by Friday and any precip, many fall as sleet or even snow down to low levels across Scotland and perhaps parts of Northern Ireland. completely around during the mid point of this upcoming week. By Friday into next weekend, the ridge which will bring toasty temps to Western Europe with highs into the low 70s across France, Belgium, Netherlands across to Germany, may well extend NW into the Southeast of Britain. Highs may top 70F (21C) in London on Tuesday but while we enjoy temps 5-10C above normal. Major arctic air is building south and what will happen is the high slides NW from the UK by Wednesday, Thursday, this allows arctic air will drop south amid lower heights.

At this same time, arctic air is driving SE through Western and Central Canada into the Northern Tier of the US and by next weekend on into the following week, expect MAJOR cold from the Rockies to Plains on east as the front slides towards the Atlantic Seaboard. A wild thermal gradient

Here’s the ECMWF interpretation for Tuesday. A rather warm look for much of Europe and North America with a trough over Greenland.

Here’s Saturday…

Notice the positive heights building over the North Atlantic and Greenland while this sends troughs into Europe and the Central US. Remember what I’ve been saying about the significant height rises over the arctic, this was the indicator that arctic air was coming south and combine this with a major reversal in the ridge-trough positions across the Mid-latitudes is allowing for this early season cold to drop into the UK and heart of North America.

Highs will range from 4-8C above normal across much of Western Europe extending up into SE of the UK and they have been across much of the continent over the last several days but the core of warmth is now shifting west.

Here’s what the GFS has regarding anomalies for Tuesday. Rather warm right? The key for maximum warmth will be sunshine and with this warm, moist air mass, a lot of cloudcover tends to be asspciated with it. Get any sunshine in the Southeast of England on Tuesday and you’ll see 21C but with cloud, more like 17 or 18C.

Courtesy of WeatherBELL Models

Check this out for Saturday…

Courtesy of WeatherBELL Models

So how cold may it get?

As it stands right now I recon much of Scotland will struggle to see a high much above 6C with some areas maybe having a hard time reaching 4C. Any precip and sleet or snow may fall. Whether it lies is another thing. As for Northern Ireland, Northern and central England and Wales, highs of 5-7C and for Southern England and Ireland, probably no warmer than 8-9C. Remember a north to northwest wind blowing at 10-20 mph will shave a good 3-6C off that number so for Scotland it may feel more like freezing. Out hiking? MAKE SURE AND DRESS FOR BITTER CONDITIONS. -5 to -10C above munro levels. Winds howling at gale-force wind reduce the realfeel temperature well below -20C with blizzard conditions possible.

What about snow?

Here’s what the latest GFS suggests. This could change and I think it’s likely to change with an increase in snow potential.

For Saturday..

Courtesy of WeatherBELL Models

For Sunday…

Courtesy of WeatherBELL Models

The below chart shows what the US is looking like tomorrow. Keep in mind that it’s as the hammer of arctic air begins to show it’s hand over the Northern Rockies, that’s when the blow torch really gets going out over the Plains and we can that what starting tomorrow. The incoming cold front, as it draws increasingly cold air down into the heart of the nation, this will significantly sharpen the front and thermal gradient. It will pump the ridge to the east and crank that southwest wind, a perfect setup for temperatures soaring 20-30F above normal. This will be occuring at the same time, temperatures plummet over the Interior Northwest, Rockies and Plains as we progress through the upcoming week. By next weekend, expect temperatures of 20-30F below normal.

Tomorrow…

Courtesy of WeatherBELL Models

Check the below chart out for Thursday. Just look at how cold the air is driving into the Plains and also notice how sharp the thermal boundary has become. Daytime maximums over MT, WY into CO and the western Dakotas may have a tough time reaching 20F while early this week it could hit 90F over W S. Dakota and near 95F in W Neb. Highs of 80F+ looks possibly in Chicago, Detroit and eventually all the way to the Big Cities of the Northeast.

Courtesy of WeatherBELL Models

Finally, here’s for Saturday, just look at the coverage of arctic cold. This GFS chart suggests near 30F below normal all the way to S Texas. Impressive!

This could be the coldest end to an October and start to a November in many years.. Stay tuned for more later!

Courtesy of WeatherBELL

 

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