US In Midst Of Impressive Cold Pattern

Written by Mark Vogan on November 30, 2013 in United States of America with 0 Comments

While this past Thanksgiving week has been cold, the next blast will be considerably stronger, taking aim at the Rockies and Plains. A major snowstorm is possible along the thermal contrast zone separating mild from bitter cold. As the trough dives south over the West, so ridging returns to the East, bringing the return of 80s, 70s, 60s and 50s from Louisiana and Florida up to Maine and eastern Canada.

What’s amazing about this current cold pattern over North America is that we are seeing a largely positive NAO and AO which ‘typically’ doesn’t correlate well with cold for NA, however, one may argue that these signals aren’t the best guide until true winter arrives. Another fascinating point about the cold we’ve seen so far is that this Thanksgiving week has most certainly been one of the coldest Thanksgiving week’s for the US on record, especially across the South.

While it was cold this week, it’s likely to be far worse this upcoming week with pretty much the coldest air mass in the entire hemisphere coming south from the arctic as major ridging builds into Alaska and hooks up with a ridge building over Greenland. This setup pretty much drives the motherlode of cold south. I showed you the 850mb temps in yesterday’s post over Montana by next Friday and Saturday and there’s no change. Astonishing thicknesses of 486, 5k foot temps of -30C and overnight lows widely into the -30sF. We could well witness the first -50 in about 5 to 8 years over the Rockies with this intensity of air mass coming down, supporting widespread -30s and -40s over much of Montana, Wyoming perhaps down to Colorado and east into the Dakotas.

Below are the ECMWF charts over the next 10 days.

Sun 1

Geopotential3250032hPa32and32Temperature32at3285032hPa_North32America_24

Tue 3

Geopotential3250032hPa32and32Temperature32at3285032hPa_North32America_72

Thu 5

Geopotential3250032hPa32and32Temperature32at3285032hPa_North32America_120

Sat 7

Geopotential3250032hPa32and32Temperature32at3285032hPa_North32America_168

Mon 9

Geopotential3250032hPa32and32Temperature32at3285032hPa_North32America_216

Tue 10

Geopotential3250032hPa32and32Temperature32at3285032hPa_North32America_240

[s2If current_user_can(access_s2member_level1)]

[/s2If][s2If is_user_logged_in() AND current_user_cannot(access_s2member_level1)]

That’s it, [s2Get constant=”S2MEMBER_CURRENT_USER_DISPLAY_NAME” /]!

To continue reading, you need to have a valid subscription to access premium content exclusive to members. Please join a subscription plan if you would like to continue.[/s2If][s2If !is_user_logged_in()]