2:30 PM | *Next week's Arctic air to nearly extend from coast-to-coast*

00Z European ensemble forecast map of 850 millibar (lower atmosphere) temperature anomalies for next Monday night; map courtesy tropicaltidbits.com

Overview

This week’s Arctic air outbreak is only the opening salvo.  Old Man Winter was pretty embarrassed by his performance during December in the eastern half of the nation and is primed to make up for it with multiple Arctic blasts during the month of January and perhaps even considerably longer than that.  The overall weather pattern underwent a significant change around New Year’s Day from the record-breaking warmth of December in much of the eastern half of the nation and the end result will be much more in the way of sustained cold air outbreaks.  In fact, there are signs for widespread Arctic air next week with an initial shot arriving early in the week following a Sunday storm and then a reinforcing blast at mid-week.  By the middle of next week, colder-than-normal conditions will nearly extend from coast-to-coast.

00Z European ensemble forecast map of 500 millibar (upper atmosphere) height anomalies for next Monday night; map courtesy tropicaltidbits.com

Next week’s Arctic express

Numerous teleconnection indices including the Arctic Oscillation (AO), North Atlantic Oscillation (NAO) and Pacific North America (PNA) suggest the overall weather pattern will continue to push Arctic air masses from Canada into the eastern US over the foreseeable future.  Several computer forecast models are indicating there will be a deep trough in the upper atmosphere (at the 500 millibar level) by the middle of next week along with a ridge along the west coasts of Canada and US.  The 500 millibar height anomaly forecast map (above) for next Monday night (January 11th) from the 00Z European ensemble model run shows a deep upper level trough (blues) in the eastern US along with high-latitude high pressure ridging to the north across Canada and Greenland (oranges).  As a result of this high-latitude blocking pattern in the upper atmosphere, it appears that another Arctic air mass will drop into the Midwest and eastern US early next week and then this will be reinforced by a second blast at mid-week.  The 850 mb temperature anomaly forecast map (below) for next Monday night by the 00Z Euro ensemble run shows the widespread nature of next week’s influx of Arctic air with colder-than-normal (blues) conditions virtually extending from coast-to-coast.  As far as precipitation is concerned, the initial shot of Arctic air that arrives early next week looks like it will be preceded by a rain event in the Northeast US around the Sunday time frame.  Beyond that, the combination of high-latitude blocking and additional Arctic air intrusions along with an active southern branch of the jet stream enhanced by El Nino should keep storminess on the table at least for the next couple of weeks. 

Meteorologist Paul Dorian

Vencore, Inc.