WEATHERAmerica Newsletter, Saturday, January 26, 2019 at 10:05 P.M. CT; Near Term Forecast

[Larry Cosgrove]

SHORT RANGE OUTLOOK

(Through The Next 72 Hours)

 

F5 Weather

Monster Arctic Vortex May Generate A Major Winter Storm Along East Coast

NOAA/NESDIS

University Of Wisconsin Weather Server (3)

UQAM Meteocentre (3)

College Of DuPage Weather Laboratory (2)

We will have to watch developments rather intently over the eastern two-thirds of the nation, as the chance for surprise exists concerning the arrival of extremely bitter Arctic air and the chance for frontal wave cyclogenesis in Georgia and the Carolinas on Tuesday and Wednesday. The lead player in the complicated forecast is a massive cAk motherlode covering much of Canada and the Upper Midwest. An Alberta Clipper type disturbance will dig southeastward, then turn east along the IL and WI border into Lower MI on Monday. Most communities along and 150 miles below Interstates 80 and 90 will probably see a mix, change or ice scenario, while band of precipitation from the eastern Dakotas through N MI and S ON is hit with near blizzard conditions (heavy snow and strong winds). 

An interesting turn, of course, deals with the southward rush of pure, rarefied Arctic air. When vorticity associated with the parent trough hits the frontal structure and subtropical jet stream currently present along the Gulf of Mexico and Atlantic Ocean shorelines, a case can be made for a low pressure to organize in the vicinity of the Piedmont. If this system starts to build along the coast, rain will transition to sleet and freezing rain, ending as snow from Virginia north into New England. If the cyclonic circulation starts off the VA Capes, a case for important snow and sleet can be made along the Interstate 95 corridor. Then again, if now system organizes (still a possibility), rainfall will be succeeded by brutal cold, strong winds and very low dewpoints.

Western States, Under Ridging, Stay Mostly Dry With Seasonable To Cold Temperatures

CIRA/RAMMB

PivotalWeather.Com (3)

ECMWF

While the eastern two-thirds of the country is visited by what may be a record-cold air mass with origins in Siberia, the West will sit under a thumb-projection ridge. Some of the colder values could leak into the Intermountain Region, but I would not be surprised to see the West Coast remain mild, with bouts of downslope winds from the higher elevations to the coast. A -EPO styled ridge like the one forecast by the numerical models tends to be quite durable, and may stick around into next weekend.