WEATHERAmerica Newsletter, Saturday, February 8, 2025

[Larry Cosgrove]

SHORT RANGE OUTLOOK

(Through The Next 72 Hours)

 

Will The Unusual Warmth Across the Southern Half Of The USA Go Away Anytime Soon?

METEOBLUE

PivotalWeather.Com (3)

ECMWF

Yes. But the structure of the wind field aloft at 500MB presents a natural barrier, even considering how a cAk air mass is far more dense than that of the warmth ahead of it. Most guidance and analogs take the leading edge of the chilled regime just past the Gulf Coast, then stalling in a manner that leaves the Florida Peninsula still very warm. The motherlode of the bitter cold stays over western Ontario for much of the next three weeks. While the area from Texas to Virginia is certainly getting colder, the worst of this domain stays in Canada and the northern third of the USA. The shallow layer of the incoming cold will encourage overrunning against the slowly-descending frontal structure, so Kansas/Oklahoma into mid-Appalachia and the Mid-Atlantic/New England may get bursts of snow and a few periods of freezing drizzle and sleet within the next 72 hours. The western states may snap out of the cold somewhat with a shortwave ridge nearby.

Bitter Cold From Canada Is Just Waiting On A Storm

METEOBLUE

UQAM Meteocentre (3)

College Of DuPage Weather Laboratory (3)

At some point in the next few days, one of the storms off of the West Coast will consolidate and head through California and Oregon, and across the Intermountain Region. One of these disturbances will alter the general pattern of weather in North America so as to displace the area of bitter cold over our northern neighbor. But there are complications. The greatest of these obstacles is the subtropical high straddling the Greater Antilles and Sargasso Sea, A linear positive height anomaly such as this will prove very hard to dislodge or crush, simply springing back up when a trough passes through to its north. In this case, that means the USA. But a factor which favors more and stronger cold intrusions is the impressive -AO/-NAO blocking signature, which tends to impart secondary cyclogenesis in or near the Virginia Capes. The system exiting the Northeast on Sunday will set up moderate to heavy snow bands from the Great Lakes through New York, New England, then advance through Nova Scotia and Newfoundland. But the worst this pattern has to offer is probably awaiting us in the medium range.

The first such impulse will affect an area from the south central U.S. into middle Appalachia on Monday and Tuesday, then impact the Virginias and Mid-Atlantic as a rain>sleet>snow event. Thunderstorm threats will resume from the Red River Valley (TX/OK) into the Mid-South on February 11-12, then followed by a brief cold/dry air mass.