WEATHERAmerica Newsletter, Sunday, March 30, 2025; EXTENDED PERIOD FORECAST

[Larry Cosgrove]

EXTENDED PERIOD FORECAST

(Between Day 11 And Day 15)

 

Storm Exits Through The Maritime Provinces, While Another Takes Shape across the Intermountain Region

CIMSS (2)

NOHRSC (2)

TropicalTidbits.Com (Dr. Levi Cowan) (3)

NOAA/PMEL

NOAA/CPC

IRI/Columbia University

HPRCC/University Of Nebraska (2)

Environment Canada

TropicalTidbits.Com (Dr. Levi Cowan) (5)

ECMWF (3)

NOAA/CPC

Something to keep in mind: we are in a progressive 500MB longwave pattern across North America, with a series of intense storms in the semizonal jet stream across the Pacific Basin. With a mean Gulf of Alaska Low. In synoptic climatology that is not a formula for long-lived cold. Rather, the cold front that may push through the eastern two-thirds of the USA in Week 2 is transient, and we should not see any well-developed Arctic intrusion like the one that punches through eastern Canada in the medium range.

Part of the concern for cold air, aside from the recent breakup of the circumpolar vortex at 10MB (usually a favorable factor between October 15 and February 15), is the vast snow and ice coverage above 50 N Latitude. All of that frozen moisture helps keep cold air going, especially further north where sun angle matters less against cold ground and extant snowpack. But the numerical models keep moving the cold domes east. And the oncoming major troughs keep advecting warmer air from dry, dusty and warm Mexico and West Texas. At some point, the snow line will retreat, and warm air masses will make bigger gains into Canada.

I suspect that by mid-April, we will see a trough West, ridge Central, trough East alignment, with closed lows near the Four Corners and in Newfoundland. Strongest potential for severe weather would be in the Missouri and OOhio Valleys, given the cT punch that we keep seeing from the lower High Plains into Texas, Oklahoma and Kansas.

 

Prepared by Meteorologist LARRY COSGROVE on 
Saturday, March 29, 2025 at 1:30 A.M. CT

Disclaimer: 
The previous statements are my opinions only, and should not be construed as definitive fact. Links provided on this newsletter are not affiliated with WEATHERAmerica and the publisher is not responsible for content posted or associated with those sites.

Copyright 2025 by Larry Cosgrove

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