WEATHERAmerica Newsletter; SHORT RANGE OUTLOOK; Saturday, August 16, 2025

[Larry Cosgrove]

SHORT RANGE OUTLOOK

(Through The Next 72 Hours)

 

Vast Sonoran Heat Ridge Controls Central, Western USA....

METEOBLUE

PivotalWeather.Com (3)

ECMWF

As Sonoran heat ridges go, the one setting up across the USA from the West Coast to the Mississippi Valley is impressive. Monsoonal moisture from the fetch set up from Mexico will enable cases of diurnal + orographic thunderstorms over the Desert and Intermountain Regions, which could in a few cases lessen daytime temperatures. But the thermal and thickness profiles are showing extreme heat, and in the south central states this could be bothersome as chances for seabreeze and nocturnal convection could be limited by the compressed/subsident nature of the big anticyclone.

....But Major Hurricane Erin, Oncoming Deep Upper Low In Canada Are Main Influences East Of The Mississippi River

METEOBLUE

TwisterData.Com (3)

University Of Wisconsin Weather Server (3)

College Of DuPage Weather Laboratory

Hurricane Erin will grow into a Category 5 beast after its eyewall cyclone is replenished, slowly recurving poleward as it grazes the Turk/Caicos chain in the next 48 hours. It seems likely that this system will grow into a transitional large cold cyclone by the time it reaches Cape East, Newfoundland next weekend. The close pass of that much energy and the circulation to the East Coast (which should involve the Outer Banks NC in 3 or 4 days) will interact with the weakness over Appalachia and the upstream storm in the Prairie Provinces. That would mean the passage of a cold front first through the Midwest/Great Lakes and then into the Mid-South and Eastern Seaboard next weekend. Severe thunderstorm threats on August 17-18 will almost certainly regroup in the hot and humid atmosphere of the Northeast from Wednesday through Friday of the new week.