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

[Larry Cosgrove]

MEDIUM RANGE OUTLOOK

(Four To Ten Days From Now)

 

Deep Trough, Polar Air Mass Likely To Prevent Hurricane Approach to Cuba And Florida....

ECMWF (4)

PivotalWeather.Com (4)

The GFS series has consistently shown a hurricane threat to the Greater Antilles and Florida in the medium range. While there may be a tropical cyclone involved, possibly a hurricane, the presence of a trough over eastern North America, rooted to a Hudson Bay Low, strongly suggests a recurvature away from Florida and Cuba in this time frame. It is possible that a cold front could be involved at the surface (note the lower temperatures coming across the Midwest and Great Lakes by 168 hours) that could interact with tropical energy and present a threat to New England and the Maritime Provinces in the longer term. That frontal structure itself could set up a severe weather + flooding rain episode along the Eastern Seaboard by next weekend.

....Heat Ridge Bakes Western Half Of The USA; The East Cools Down

UQAM Meteocentre (4)

TwisterData.Com (4)

TrueWx.Com (4)

College Of DuPage Weather Laboratory

While remnants of the Mexican monsoonal fetch could maintain chances of showers and thunderstorms in parts of the Desert and Intermountain Regions, the presence of such a strong Sonoran heat ridge should ultimately limit precipitation potential from the High Plains to the West Coast. Shortwaves ejecting out of the Gulf of Alaska Low may enable convective or stratiform rains over the Pacific Northwest and much of the Prairie Provinces into the Upper Midwest in the medium range. Conversely, the further east and north in North America, temperatures will likely be cooler than normal with periodic bouts of northwest-flow thunderstorms.