WEATHERAmerica Newsletter; Next Ten Days; Saturday, July 12, 2025

[Larry Cosgrove]

SHORT RANGE OUTLOOK

(Through The Next 72 Hours)

 

A Cool Canada Vs. Warming USA Alignment?

METEOBLUE

PivotalWeather.Com (3)

TwisterData.Com (3)

ECMWF

College Of DuPage Weather Laboratory

After many missteps and sudden changes, the numerical model families seem to be settling into a stable pattern through the rest of July. The powerful Aleutian and Gulf of Alaska Lows look to track along or just above the International Border. The Sonoran heat ridge starts to slide eastward in an eventual merger with the Bermuda High. Monsoonal moisture which has moved into Texas (with destructive flooding rains as a result) start a retrogression process toward the Desert and Intermountain Regions. A broad cold upper low forms in Nunavut AR and briefly drops into Hudson Bay later in the new week. But before any changes transpire, there could be significant convective threats in a stripe from West Texas into Missouri, and clusters of thunderstorms from Florida into the Mid-Atlantic states. Note that most of the temperatures are hot where it is not raining. This is a key to the longer term forecast, as the trough complex off of the West Coast helps to pump up the subtropical high which is shown to cover at least 2/3 of the lower 48 states.

A Heat Ridge Merger? A Gulf Coast Tropical Threat?

METEOBLUE

ECMWF (4)

TrueWx.Com (4)

College Of DuPage Weather Laboratory

Whereas most of the earlier numerical model guidance was showing a complete sweep of the Midwest and Eastern Seaboard into some very cool weather, the schemes have done an about face in the medium range and longer term. The series of cold pools that start out in Alaska and the Arctic regions reach into the states bordering Canada, but progress no further. Many schemes have plentiful thunderstorms above the Interstate 90 corridor from Seattle WA to Boston MA. Locations below that highway will see a repetition of highs in the 95-100 or higher range, all the while with less diurnal convection east of the Front Range. The gradually shifting/spreading moist atmosphere with the monsoon may reach as far west as the California High Sierra. This comes down to a generally cool Canadian vs. hot American forecast that lasts a while. Maybe into August.