WEATHERAmerica Newsletter, Saturday, May 2, 2026; MEDIUM RANGE OUTLOOK

[Larry Cosgrove]

MEDIUM RANGE OUTLOOK

(Four To Ten Days From Now)

 

Heat Builds Along The West Coast; The Midwest And The Northeast Stays Cool

WeatherBELL (4)

TrueWx.Com (4)

TwisterData.Com (4)

College Of DuPage Weather Laboratory

The passage of the storm and cold front through the Great Lakes and Mississippi Valley on May 6-7 will serve to reinforce the cooler than normal temperature array that has consistently visited the Great Lakes, Midwest and the Northeast since the winter months. The effect is not as cold as the time previous, but surely will eliminate any thought of heat, humidity and coming holidays at seashores. There will be warm/humid/unstable air mass returns over the south central states ahead of troughs and surface storms, probably twice during the medium range. But the real heat, as such, will be over the Desert Regions and Florida Peninsula, the two locations nearest to the extant heat ridges. This means dryness, however, with the best precipitation potential remaining from the Great Plains into the Ohio and Tennessee Valleys during the medium range.

The "Thunderstorm Trap" Sets Up Over The South Central USA

ECMWF (4)

PivotalWeather.Com (4)

It is worth noting that while thunderstorm potential will be fairly high through the first two weeks of May, there will come a point when the Sonoran and Bermudan heat ridges assert presence and return dryness to the forecasts of much of the nation. Most El Nino episodes favor tropical/subtropical heat and drought, which as summer arrives ultimately gains in latitude and general coverage. As we move into next weekend, another low in the southern branch will gather in the Southwest, and proceed to move into southern Colorado. Some higher elevations in that state may see a lot of late-season wet snow, but elsewhere the return of the Gulf of Mexico moisture will mean some intense thunderstorms. The first formation zone will likely be from Kansas through Oklahoma and Texas, perhaps progressing through the middle/lower Mississippi Valley into Appalachia by May 12.

This is a heat-suppression mechanism, since extensive cloud cover will block the warm May sun and vertical motion will act as an offset at the surface. Still, the drainage of colder values from the Prairie Provinces will stop . The "hot zones" in the Desert Regions and Florida Peninsula are a reaction to the two subtropical highs, which will expand after the low pressure in the Heartland progresses through the Ohio and Tennessee Valleys. Given the wide scope of this trough, there may be at least two days' worth of severe weather and heavy rainfall risks across a sweep from the south central U.S. into parts of the Eastern Seaboard by the middle of this month.