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

[Larry Cosgrove]

SHORT RANGE OUTLOOK

(Through The Next 72 Hours)

 

Heat Takes A Back Seat To A Polar Air Mass

METEOBLUE

PivotalWeather.Com (3)

ECMWF

Moderated? Yes. Completely gone from the U.S. forecast? No way!

The 500MB flow is still amplified, with -EPO and -NAO signatures strong enough to influence the position of the polar westerlies. Shortwaves in the flow dig southeastward. from above the Arctic Circle, dragging down polar air masses. At the same time, the position and strength of the Madden-Julian Oscillation (Phase 8) connected to the southern branch is still exporting disturbances from the central equatorial Pacific Basin. And while there are reliable signs that the MJO connection will be severed in about 10-15 days, the current reality basically dictates that the recent hot spells will not return until the second half of this month.

So while the cold snap in the Great Lakes/Midwest is falling apart, another surge of cPk values will replace the regime in a swath from the Great Plains into the Northeast by late in the new week. There may still be some cases of wet snow in Ontario and Quebec, and also in the mountains of Wyoming and Colorado in tandem with a storm arriving in California on Tuesday. For many in the cooler air masses, cloudiness and stratiform rain will confirm that it is still spring, and the heat of a few days ago was the proverbial tease of what is to come this summer.

Severe Thunderstorm Chances Return In Early Week

METEOBLUE

UQAM Meteocentre (3)

TwisterData.Com (3)

University Of Wisconsin (3)

College Of DuPage Weather Laboratory

It will not take long for May tio show its ugly side. While the weekend has gotten off to a splendid start in much of the lower 48 states, the quick return of a Gulf of Mexico moisture fetch into Texas and then the Mississippi Valley will soon be underway. One contributor to greater thunderstorm production will be a 500MB low dropping out of the Northwest Territories, which eventually will create a vortex in Ontario and James Bay. This is of course a cold signature, which after the passage of the storm in California (through Texas and the Mid-South) will create a warm West vs. cool Central/East alignment lasting into next weekend.

While the initial thunderstorm risk will be in the Midwest in early week (and it being May, large hail is a first-order threat; cold air aloft against mild/warm temperatures at surface), I expect a relocation of the cumulonimbi to Texas/Oklahoma on Tuesday and Wednesday. With some luck, the parched Southeast may also share in the beneficial rainfall. Be sure to monitor the instability and vertical motion parameters shown here, which hold the key to understanding the locations points for tornadoes and torrential rain potential.