May 15, 2025 Thursday Weather

Enhanced Risk of Severe Weather in Great Lakes

Good afternoon!

Bit of a delay today as I am on lunch break from jury duty here in Atlanta. But I’d like to mention that yesterday’s forecasts for the most extreme heat > 104°F in Austin didn’t pan out. The key was more moist air and higher dewpoints from the Gulf of Mexico won out over the advancing dry line from the west. This kept Dallas Fort Worth in the lower-90s and Austin at 101°F.

ECMWF HRES melted down with huge forecast busts in Dallas Fort Worth, but came back to earth in Austin in the 00z cycle prior to Wednesday’s highs.

I’ll note also that HRRR did well with Austin but also busted hard in DFW. I assume this a boundary layer problem that kept the dry air from the west mixing out the moisture laden air mass across eastern Texas. In the end, while actual temperatures were lower, the humidity was higher meaning more stressful heat index values.

High Temperatures on Wednesday | Verification dataset URMA

Mid-90s still abnormally warm (15°F to 20°F above normal) across Oklahoma and north Texas.

RRFS-A Radar Simulation | Severe Weather Enhanced Risk

Next 18-hours through Friday 3 AM

RRFS has impressive supercells through Chicago and Milwaukee and then crossing Lake Michigan.

Atlantic Satellite Image

Cool extratropical storm in the North Atlantic.

Very dusty across the Eastern Tropical Atlantic — a situation we’ll see for the next 1-2 months with ebbs and flows of the Saharan Air Layer (SAL) interspersed with tropical waves. The tropical storm season out here cranks up in July.

The Main Development Region (MDR) from the Lesser Antilles to the coast of Africa has a discernible SAL and dusty layer largely suppressing rain showers and storms due to stability.

Satellite Imagery This Morning Across Lower 48

Powerful low pressure system centered over the Dakotas!

Current Radar: 12:24 PM ET

Waiting for storms to fire …

Frontal Boundaries at 8 AM | Weather on Wednesday

Major severe weather risk (ENHANCED) along band of storms that will develop this afternoon and spiral through the Great Lakes.

High Temperatures Today | Thursday May, 15 2025

74.8°F is the Lower 48 average high temperature with 205 million at least 80°F.

Into the 90s across Illinois into Chicagoland. 80s in lower Michigan

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Temperature Analysis | 11:45 AM ET

Very warm in the Midwest and Great Lakes —> fuel thunderstorms.

Temperature Anomaly | 11:45 AM ET

Overall the Lower 48 is only +0.2°F and above normal [1991-2020] with western chill almost balancing out the warmth centered on the Midwest and Great Lakes

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