Weekly Weather Watch: Wednesday, May 21st, 2025
A dynamic weather pattern continues this week, with severe storms and flash flooding threatening parts of the Ohio Valley and Mid-Atlantic today. Scattered strong storms may bring hail, damaging winds, and isolated tornadoes, while multiple rounds of rain elevate flood risk in areas like Pittsburgh and the Central Appalachians. A deep upper low over the Great Lakes is ushering in much cooler-than-normal temperatures across the Northern Plains to the Northeast, with highs 20–35°F below average. In contrast, heat continues across the southern and western U.S., with some record-warm nights expected in Florida and southern California, and increasing heat stress forecast for south Texas. Looking ahead to the weekend, a heavy rain setup develops over the Ozarks, with flash flooding likely to expand Sunday into the Lower Mississippi Valley. As this system shifts east early next week, a wave of rain and cooler weather will spread through the South and Appalachians, while heat builds again in the Intermountain West. A late-season frost is expected to hit parts of Canada’s Maritimes and Ontario, meanwhile, Saskatchewan has some air quality issues due to wildfire smoke.
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HEADLINERS:
A multi-day heavy rain threat in the Ozarks and vicinity this weekend.
Severe Weather and flash flooding are expected over the Ohio Valley/Mid-Atlantic today.
Above-average temperatures across the southern tier states and the West; below
average temperatures from the Northern Plains to the Northeast/Mid-Atlantic.
Slight risk of high winds for parts of the California coast, Wed-Fri, May 28-30.
List via NOAA’s WPC & SPC.
ON THE RADAR:
KEEP AN EYE TO THE SKY:
IN THE GAUGES:
GRAB A RULER:
RECORDS MADE TO BE BROKEN:
ARE YOU CIRRUS?!
1896 The mercury rose to 124 degrees at Salton, CA, making it the hottest day on record for May.
1857 In Baghdad, Iraq, a dust storm lasted the entire day. Then, at about 5 pm, a darkness set in, deeper than the darkest night, and terrorized local residents.
1918 An F5 (unofficial) tornado swept foundations bare along a 37-mile path from Carroll County to Webster County, IA. Mattresses were found two miles away, and four people were killed.
The weather pattern is about to make a pretty sharp turn across the country. California starts the week with unusual October heat, including highs well into the 90s and even lower 100s in the Central Valley. Meanwhile, much cooler fall air has reached the Great Lakes and Northeast. The Gulf Coast and Southeast stay unsettled, and there’s that record to watch: a tropical depression is likely to develop over the Gulf this week and could strengthen as it moves northeast. If it becomes a hurricane after the 8th, 2026 will have the latest-first hurricane in the Atlantic Basin record.