Posted July 17, 2018 9:09 p.m. EDT
Much cooler and less humid air will extend Wednesday from the Midwest to the Tennessee Valley, the southern Appalachians and coastal areas of the Northeast. Strong sunshine will keep temperatures seasonable during the day, but it will turn significantly cooler at night.
Coastal areas from the Carolinas, Georgia and Florida to Louisiana and Arkansas will be very humid air, with drenching showers and thunderstorms. A few of the storms may cause flash flooding and sporadic power failures.
The Great Plains will be split, with cool air over the northern fringe and very hot, humid air over Texas. Between South Dakota and eastern Oklahoma, severe thunderstorms will develop, bringing strong gusts and flash flooding. Where repeated storms occur, beginning Tuesday or early Wednesday, the risk of flash flooding will be highest.
Most of the West will be dry and sunny. A few storms are expected across the Southwest deserts, but it should be calmer than the past few days. While the storms will mostly continue to abate into the weekend, heavy rain and gusty wind may continue in spots.
FOCUS: Monsoon Eases Across the Southwest
Thunderstorms associated with the annual summer monsoon in the Southwest will become much more scattered late this week and into early next week as slightly drier air arrives from the northwest. Isolated storms may cause flash flooding in spots.