Saharan dust exits as thunderstorms return to South Florida

WEST PALM BEACH, Fla. (CBS12) — South Florida is finally beginning to break out of the unusually dry and extremely hot pattern of recent days as Saharan dust moves away and tropical moisture returns, setting the stage for more widespread thunderstorms this afternoon.

Temperatures will be slightly lower today, with highs generally reaching the low to mid-90s. However, the returning moisture means humidity will remain high, pushing heat index values—the temperature it feels like when humidity is included—to between 105 and 110 degrees. A Heat Advisory is in effect for all of South Florida from 11 a.m. to 6 p.m.

The biggest change will come after midday as scattered showers and thunderstorms begin developing earlier and become more widespread than they have during the recent stretch of Saharan dust. A southwest wind will keep the Atlantic sea breeze closer to the coast, making coastal communities some of the favored areas for afternoon and evening storms.

A few thunderstorms could produce wind gusts between 40 and 50 mph, as storms in St. Lucie county did yesterday along with frequent lightning and torrential rainfall.

Storms that repeatedly develop or move over the same neighborhoods could also produce localized flooding, particularly in urban and poor-drainage areas.

The increase in thunderstorms should provide at least some temporary relief from the heat. If storms become widespread early enough, temperatures could fall quickly during the afternoon and the Heat Advisory could potentially end before its scheduled 6 p.m. expiration.

Friday brings another round of scattered thunderstorms as deeper tropical moisture continues spreading across the region. Temperatures will remain in the low to mid-90s, but afternoon storms should become a more regular part of the forecast after several days of unusually suppressed rainfall.