Hurricane season is days off, but no one told Alberto. Rock Hill area will be soaked

A tropical weather system that is jumping the gun on the start of hurricane season is poised to bring periods of heavy rain to the Rock Hill area and the rest of the Southeast this week.

The National Weather Service has issued a Flash Flood Watch through Tuesday morning for the western Carolinas, and meteorologist Harry Gerapetritis says the watch “will likely need to be expanded and extended at some point.”

“A potentially serious flash flood and landslide threat will set up over our area through the short term period from Monday to Wednesday,” Gerapetritis says.

Subtropical Storm Alberto, which is expected to organize better and become a tropical storm on Sunday, is forecast to make landfall early Monday afternoon in the Florida Panhandle. Meteorologists say Alberto will have a huge shield of rain on its eastern and northeastern flank, and that rain is predicted to sweep into the Carolinas.

Alberto is forecast to weaken as it moves inland, but as the center of the storm’s remnants push northward Tuesday through Tennessee, the Rock Hill area and the western Carolinas could feel the heaviest of the rain.

The precipitation from Alberto would be in combination with an already-moist air mass that has been stuck in place across the Southeast for about 10 days.

Rainfall from the tropical system is expected to begin affecting the region late Sunday night and continue through midweek. The good news is that rainfall chances are rather low Sunday, giving area residents one more fairly nice day from the Memorial Day weekend.

Showers are forecast to arrive after midnight Sunday, then continue through Memorial Day and Tuesday.

Meteorologist Bob Henson of the website Weather Underground said late Saturday that parts of the South – possibly including the Rock Hill area – might catch a break if a swath of dry air gets trapped on the east side of Alberto.

Henson said some computer guidance indicates the precipitation around the storm could get broken into two parts – one affecting Alabama and western Georgia, and the other pushing northward along the coast from Florida to North Carolina. If that were to happen, the western Carolinas might escape the worst of the rain.

Gerapetritis said the heaviest rain, along with a possible chance of severe weather, could come Tuesday afternoon and evening. That’s when the center of Alberto’s remnants would be closest to the western Carolinas, in central Tennessee.

Steve Lyttle on Twitter: @slyttle