FORT LAUDERDALE, Fla. — South Florida remains under a tropical storm warning Friday morning as the region braces for a system to arrive from the southeastern Gulf of Mexico on Friday afternoon or night, according to the National Hurricane Center.

South Florida could get between 4 and 8 inches of rain with some isolated areas getting as much as 12 inches of rain.

The National Hurricane Center, in its 8 a.m. Friday update, kept half of the state included in the Tropical Storm Warning with a growing system expected to become Tropical Storm Alex.

The disturbance now has sustained tropical-storm-force winds of 40 mph, and is located about 420 miles southwest of Ft. Myers and about 125 miles north of Cozumel, Mexico, while moving northeast at 6 mph. Tropical-storm-force winds extend 60 miles outward.

The system has yet to organize its circulation to be labeled a full-fledged named storm. However, forecasters anticipate that the system will become a tropical storm by tonight. If it forms, it will be Tropical Storm Alex — the Atlantic’s first named storm of 2022.

“On the forecast track,” the NHC said, “the system is forecast to move across the southeastern Gulf of Mexico through tonight, across the southern and central portions of the Florida Peninsula on Saturday, and then over the southwestern Atlantic north of the northwestern Bahamas Saturday afternoon through Sunday.”

Heavy rains will begin to affect South Florida and the Keys beginning today and continuing through Saturday. Those areas could see up to 12 inches of rain and may produce considerable flash and urban flooding.

All of South Florida also will be under a flood watch from midnight Friday through Sunday morning, the National Weather Service Miami said.

The hurricane center predicted the system’s wind speeds will reach a maximum of 50 mph by Sunday evening.

The system is expected to cross Florida and into the Atlantic Ocean during the day on Saturday. It is expected to be heavily lopsided with the heaviest rain and strongest wind gusts to the east and south of its center, the National Weather Service said.

Fort Lauderdale and Miami are both included in the area expected to have the highest potential of flash flooding through Saturday, according to the National Weather Service.

A system officially becomes a tropical storm when its maximum sustained winds are between 39 mph and 73 mph. Systems become hurricanes when the maximum sustained winds are 74 mph or greater.

This is a La Niña year, meaning water temperatures will be warmer than usual and there’s less wind shear to tear apart storms.

Warm water temperatures are an optimal factor in tropical storm and hurricane development. In mid-June of last year, Tropical Storm Claudette formed in the Gulf waters and came ashore in Louisiana.

Current water temperatures are about one to two degrees higher than average for this time of year, AccuWeather Meteorologist Jake Sojda said, creating favorable conditions for the disturbance to develop.

Hurricane season officially starts June 1 and ends Nov. 30.