The hurricane center said the system has a high chance of becoming a tropical cyclone during the next 48 hours. Andrea is the first named tropical storm to form in the Atlantic this season.

At 6 p.m., the center of the Atlantic season's first named storm was located about 310 miles southwest of Tampa and 320 miles south-southwest of Apalachicola, the National Hurricane Center in Miami said .

It was moving at 3 mph with maximum sustained winds of 40 mph.

A tropical storm warning was in effect for the west coast of Florida from Boca Grande to Ochlocknee River. A tropical storm watch was in effect for Flagler Beach to Surf City, North Carolina.

The hurricane center said a norteastward motion at a faster forward speed is expected on Thursday and that should continue until Friday.

The center of the storm is expected to reach Florida's Big Bend on Thursday afternoon or evening. It will then move over southeastern Georgia and eastern South Carolina on Thursday night and Friday.

Meanwhile, in South Florida, light to moderate rain in Broward and south Palm Beach counties was expected Wednesday afternoon.

There is a 60 percent chance of rain across the eastern metro areas, the National Weather Service said. In Key West there is a 90 percent chance. It  is not expected to directly impact South Florida, however scattered showers and occasional thunderstorms are possible.

Invest 91L which is located over the central Gulf of Mexico this morning has become a little better organized over the last 6 hours or so. This organization is supported by buoys in the area which are reporting wind gusts to 40 mph early this morning. Additionally, satellite loops show some deep convection firing on the eastern side of this system as dry air across the western Gulf of Mexico has all but squashed thunderstorm development on the western quadrant of this system. As I have mentioned previously, I expect this to be an eastern weighted storm and I have no changes in that thinking.