MIAMI -

Tropical Storm Patty has formed in the Atlantic east of the Bahamas, but forecasters expect the storm to be short-lived.

The National Hurricane Center in Miami named the storm Thursday afternoon.

Patty's center was about 484 miles east of Miami and it was moving south-southwest at 3 mph.  Its maximum sustained winds were 40 miles per hour.

Forecasters say the storm was expected to weaken Friday. No coastal watches or warnings were in effect.

Further out in the Atlantic, NWS forecasts say a tropical wave has a 80 percent of developing into a tropical system in the next 48 hours. A tropical storm warning could be required for portions of the Leeward Islands this weekend.