Tropical Storm Iselle slowly gained strength far off Mexico's southern Pacific coast on Thursday but was not expected to threaten land.

Iselle had maximum sustained winds near 50 mph, a slight increase from when the storm formed Wednesday, the U.S. National Hurricane Center in Miami reported.

Forecasters predicted the storm will head toward cooler waters in the next few days and dissipate.

Iselle was centered about 355 miles south of the tip of Baja California and was moving northwest at about 8 mph.

Click here to track the storm at the Naional Hurricane Center.