Tropical Depression Nine has developed in the Atlantic and forecasters believe it could intensify into the season's first hurricane before reaching the US Gulf Coast. The National Hurricane Center says the system could strengthen rapidly in the Gulf. AccuWeather and The Weather Channel are also watching Tropical Storm Isaias, which is advancing on a like course toward the coast.

Separately, an AccuWeather heat advisory continues for inland areas near San Francisco until 10 p.m. Thursday. Coastal areas fall outside the warning.