Tropical Depression Nine has developed in the Atlantic and forecasters expect it to strengthen 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 monitoring Tropical Storm Isaias, which is moving along a comparable track toward the coast.

Separately, an AccuWeather heat advisory continues for inland areas near San Francisco until 10 p.m. Thursday. Coastal areas are not included in the warning.