Tropical Depression Nine has developed in the Atlantic and forecasters say it may develop into the season's first hurricane before reaching the US Gulf Coast. The National Hurricane Center says the system could escalate fast in the Gulf. AccuWeather and The Weather Channel are also watching Tropical Storm Isaias, which is developing on a similar path toward the coast.

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