Tropical Storm Helene is expected to unleash mudslides and flooding in Cuba before reaching major hurricane strength on Thursday as it hits Florida with life-threatening ocean surge, the U.S. National Weather Service said.

Tropical Storm Helene formed Tuesday in the Caribbean Sea and could strengthen into a major hurricane while moving north toward the U.S., forecasters said. Heavy rains and big waves already lashed the Cayman Islands, and some Florida residents began to evacuate or fill sandbags ahead of anticipated flooding.

Tropical Storm Helene continues to strengthen and is forecast to make landfall on the Big Bend Coast of Florida late Thursday night.

Another storm system is taking aim at Florida, this time possibly the Panhandle with storm effects all along the Gulf Coast. Tropical Storm Helene, soon to be a hurricane, is sweeping up from the Caribbean Sea into extremely warm waters that are fuel for tropical cyclones.

Florida residents are already evacuating and filling sandbags days ahead of anticipated flooding from Tropical Storm Helene

Tropical Storm Helene promised to become a hurricane on Wednesday as it rapidly intensified in the eastern Gulf of Mexico, threatening to bring life-threatening storm surge to Florida within the next two days.