A tropical storm swirling in the US Gulf is expected to bring heavy rain and “life-threatening storm surge” to the southeast of the country, according to the National Hurricane Center (NHC).

Tropical Storm Bertha was located about 105 miles (165 kilometers) south of Panama City, Florida, with winds of 40 mph (65 km/h) on Monday.

“Bertha will move near or along the northern Gulf Coast over the next few days,” the Miami-based NHC said.

The storm could cause flooding and storm surge in Alabama, Florida, Louisiana and Mississippi as it moves west toward Texas. Some areas could receive 8 inches (20 cm) of rain on Friday, and “isolated” tornadoes could spawn in Florida, forecasters say.

In an update Monday night, forecasters said the tropical storm could gain strength in the coming days, before making landfall in New Orleans, Louisiana, on Wednesday.

The bulletin added that tropical storm-force winds extended 70 miles outward from the center of the storm, and that the storm was moving northwest at about 3 mph.

“A tropical storm watch is in effect for the Ochlockonee River, Florida, westward to the Jefferson/Plaquemines Parish border in Louisiana,” forecasters said.

Swells are expected to reach between 1 and 4 feet along parts of the Louisiana and Mississippi coasts, officials said. Flash flooding could occur in urban areas.

The storm’s arrival comes amid sweltering summer heat in the southern United States.

In New Orleans, sandbags are being distributed to prevent flooding. Residents have also been asked to ensure local storm drains are clear.

Bertha is forecast to weaken back to a tropical depression on Thursday and could dissipate by the end of the week as it approaches the Texas coast.

This is only the second named storm of the season, after Tropical Storm Arthur caused some flooding in the United States last month.