MIAMI, United States (AFP)—Hurricane Isaias intensified to Category 2 in the Gulf of Mexico’s warm waters on Thursday as it churned toward the southern United States, the National Hurricane Center (NHC) said.

The first hurricane of the Atlantic season, Isaias is forecast to make landfall in Florida, Alabama or Mississippi overnight Friday to Saturday, according to the NHC.

It warned residents in the likely impact zone that emergency preparations to protect lives and property from high winds and storm surges “should be rushed to completion.”

A storm surge warning, which brings the danger of life-threatening inundation, was in effect for the mouth of the Mississippi River to the Suwannee River while a hurricane warning was in effect from Ocean Springs, Mississippi, to the Gulf County Line in Florida, the NHC said in its latest update.

Isaias, which was about 325 miles (525 km) south of the Mississippi River delta, was packing maximum sustained winds of 100 mph (155 kph), making it a Category 2 hurricane on the Saffir-Simpson scale.

Isaias comes unusually late as the first hurricane of the Atlantic season, which began June 1. The Pacific has already seen several hurricanes, including Polo, which at one point reached top level 5 in strength.