NEW ORLEANS — The U.S. Gulf Coast braced Friday for a fast-moving blast of wind, heavy rain and rising water as deadly Tropical Storm Nate threatened to reach hurricane strength before a weekend landfall.

The National Hurricane Center in Miami issued hurricane and storm surge warnings for southeast Louisiana and the Mississippi and Alabama coasts. A hurricane warning was issued a few hours later for metropolitan New Orleans and Lake Pontchartrain.

Forecasters said in a Friday evening advisory that the storm was growing in strength, with maximum sustained winds increasing to 60 mph (95 kph) and higher gusts.

“Additional strengthening is forecast during the next 36 hours, and Nate is expected to become a hurricane by the time it reaches the northern Gulf of Mexico,” the advisory said.

States of emergency were declared in all three states as Nate — which has already killed at least 21 people in Central America — became the latest in a succession of destructive storms.

Nate is forecast to dump 3 to 6 inches of rain on the region — with isolated totals of up to 12 inches. That much rain led authorities to warn of flash flooding and mudslides.