Tropical Storm Nate was upgraded Friday at 11:30 p.m. ET to a Category 1 hurricane with estimated maximum winds of 75 mph, the National Hurricane Center announced.

Nate's location was about 95 miles WNW of the western tip of Cuba, and about 495 miles SSE of the mouth of the Mississippi River.

It was moving at NNW at 22 mph, the National Hurricane Center said.

"An Air Force Reserve Hurricane Hunter aircraft just penetrated the center of Nate and reported the hurricane-force winds," read the National Hurricane Center bulletin.

Tropical Storm Nate had gained force as it sped past Mexico's Yucatan Peninsula late Friday after drenching Central America in rain that was blamed for at least 21 deaths. Forecasters said it was likely to reach the U.S. Gulf Coast over the weekend, likely Saturday night.

A tropical storm that killed at least 22 people in Central America is now forecast to strengthen into a hurricane over the weekend before roaring ashore in New Orleans.

Hurricane watches and warnings were already in effect for coastal areas of four southeastern U.S. states, including metropolitan New Orleans, according to the National Hurricane Center. Tropical storm warnings have extended into central Alabama, Mississippi, northern Georgia -- including Atlanta -- and the western panhandle of Florida.

Louisiana Gov. John Bel Edwards declared a state of emergency on Thursday as the state braces for a direct hit. Edwards mobilized 1,300 National Guard troops, with 15 going to New Orleans to monitor the troubled pump and drainage system there.

In a press conference Friday afternoon, Edwards instructed Louisianans in affected areas to gather supplies now and be positioned to hunker down by 8 p.m. Saturday.

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