Hurricane Nate expected to make landfall on Gulf Coast as Category 2 -- live updates

NEW ORLEANS -- Gulf Coast residents scrambled to finalize storm preparations as Hurricane Nate raced swiftly over the central Gulf of Mexico on Saturday, gaining added strength as forecasters said it would smash into the U.S. coast during the night.

Louisiana's governor urged his state's residents to take Nate seriously, saying the storm "has the potential to do a lot of damage." 

"No one should take this storm lightly. It has already claimed the lives of at least 20 people," Gov. John Bel Edwards said Friday. "We do want people to be very, very cautious and to not take this storm for granted." 

A hurricane warning is in effect from Grand Isle, Louisiana, to the Alabama-Florida border and also included metropolitan New Orleans nearby Lake Pontchartrain. A tropical storm warning extended west of Grand Isle to Morgan City, Louisiana, and around Lake Maurepas and east of the Alabama-Florida border to the Okaloosa-Walton County line in the Florida Panhandle.

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 this hurricane season.

Follow along with the latest updates below. All times are Eastern unless otherwise noted.

1:10 p.m.: Louisiana cuts early voting short for hurricane

Early voting is wrapping up sooner than scheduled in parts of Louisiana because of Hurricane Nate.

Meg Casper Sunstrom, spokeswoman for the secretary of state's office, said voters in some southeastern parishes will have until 3 p.m. on Saturday to cast their ballots early. The parishes affected are in the New Orleans-area, including Orleans, St. Bernard, Plaquemines and St. Tammany parishes.

Early voting will close as scheduled at 6 p.m. local time in the state's other parishes.

Saturday is the last day of the week-long early voting period. Louisiana has a statewide election Oct. 14, and New Orleans has a hotly contested mayor's race on the ballot.

12:30 p.m.: Alabama under tropical storm warning

The National Weather Service is placing much of Alabama under a tropical storm warning.

Forecasters said Saturday that Hurricane Nate could bring wind gusts of up to 60 mph across much of the central part of the state, which includes Birmingham, the state's largest city.

The storm is expected to down trees and cause significant power outages. Isolated tornadoes were also possible Sunday afternoon.

On Alabama's Gulf coast, some communities have already imposed mandatory curfews from Saturday evening through Sunday morning. They've also ordered beaches and fishing piers closed and issued voluntary evacuation orders.

On Florida's Panhandle, officials have ordered evacuations in some low-lying areas. They're also warning beachgoers to stay out of the Gulf of Mexico as the storm is already whipping up deadly rip currents and rough surf.

12:22 p.m.: New Orleans prepares for Nate's storm surge

CBS News correspondent Michelle Miller is in New Orleans and reports that a mandatory curfew goes into effect at 7 p.m. local time Saturday. Mayor Mitch Landrieu issued mandatory evacuation orders for areas outside of the city's storm protection system.

City officials closed off about 200 floodgates on Friday night, ahead of a storm surge that could be as high as 10 feet, Michelle reports.

Water is already spilling onto streets in the city's Venetian Isles neighborhood from an unusually high tide. Residents had until noon Saturday to leave.

"Can't call anybody, not coming, so it is a good idea to leave for most people," one resident told Miller.

Others have already left their homes. The first evacuees began arriving at one shelter in Plaquemines Parish. About 20 were there by late Friday night with more expected to come.

"They take very good care of us opening these centers so we can have a place to go, and I appreciate that," East Bank resident Betty Duplessis told Miller.

11:06 a.m.: Nate expected to make landfall as Category 2 storm, NHC says

Strengthening Hurricane Nate is now expected to be a Category 2 hurricane at landfall on the central Gulf Coast in coming hours.

The National Hurricane Center in Miami says Nate's top sustained winds have recently risen to 90 mph and the core is now about 180 miles south-southeast of the mouth of the Mississippi River.

As of 11 a.m. Saturday, Nate was accelerating to 26 mph and headed north-northwest on a course expected to take it onto the central Gulf Coast on Saturday night. Forecasters say the hurricane-force winds extend out up to 35 miles, mainly to the east of the eye.

In addition to hurricane warnings and tropical storm warnings already in place along a wide stretch of Gulf Coast, a new tropical storm warning has been issued in the Florida Panhandle from east of the Okaloosa-Walton County line to Indian Pass, Florida.