how hurricanes are named orig_00002729.jpg
how hurricanes are named orig_00002729.jpg
Now playing
01:38
How are hurricanes named?
Now playing
01:54
Why snow and blackouts in Texas are a preview for all of us
Now playing
01:29
Steer like this to stay out of accidents in the snow
nor
nor'easter explainer orig nws_00002211.jpg
Now playing
01:03
What is a nor'easter?
east coast storm waves noreaster orig mg_00001813.png
PHOTO: Brandon Clement / Live Storms Media
east coast storm waves noreaster orig mg_00001813.png
Now playing
01:07
Massive waves crash over top of coastal homes
Larry Pierson, from the Isle of Palms, S.C., purchases bottled water from the Harris Teeter grocery store on the Isle of Palms in preparation for Hurricane Florence at the Isle of Palms S.C., Monday, Sept. 10, 2018. (AP Photo/Mic Smith)
PHOTO: Mic Smith/AP
Larry Pierson, from the Isle of Palms, S.C., purchases bottled water from the Harris Teeter grocery store on the Isle of Palms in preparation for Hurricane Florence at the Isle of Palms S.C., Monday, Sept. 10, 2018. (AP Photo/Mic Smith)
Now playing
00:57
How to prepare for a hurricane
IN SPACE - In this handout photo provided by NASA, Hurricane Patricia is seen from the International Space Station. The hurricane made landfall on the Pacfic coast of Mexico on October 23. (Photo by Scott Kelly/NASA via Getty Images)
PHOTO: NASA
IN SPACE - In this handout photo provided by NASA, Hurricane Patricia is seen from the International Space Station. The hurricane made landfall on the Pacfic coast of Mexico on October 23. (Photo by Scott Kelly/NASA via Getty Images)
Now playing
01:07
Why hurricanes are so hard to predict
PHOTO: Courtesy Amy Lloyd
Now playing
01:06
Why flash floods are so dangerous
Now playing
01:26
Hurricanes: What you don't know
LAS VEGAS, NV - JULY 07:  Lightning strikes during a thunderstorm on July 7, 2015 in Las Vegas, Nevada. The monsoon storm dropped heavy rain and hail in parts of the valley causing street flooding and power outages.  (Photo by Ethan Miller/Getty Images)
PHOTO: Ethan Miller/Getty Images North America/Getty Images
LAS VEGAS, NV - JULY 07: Lightning strikes during a thunderstorm on July 7, 2015 in Las Vegas, Nevada. The monsoon storm dropped heavy rain and hail in parts of the valley causing street flooding and power outages. (Photo by Ethan Miller/Getty Images)
Now playing
01:36
How to protect yourself from lightning
Now playing
01:21
What is a polar vortex?
PHOTO: Franck Verdière/Twitter
Now playing
01:10
What 'rapid intensification' means for storms
A plea for help on a New Orleans rooftop, days after Hurricane Katrina struck the city in 2005.
PHOTO: AFP/Getty Images
A plea for help on a New Orleans rooftop, days after Hurricane Katrina struck the city in 2005.
Now playing
02:14
Top five costliest hurricanes in US history
Storm chasing photographers take photos underneath a rotating supercell storm system in Maxwell, Nebraska on September 3, 2016. Although multiple tornado warnings were issued throughout the area, no funnel cloud touched down. / AFP / Josh Edelson / XGTY
RESTRICTED TO EDITORIAL USE  / MANDATORY CREDIT:  "AFP PHOTO / Josh EDELSON" / NO MARKETING / NO ADVERTISING CAMPAIGNS /  DISTRIBUTED AS A SERVICE TO CLIENTS  ==        (Photo credit should read JOSH EDELSON/AFP/Getty Images)
PHOTO: JOSH EDELSON/AFP/AFP/Getty Images
Storm chasing photographers take photos underneath a rotating supercell storm system in Maxwell, Nebraska on September 3, 2016. Although multiple tornado warnings were issued throughout the area, no funnel cloud touched down. / AFP / Josh Edelson / XGTY RESTRICTED TO EDITORIAL USE / MANDATORY CREDIT: "AFP PHOTO / Josh EDELSON" / NO MARKETING / NO ADVERTISING CAMPAIGNS / DISTRIBUTED AS A SERVICE TO CLIENTS == (Photo credit should read JOSH EDELSON/AFP/Getty Images)
Now playing
00:59
The difference between a tornado watch and a warning
DODGE CITY, KS - MAY 24: A tornado is seen south of Dodge City, Kansas moving north on May 24, 2016 in Dodge City, Kansas. About 30 tornadoes were reported on Tuesday in five different states from Michigan to Texas. Damage to homes and property was also reported in Ford County, Kansas. (Photo by Brian Davidson/Getty Images)
PHOTO: Brian Davidson/Getty Images
DODGE CITY, KS - MAY 24: A tornado is seen south of Dodge City, Kansas moving north on May 24, 2016 in Dodge City, Kansas. About 30 tornadoes were reported on Tuesday in five different states from Michigan to Texas. Damage to homes and property was also reported in Ford County, Kansas. (Photo by Brian Davidson/Getty Images)
Now playing
01:41
How to prepare for severe weather
weather storm chaser convergence nccorig_00010423.jpg
weather storm chaser convergence nccorig_00010423.jpg
Now playing
06:39
Traffic puts tornado chasers' lives in danger
(CNN) —  

Alabama, Florida and Mississippi are preparing for states of emergency as Subtropical Storm Alberto heads toward the Gulf of Mexico.

Florida Gov. Rick Scott issued the declaration for all 67 counties in his state. Mississippi Gov. Phil Bryant authorized the use of the National Guard, his office said in a statement.

Alabama Gov. Kay Ivey issued a state of emergency for 40 counties that will go into effect at 6 a.m. Sunday, according to a statement from her office. Ivey activated the state’s Emergency Operations Center in Clanton, the statement said. The Alabama National Guard also activated its High Water Evacuation Teams.

The first named storm of this season, Alberto is expected to strengthen as it moves up the Gulf this weekend, the National Hurricane Center said, bringing heavy rains and possible floods to Florida and much of the Southeast in the coming days.

“Do not think that only areas in the cone will be impacted – everyone in our state must be prepared,” Scott said in a statement.

Click here to track the storm

Cuba is expected to get as much as 15 inches of rain, the hurricane center said in an advisory Saturday morning, and the Florida Keys and South Florida could get as much as 10 inches.

“Swells from Alberto will create dangerous surf and rip currents along the Gulf Coast,” the National Weather Service said.

The center of the storm is expected to be move close to the western tip of Cuba on Saturday afternoon, then track up the eastern Gulf of Mexico in the night through Monday.

The city of New Orleans urged residents and businesses to “get prepared and stay informed” about the storm. The main threat is from heavy rain that could lead to flooding, the city said, but also high winds and storm surge could cause problems.

“I strongly encourage everyone to be safe and stay informed,” Mayor LaToya Cantrell said in a statement.

Hurricane season doesn’t officially begin until June 1, but Alberto apparently missed the memo. The tropical system became a subtropical storm Friday, the hurricane center said. As it travels up the warm waters of the Gulf, it could well become a full tropical storm.

As of 11 a.m. ET Saturday, parts of Cuba and the Florida Keys were under a tropical storm warning, and a tropical storm watch is in effect for parts of Florida, Georgia and Louisiana, meaning the conditions for a full storm are possible in the next 48 hours.

The early storm doesn’t necessarily mean it will be a busier-than-usual hurricane season though. The official National Hurricane Center forecast released Thursday said the season is likely to be near or above normal.

CNN’s Brandon Miller, Amir Vera and AnneClaire Stapleton contributed to this report.