(CNN) – Tropical Storm Marco strengthened significantly on Saturday and could hit Louisiana as a hurricane by Monday, according to the latest National Hurricane Center forecast.
Marco, which could reach hurricane status as soon as Saturday night, is one of two tropical systems expected to impact the Gulf Coast in the coming days.
The storm marched past the Yucatan Peninsula earlier on Saturday and is moving north into the Gulf of Mexico, according to the hurricane center.
A hurricane watch has been issued from Intracoastal City, Louisiana, to the Mississippi-Alabama border, including Lake Pontchartrain and New Orleans.
Much of the Alabama coast is under a tropical storm watch.
Meanwhile, Tropical Storm Laura is moving away from western Puerto Rico and is expected to move over the island of Hispaniola Saturday night into Sunday, according to the hurricane center’s latest advisory.
A tropical storm watch has been issued for the Florida Keys from Ocean Reef to Key West and for the Dry Tortugas, as Laura is expected to pass just south of the Keys on Monday, forecasters said.
Laura is expected to strengthen to a hurricane in the warm waters of the Gulf of Mexico by Tuesday and make landfall in Louisiana on Wednesday.
The storm could become a Category 1 hurricane but that prediction might be conservative as the warm Gulf waters could allow for rapid strengthening of the storm, according to the weather service.
While it’s unclear how the storms will develop, forecasters say two potential hurricanes could make landfalls in Louisiana within a few days.
Authorities in Grand Isle, Louisiana, have called all campers, RVs and boaters to voluntarily evacuate due to the potential impact of the storms. A state National Guard unit was placing sand sacks along the town and officials were preparing generators and pumps, the Louisiana Coastal Protection and Restoration Authority tweeted.
The mayor of Jean Lafitte, Louisiana, and the president of Jefferson Parrish have issued voluntary evacuation orders for the towns of Jean Lafitte, Lower Lafitte, Crown Point and Barataria, according to a news release from Jefferson Parrish.
The order went into effect at 6 p.m. CST.
Residents are advised to bring all vehicles, boats and campers to higher ground.
“We want to make sure residents are safe as these storms approach so we are taking all the necessary precautions to be fully prepared,” said Jean Lafitte Mayor Tim Kerner in the release.
Mandatory evacuations have been issued in Plaquemines and Lafourche parishes starting Sunday evening.
Lafourche Parish has evacuation orders that begin at noon Sunday.
Louisiana Gov. John Bel Edwards requested a federal emergency declaration from the White House Saturday, according to a news release from his office.
At least 14 parishes have already issued emergency declarations, Edwards said.
“This is unlike anything we have seen, with two hurricanes expected to impact our state nearly back to back,” Edwards said in the release. “This may mean that people will have to shelter in place for more than 72 hours and that there may not be time to do things like restore lost power between the two storms.”
Having two systems so close to the US at the same time complicates things to say the least.
“It’s always tough to predict hurricanes, especially their intensity,” CNN meteorologist Dave Hennen says. “In this case, it’s tough to say at this point which storm will be the strongest. The storms could potentially interact with each other and that makes this forecast (or two) even more complicated.”