Beaches in Florida were largely empty ahead of Memorial Day as a slowly intensifying storm carrying brisk winds and heavy rain approached the U.S. Gulf Coast on Sunday. The storm disrupted plans from Pensacola in the Panhandle to Miami Beach on Florida’s southeastern edge.

Lifeguards posted red flags along the white sands of Pensacola Beach, where swimming and wading are banned due to high surf and dangerous conditions.

Subtropical Storm Alberto – the first named storm of the 2018 hurricane season – prompted Florida, Alabama and Mississippi to launch emergency preparations Saturday. Rough conditions were expected to roil the seas off the eastern and northern Gulf Coast region through Tuesday.

“These swells are likely to cause life-threatening surf and rip-current conditions,” the National Hurricane Center in Miami said in a statement. The governors of Florida, Alabama and Mississippi all declared states of emergency ahead of the storm.

The hurricane center said Sunday a tropical-storm warning was in effect from Bonita Beach, Florida, to the Mississippi-Alabama border.

On Sunday, gusty showers began lashing parts of Florida, and authorities were warning of the possibility of flash flooding.

The National Weather Service said Sunday tropical-storm warnings cover the entire Florida Gulf Coast and inland portions of the Florida Panhandle, as well as parts of coastal Alabama. Isolated tornadoes were possible across the region on Sunday and Monday. Alberto is expected to strengthen until it reaches the northern Gulf Coast, likely on Monday night.

The NWS said waves as high as 18 feet could pound the popular Gulf beaches in Baldwin County, Alabama, and northwestern Florida on Monday. A high-surf warning was in effect through 7 p.m. Tuesday local time.

A tropical storm warning remained in effect for Cuba’s western Pinar del Rio province, where heavy rains could trigger flash floods and mudslides, the NHC said.

Mexico canceled its watch for the resort-dotted coast of the Yucatan peninsula, where the storm brought heavy rain. There were no immediate reports of emergencies. In Cancun, local newspapers showed scenes of some streets flooded to mid-hubcap level.

The downpours could dampen Memorial Day, the unofficial start of the summer tourist season along Gulf beaches. Along with heavy rains and high winds come rough seas and a threat of rip currents from Florida to Louisiana that can sweep swimmers out to sea.

The remains of Alberto will move into the listening area starting this evening and tomorrow (Tuesday, May 29, 2018). The National Weather Service has issued a flash-flood watch for the entire listening area starting at 7 a.m. Central, Tuesday, May 29 and expiring at 7 a.m. Central, Wednesday, May 30, 2018.