Florida braces for flooding and possible tornadoes after Tropical Storm Eta makes landfall in the Keys

 (CNN) -- The Florida coast is bracing for Tropical Storm Eta after it pummeled the Florida Keys with life-threatening storm surge and flooding.

The storm made landfall in Lower Metacumbe Key late Sunday night with maximum sustained winds of 65 mph, according to the National Hurricane Center. Eta is expected to strengthen into a hurricane by late Monday into early Tuesday as it moves into Florida Bay.

More than 23 million people in south Florida are under some type of hurricane or tropical storm advisory, with 21 counties under a state of emergency. As of early Monday morning, more than 30,000 customers are without power as the storm continues north, according to Poweroutage.us.

Ahead of the storm, many schools in south Florida were closed Monday and bridges were locked down in anticipation of high winds. Hurricane force wind gusts could remain through Monday afternoon, according to a Hurricane Warning issued by the National Weather Service.

Heavy rain and winds will stretch from Miami to Naples through Tuesday, and a storm surge of up to four feet is possible for parts of south Florida and the Keys. Flooding is also expected along low-lying roads and properties across the region as heavy rains -- about three to five inches -- are forecast, with some areas seeing more than a foot throughout the duration of the storm this week.

Eta is expected to make landfall again just north of Tampa on Friday as a tropical storm.

Schools close and shelters open as state prepares for Eta

At least five school districts in south Florida, including Miami-Dade, will close on Monday due to Eta's potential impact, the districts announced on social media.

In Miami-Dade, all bridges were locked down Sunday, according to Mayor Carlos Gimenez. He said the area anticipated 40 to 60 mph winds beginning Sunday night through Monday afternoon, as well as the possibility of tornadoes.

Pet friendly shelters were also opened in Monroe County -- home to the Florida Keys -- ahead of the storm, according to a tweet from the county, with Covid-19 protective protocols being strictly enforced.

Collier County also suspended all Collier Area Transit (CAT) bus service Monday due to predicted high winds, the county said on twitter.

In Oakland Park, heavy rains and flooding has the city's public works system "at or near capacity" already, according to Oakland Park Public Information Officer David Rafter.

"Oakland Park Public Works and Parks personnel have been working throughout the night and all day addressing the flooding concerns to the best of our ability," Rafter said in an Tropical Storm Eta update.

Mariners are also being warned to stay off the water as extremely strong winds can cause hazardous waves that would "likely capsize or damage vessels," according to NWS.

Third landfall for Eta

Eta has already made landfall at least twice before, in Cuba on Sunday morning and as a Category 4 hurricane in Central America last week, which is still reeling from its aftermath.

Emergency disaster plans are in place in Cuba and Mexico, and relief efforts continue in Guatemala and Honduras, which have been the hardest hit so far.

In Honduras, 38 people have died, eight people remain missing and more than 60,000 have been evacuated from their homes, according to the country's Permanent Contingency Commission.

Guatemala's National Disaster Reduction Coordinator (CONRED) reported Saturday that 116 people remain missing, mostly due to the landslide in the remote village of Quejá, in the central Alta Verapaz region.

At least 8,938 people have been evacuated and 5,780 remain in temporary shelters, the agency said.

Eta is the 28th named storm of the 2020 hurricane season, tying the record for the number of named storms in a single season set back in 2005.

Although the season has been extremely active, Eta is the first named storm to make landfall this year in Florida and the 12th named storm to make landfall in the continental US this season, the most in one year.

The-CNN-Wire™ & © 2020 Cable News Network, Inc., a WarnerMedia Company. All rights reserved.