Idalia to flood parts of Florida Keys coast. Will schools, offices or parks close?

Tropical Storm Idalia could bring tropical storm-force winds, storm surge and coastal flooding to parts of the Florida Keys, the National Hurricane Center said.

A tropical storm warning was issued at 11 p.m. Sunday for the western Straits of Florida and the southeastern Gulf of Mexico. The alert also covers the Dry Tortugas, a remote island 70 miles west of Key West and home to Dry Tortugas National Park.

A tropical storm warning means that tropical storm conditions are expected somewhere within the warning area within 36 hours or less.

READ MORE: How will Tropical Storm Idalia affect South Florida weather? What the forecast says

Other parts of the Lower Keys are under a tropical storm watch. The designations remained in effect as of Monday night.

A storm surge — an abnormal rise of water generated by a storm over and above the predicted astronomical tides — of one to two feet is expected through the Lower and Middle Keys.

Meanwhile, the National Weather Service in Key West on Monday night issued a coastal flood warning for the Lower Keys as 2 to 2.5 feet above mean high tide is expected in the area.

“Roads may be impassable, low-lying properties may be inundated,” the weather service said.

A coastal flood advisory was issued for the Middle Keys and a flood statement for the Upper Keys. In the Middle Keys, the weather service expects saltwater flooding on low elevation streets, some overflown drains and several overtopped docks and seawalls.

Are Florida Keys schools open? The airport?

As of Monday night, Keys public schools and Monroe County’s and other municipalities’ government offices were expected to stay open as the storm passes by the island chain Tuesday and Wednesday.

“Normal operations, with obviously, heightened precautions,” Monroe County Administrator Roman Gastesi told other government officials during an Emergency Management conference call Monday evening.

This also includes all services such as Key West International Airport and garbage pickup, county officials said during the call.

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Which parks are closed?

Two state parks — Bahia Honda State Park and Fort Zachary Taylor Historic State Park — will be closed Tuesday, said Monroe County Emergency Management Director Shannon Weiner.

Dry Tortugas National Park will also be closed, Park Service officials said in a statement Monday afternoon.

“All closures will remain in place until the severe weather has passed and the National Park Service determines that employee and visitor facilities are safe,” the statement reads.. “If the storm track changes, the park may issue a new advisory with updated status, including any lifting of closures.”

Florida Keys forecast

Jonathan Rizzo, warning coordination meteorologist with National Weather Service in Key West, said the concern for the Keys is that the storm is coinciding with annual “king tides,” or higher-than-average tides that affect the island chain this time of year.

As the storm passes by the Lower Keys, Rizzo said some areas could expect to see tides two feet above normal, causing at least heavy street flooding in some spots, especially in Key West.

“This is not going to be insignificant,” Rizzo said.

These higher tides could be an issue as far east as Long Key, he said.

The stormy weather is expected to make its presence known in the Keys sometime Tuesday morning and last until Wednesday as the intensifying storm makes its way north, said Rizzo, adding that Idalia is anticipated to be a very powerful storm by the time it makes landfall in the Big Bend area of northern Florida.

“This is a candidate for rapid intensification,” he said.

The good news for people living in areas of Key Largo — who get the worst of king tide flooding from Florida Bay in late summer and early fall — is that the winds from Idalia are coming from the south, leaving little opportunity for the system to back up water into the bay.

Tuesday will be a windy day in the Keys, with sustained winds between 20 and 25 mph, with stronger gusts, possibly even as high as 60 mph, Rizzo said. But, he said such conditions are not unusual during typical thunderstorms that pop up in summer afternoons in South Florida.

“Before anyone gets too alarmed by that, we call those severe thunderstorms,” Rizzo said.