Fog that closed Sunshine Skyway bridge could be back Wednesday morning

It was like hitting triple sevens on a slot machine.

Conditions lined up perfectly Tuesday morning to create soupy sea fog that forced the Florida Highway Patrol to close the Sunshine Skyway bridge — for about seven hours.

Wednesday morning: Thick fog returns to Tampa Bay, but Sunshine Skyway Bridge remains open to traffic

The blanket of moisture was so thick that troopers reported visibility of less than 100 feet at the mouth of Tampa Bay. It lingered so long that the landmark bridge remained closed for half the day, snarling traffic all morning as commuters sought alternate routes.

First, there was the dew point, about 70 degrees, said Ashley Batey, a meteorologist at 10Weather WTSP. Then there was the water temperature, about 72 degrees. Together, they created that steam room atmosphere.

Add in a slightly warmer air temperature, about 75 or 76 degrees, and you had the "perfect breeding ground for fog."

"You need the right combination of warm air moving over cooler water" to make sea fog, Batey said. And without a stiff wind to blow it away, a fog bank will hang around.

Tuesday morning, according to Batey, the breeze only blew about 5 to 7 mph.

The long closure was unusual for the Skyway, which the Florida Department of Transportation says gets about 54,000 vehicles a day. FHP Sgt. Steve Gaskins said the bridge is shut down between eight and 12 times in an average year, usually for an hour or two due to high winds.

"It's rare that No. 1, fog causes it, and No. 2, for that length of time," Gaskins said. "But it's Mother Nature doing her thing."

Tampa Bay may strike the fog jackpot again today.

The humid air was expected to remain in the area overnight, putting more thick sea fog on the radar — literally — this morning.

"Tomorrow morning I'd be very cautious about that being a possibility," Batey said.

The National Weather Service agreed.

"We'll probably be looking at it again late tonight and tomorrow morning," said National Weather Service meteorologist John McMichael.

Gaskins urged people to check the weather and the status of the bridge before leaving their houses this morning. Even if the Skyway is open, the fog could cause poor driving conditions.

"If you know the fog's coming," he said, "plan in advance."

If you see thick fog in the morning, snap a picture and tweet it @TB_Times or post it on the Times' Facebook page.

Contact Zachary T. Sampson at zsampson@tampabay.com at (727) 893-8804. Follow @ZackSampson.