Tropical Storm Idalia has gained strength and should become a hurricane “at any time,” the National Hurricane Center said in its 11 p.m. update Monday night. Forecasters predict the system will be a major hurricane before it reaches Florida’s Gulf Coast on Wednesday.
Much of the west coast of Florida, including the Tampa Bay area, is under a hurricane warning. The Tampa Bay area is also under a storm surge warning. Forecasters said the risk continues for life-threatening storm surge and dangerous hurricane-force winds along portions of Florida’s west coast and the Panhandle.
A hurricane warning means that hurricane conditions are expected somewhere within the warning areas in the next 12 to 24 hours. A storm surge warning means there is a possibility of life-threatening inundation from rising water moving inland from the coastline.
“This is the most dire warning we can issue in terms of water threats from a tropical storm or hurricane,” said Michael Brennan, the National Hurricane Center director in an 11:30 a.m. live update.
The Tampa Bay area is likely to begin seeing tropical storm-force winds on Tuesday.
The hurricane center’s updated forecast cone on Monday showed Idalia already reaching major hurricane status by the time it nears the Tampa Bay area. Based on the current track, forecasters anticipated the storm could bring 4 to 7 feet of dangerous storm surge to the region.
Most of the Tampa Bay area sits just outside Idalia’s forecast cone. Forecasters warn storm impacts can reach outside the cone.
“It cannot be emphasized enough that only a small deviation in the track could cause a significant change in Idalia’s landfall location in Florida due to the paralleling track to the west coast of the state,” the hurricane center said.
Possible impacts for Tampa Bay
Conditions are expected to deteriorate in the Tampa Bay area on Tuesday. Forecasters expect the area will see winds of at least tropical storm strength by Tuesday evening.
Much of the Tampa Bay area could see between 6 and 10 inches of rain, according to the hurricane center.
Forecasters said a few tornadoes will be possible on Tuesday along the west central Florida coast and the tornado threat will continue north into the Big Bend area by Tuesday night.
Forecasters warned a combination of dangerous storm surge and the tide will cause normally dry areas near the coast to flood from rising waters.
The next full moon will arrive on Wednesday, bringing with it the highest tides of the month. That could have big implications for flooding levels in the Tampa Bay area, according to Jeff Masters, a hurricane scientist formerly with the National Oceanic and Atmospheric Administration.
The hour that now-Tropical Storm Idalia delivers its peak storm surge to the Tampa Bay area is a key detail for just how severe the flooding will be, Masters said.
For instance: The difference between high and low tide in St. Petersburg is roughly 3 feet, 2½ inches. Right now, the hurricane center is predicting more than 4 feet of surge for the area.
”If peak surge happens to come in at low tide, and you get a 4-foot surge, maybe it’s only going to be a foot above normal,” Masters said. “But if it comes in at a high tide, 4-foot surge now is going to be record-setting.”
The peak high tide is expected to arrive in St. Petersburg just before 2 p.m. Wednesday. So timing is everything, Masters said.
Regardless if the storm were to make landfall directly in the Tampa Bay area, it still poses a risk to residents with dangerous storm surge and heavy rainfall, according to Ali Davis, a meteorologist with the National Weather Service’s Tampa Bay office in Ruskin.
Having a storm surge coincide with the high tide is going to lead to a higher surge value. Meteorologists are already baking those high-tide values into their forecasts, so when you see a surge prediction like “4 to 7 feet,” the public should know that it already includes tide levels, Davis said.
”It’s kind of unfortunate timing right now,” Davis said in a phone interview Monday, referring to the full moon and higher-than-normal tides. ”People need to stay alert listen and listen to any evacuation orders that come from their local officials. People still need to pay attention, even if this is making landfall north.”
Where is Tropical Storm Idalia?
The hurricane center said in its 11 p.m. update that Idalia was moving north at nearly 8 mph and was about 10 miles northwest of the western tip of Cuba. The tropical storm is likely to continue north over the southeastern Gulf of Mexico by early Tuesday, forecasters said. Idalia is likely to pick up speed and turn north-northeast over the southeastern Gulf of Mexico by early Tuesday and reach the Gulf coast on Wednesday.
“Idalia could become a hurricane at any time, and is forecast to become a major hurricane by late Tuesday or Tuesday night,” the forecast stated.
Idalia’s maximum sustained winds increased to 70 mph Monday. Tropical force winds extend outward about 150 miles from the center, according to the 11 p.m. update.
Rapid intensification is expected before Idalia makes landfall on Florida’s west coast. Forecasters are now calling for Idalia to strengthen into a hurricane at any time and to become a major hurricane by late Tuesday.
“Unfortunately, we are expecting Idalia to rapidly strengthen and become a hurricane ... and then intensify to a major hurricane before it makes landfall,” Brennan said.
Rapid intensification, when a storm’s top wind speeds rise by at least 35 mph in a day, is difficult to predict. When it occurs, it leaves coastal areas with little time to prepare.
Forecasters said Monday night it is increasingly likely portions of Florida will see “life-threatening storm surge and dangerous winds.”
“Interests along the southeastern U.S. coast should monitor the progress of this system. Additional watches and warnings along the southeast United States coast will likely be required on Tuesday,” the 8 p.m. update said.
A list of watches and warnings
A storm surge warning is in effect for Englewood northward to Indian Pass, including Tampa Bay.
A hurricane warning is in effect for the Cuban province of Pinar del Rio; and the middle of Longboat Key northward to Indian Pass, including Tampa Bay.
A tropical storm warning is in effect for the Yucatan Peninsula from Tulum to Rio Lagartos, including Cozumel; Isle of Youth Cuba; Dry Tortugas Florida; Chokoloskee northward to the middle of Longboat Key; and west of Indian Pass to Mexico Beach.
A storm surge watch is in effect for Chokoloskee northward to Englewood, including Charlotte Harbour; and the mouth of the St. Mary’s River to South Santee River, South Carolina.
A hurricane watch is in effect for Englewood to the middle of Longboat Key.
A tropical storm watch is in effect for Lower Florida Keys west of the west end of the Seven Mile Bridge; and Sebastian Inlet, Florida, northward to South Santee River, South Carolina.
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