One forecaster nicknamed this storm "the Joker" — a swirling mass of chaos that has confounded weather experts for the past week.
On Sunday, the Joker may have showed its hand: Tropical Storm Fay strengthened and appeared headed into the Gulf of Mexico. A storm in the gulf can be as unpredictable as a pinball, until it smashes into one unlucky place. That's why this storm demands attention, even though it's too early to say for sure if it will rip into Tampa Bay.
"This is the biggest threat since Charley," said Jeff Masters, founder of the blogweatherunderground.com, referring to the 2004 storm that veered away from Tampa Bay and smashed into Charlotte County.
According to the forecasts, Fay could turn into a hurricane, smash into Tampa Bay, flood coastal areas and tear into buildings — a worst-case scenario for local residents, many of whom were not aware of the threat until late in the weekend. Or it could stay a tropical storm and veer away — the best-case scenario.
Here is a look at the best and worst cases for the Tampa Bay area.
HITTING SOUTH OF TAMPA BAY: With apologies to our friends to the south, this is the best case scenario for the Tampa Bay area.
A hurricane's counterclockwise winds push strongest as they sweep over water just south of the storm, pushing fiercely to the east. This means that if Fay smashes into Florida's west coast, neighborhoods north of the eye are likely to suffer less damage than neighborhoods to the south. If the hurricane stays far enough south of Tampa Bay, residents here might barely notice it.
HITTING TAMPA BAY: This possibility breaks into two scenarios: bad or awful.
"Just to the north of you, that's probably the worst," said Richard Pasch, senior hurricane specialist with the National Hurricane Center.
He's talking about what would happen if Fay smashed into a point north of St. Petersburg, someplace near Indian Rocks beach, with wide powerful bands that shoved waves up into Tampa Bay, creating coastal flooding. This is the awful scenario.
Masters, the forecaster who started calling Fay "the Joker," said he doesn't think Fay will become powerful enough to create the devastating 20-foot storm surge that Tampa Bay emergency planners have fretted about for years. But flooding would be very disruptive for coastal residents.
Also, because the bay area has not been directly hit by a hurricane in decades, Masters theorized that many structures might not be built to withstand damage from a Category 1 hurricane, with winds of 74-95 mph.
The Tampa Bay area could still have a bad day even if Fay strikes somewhere besides the exact worst spot. The sheer force of the winds can uproot trees and tear off roofs. Fay is a wide storm, meaning large portions of Tampa Bay could experience heavy rainfall and possibly local flooding.
In either case, electric outages are likely. Which is one reason that by now, all residents should have three days' food, water and medicine, plus a portable radio with extra batteries.
BRUSHING PAST TAMPA BAY: Even if the eye of the storm never touches the counties that make up Tampa Bay, they could still suffer some flood and wind damage, because the storm's rotating bands can whip up trouble many miles away. So even if Fay merely grazes the coast, it could still be a problem. Most models expect the storm to veer east eventually into the coast.
If Fay goes far enough north, its effect on Tampa Bay will be just as minimal as if it goes to the south. But any scenario that saves this area could spell trouble somewhere else.
Masters said if Fay does cruise north, parallel to the coast, there's a chance it could shove waves up over the Continental Shelf and onto the shores of the Big Bend area of Florida, causing serious flooding.
Times staff writer Stephanie Garry contributed to this report.