The pattern that brought all this heat helps spare Tampa Bay from Hurricane Michael strike

You know those dreadfully hot days that most of us have been complaining about of late? Those days when we looked at the calendar and wondered why we were still sweating in T-shirts and shorts a couple of weeks into fall instead of breaking out the long sleeves?

Turns out the same conditions that have been churning out all this heat are the same ones that may have helped Tampa Bay avoid a catastrophic hurricane strike.

Hurricane Michael, which passed through the Gulf of Mexico and barreled toward the Florida Panhandle with Category 4 force, was kept in place by a leftover summertime weather pattern that has been plaguing southeast Florida with hot days, according to forecasters with the National Weather Center.

It's a pretty typical summertime pattern, an area of high pressure that generally settles over the southeastern portion of Florida for the duration of season. This year, the high pressure has been especially persistent, resulting in one of the hottest Septembers on record.

That thick air pressure acted as a shield, keeping the fast moving hurricane at a distance.

Normally, the high pressure, also called a ridge, will begin to dissipate over the first few months of fall and be overtaken by cold fronts. But this year, that isn't expected to happen until the middle or end of October.

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"[The high pressure's] been a pretty prominent feature during the summer months," said Tony Hurt, a meteorologist with the Weather Service. "It's pretty typical to last along the summertime but be weaker or stronger at certain points. We're in the fall now, but it's still there. At some point during the fall, it will weaken.

"The [pressure] itself prevented the storm from moving east and helped keep it in the Gulf of Mexico. A storm can't really move through an area of high pressure, so it has to go around it."

That is unless a cold front — or trough in meteorologist speak — were to shove the storm to the east while it was still south of the Florida Panhandle, placing Tampa Bay in its cross-hairs.

Over the past week, one such cold front had been moving from the Midwest toward the Southeast. But Hurricane Michael was moving fast enough that the front couldn't push it until after it closed in on the Panama City area on Wednesday afternoon.

"That trough's been pushing to the east across the United States and it will push the storm later (Wednesday)," Hurt said. "The cool air associated with it is what defines a cold front. It will move across some of the Southeast, but as to if it would reach this far down south, that isn't too likely."

Tampa Bay will have to wait a bit longer for cooler weather. Even after the cold front arrives — and sweeps Michael away — it will produce drier conditions but not the cooler weather that would generally signal fall.

That helps explain why Tampa Bay was buffered from Michael's devastation. The reason why it got so powerful — and so fast — is a bit more of a mystery.

On Monday, Michael was still categorized as a tropical storm located at the southern tip of Cuba. But it only took two days for it to intensify and become the first Category 4 storm to hit the Florida Panhandle since hurricane strength started to be recorded in 1851. For many, it felt like a switch had been turned on as the storm intensified just before making landfall.

"Rapid intensification of hurricanes is still a challenge for forecasters," said Dan Noah, a meteorologist with the National Weather Service. "That is where all the research has been going to over the last decade. Initially, when we thought it would just be a tropical storm, there was nothing in the models that would suggest the intensification. However that all changed on Monday."

Noah said a three-day storm outlook can be pretty accurate and that the National Hurricane Center predicted Michael would reach Category 3 and 4 strength on Wednesday. But any further out than three days is subject to a lot of change.

"The models do much better for the first three days than they do after that," Noah said. "Especially with intensification. When you begin to make a prediction, a small error at the beginning makes for a much larger error further down."

Contact Devin Rodriguez at drodriguez@tampabay.com or follow @devinreports on Twitter.

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