Jeff Berardelli is WFLA’s Chief Meteorologist and Climate Specialist

TAMPA, Fla. (WFLA) — Parts of Tampa Bay were pounded with hail, lightning, wind and even a 90-mph tornado on Wednesday night. While it’s not unheard of in June, it’s certainly not typical. So what happened?

At 7 p.m. on Wednesday, a tornado hit Pinellas Park and Largo, causing extensive damage. That damage was surveyed by Tampa Bay’s National Weather Service and was found to be an EF-1 with 90 mph winds and was on the ground for 2 miles from Pinellas Park to Largo.

For everyone else nearby who did not experience the tornado, many did get pelted by hail. The largest reported was the size of quarters. It was widespread and that’s rare for summer.

The reason behind the hail is a large upper level low — or cold pool of air aloft — which is still moving across the state now. The upper level low broke off from the jet stream and drifted southward from the North Atlantic, carrying with it the colder air in the clouds.

When the colder air at cloud level is mixed with very hot-humid air at the surface, that large contrast often leads to explosive develop in thunderstorms. Add to it a collision of Tampa Bay breezes, sea breezes and outflow from thunderstorms, and you have the perfect ingredients for fast vertical motion.

And it’s that fast vertical motion — called updrafts and downdrafts — that helps hail grow. Here’s how it works. Inside most thunderstorms here is a freezing layer — a layer at which the air drops below freezing above it. When water droplets are carried upward above the freezing line, they can freeze into hail stones.

In smaller thunderstorms, these hail stones may immediately fall toward the ground and melt before reaching the surface. But on days like Wednesday where the updrafts are strong enough, the hail can be suspended and lofted up and down through the cloud many times, adding a layer of ice each trip up, and getting larger and larger.

If you were to cut open a large hail stone, you may see layers that look like tree rings or the inside of an onion. When the hail stones become too large for the updrafts to hold them up in the cloud, they will fall to the ground.

So, on Wednesday, the Tampa Bay area had the perfect combination of cold air aloft and also very strong vertical motion in thunderstorms. The good news is the pattern will be returning to normal again as we head into the weekend.