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Extreme Cold Front Packs 100 mph Winds

Posted on Monday, January 24, 2011 at 5:00 PM MST

ST. PETE BEACH, FL -- One of the best setups I've seen in years brought an historic severe weather outbreak to the Florida Peninsula on Tuesday, with stories making national headlines. St. Petersburg was ground zero for the most extreme winds, as estimated sustained winds of 90 mph collapsed a gas station canopy trapping a woman in her car and tore roofs off of nearby buildings.

Go back a couple days to Sunday. The Storm Prediction Center issued its first outlook for a possible outbreak, as the severe weather potential on the Day 3 outlook was upgraded to 5% for Florida, southeast Georgia, and coastal South Carolina. On Monday morning, the Day 2 Outlook had been upgraded to slight risk for the Florida Peninsula. The National Weather Service Tampa Bay office issued a Special Weather Statement warning of a possible severe weather outbreak across West-Central Florida on Tuesday, as the environment was forecast to be supportive of discrete supercells, strong tornadoes, and damaging winds ahead of the front.

Waking up Tuesday morning, the anticipation was just through the roof. The SPC morning outlook was still at slight risk for the Florida peninsula. The tornado probability had been upgraded to 5% and damaging wind probability had been upgraded to 15%. The forecast had shifted slightly to be more linear (aka a squall line) with embedded supercells and tornadoes, but still had the Tampa Bay Area as ground zero. Just as predicted, a warm front lifted through the Florida peninsula, pushing temperatures upwards of 80 degrees and dewpoints close to 70.

By noon, a corridor of strong 0-6 km shear (from the west at 50-55 kts) had set up between Tarpon Springs and Sarasota, extending about 100 miles east and west. With the northeast storm motion along the squall line, I knew that every cell would start rotating as soon as it hit the shear. The midday SPC outlook came out around 12:30, and had upgraded the damaging wind probability to 30% along the Interstate 4 corridor, extending about 70 miles north and south. Pinellas County was smack in the middle of it. My target was set then: St. Pete Beach.

Shortly after 1 PM, the SPC issued a mesoscale discussion for the Florida peninsula, stating the setup was becoming more and more favorable for a severe weather outbreak and a watch would likely be issued soon. Less than an hour later, a Tornado Watch was issued for the Florida peninsula north of Lake Okeechobee and the adjacent coastal waters. As the leading edge of the storm began to get into the strong shear about 75 miles west of Pinellas County, they bowed out and exploded. Everything was in place perfectly, so I sat down and began the tantalizing wait for the storms to arrive.

I left for the beach shortly after 3:30 PM. While I was enroute, the first Tornado Warnings of the day were issued for Pasco and Hernando counties. My first stop was at St. Pete Beach near 44th Ave. There wasn't much to see, so I headed south to Pass-a-Grille to get things set up.

I was parked and set up at Pass-a-Grille shortly before 4:30 PM. With strong southerly winds, it was warm and damp, with very ominous skies over the Gulf of Mexico. By 4:45, lightning was bristling the sky and it had started to spit rain. Just before 5, after a couple pretty close lightning strikes, I could see the line of heavy rain approaching, so I ran back to the cover of the car.

At 5:00, a Severe Weather Statement was issued for Clearwater Beach for extreme wind, quarter-sized hail, and constant cloud-to-ground lightning. A Severe Thunderstorm Warning was issued for southern Pinellas County a few minutes later. I moved about 150 yards south to get a clearer view of the storm, battened down the hatches, and got ready for intercept. The first line of heavy rain started impacting Pass-a-Grille just before 5:10 PM.

After about a minute of watching the deluge hitting the windshield, I noticed the car all of a sudden started to rock quite violently. I opened a leeward window, to find that winds had easily accelerated to 80 mph, with some gusts estimated to be as high as 100 to 110 mph. I cracked open the window, grabbed the camera and started filming. While I was filming, a Tornado Warning was issued for St. Petersburg for a radar-detected tornado near 54th Ave N. I thought about going after it, but realized there was no way I could catch it so I resumed filming.

The squall line had passed within 15 minutes. At 5:30 PM, a second Tornado Warning was issued for another radar-detected tornado near MacDill Air Force Base. It was real sketchy leaving Pass-a-Grille, as the only road on and off the island was under almost a foot of water. By the time I made it up to Pinellas Bayway, another Tornado Warning was issued for southwest Hillsborough County for a waterspout that was sighted near Riverview.

I headed to downtown St. Petersburg to see if I could catch back up with the storm, but it was to no avail. The severe weather notifications on my phone were beeping nonstop with Tornado Warnings being issued. After discovering many roads downtown were flooded and impassable, I decided to head home to follow the rest of the storm.

By the time it was all said and done, 14 Tornado Warnings were issued in the Tampa Bay area between 5 and 7 PM. 5 Tornadoes were reported by spotters and storm survey crews on the Florida peninsula. The heaviest straight-line wind damage was in St. Petersburg, where the canopy of a gas station collapsed, trapping a woman in her car, and also ripped roofs off of buildings. Sustained winds in St. Petersburg were estimated to be 90 mph. Tornado damage was reported in Lake County (northwest of Orlando), mainly with roofs being torn off of homes.


Posted In: Chase Recaps

Tagged: Cold Front, Squall Line, Straight Line Winds, Tornado, Memorable