Tallahassee white-out: Science, stats behind the strikes of the May 17 lightning storm

If you were looking west around sundown last Friday evening you could start to see an almost constant flickering in the sky.

As the sun set and it became darker the area moved close enough that you could tell that a massive lightning event was heading toward Tallahassee. The associated thunder started as faint continuous rumbling but became louder and louder as the storm bore down on us.

The area of storms that produced our lightning had formed over the Mobile, Ala., area earlier in the day. As the storm neared, numerous tornado watches and severe weather warnings were posted.

Between 8:30 and 9:30 p.m., some of the the strongest storm cells were centered over Gadsden County, about 15 miles northwest of downtown Tallahassee. Tops of the storms reached about 55,000 feet above ground, and the full majesty of the lightning revealed itself with in-cloud (IC) and cloud to ground (CG) lightning flashes. Even before the rain began in Tallahassee, a total of 1,494 lightning flashes were recorded, corresponding to a flash rate of 25 flashes per minute or about one flash every 2 seconds — almost continuous lightning.

Of this total, 854 struck something on the surface.

The storms continued to move east and were over the city between about 10 p.m. and 10:30 p.m. A careful look at the location dots shows that there are fewer of them over the city than farther east. The flash rate re-intensified and the dots again become closer together as the storm moved out of the city. Also, a new storm formed southwest of Tallahassee near Woodville.

Although the flash rate briefly decreased while the storm was over Tallahassee, the rainfall still was intense. My electronic rain gauge showed a peak rain rate of 15.03 inches per hour. It was really raining “cats and dogs” at my house (but Kerry my weather dog stayed firmly on the ground).

Thankfully this extreme rain rate lasted only about a minute, but I still ended up with a total of 2.35 inches — an impressive total for about a 30 minute period. If the peak rate had continued for a full hour, the 15 inches would have led to major flooding

Last Friday’s lightning spectacular left me in awe. I don’t recall seeing anything like it in all of my 76 years. Between 8 p.m. and 11 p.m. the storm produced 8,751 total flashes.

It was an event that I will long remember. I thought it rivaled the light shows at Disney World!

Henry Fuelberg is a Professor of Meteorology at Florida State University. He was assisted in this article by Randy Gaynor, a Meteorology Graduate Student at FSU.

This article originally appeared on Tallahassee Democrat: Tallahassee lightning storm: The stats behind the strikes