A small tornado rapidly developed near the intersection of two - and perhaps three - low level boundaries at around 605 PM EDT July 20th, 2005. The primary boundary was an outflow from an intense cell developing near Seminole, moving northwest. The collision point appeared to be the nearly stationary gulf coast sea breeze, which was located a few miles inland (note the broken green line in western Pinellas County). A third boundary may have also existed, traveling northeast from a weakening storm west of the southern Pinellas coastline.

The tornado, which touched down along Ulmerton Road just east of Seminole Boulevard, moved northwest for about 1/2 mile (Figure 2), caused damage at five mobile home parks. Much of the damage occurred at the Palm Hill Country Club mobile home park. Click here for more details.

Figure 1. Base reflectivity, 609 PM EDT. Note the arcing outflow boundary from the stronger storm over Seminole and St. Petersburg.

Since the storm affected a heavily populated area during the evening commute, there were a number of eyewitnesses. One provided a very descriptive account of this unique event. This eyewitness noted a funnel shaped debris swirl which grew to a little more than two stories in height. As it crossed over Ulmerton from south to north, the swirl was rather small, but became wider and taller on the north side of the road. At that point, larger debris (such as wood pieces and shingles) turned the mass a brownish color; soon after, the swirl struck a transformer or small substation, which sparked.

In addition, the resident had driven out of heavy rain from the east into no precipitation when the tornado occurred. The sky toward the Gulf was bright. Given that the twister developed at the leading edge of the strongest storm, it is possible that the event may have been a gustnado.

Figure 2. Track of Largo tornado (red curve) as overlay on map of west central Pinellas County. Click on image for a zoomed view.

After Hurricane Dennis disrupted the flow pattern, a more typical early summer pattern developed across west central and southwest Florida around July 10th. The general east to southeast flow produced its share of strong to severe thunderstorms, producing not only the above tornado and land/waterspout near Punta Gorda, but a few other notable events. An apparent downburst took down several small trees and blew loose objects around in the Keystone community northwest of Tampa on July 12th. Another downburst uprooted a mangrove and knocked down a large entry sign in a Clearwater community on Old Tampa Bay (right). In each case, the wind gusts appear to have been near or a little below severe limits (58 mph).