Damaging Winds ahead of Severe Thunderstorm Outflow Boundary on Monday July 25th, 2011

by Angela Enyedi

A classic Gulf of Mexico sea breeze front advanced very quickly northeast across northeast Florida Monday afternoon July 25th. The evolution of this system can be seen in Figure 1.

The outflow boundary ahead of these strong thunderstorms began to race ahead of the main line. The Jacksonville radar imagery began to show wind speeds as high as 55 knots (63mph) just above the surface that were producing isolated reports of damage (trees and powerlines down) as it tracked through Clay/Braford counties and into Duval/St Johns counties (Figure 2). The outflow boundary eventually went on to merge with the east coast sea breeze front that was sitting right along the Atlantic coast and more severe thunderstorms exploded from St. Augustine southward to Palm Coast, with more isolated reports of tree damage and small hail.

The storms finally weakened as they pushed into the Atlantic coastal waters during the late afternoon hours.

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