Thunderstorm Wind in Duval County, Florida

The Jacksonville Port Authority reported two large 125 foot tall container ship cranes collapsed at Blount Island Marine Terminal. Each container was 950 tons. A squall line was moving across the area when the collapsed occurred. The KJAX Doppler radar indicated 45 to 50 knot velocities at approximately 600 feet msl. Each crane cost $6 million.

A deepening upper level trough over the southeast region lifted a deep plume of tropical moisture over the forecast area. A strong low level 850 mb jet of 50-55 knots was in place. Backing winds advected instability inland from the Gulf of Mexico across north Florida which coincided with the passing of a second pre-frontal squall line as it tracked across north Florida and Southeast Georgia in the afternoon. Low level storm relative helicities increased to 200-350 M2/S2. Widespread severe storms developed across the forecast area during the afternoon.