Florence (2012)

A tropical wave that left the west coast of Africa on 2 August 2012 developed into a well-defined low on 3 August and became a tropical depression around 1800 UTC about 130 nautical miles south-southwest of the southern Cape Verde Islands. It strengthened to Tropical Storm Florence by 0600 UTC 4 August and moved generally west-northwest and then west as a subtropical ridge built north of the storm. Convection and organization peaked early on 5 August, then dry air and moderate easterly wind shear caused steady weakening; Florence became a tropical depression by 0600 UTC 6 August, degenerated to a remnant low that day, and the remnant trough dissipated by 10 August north of the Dominican Republic.

Florence did not make any landfalls. The system remained over the eastern Atlantic throughout its life and dissipated well east of the northern Leeward Islands, so there were no coastal impacts associated with a landfall.

The storm’s maximum intensity was 50 knots (about 58 mph) with a minimum central pressure of 1002 mb, reached around 0000–0600 UTC on 5 August. At its peak Florence was a moderate tropical storm (below hurricane strength).

Because Florence stayed over open water, there were no measured storm surge reports tied to the cyclone and no significant onshore rainfall impacts recorded in the NHC findings. Satellite and scatterometer data were used to monitor the system, but no ships reported tropical-storm-force winds in the vicinity.

There were no reported deaths, injuries, or damage associated with Florence. The storm’s primary impacts were limited to the marine environment and to satellite-observed changes in the storm’s structure as Saharan dry air wrapped into and eventually disrupted its circulation.

Noteworthy details include that the storm’s genesis was not well predicted—forecasters first gave the wave a low (<30%) chance of development only about 12 hours before formation—and dry air from the Saharan Air Layer played a key role in halting intensification. Official track forecasts performed better than recent averages for this storm, and intensity forecasts were comparable to guidance, with no watches or warnings required.