A low pressure system in the eastern Gulf of Mexico assisted in the formation of three separate squall lines, which moved east through the Florida Keys and surrounding coastal waters from the evening of October 18th through morning of October 19th.  Widespread gale-force wind gusts and street flooding occurred across the Lower and Middle Florida Keys, along with a damaging waterspout across the Anchorage at Key West Harbor.

Marine Thunderstorm Wind in HAWK CHANNEL FROM WEST END OF SEVEN MILE BRIDGE TO HALFMOON SHOAL OUT TO THE REEF, GULF OF MEXICO
From 18-OCT-11 17:05:00 to 18-OCT-11 17:05:00 (EST-5)
Location: KEY WEST
Magnitude: 35.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

A wind gust of 35 knots (40 mph) was measured at the Weather Forecast Office at Key West.

Marine Thunderstorm Wind in HAWK CHANNEL FROM WEST END OF SEVEN MILE BRIDGE TO HALFMOON SHOAL OUT TO THE REEF, GULF OF MEXICO
From 18-OCT-11 21:44:00 to 18-OCT-11 21:44:00 (EST-5)
Location: BIG COPPITT KEY
Magnitude: 36.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

A wind gust of 36 knots (41 mph) was measured at the Naval Air Station Key West on Boca Chica Key.

Marine Thunderstorm Wind in HAWK CHANNEL FROM WEST END OF SEVEN MILE BRIDGE TO HALFMOON SHOAL OUT TO THE REEF, GULF OF MEXICO
From 18-OCT-11 22:38:00 to 18-OCT-11 22:38:00 (EST-5)
Location: KEY WEST
Magnitude: 34.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

A wind gust of 34 knots (39 mph) was measured at Key West International Airport.

Marine Thunderstorm Wind in HAWK CHANNEL FROM WEST END OF SEVEN MILE BRIDGE TO HALFMOON SHOAL OUT TO THE REEF, GULF OF MEXICO
From 18-OCT-11 23:44:00 to 18-OCT-11 23:44:00 (EST-5)
Location: KEY WEST
Magnitude: 36.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

A wind gust of 36 knots (41 mph) was measured at the Weather Forecast Office in Key West.

Marine Thunderstorm Wind in HAWK CHANNEL FROM WEST END OF SEVEN MILE BRIDGE TO HALFMOON SHOAL OUT TO THE REEF, GULF OF MEXICO
From 18-OCT-11 23:45:00 to 18-OCT-11 23:45:00 (EST-5)
Location: BIG COPPITT KEY
Magnitude: 39.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

A wind gust of 39 knots (45 mph) was measured at the Naval Air Station Key West on Boca Chica Key.

Marine Thunderstorm Wind in HAWK CHANNEL FROM OCEAN REEF TO CRAIG KEY OUT TO THE REEF, GULF OF MEXICO
From 19-OCT-11 07:35:00 to 19-OCT-11 07:35:00 (EST-5)
Location: KEY LARGO
Magnitude: 36.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: C-MAN Station

A wind gust of 36 knots (41 mph) was measured at Molasses Reef Light.

Marine Thunderstorm Wind in HAWK CHANNEL FROM CRAIG KEY TO WEST END OF SEVEN MILE BRIDGE OUT TO THE REEF, GULF OF MEXICO
From 19-OCT-11 08:18:00 to 19-OCT-11 08:18:00 (EST-5)
Location: MARATHON
Magnitude: 36.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: C-MAN Station

A wind gust of 36 knots (41 mph) was measured at Sombrero Key Light.

Waterspout in BAYSIDE AND GULFSIDE FROM CRAIG KEY TO HALFMOON SHOAL OUT TO 5 FATHOMS, GULF OF MEXICO
From 19-OCT-11 04:00:00 to 19-OCT-11 04:00:00 (EST-5)
Location: KEY WEST
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A waterspout was observed moving east from near Wisteria Island to near Fleming Key, with a spray ring visible.  The waterspout moved through the anchorage at Key West Harbor, damaging a vessel's cabin and hull after driving it ashore.