South Florida 1998 Groundhog Day tornado outbreak

On February 1, 1998, a low pressure center formed in the Gulf of Mexico and deepened to a minimum central pressure of 989 Mb. As it moved across the northeast Gulf and in response to the tightening pressure gradient, winds over south Florida increased to gale force during mid-morning of February 2. A warm front moved north from the Florida Straits and ushered in tropical air to the Florida Keys and the southern peninsula by midday. An area of severe thunderstorms developed in the warm sector over the southeast Gulf of Mexico and moved into the lower Keys beginning around mid-afternoon February 2. The severe thunderstorms then spread to the southeast Florida coast by evening.

As the severe thunderstorms moved across the region, both Key West WSR-88D (KBYX) and Miami WSR-88D (KAMX) indicated several signatures of the impending severe weather. At 2301 UTC, KBYX indicated a very well defined hook echo as well as a TVS. In fact, during several volume scans in this event, KBYX showed multiple vortex signatures. As the system continued into south Florida, KAMX did not consistently show tornadic signatures, but the velocity images indicated very strong straight line winds and the reflectivity image showed a well defined bow echo developing prior to 0124 UTC.

During this severe thunderstorm and tornadic outbreak, the strong cell that produced the hook echo mentioned above weakened slightly as it moved northward and produced an F1 tornado in the middle Keys causing moderate damage. Also, a C-MAN instrument at Long Key measured a gust to 119 mph. Most residence in the lower and middle Keys were without power until the following day. Four confirmed tornadoes were observed in Miami-Dade and Broward counties along with surface wind gusts in excess of 100 mph at Miami International Airport associated with the rear flank downdraft as an F1 tornado touched down just north of the site. This tornado moved north-northeast intensifying to an F2 and moved across Opa-Locka Airport in Miami-Dade county then across Hollywood North Perry Airport in Broward county. A total of 235 aircraft was either damaged or destroyed at the three airports. The total loss to aircraft, marine and structural buildings was calculated at $120-148 million. Outside of a tropical system, this was the costliest tornadic outbreak in south Florida's history.