Analysis and Detection of Tornadoes Associated with Hurricane Emily

Hurricane Emily made final landfall during the predawn hours on July 20, 2005 along the coast of northeastern Mexico. The center of Emily passed near San Fernando, Tamaulipas, Mexico approximately 80 miles south of Brownsville, Texas. Spiral rainbands, tropical storm force winds, and periodic rain squalls occurred across the state of Tamaulipas, Mexico, and Deep South Texas. Since the center of Emily made landfall south of the United States, the catastrophic damage was limited to the cities and towns in northeast Mexico.

Data from the National Weather Service Forecast Office (NWSFO) Brownsville, Texas WSR-88D, indicated rainband activity moving westward from the Gulf of Mexico into NWSFO Brownsville's county warning area (CWA) in association with Emily. Doppler velocity data and storm relative motion products indicated velocity rotation couplets embedded in the stronger rainbands. The identification of these rotation signatures, the proximity of the rotational couplets to the radar, and the tropical nature of the local environment contributed to several successful tornado warnings with lead times ranging from 10 to 33 minutes.

An analysis of the operational aspects of this event highlights the best practices of the local operational meteorologists during a tropical event. The analysis begins with a review of the hurricane track forecasts preceding final landfall, with an emphasis on the quality and consistency of the available numerical model guidance. A thorough study of the synoptic, mesoscale, and microscale features leads to the post event storm summary. Finally, an examination of the operational products, office practices, and situational awareness issues shows that situational awareness training, proper meteorological analysis, and a continuous effort to collaborate meteorological decisions, can increase the warning meteorologist's confidence when issuing tornado warnings during landfalling tropical systems.