Verification of the tornado events in the Norman Oklahoma NWSFO county warning area for the May 3, 1999 severe weather outbreak

The events of 3 May 1999 in Central Oklahoma represented one of the worst tornado outbreak in nearly 50 years in Oklahoma, along with the first recorded tornado with F-5 damage in metro Oklahoma City (the most significant singular event in Oklahoma weather history since 1947). Over 50 tornadoes were verified within the Norman Oklahoma National Weather Service Forecast Office (NFWSO) county warning area alone.

We will describe the chronology of events that led to preliminary and near-final conclusions on the location, times, and strengths of the tornado damage paths. The verification process began from real-time verification during the actual warning operations, then damage surveys in the few days following the event, and finally, more-detailed damage analyses using WSR-88D data, storm chaser/spotter logs and video, high-resolution aerial photography, and engineering survey information. The documentation of the 3 May 1999 tornadoes is unique relative to past outbreaks due to the amount of information used to detail numerous short track tornadoes and small breaks between successive tornadoes. Several factors led to such a plethora of detailed information from this event, including lessons learned from previous, yet contemporary outbreaks in Central Oklahoma, the fact that some of the violent tornadoes hit major population areas, and the popularity of the event with the media, public, and government agencies.

A number of individuals have contributed to the damage analysis of the May 3 events, and the list is too large to include here. See the poster at the conference for details.