For several days, forecasters have been calling for severe weather to move into the Plains on the afternoon of May 3. On that morning, SPC forecasters are on alert, analyzing detailed weather balloon and satellite data. Storm Prediction Center Tuccumcari, NM wind profiler time series on May 3, 1999. Courtesy NWS From what they are seeing, it is becoming apparent that conditions will be favorable for the development of powerful thunderstorms. Dan McCarthy, Warning Coordination Meteorologist at the SPC, is on duty that morning.
Surface observations show a high degree of instability.
Atmospheric profilers over eastern New Mexico reveal a band of strong winds at 15,000 to 20,000 feet, approaching western Texas. These winds are expected to move into Oklahoma by the early afternoon or evening. The two main ingredients for tornadic storms are now in place. By the mid-afternoon, it is clear that the situation is becoming more and more unstable. After a quick briefing and a review of the newest satellite and Doppler radar data, it becomes clear that the air mass has destabilized even further, jet stream winds are on the rise, and towering cumulus clouds, which form the building blocks of thunderstorms, are beginning to gather.