2 Tornado FormationSevere “Super Cell” Thunderstorm (1% spawn tornadoes)Often occur along cold fronts and move to NEStrong updraftsWind shear (change in direction or strength of winds from top to bottom of storm)
8 USA Tornado SeasonMost common when temperature gradient in central U.S. is greatest.
9 USA Tornado Occurrence About tornadoes spotted each year.
10 Tornado Classification Fujita F-scaleF0 (winds < 120 mph) to F5 (winds mph)based on rotational wind speed and damage doneSize: Tornadoes generally < 1/4 mile wide (damage path only 150 ft.)
11 Largest Tornado Outbreak Deadliest TornadoTri-state tornado outbreak of March 18, 1925Kills 689 people in Missouri, Illinois & IndianaLargest Tornado OutbreakApril 3-4, 1974 Super-Outbreak148 tornadoes overnight across 11 states
12 Tornado Forecasting NEXRAD doppler radar (WSR-88D) 138 stations across the USAIntensity of storm noted by amount of reflection off rain, hail, and ice crystals.Hook cloud is an indicator.Orlando, Florida