- Observation/archive criteria
- Surface winds >= 58 mph
- Surface hail diameter >= 1 inch
- Tornado of any size
- You need one or more of these for a storm to be classified a severe thunderstorm
- Other meteorological properties
- Four-stage event: Cumulus, mature, SR, and Dissipative
- Severe Right-Moving Stage (SR)
- Strongly rotating supercell storm that moves to the right of the near tropospheric wind vector (this stage produces large hail, high winds and or tornadoes)
- Long lived (can be in quasi steady sate SR stage for several hours) - thus can produce a tornado family
- Strong updraft of supercell >= 100 miles per hour, can produce semi-barrier
- Most Hailstorms are in Cheyenne, Wyoming
- Most Tornadoes are near Oklahoma City
- Tornado Alley, mid US. They have the most tornadoes every year
- Dixie Alley, down towards Florida, has far deadlier tornadoes usually. This is due to the fact that tornadoes down there tend to be closer to winter and in the middle of the night, so people aren’t paying attention
- During the winter convection starts in the middle of the night from hot and cold air interacting, causing tornadoes at night
- Most Thunderstorms are around Tampa, Florida
- Tornado watches come from the NSPC (National Storm Prediction Center)
- A thunderstorm day is a day when thunder is heard
- SPC (Storm Prediction Center), NOAA (National Oceanic and Atmospheric Administration) -> Forecast -> Tornado Watch Boxes
- Local National Weather Service -> Warning