Significant tornado parameter

The Significant Tornado Parameter highlighting a risk for tornadoes across Mississippi and Alabama on March 15, 2025

The Significant Tornado Parameter, often abbreviated as STP or SigTor, ^[1] is a composite index used by the Storm Prediction Center to highlight areas across the United States where multiple ingredients for the development of tornadic supercells overlap, ^{[2] [3] [4] [5]} and the capability of potential tornadic supercells producing "significant" tornadoes of EF2 intensity or higher. ^[6] Values greater than 1 indicate an increased potential of significant tornadoes. ^[7]

Equation

The equation used to calculate the parameter is as follows: ^[8]

STP = ⁠MLCAPE/1500 J/Kg^-1⁠ x ⁠2000-mlLCL/1000 m⁠ x ⁠ESRH/150 m/2 s^-2⁠ x ⁠EBWD/20 m/s^-1⁠ x ⁠200+mlCIN/150 J/Kg^-1⁠

See also

• Tornado intensity
• Convective available potential energy

References

1. "Significant Tornado Parameter (STP)". NOAA . Retrieved 2025-04-21.
2. Thompson, Rich. "EXPLANATION OF SPC SEVERE WEATHER PARAMETERS". Storm Prediction Center . Retrieved 2025-04-21.
3. US Department of Commerce, NOAA. "Is tornado frequency increasing in parts of the U.S.?". National Weather Service . Retrieved 2025-04-21.
4. "Significant Tornado Parameter (with CIN) Stats". National Weather Service . Retrieved 2025-04-21.
5. "Forecasting severe convective storms". European Storm Forecast Experiment . Retrieved 2025-04-21.
6. "Mid-Century Significant Hail and Tornado Potential". Guy Carpenter. Retrieved 2025-04-21.
7. "Convective Parameters - SigTor". National Weather Service . Retrieved 2025-04-21.
8. "Warning Methodology - Screen, Rank, Analyze, Decide (SRAD)" (PDF). National Weather Service . p. 9. Retrieved April 21, 2025.