Article · Wikipedia archive · Last revised Jul 30, 2026

Significant tornado parameter

The Significant Tornado Parameter, often abbreviated as STP or SigTor, 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, and the capability of potential tornadic supercells producing "significant" tornadoes of EF2 intensity or higher. Values greater than 1 indicate an increased potential of significant tornadoes.

Last revised
Jul 30, 2026
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The Significant Tornado Parameter highlighting a risk for tornadoes across Mississippi and Alabama on March 15, 2025 source ↗

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,2345 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

See also

References

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.