Showalter Index Calculator

Slight Risk for Excessive Rainfall and Severe Thunderstorms Thursday

Additional rounds of thunderstorms are expected Thursday and Thursday night across Oklahoma and north Texas, with risks for both large hail and flash flooding. Strong winds may accompany any storms from east Texas northeast through the lower Great Lakes. Read More >

Showalter Index

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What does my answer mean?

Showalter Index greater than 0: Stable, but weak convection possible for SI = 1-2 if strong lifting is present.
Showalter Index between 0 and -3: Moderately unstable.
Showalter Index between -4 and -6: Very Unstable.
Showalter Index between less than -6: Extremely Unstable.

Slight Risk for Excessive Rainfall and Severe Thunderstorms Thursday

Showalter Index

by Tim Brice and Todd Hall

Enter the temperatures that you would like:

What does my answer mean?

What is the formula for the Showatler Index?