Showalter Index Calculator

Severe Weather and Flooding Threats for the Central U.S.; Fire Weather Concerns for the Western U.S.

Severe weather and flooding threats will continue for portions of the central U.S. through Thursday, focused from the central High Plains to the Mid-Mississippi Valley. Hot and dry conditions will fuel fire weather concerns for the Intermountain West, and dry thunderstorms may spark additional wildfires. Dangerous heat will build across the southern U.S. Friday into the weekend. 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.

Severe Weather and Flooding Threats for the Central U.S.; Fire Weather Concerns for the Western U.S.

Showalter Index

by Tim Brice and Todd Hall

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What does my answer mean?

What is the formula for the Showatler Index?