Showalter Index Calculator

Severe Thunderstorms and Heavy Rainfall in the Northern Plains and Midwest; Fire Weather Threat in the West

Severe thunderstorms will continue to be possible over parts of the northern Plains and upper Midwest through Saturday which could bring large hail, damaging winds, and possible tornadoes. Heavy to excessive rainfall may produce flooding over a part of the Midwest today. Elevated to critical fire weather are expected today into this weekend over parts of the central Rockies and Great Basin. Read More >

Showalter Index

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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 Thunderstorms and Heavy Rainfall in the Northern Plains and Midwest; Fire Weather Threat in the West

Showalter Index

by Tim Brice and Todd Hall

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