Showalter Index Calculator

Severe Thunderstorms in the Northeast and Northern Plains; Critical Fire Weather in the West

Scattered severe thunderstorms capable of damaging wind gusts and hail are forecast across the Northeast U.S. and North Dakota today. Heavy to excessive rainfall is possible over eastern New Mexico into western Texas and over the western Florida peninsula today. Critical fire weather conditions will persist today over parts of the interior Northwest 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 in the Northeast and Northern Plains; Critical Fire Weather in the West

Showalter Index

by Tim Brice and Todd Hall

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