Showalter Index Calculator

Snow in the Northern Rockies and Lower Great Lakes; Critical Fire Weather in the Southwest and Southern Plains

Moderate to heavy mountain snow and strong winds are expected across the Northern Rockies. Lake effect snow will continue downwind of the Lower Great Lakes. Gusty winds and dry conditions will result in critical fire weather conditions in the Southwest and Southern Plains Wednesday through Friday. Extremely critical fire weather conditions are expected Thursday in portions of New Mexico. 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.

Snow in the Northern Rockies and Lower Great Lakes; Critical Fire Weather in the Southwest and Southern Plains

Showalter Index

by Tim Brice and Todd Hall

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