Areas of Excessive Rainfall and Severe Thunderstorms Thursday

Scattered severe thunderstorms capable of damaging wind gusts and hail are forecast across the Northeast U.S. and North Dakota Thursday. Heavy to excessive rainfall is possible over eastern New Mexico into western Texas and over the western Florida peninsula Thursday. Read More >

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EHI

The Energy Helicity Index (EHI) is a number which represents the combination of instability and storm relative helicity. Our calculation uses mixed layer CAPE (surface to 3000ft average parcel) and 0-3 km storm relative helicity. Values greater than 2 or 3 have been correlated to cyclonic supercells with increased tornadic potential. Negative values are indicative of an environment favorable for anti-cyclonic (left moving) supercells, but tornadoes associated with anti-cyclonic supercells are extremely rare.

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Areas of Excessive Rainfall and Severe Thunderstorms Thursday

Convective Parameters - EHI