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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 >

Automatically generated image showing areas of convective inhibition.

 

Thumbnail of automatically generated image showing areas of convective inhibition. Thumbnail of automatically generated image showing areas of convective inhibition. Thumbnail of automatically generated image showing areas of convective inhibition.
Hour - 1 Hour - 2 Hour -3

4 Panel Display | Animated Loop

CIN 

The image is a surface based measurement of Convective INhibition (CIN) or what is sometimes more commonly referred to as the strength of the cap.  The value is capped off at 500 J/KG.  In cases where there is no surface based CAPE available this parameter is set to 500 J/KG.

The yellow contours are the Lid Strength Index (LSI).  This is another measure of how strong the cap is.  It shows the thermal difference between a lifted surface parcel and the warmest part of the cap.  Higher values indicate a more stable layer.

In general, the Cap is said to be breakable when CIN is 30 J/Kg or less and/or the LSI is 2 degrees or less.  A negative LSI is rare, but is indicative of freely buoyant low level instability.

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