National Weather Service United States Department of Commerce

Severe Thunderstorms and Excessive Rainfall in the Central U.S.; Heat Building in the Western U.S.

A cold front pressing east across the central U.S. will be the focus for areas of strong to severe thunderstorms and excessive rainfall through this weekend. Strong to severe thunderstorms my bring damaging winds, hail, and a few tornadoes while excessive rainfall may lead to areas of flooding. Heat will build across the western U.S. with heat-related watches, warnings, and advisories issued. Read More >

Automatically generated image showing areas of the significant tornado parameter.

 

Thumbnail of an automatically generated image showing areas of the significant tornado parameter. Thumbnail of an automatically generated image showing areas of the significant tornado parameter. Thumbnail of an automatically generated image showing areas of the significant tornado parameter.
Hour - 1 Hour - 2 Hour -3

4 Panel Display | Animated Loop

Significant Tornado (SigTor) 

A composite index that includes 0-6 km bulk wind shear, 0-1 km storm-relative helicity, surface based CAPE, surface parcel CIN, and surface parcel LCL height. Values greater than 1 are indicative of increased potential of significant tornadoes.

The contours are the Lifted Condensation Level or LCL.  A lower LCL typically increases tornadic risk because it is indicative of air parcel acceleration occurring closer to the surface. 

 

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