National Weather Service United States Department of Commerce

Areas of Extreme Heat and Excessive Rainfall Potential

Dangerous and extreme heat will remain across portions of the central U.S. this week, persisting across the mid to lower Mississippi Valley, Gulf Coast, southern Plains and portions of Texas. A heat wave over the Southwest U.S. will peak this weekend. Heavy to excessive rainfall may produce flash flooding from the Delmarva Peninsula north into the Hudson Valley today and tonight. 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

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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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