National Weather Service United States Department of Commerce

Heat Wave Persists Over the Central U.S.; Significant Flooding Expected in the Northern Mid-Atlantic Tuesday

Dangerous and extreme heat will remain across portions of the Central U.S. this week, persisting across the Mid to Lower Mississippi Valleys, Gulf Coast, Southern Plains and portions of Texas. A heat wave over the Southwest will intensify late this week. Severe thunderstorms and flash flooding will spread from the Great Lakes/Ohio Valley to the Mid-Atlantic and Northeast the next few days. 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.
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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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