National Weather Service United States Department of Commerce

Frigid Airmass to Bring Significantly Colder Temperatures; Heavy Lake-effect Snow; Fire Concerns Across the Central Gulf Coast

A frigid cold airmass will bring significantly colder weather across the eastern two thirds of the country early this week. Temperatures will tie or break many records across the Southeast through tonight. Moderate to heavy lake effect snow will continue downwind of the Great Lakes. Gusty winds and dry conditions will support an elevated fire weather threat across the Central Gulf Coast. 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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