National Weather Service United States Department of Commerce

Tracking a Couple of Storm Systems Across the Country

Showers, along with a few strong to severe thunderstorms, are expected from the Great Lakes, New England and southward into the Ohio and Tennessee Valleys. In the wake of this system, a stronger storm is expected to track from the Pacific Northwest, Plains and through the Eastern U.S. this weekend. Strong winds, showers and a larger drop in temperatures are expected this weekend into Monday. Read More >

Automatically generated image showing areas of surface-1km vertical shear.

 

Thumbnail of an automatically generated image showing areas of surface-1km vertical shear. Thumbnail of an automatically generated image showing areas of surface-1km vertical shear. Thumbnail of an automatically generated image showing areas of surface-1km vertical shear.
Hour - 1 Hour - 2 Hour -3

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Shear (0-1km) 

Surface-1-km Vertical Shear is the difference between the surface wind and the wind at 1-km above ground level. These data are plotted as vectors with shear magnitudes contoured. 0-1-km shear magnitudes greater than 15-20 knots tend to favor supercell tornadoes.

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