National Weather Service United States Department of Commerce

Storm Impacting the Northwest U.S.; Fire Weather Conditions in Southern California; Severe Weather in the South

A Pacific storm is bringing areas of low elevation rain, moderate to heavy mountain snow, and high winds to the Northwest. Strong Santa Ana winds and very dry conditions are producing elevated to critical fire weather conditions in southern California. Isolated strong to severe thunderstorms are possible through early Wednesday morning across parts of northeast Texas into western Tennessee. 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

4 Panel Display | Animated Loop

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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