National Weather Service United States Department of Commerce

Scattered Severe Thunderstorms Across the Northern Plains; Fire Weather Concerns in the Western U.S.

Scattered severe thunderstorms are forecast across central and eastern North Dakota, as well as far northwest Minnesota Saturday (Slight Risk level 2 of 5). Damaging wind gusts are the primary threat. Elevated to critical fire weather conditions will persist through the weekend across the Western U.S. Isolated dry thunderstorms could lead to new fire starts over portions of the northern Rockies. Read More >

Automatically generated image showing areas of storm relative helicity.

 

Thumbnail of an automatically generated image showing areas of storm relative helicity. Thumbnail of an automatically generated image showing areas of storm relative helicity. Thumbnail of an automatically generated image showing areas of storm relative helicity.
Hour - 1 Hour - 2 Hour -3

4 Panel Display | Animated Loop

Helicity (0-1 Km) 

This is the 0-1 km (approximately 0-3,000 Ft. AGL) storm relative helicity which is a measure of the amount of low level wind shear available for tornadogenesis. This is not a good indicator of supercell potential which is related more strongly to 0-6 KM vertical shear. Values greater than 100 m**2/s**2, do suggest an increased threat of tornadoes provided a supercell is present.  Larger values are generally better, but there are no clear "boundaries" between non-tornadic and significant tornadic supercells.

The arrows indicate the approximate right supercell storm motion using the Bunkers technique.

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