National Weather Service United States Department of Commerce

Heat Continues for the East and South-Central U.S.; Strong to Severe Storms Across the Mid-Atlantic and Northeast

The extremely dangerous heat wave continues across the East Coast and much of the South-Central U.S. today. Record high temperatures are expected for some areas especially across the Mid-Atlantic where extreme heat risk conditions reside. There is a Slight Risk (level 2 of 5) of severe thunderstorms today for the northern Mid-Atlantic into portions of southern New England. 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.

Back to Convective Parameters Home