Excessive Rainfall Potential for the Southeast; Heat Expands for Center of the Nation; Critical Fire Weather for Pacific Northwest

Flash flooding threatens areas from the Tennessee Valley to the Carolinas as storms repeat along a stalled front. Monsoonal storms may trigger flooding in the Southwest. Dangerous heat expands across the Desert Southwest, Plains, mid-Mississippi Valley and Southern Tier. Critical fire weather for interior Pacific Northwest. Cooler, drier air brings brief relief to the Great Lakes and Northeast. Read More >

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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Excessive Rainfall Potential for the Southeast; Heat Expands for Center of the Nation; Critical Fire Weather for Pacific Northwest

Convective Parameters - Helicity