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 >

Dispersion Index Table

DISPERSION INDEX TABLE

 
Dispersion Index Interpretation
>100 Very Good (but may indirectly indicate hazardous conditions.)
60-100 Good (typical burning values)
41-60 Fair to Good (climatological afternoon values for most inland forests.)
21-40 Fair (stagnation if accompanied by persistent low wind speeds.)
13-20 Poor to Fair (stagnation, if persistent; better than average for nighttime.)
7-12 Poor (stagnant, but near average at nighttime.)
1-6 Very Poor (climatological nighttime value for most locations.)