National Weather Service United States Department of Commerce

Stormy Western U.S.

An active and complex weather pattern is in store this weekend through next week, as multiple storms track from West Coast to East Coast. The activity starts today as a vigorous system moves through north-central California into the Intermountain West with rain, perhaps a few thunderstorms and heavy mountain snow. This system will move into the Upper Midwest tomorrow with a swath of heavy snow. Read More >

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.)