National Weather Service United States Department of Commerce

Significant Severe Weather in the Upper Midwest; Blizzard Conditions in the Cascades; Heavy Rain and Thunderstorms in Hawaii

Significant severe thunderstorms, including the risk for strong to intense tornadoes, are expected across the Upper Midwest this afternoon and evening. An atmospheric river will bring blizzard conditions to the northern Cascades. A powerful Kona storm is expected to impact Hawaii today into Saturday, bringing heavy rainfall and strong winds. Read More >

Smoke dispersal is categorized by using the Ventilation Rate. Ventilation Rate forecasts for a specific point can be found using the Fire Weather Dashboard. Click a spot on the map and scroll down to find daily and hourly Ventilation Rate values for the next few days.

 

Fire Weather Dashboard

 

The link above is configured to display smoke dispersal categories as shown here:

 

  Smoke Dispersal Vent. Rate, knot-feet (x1000)
     Excellent             150 or greater
     Very Good 100 to 149.99
     Good 60 to 99.99
     Fair 40 to 59.99
     Poor less than 40

 

Ventilation Rate = Transport Wind (kts) Mixing Height (ft)