Outlook for Bitterroot Valley south

Smoke: Smoky conditions will persist throughout the Bitterroot Valley today as smoke that pooled overnight stays trapped by stable atmosphere. This afternoon following inversion break, smoke should scour out of the valleys with an increase in instability and a switch to westerly winds. This evening, smoke pools into the Bitterroot Valley as a result of anticipated fire growth on the Lolo Peak, Hidden and other Idaho wildfires.

Fire: Wildfires will have the potential to become more active this afternoon following inversion break and in increase in instability. This will result in an increase in smoke output that will settle in the Bitterroot Valley overnight. A red flag warning for abundant lightning, low humidity and higher velocity winds may result in new wildfire starts and perimeter growth on current wildfires.

Other: Forecast atmospheric instability due to a passing cold front through the weekend should result in an improvement in air quality Sunday. Periods of heavy smoke on highway 12 corridor west of Lolo continue during the early morning hours.

Daily AQI Forecast for Aug 12, 2017
Yesterday Fri   Forecast Sat Sun
Station hourly 8/11 Comment for Today -- Sat, Aug 12 8/12 8/13
Missoula Boyd Park
Smoke from wildfires surrounding Missoula will converge in the area resulting in a daily average "Unhealthy for Sensitive Groups" level throughout the day. Air quality worsens overnight as smoke pools in the valley.
Lolo-U.S. 93
Conditions improve following inversion break this afternoon, however smoke from the Lolo Peak wildfire will move down the highway 12 corridor into Lolo this afternoon. Air quality worsens overnight as smoke pools in the valley.
Florence-U.S. 93
Persistent "unhealthy for sensitive groups" expected during daylight hours. Air quality worsens overnight as smoke pools in the valley.
Stevensville
Persistent "unhealthy for sensitive groups" expected during daylight hours. Air quality worsens overnight as smoke pools in the valley.
Hamilton PS 46
Persistent "unhealthy for sensitive groups" expected during daylight hours. Smoke will pool in the valley overnight.
Issued Aug 12, 2017 by Tod Johnson and Chris Hall, Air Resource Advisors
Air Quality Index (AQI) Actions to Protect Yourself
Good None
Moderate Unusually sensitive individuals should consider limiting prolonged or heavy exertion.
USG People within Sensitive Groups* should reduce prolonged or heavy outdoor exertion.
Unhealthy People within Sensitive Groups* should avoid all physical outdoor activity.
Very Unhealthy Everyone should avoid prolonged or heavy exertion.
Hazardous Everyone should avoid any outdoor activity.

Disclaimer: Forecasts may be wrong; use at own risk. Use caution as conditions can change quickly. See your health professional as needed. Smoke sensitive groups should take appropriate precautions.