Posted: Sep 19, 2012 9:59 AM by Meteorologist Mike Heard
Updated: Sep 19, 2012 10:12 AM
Air quality worsening this morning across SW Montana. According to MDEQ at 9am this morning ratings for Butte are now "UNHEALTHY". Bozeman, Helena and West Yellowstone are rated as "Unhealthy for sensitive groups".
Morning visible satellite imagery show extensive smoke trapped in the valleys across central Idaho and across western and central Montana. High pressure producing stable atmospheric conditions and valley inversions will continue to allow the smoke to linger.