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Winter Air Quality Update & Forecast
Monday, March 4, 2019 9:41 AM

Locations and Air Quality Conditions


Current Situation Forecast
Strong inversions are present in most western valleys this morning, with temperatures around 20 below in many locations. Nearby ridge tops are about 20 degrees warmer. This cap over the cold air is causing air quality concerns across western Montana. Air quality is currently UNHEALTHY in Seeley Lake. UNHEALTHY FOR SENSITIVE GROUPS in Butte, and MODERATE in Libby, Frenchtown, Hamilton, and Helena. The inversions are being caused by high pressure over the area, causing clear skies and light winds. High pressure will remain over the region through Tuesday. The abundant sunshine on Monday should help many valleys warm into the single digits by this afternoon. Air quality may briefly improve before inversions set back up this evening. Another cold night with widespread air quality impacts is expected tonight into Tuesday morning. Expect MODERATE air quality in most western valleys with some periods of UNHEALTHY FOR SENSITIVE GROUPS to UNHEALTHY possible. Most areas should see air quality improve by Tuesday afternoon, with air quality generally ranging from GOOD to MODERATE. There may be a few stubborn valleys that continue to have poor air quality throughout the day on Tuesday.

Clouds start to increase on Tuesday night as the next weather system begins to move into the area. The increased clouds should help keep temperatures from dipping too low by Wednesday morning. The storm system on Wednesday will usher in (relatively) warmer temperatures. The increased winds, scattered snow showers, and lack of strong inversions, should lead to GOOD air quality for most locations on Wednesday. By Thursday, temperatures could reach above freezing for some areas with generally GOOD air quality expected.

Air Quality Bureau
Montana Department of Environmental Quality
Phone: (406) 444-3490
Email: DEQMTSmoke@mt.gov




Clear skies across the region have led to strong inversions in many valleys. Below, the Swan Mountains.  

Clear skies across the region have led to strong inversions in many valleys.  Below, the Swan Mountains.
Source: CMP Montana

 
Clear skies and light winds will cause strong inversions and very cold temperatures once again Tuesday morning.

Clear skies and light winds will cause strong inversions and very cold temperatures once again Tuesday morning.
Source: Weather Underground

But warmer temperatures are on the way! By Thursday, temperatures may get above freezing for many parts of Montana.

But warmer temperatures are on the way! By Thursday, temperatures may get above freezing for many parts of Montana.

Source: Weather Underground 




Real time particulate information is currently available in most of the larger urban areas from MTDEQ's Today's Air website.

Today's particulate report below compares particulate levels received from DEQ's
reporting stations with MTDEQ’s Health Effect Categories.

Locations and severity of PM 2.5 particulate values over the past 24 hours from the time above.
Health Effects Categories City
  Hazardous  
  Very Unhealthy  
  Unhealthy  Seeley Lake
  Unhealthy for Sensitive Groups  Butte
  Moderate

 Frenchtown
Hamilton
Helena
Libby
 

  Good

  

B1(x) One-hour BAM value (number of values)
B8(x) Eight-hour average BAM
B24 24 hour  average BAM value