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Winter Air Quality Update & Forecast
Friday, December 19, 2014 9:41 AM

Locations and Air Quality Conditions


Current Situation Forecast
Air quality impacts are present across western Montana this morning. 24 hour average air quality is currently UNHEALTHY FOR SENSITIVE GROUPS in Libby, Flathead Valley, Helena, Butte, and Seeley Lake, and MODERATE in Frenchtown, Missoula, and Hamilton. Hourly concentrations have been improving in Missoula, Butte, and Hamilton this morning. Dispersion conditions are expected to improve slowly between now and Sunday morning across western Montana. A weak disturbance moving through today may help flush out some valleys, especially in southwest Montana. I expect Butte and Hamilton will be the first to see improvement later today. The Helena Valley and parts of northwest Montana will likely have to wait a little longer. There may be some improvement overnight tonight and Saturday as winds increase aloft and fight to clear the inversions. All areas are expected to see full clearing and good air quality by Sunday morning when strong northwest flow aloft settles over the area. Expect air quality to range from MODERATE to UNHEALTHY FOR SENSITIVE GROUPS with improvement beginning later today and continuing on Saturday. By Sunday all areas should have GOOD air quality.

Beginning Sunday, Montana will be under a fairly unsettled weather pattern that will last well into next week. The strong northwest flow will be replaced by a trough of low pressure around midweek that may bring holiday snow to some areas. Throughout this period there should be good air quality in most locations. Inversions should be fairly weak most nights, although the occasional air quality impacts may occur during the overnight periods.

This site will be updated again on Monday, December 29th. Have a safe and happy holiday!

Kristen Martin
State Air Quality Meteorologist
Air Resource Management Bureau
Montana Department of Environmental Quality
Phone: (406) 444-0283
Email: kmartin@mt.gov




The inversions remain in place in the Bitterroot Valley this morning. This area may start to see improvement later today. 

The inversions remain in place in the Bitterroot Valley this morning. This area may start to see improvement later today.
Source: USFS

 
Widespread clouds this morning over western Montana as a disturbance move in from the west.

Widespread clouds this morning over western Montana as a disturbance move in from the west.
Source: NWS

Ventilation conditions are expected to improve in the southwest Montana today.

Ventilation conditions are expected to improve in the southwest Montana today.

Source: University of Washington 

The high pressure is slowly being pushed out of the state today. The impacts will likely linger through tomorrow before all areas see air quality improve.

The high pressure is slowly being pushed out of the state today. The impacts will likely linger through tomorrow before all areas see air quality improve.
Source: Weather Underground

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

Today's particulate report below compares particulate levels received from DEQ's
reporting stations with MDEQ’s wildfire health advisory levels.

Locations and severity of PM 2.5 particulate values since midnight of the date above.
Health Effects Categories City
  Hazardous  
  Very Unhealthy  
  Unhealthy  
  Unhealthy for Sensitive Groups  Libby
Flathead Valley
Helena
Butte
Seeley Lake
  Moderate

 Frenchtown
Missoula
Hamilton
 

  Good

 All other reporting sites. 

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