09/19/2014 Idaho DEQ Smoke Forecast

Updated 1000am MDT Friday, September 19, 2014

Valid through Noon MDT Monday, September 22, 2014

Smoke Outlook

The areas of concern today will be focused on the Hells Canyon and McCall region of the state, there is transport of smoke from fires burning in California and Oregon that is moving into the southern portion of the state.   It should be noted that widespread haze and light smoke is forecast across most of southern Idaho in the Snake River Plain and south today.  Smoke impacts were relatively widespread yesterday as DEQ’s monitors were slightly elevated into the Moderate category across all of monitors in the Twin Falls, Boise, Lewiston, and Coeur d’Alene Regional Offices (except in Boundary County).  The Grangeville monitor reported a 24hr AQI of Unhealthy for Sensitive Groups yesterday.  The Salmon Monitor also reported impacts and was in the Moderate Category yesterday.

The upper level low pressure system is currently located over California and will move to the northeast as we go through the weekend.  An upper level ridge will build over northern Idaho today and tomorrow.  The clear skies will bring warmer days as well as potentially strong nocturnal inversions as temperatures will be able to drop quite rapidly near rivers and lakes.  This pattern begins to shift to a more progressive pattern on Monday; however, confidence is low in any weak disturbances that pass through the northern part of the state until a strong cold front moves in on Tuesday.  Across southern Idaho, the upper level low will approach the state by Sunday.  This will bring a chance of showers to the southwest. 

Smoke impacts today will continue to be strongest in the Treasure Valley and McCall region.  Smoke will settle into the drainages again this evening.  The Garden Valley and Idaho City regions look to receive decent transport of smoke from the Freeze-Out Ridge Fire this evening.  Higher values should be expected in the morning before the inversion breaks.  The transport winds will continue to shift today and Saturday and have a strong westerly component.  The zonal wind pattern and the decrease in fire activity last night will help limit the intensity of any smoke impacts today and tomorrow morning, especially across the Clearwater Drainage.  By Saturday, an easterly-southeasterly wind develops and will transport smoke back into the Clearwater Drainage.  Transport of smoke from the fires in California will be very limited, if occurring at all, due to the position of the upper level low pressure system.  This should lead to a reprieve in the southern parts of the state this weekend and into Monday.  

View DEQ near-real time monitoring at:  http://airquality.deq.idaho.gov/

Smoke forecasts are dependent on predicted fire growth and weather.  If conditions change unexpectedly, impacts could occur.  When visibility starts to go below 5 miles, sensitive groups should minimize outdoor activities.  Everyone else should minimize prolonged or physical activity outdoors.  Refer to the Smoke and Health Tab on the Idaho Smoke Information Blog for additional health information. 

Your eyes are your best tools to determine if it’s safe to be outside.  Even if you smell smoke, the air quality may still be good. 

AQI Category	Visibility (miles)
Good	11+
Moderate	6-10
Unhealthy for Sensitive Groups	3-5
Unhealthy	1½  -2¾
Very Unhealthy	1-1¼
Hazardous	Less than 1