08/26/2015 Idaho DEQ Smoke Forecast

Updated Noon MDT Thursday, August 27, 2015

Valid through: Noon MDT Friday, August 28, 2015

Smoke Outlook

Air quality is currently ranging from Good to Hazardous across all of Idaho with higher impacts across the Clearwater Basin Drainage, the Treasure Valley, and the Salmon-Challis area.  Air quality is forecast to remain in the Moderate to Unhealthy category for the 24hr standard across central Idaho.  Impacts are from regional fires burning in Washington State, California, Oregon, and a multitude of local fires in the Clearwater drainage, the northern Panhandle, and Central Idaho Mountains.

Nez Perce Reservation:  24-hour monitor readings range from Unhealthy to Hazardous.  Hourly readings are fluctuating from Moderate to Hazardous, depending on location and wind direction.  The Nez Perce Tribe will continue their Air Quality Advisory.  Please contact the Nez Perce Tribe for more information: airquality@nezperce.org.

An upper level low pressure system located off the coast of Oregon and Washington is flattening the upper level ridge and allowing for some moisture to enter the area; however, the atmosphere is fairly stable which is limiting the convective potential today. No major weather changes are expected until the end of this week with increasingly unsettled weather with the chance for afternoon thunderstorms across the Bitterroot Range this afternoon.  On Saturday, a strong, dry, cold front will move into Idaho and bring gusty winds and no major precipitation.  This will signal the beginning of a pattern change as an active weather pattern begins to establish with several minor lobes of energy entering the area this weekend and into next week.

 

The strongest smoke impacts are occurring across the Clearwater drainages, Central Idaho Mountains as well as southwest Idaho.  This will continue into Saturday.  Expect to experience impacts from the Canada border south to the Salmon River corridor.  The highest impacts are expected to be within the drainages of the Clearwater, Salmon, Lochsa, down into the Lewiston-Clarkston Valley.  In southern Idaho, impacts will be greatest within the drainages around McCall and Garden Valley and generally north of a line running from Weiser to Salmon.  Conditions have generally improved across southern Idaho with values in the Good and Moderate range across all monitors.  Nocturnal drainage flow will contribute to greater impacts in all of Idaho tonight, especially within the drainages into the Lewiston-Clarkston area and the Snake River Plain off the Central Idaho Mountains.  High level smoke is expected from California fires as the southwesterly flow pattern continues to drive the weather over Idaho.  Impacts in the central Idaho region will continue to be quite strong as temperatures and winds will serve to increase fire activity. 

DEQ Air Quality Advisories:

Idaho DEQ has issued an Air Quality Advisory:

·         Coeur d’Alene Regional Office for Boundary, Bonner, Kootenai, Shoshone, and Benewah Counties through August 28^th at 12:00noon when it will be extended or lifted.

·         Lewiston Regional Office for  Latah, Nez Perce, Lewis, Clearwater, Idaho Counties, river corridors and surrounding areas (off the Nez Perce Reservation) through August 28^th at 10:00am when it will be extended or lifted.

·         Idaho Falls Regional Office for Lemhi County until August 27^th at 12:00 noon when it will be extended or lifted.

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

How to estimate air quality based on visibility for areas without an air quality monitor or airport visibility estimate:

a. Face away from the sun.

b. Determine the limit of your visible range by looking for targets at known distances (miles).

c. Visible range is when an object you can easily see in the distance disappears.

d. Use the visibility values above to determine the local wildfire smoke category.