08/25/2015 Idaho DEQ Smoke Forecast

Updated Noon MDT Tuesday, August 25, 2015

Valid through: Noon MDT Wednesday, August 26, 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, Central Idaho Mountains, and the Owyhees.

Nez Perce Reservation:  24-hour monitor readings range from Unhealthy to Hazardous.  Hourly readings are fluctuating from Unhealthy 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 ridge of high pressure centered over the desert Southwest is keeping a ridge all the way into Montana, which will maintain warm temperatures and light winds for all of Idaho.  There are minor disturbances embedded within this ridge which can be blamed for this morning’s thunderstorms and may allow for isolated thunderstorms late this afternoon and evening across northern Idaho and will be the source for potential storms across the Southeast Highlands tomorrow afternoon.

 

The strongest smoke impacts are occurring across the Clearwater drainages, Central Idaho Mountains as well as southwest Idaho.  This will continue into the afternoon and evening.  Expect to experience impacts from the Canada border south to the Idaho/Nevada and Idaho/Utah border.  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, except in Weiser, where the monitor is currently reading Unhealthy for Sensitive Groups.  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 the ridge limits mixing and wind speeds into Thursday and Friday.  No major weather changes are expected until the end of this week with increasingly unsettled weather with the chance for afternoon thunderstorms.

DEQ Air Quality Advisories:

Idaho DEQ has issued a state-wide Forecast and Caution for all counties.  This will be re-evaluated Tuesday, August 26^th at 3pm MDT.

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.  Visit the Idaho Smoke Blog for more information at http://idsmoke.blogspot.com/

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.