09/18/2014 Idaho DEQ Smoke Forecast

Updated 1000am MDT Thursday, September 18, 2014

Valid through Noon MDT Friday, September 19, 2014

Smoke Outlook

The areas of concern continue to be in the Clearwater Basin due to the proximity of local fires, there is transport of smoke from fires burning in California and Oregon that is advecting into the southwest portion of the state.  Smoke from fires in Oregon is also impacting the northern part of Idaho.  Smoke impacts were relatively widespread yesterday as DEQ’s monitors were slightly elevated into the Moderate category across all of monitors in the Boise, Lewiston, and Coeur d’Alene Regional Offices.

The upper level ridge has shifted to the east and is centered over the Continental Divide.  An upper level low pressure system has brought scattered to isolated thunderstorms across most of southern Idaho and across portions of Nez Perce, Lewis, Idaho, and Clearwater Counties this morning.  Any precipitation near fires will limit smoke production and potentially scour the air.  The atmosphere will remain unstable today as this upper level system passes through.  This will provide the opportunity for isolated afternoon thunderstorms and showers.  As such, there remains a chance for breezy and gusty winds across the higher elevations in the Central Idaho Mountains and near any thunderstorms.  Surface winds across the Clearwater drainage looks to be from the west-southwest across north Idaho at wind speeds between 5-10 mph.  Locally, the L-C Valley is forecast to have a stronger northwest component this afternoon.  Mixing heights are between 3,000- 6,500 feet AGL across Idaho today as high moisture content will contaminate and cap vertical lift.

Smoke impacts today will continue to be strongest across the Clearwater with locally heavy impacts near fires with some light transport into central and north Idaho.  Smoke will settle into the drainages again this evening.  Smoke from fires in California and Oregon will bring light smoke through the Snake River Plain as far east as Twin Falls; however, smoke is forecast to drain into the Upper Snake via the Lemhi Valley and the eastern Lost River Range.  Higher values should be expected in the morning before the inversion breaks.  Smoke from fires burning in Washington and Oregon will be transported into the Panhandle and Central regions, respectively once more this afternoon.  The split flow pattern will shift the transport winds to the west-northwest tomorrow which will allow higher impacts from the Freezeout Ridge Fire south into the Treasure Valley.  The Johnson Bar Fire looks to send smoke over the Central Idaho Mountains and into the Salmon-Challis region of Idaho beginning late tonight/early tomorrow morning.

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