08/01/2016 Idaho DEQ Smoke Forecast

Updated 11am MDT Monday, August 1, 2016

Valid through Noon MDT Tuesday, August 2, 2016

Smoke Outlook

Air quality is forecast to remain in the Good to Moderate air quality category across the state today.  Impacts are near the Pioneer Fire outside Idaho City where current monitor readings are elevated into the Moderate category.  Additional impacts are being recorded east in the Ketchum area which is currently reading in the Unhealthy for Sensitive Groups category.  East Boise is also in the Moderate Category for PM₁₀.  In north Idaho, monitor readings are currently in the Moderate category across the Weippe and Camas Prairies and down into the Lewiston-Clarkston Valley.  This is likely due to the fires currently burning in eastern Washington and Oregon.  Expect higher readings in the evening and early morning before improving during the day.

Due to a shortwave upper level ridge pattern currently over Idaho, winds will be light at the surface as well as in the transport layer.  Skies will be clear and thermal lows will develop across the larger valleys over the Upper Snake and the Columbia Basin.  Inversions will be stubborn to mix out today.  Mixing heights are expected to reach 3,000-9,000 feet AGL today with good ventilation across all airsheds in the afternoon.  Generally, winds will be from the west-southwest at the surface at 5-10 mph with locally northwest winds across the Treasure Valley and Palouse with locally northwest to northeast winds over the Camas and Weippe Prairies.  Transport winds will be from the northwest at 5-15 mph.  Minimum RH levels are in the 10-15 % range across much of the state with the northern Panhandle experiencing minimum RH levels in the 15-20% range.

Tomorrow, an upper level low will make its way over Washington and bring a tight surface pressure gradient to Idaho.  A cold front will pass southwest Idaho in the late afternoon.  This will provide much stronger sustained winds with gusts in the 20-30 mph range across the Columbia Basin and into Idaho and 30-50 mph across the Upper Snake River Plain and into the Big and Little Lost drainages.  As a result of the increased wind speeds, mixing and ventilation will improve as well as transport.

Smoke impacts today are likely to occur downwind of the Pioneer fire.  This includes Idaho City, Ketchum, and the Middle Snake River Plain from Mountain Home to Pocatello.  Transport into Salmon is again likely during the day today.  Transport from fires in eastern Oregon and Washington are expected to affect the Palouse, Weippe, and Camas Prairies in central Idaho this morning and early afternoon and should lift this afternoon before settling in valleys tonight.  Tonight, surface level smoke will drain down into the Snake River Plain in and around the Arco Desert region before dispersing to the northeast via the Upper Snake.  Drainage also is likely into at least east Boise with possible impacts into the Meridian and Nampa areas.  Impacts are expected to be highly localized, once the inversion lifts tomorrow morning, again most likely affecting Ketchum and Salmon as well as the Palouse, Camas, and Weippe Prairies to a lesser extent.  There is a slight chance for impacts into the Purcell Trench tomorrow afternoon.

Air Quality Advisories:

·         The Twin Falls Regional Office has issued a Stage 1 Forecast and Caution for Blaine County.  Valid through 1pm August 3, 2016.

View real time smoke monitoring at:  http://www.airnow.gov/index.cfm?action=topics.smoke_wildfires

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.  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.