09/02/2016 Idaho DEQ Smoke Forecast

Updated 8am MDT Friday, September 2, 2016

Valid through Noon MDT Tuesday, September 6, 2016

Smoke Outlook

Air quality is forecast to continue to remain in the Good to Moderate air quality category across the state today.  All monitors are reading in the Good Category expect for Twin Falls, which is not reporting, and Salmon, which is reading in the Unhealthy Category.  Lowman and Garden Valley were in the Unhealthy Category for yesterday’s 24 hour AQI, and Garden City were in the Moderate Category on a 24 hour AQI reading.  Continue to expect higher readings and impacts in the morning before clearing after 1pm.

                                                  

The upper level low pressure system will begin to track east. This will provide for widespread showers across northern and central Idaho and account for strong, afternoon winds across much of eastern Idaho. We should see increased cloud cover over the Central Idaho Mountains and Snake River Plain and significantly cooler temperatures.  For today, surface wind speeds will range from 5-20 mph with higher speeds across the Central Idaho Mountains and eastern Idaho.  Gusts at the surface will reach up to 35 mph across the Upper Snake River Plain and the Central Idaho Mountains.  Surface wind direction will be from southwest with locally northwest winds within the Treasure Valley and western Magic Valley.  Expect northwest to southwest winds across northern Idaho.  Mixing heights will range from 3,000-7,000 feet AGL.  Transport wind speed will be between 10-25 mph and be from the southwest with locally northwest winds over the Treasure Valley, western Magic Valley, and the Clearwater drainages of central Idaho.  Ventilation is forecast to be POOR in the morning and GOOD.  Inversions are expected to break between 10am-12noon.

The weather Saturday through Tuesday will exhibit a gradual shift from unsettled, rainy weather across northern Idaho with strong, gusty winds across southern Idaho to a more zonal flow regime as the upper level low pressure system weakens, fills, and tracks to the northeast out of our area of influence.  As this westerly pattern develops by Tuesday, expect temperatures to begin to rise at that time.  While this low pressure system remains overhead on Saturday and Sunday, there will be a continued slight chance for showers across much of the northern Panhandle and central Idaho. On Saturday, winds at the surface will range from 5-10 mph in northern Idaho and 8-12 mph in southern Idaho.  Wind direction will be south-0southwest to west-northwest across northern Idaho and northwest to southwest over southern Idaho.  The strongest winds will be across the Southeast Highlands.  There will be a slight chance for showers across the extreme northern Panhandle and eastern Central Idaho Mountains. Skies will be partly sunny to partly cloudy.

Sunday looks to bring widespread precipitation across the state as a secondary disturbance passes through Idaho and settles along the Continental Divide.  Expect widespread showers across all of Idaho except within the Treasure Valley and Purcell Trench where there will be a slight chance of rain.  With that, skies will be partly cloudy to cloudy.  Winds in southern Idaho will range from 10-15 mph and be from the northwest-west-southwest across the Snake River Plain and northwest-west outside of that.  Winds in north Idaho will be from the north-northwest at 5-10 mph.

Monday will see a continued slight chance of showers across central and northern Idaho.  South Idaho will see fair weather conditions with winds from the west-southwest at 5-10 mph with locally northwest winds over the Treasure Valley at 5-10 mph.  Northern Idaho will see 5-10 mph at west-northwest winds with locally south-southwest winds across the Purcell Trench.  Expect similar conditions on Tuesday with continued slight chances of precipitation across northern Idaho.  Skies will be partly cloudy to cloudy with a clean bifurcation across the Salmon River drainage.

Smoke impacts are expected to be greater in the morning prior to the inversion lift.  Dispersion this afternoon looks to be good and will promote clearing after the inversion lifts around 11am-12noon today over all of Idaho.  Smoke will push to the northeast this afternoon.  The southerly flow pattern will continue to keep smoke out of the Snake River Plain today and will continue to move smoke from the Pioneer Fire northeast as to impact the Challis/Salmon area consistently all day.  Due to the strong westerly wind component, north Idaho remains relatively clear of smoke.  Tonight, expect limited drainage impacts within the Snake River Plain as well as along the western side of the Bitterroot Range. There is a chance for impacts to occur across the Camas and Weippe Prairies tomorrow afternoon with drainage impacts down the Salmon River Corridor in the evening.  South-southwest winds will keep smoke out of the Snake River Plain but looks to bring the smoke directly into the Salmon and Challis areas in the afternoon and early evening tomorrow.  That smoke is then expected to drain into the Upper Snake River Plain and Middle Snake River Plain via the Big and Little Lost and Lemhi Valley drainages primarily impacting Monteview and Terreton in the early morning hours on Saturday. Drainage smoke is also expected to enter the Upper Treasure Valley just along the eastern fringes of Boise and drain towards the Mountain Home area in the early morning. By Saturday night into Sunday, drainage smoke looks to cover much of the southwest region of the state from McCall to the communities of Garden Valley and Idaho City, south into Fairfield and the Camas reaching west to the lower Treasure Valley. Good clearing is expected Sunday afternoon.  A reduction in fire activity is expected due to cooler temperatures and higher relative humidity levels across the Central Idaho Mountains this weekend into early next week.  Expect similar nighttime drainage impacts and clearing during the day.  Inversions are expected to lift between 11am-12noon in that area, so clearing is expected in the early afternoons.

DEQ Air Quality Forecast and Cautions:                    

·         The Boise Regional Office has extended a Stage 1 Air Quality Forecast and Caution for Boise County. Valid through Friday, September 2^nd at 3:00 p.m.

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/

The USFS installed monitors near Stanley, Idaho, Garden Valley, Idaho and Lowman, Idaho.  Idaho DEQ has installed temporary monitors in Fairfield and Boise (Garden City), Idaho. The information can be found at http://smoke.airfire.org/monitoringReport/#/?date=LATEST&productType=plotTable.

·         Stanley, ID monitor is Stanley-Idaho 75

·         Lowman, ID monitor is Lowman-Jolene Drive

·         Garden Valley, ID monitor is Garden Valley-Babcock Lane

·         Fairfield, ID monitor is Fairfield-Soldier Road

·         Boise, ID monitor is Garden City-Alworth Street

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.