Air
quality is forecast to range from Good to Unhealthy for Sensitive Groups;
however hourly readings may be higher at times.
Most recent monitor observations are currently reading in the Good to
Moderate level for an hourly reading.
Yesterday saw levels that ranged from Good to Moderate with Riggins in
the Unhealthy for Sensitive Groups for a 24hr AQI. Conditions have improved dramatically across
the state as consistent southwesterly winds provided clearing of smoke at the
surface and aloft.
The upper low pressure system will begin
to track to the northeast which will further weaken the upper level ridge
currently in place over Idaho. Surface
winds will be from the west-southwest at 2-8 mph with locally northwest winds
over portions of the Upper Snake River Plain, Treasure Valley, and Camas
Prairie. Skies will be sunny. Mixing heights will range from 2,000-8,000
feet AGL across all of Idaho today with poor to marginal ventilation over the
entire Snake River Plain and from Weiser south.
Ventilation is also poor to marginal over most of western central Idaho. Transport winds will be from the
west-southwest at 5-10 mph.
Improvement of air quality is expected
to continue today with light smoke possible from Boise to Riggins and east
through the Salmon River Corridor to Salmon. This evening, regional smoke is
expected over the Middle and Upper Snake River Plain; however concentrations
will be light in comparison to previous readings. Tomorrow, expect impacts to be localized to
central Idaho, the Big, Little, and Lemhi drainages into the northern periphery
of the Upper Snake River Plain. Lofted
smoke is expected to cover the northern Panhandle tomorrow as smoke from fires
in Washington become more active today.
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.
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.
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.
|
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
|
