Air quality is forecast to continue to remain in the
Unhealthy for Sensitive Groups to Very Unhealthy category for the 24 hour AQI
across the state today; however hourly readings may be much higher at
times. Most recent monitor observations
are currently reading in the Moderate to Hazardous level for an hourly reading. Yesterday saw levels that ranged from
Unhealthy to Hazardous across central Idaho and the Panhandle. Southern Idaho
experienced widespread Moderate to Unhealthy conditions for the 24hr AQI. Areas most heavily impacted remain in and
around central Idaho, especially the Camas Prairie area, with the remainder of
central Idaho and the Panhandle not far behind.
Slight improvement has been observed across southeastern and
south-central Idaho with readings in the Moderate and Unhealthy for Sensitive
Groups over southwestern Idaho.
The upper low pressure system will remain quasi-stationary
and continue to provide unstable, moisture-laden air into southern Idaho. This will allow for a chance for afternoon
thunderstorms over the elevated regions of the Central Idaho Mountains and the
Southwest Highlands. Surface winds will
be from the west across north and central Idaho at 5-10 mph. Southern Idaho
will experience winds from the southwest at 5-10 mph with locally northwest
winds within the Treasure Valley. Skies
will be mostly to partly sunny when not obscured by smoke. Mixing heights will range from 3,000-8,000
feet AGL across all of Idaho today with poor to marginal ventilation over the
Snake River Plain and from Weiser and south within the Snake River Plain to
Gooding County. Transport winds will be
from the southeast to southwest at 5-10 mph.
This system is expected to slowly track to the southwest
through Sunday, further reducing its influence over Idaho. Tomorrow will see a widespread chance of afternoon
thunderstorms over the highlands surrounding the Snake River Plain with surface
winds ranging from 10-20 mph over all Idaho airsheds. Sunday will see southwest
to northwest winds at 5-10 mph. By
Monday, slight ridging is expected to occur which will serve to limit surface
wind speeds and inhibit the clearing of smoke. An easterly wind component will
develop over central and northern Idaho which could promote the advection of
smoke into the area.
Improvement of air quality is expected across southern Idaho
with the exception of the Lower Treasure Valley and north to McCall. It is important to note that while
improvement will occur, conditions will remain degraded; however not to the
extent experienced this past week.
Improvement from Hazardous is expected over the border of Idaho and
Washington on Saturday and Sunday; however levels will remain elevated. Expect nocturnal drainage smoke to enter the
Upper Snake River Plain via the Birch, Little Lost, and Big Lost drainages and
into the Lower Treasure Valley via the Weiser and Payette drainages each
evening with an emphasis on Sunday night into Monday. North and central Idaho will continue to see
very high levels of surface smoke throughout the weekend as the change in winds
will bring smoke from fires burning in the Northwest and southern British
Columbia.
