Updated
1000am MDT Tuesday, September 16, 2014
Valid
through Noon MDT Thursday, September 18, 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 that is advecting into the southwest portion of the state. Smoke from fires in Oregon is impacting the
northern part of Idaho. Smoke impacts
were limited to regions close to fires as DEQ’s monitors were slightly elevated
and in the Good and Moderate categories yesterday; however, the Grangeville
area experienced a 24hr AQI of Unhealthy for Sensitive Groups.
The
upper level ridge currently centered over Idaho will be suppressed today as an
upper level disturbance will traverse the ridge this morning from the Oregon
Coast and eventually pass over northern Idaho this afternoon. This will provide the opportunity for
isolated afternoon thunderstorms and showers.
Surface winds across the Clearwater drainage looks to be from the south
with a southwest component along a corridor running from the confluence of the
Snake and Salmon to the Clearwater confluence while farther east, surface winds
look to be from the south-southeast.
Conditions will be similar on Wednesday with a tightening of the surface
pressure gradient as a cold front approaches late Wednesday night into
Thursday. As such, there remains a chance
for breezy and gusty winds across the higher elevations in the Central Idaho
Mountains. The Clearwater looks to
remain under rather light wind conditions with variable wind directions.
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 will bring light smoke through the Snake River
Plain. 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. A brief pattern change will occur on Thursday, but by
Friday, another upper level ridge is forecast to develop in the same region and
persist into next Tuesday.
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
|
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