Updated 0900 MDT Wednesday,
July 16, 2014
Valid through Noon MDT Thursday,
July 17, 2014
Smoke Outlook
Garden Valley continues to be impacted by smoke from the
Whiskey Complex to the southeast. Air
quality was in the moderate AQI category yesterday. The air quality today is forecast to be
slightly worse than yesterday. Air
quality is worse in the morning before improving in the
afternoon and early evening hours and degrading again once the sun sets. Yesterday, periods of Very Unhealthy were observed before clearing out the Good after noon. Garden Valley is forecast to be Moderate
today with periods of Unhealthy and Unhealthy for Sensitive Groups in the
morning. Idaho City is currently
experiencing periods of Unhealthy air quality before improving in the afternoon
due to impacts from the Whiskey Complex.
The northwest flow aloft will slowly transition to
westerly flow by Thursday. High pressure
will dominate the area over the next two days which will bring warm
temperatures and slow surface wind speeds. The
shift to westerly, or zonal, flow will continue to limit any influx of monsoon
moisture from the Southwest into Idaho.
This will limit potential thunderstorms through Saturday.
Across the Snake River Plain, winds will be light and
generally from the southwest with a strong southerly component over the Upper
Snake River Plain. Wind speeds at the
surface will range from 2-10 mph with terrain-driven winds through
tonight. Gusts across the Treasure
Valley will reach 15 mph late this afternoon.
Transport winds from the northwest at 5-15 mph. Mixing heights will range from 7,000-10,000ft
AGL this afternoon. The lower heights
and slower wind speeds of these ranges are expected across the Lower and Middle
Snake River Plain this afternoon with higher heights and faster wind speeds across
the Upper Snake River Plain. Coupled
with daytime heating, this will allow for decent mixing this afternoon.
Smoke impacts today are forecast to be higher than
yesterday in the Treasure Valley and western Magic Valley as surface winds look
to be lighter and inversion break times are forecast to be later in the day today. Inversion break time is forecast to be
between 11am and 1pm today across southern Idaho. This will allow smoke to build at the surface
this morning. Smoke from the fires in
the West Central Mountains will continue to impact the local communities in
Garden Valley and Idaho City. Drainage winds are forecast to transport the smoke into the eastern
Treasure Valley this morning before moving to the southeast. Coupled
with local fires, transport from Oregon may provide some hazy skies aloft with
the possibility of this smoke settling in the Treasure Valley this evening once
the sun sets. The Pittsburgh Fire, 22 miles NW of Riggins
can be expected to generate light impacts to communities along the I-95 Corridor
from Grangeville to Weiser.
Expect to see light smoke and haze across most of the
state today with the southeast being the only region spared. Smoke from fires in Washington and Canadian
British Columbia are forecast transport across northern and central Idaho by
5pm this evening. Impacts from these
sources are expected to be light. This
upper level smoke will likely be a larger contributor Thursday and Friday as
the weather pattern shifts to a more zonal flow.
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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