Updated 1000am MDT Friday, September 26, 2014
Valid through Noon MDT Monday, September 29, 2014
Smoke Outlook
The areas of concern today will be focused on the Clearwater
Drainage where heavy smoke was visible within the drainages on yesterday’s visible
satellite imagery. Smoke impacts were
relatively local yesterday as all of DEQ’s monitors were in the Good category
for the 24hr AQI except for McCall, which was in the Moderate category, and the
temporary monitor in Lowell, which was in the Very Unhealthy category.
Latest satellite imagery clearly shows the upper level trough beginning
to dive south and is splitting from the upper level low pressure system
currently located off the coast of the Queen Charlotte Islands. There is a chance for morning showers across
the central and southwest parts of southern Idaho early this morning with a dry
period before showers return late this evening. Skies are expected to be partly
cloudy all day as isolated to scattered showers develop this morning before clearing
some, then showers again late in the afternoon.
Surface wind speeds will be between 5-15 mph with northwest flow in the
Southwest and Middle Snake River Plain with southwest flow across the rest
of Southern Idaho. Transport wind speed
is forecast to be in the range of 10-15 mph.
Transport wind direction is forecast to be south-southwest. This weekend looks to have persistent showery
weather across all of Idaho from I-90 south to the NV/UT border on both
Saturday and Sunday. Northerly winds
dominate the surface landscape on Saturday while easterly winds develop on
Sunday over the Clearwater Basin with speeds ranging from 5-10 mph. This weather is favorable for limiting fire
activity and smoke development; however, it also promotes low-hanging smoke in
low elevation regions and drainages.
This pattern persists into Monday as one upper level low pressure
systems tracks east; another system will approach the Washington Coast, near
Vancouver Island.
Smoke impacts today will be focused on the Central Idaho
Mountains with smoke forecast to cover Idaho north of a line running from
McCall to Salmon all the way to Sandpoint.
Light surface winds and an upper level split flow pattern will promote
limited dispersion as well as limited transport. Fires in California received some
precipitation last night which should help to limit smoke production. By Saturday, the limited movement of the
atmosphere will continue promote stagnant conditions with limited dispersion
coupled with a northerly wind shift, residual smoke is forecast to entrain to
the south. Smoke is forecast to cover a
region ranging from the Treasure Valley north to Sandpoint. On Sunday, coupled with the easterly wind
shift, impacts are forecast to stay north of the Salmon River to the Idaho
Canada border. There is a chance for
light impacts draining that evening into the Treasure Valley and east to
Mountain Home.
o
Riggins monitor is #1001
o
Lowell monitor is #1002
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
|
No comments:
Post a Comment