* WHAT...An extended period of stagnant air, with light winds
and little vertical mixing.
* WHERE...Portions of southwest and west central Idaho and
northeast and southeast Oregon.
* WHEN...Until 5 AM MST /4 AM PST/ Sunday.
* IMPACTS...Periods of air stagnation can lead to the buildup of
pollutants near the surface.
This weekend will see multiple storms with heavy rain and snow
levels starting at 6000 feet and remaining above 4000 feet.
* WHAT...Flooding caused by excessive rainfall is possible.
* WHERE...A portion of northwest Washington, including the following
county, Mason.
* WHEN...From Sunday evening through late Monday night.
* IMPACTS...Excessive runoff may result in flooding of rivers,
creeks, streams, and other low-lying and flood-prone locations.
Low-water crossings may be flooded.
* ADDITIONAL DETAILS...
- Progressively stronger storms starting Saturday will produce
heavy rain in the Olympic Mountains. Two to four inches of
rain are expected Sunday night through Monday and another
three to six inches Tuesday night into Thursday. With snow
levels above the top of the Skokomish River watershed, this
rain will likely drive the Skokomish river above flood stage
overnight Sunday and possibly above moderate stage with the
third storm.
- http://www.weather.gov/safety/flood
* WHAT...Visibility one quarter mile or less in dense fog.
* WHERE...Across the Umpqua Valley in Central Douglas County.
* WHEN...Until 9 AM PST this morning.
* IMPACTS...Low visibility could make driving conditions hazardous.
* WHAT...An extended period of stagnant air, with light winds and
little vertical mixing. This is due to an inversion near the
surface that will continue to trap pollutants.
* WHERE...Portions of southwest and west central Idaho and northeast
and southeast Oregon.
* WHEN...Until 5 AM MST /4 AM PST/ Sunday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems.
* WHAT...Visibility one quarter mile or less in dense fog.
* WHERE...South Willamette Valley.
* WHEN...Until noon PST today.
* IMPACTS...Low visibility could make driving conditions hazardous.
* WHAT...Visibility one quarter mile or less in dense fog.
* WHERE...Across the Umpqua Valley in Central Douglas County.
* WHEN...Until 8 AM PST this morning.
* IMPACTS...Low visibility could make driving conditions hazardous.
* WHAT...Visibility one quarter mile or less at times in dense fog.
* WHERE...South Willamette Valley.
* WHEN...Until 9 AM PST this morning.
* IMPACTS...Low visibility could make driving conditions hazardous.
* WHAT...Visibility one quarter mile or less at times in dense fog.
* WHERE...Central and Southern Willamette Valley.
* WHEN...Until 9 AM PST this morning.
* IMPACTS...Low visibility could make driving conditions hazardous.
* WHAT...Snow above 4500 feet. Additional snow accumulations up to
two inches.
* WHERE...In Oregon, Northern Blue Mountains of Oregon. In
Washington, Northwest Blue Mountains.
* WHEN...Until 4 PM PST this afternoon.
* IMPACTS...Plan on slippery road conditions.
* WHAT...Snow above 4000 feet. Additional snow accumulations up to
one inch.
* WHERE...Upper Slopes of the Eastern Washington Cascades Crest.
* WHEN...Until 10 AM PST this morning.
* IMPACTS...Plan on slippery road conditions.
* WHAT...Snow above 4500 feet. Additional snow accumulations up to
two inches.
* WHERE...In Oregon, Northern Blue Mountains of Oregon. In
Washington, Northwest Blue Mountains.
* WHEN...Until 4 PM PST this afternoon.
* IMPACTS...Plan on slippery road conditions.
* WHAT...Heavy snow. Additional snow accumulations up to two inches.
Winds gusting as high as 40 mph.
* WHERE...Stevens Pass.
* WHEN...Until 10 AM PST this morning.
* IMPACTS...Plan on winter driving conditions on Highway 2 near
Stevens Pass.
* WHAT...Heavy snow at or above elevations greater than 3500 ft.
Additional snow accumulations up to 3 inches.
* WHERE...West Slopes North Central Cascades and Passes.
* WHEN...Until 10 AM PST this morning.
* IMPACTS...Visibilities may drop below 1/4 mile due to falling and
blowing snow. The strong winds and weight of snow on tree limbs
may down power lines and could cause sporadic power outages. Plan
on slippery road conditions. The hazardous conditions could impact
the Tuesday morning commute.
* WHAT...Snow at or above elevations greater than 3500 ft.
Additional snow accumulations up to one inch. Winds gusting as
high as 40 mph.
* WHERE...West Slopes South Central Cascades and Passes.
* WHEN...Until 10 AM PST this morning.
* IMPACTS...Travel could be very difficult. The hazardous conditions
could impact travel across the passes. Gusty winds could bring
down tree branches.
* WHAT...Heavy snow. Additional snow accumulations up to 4 inches.
Winds gusting as high as 40 mph.
* WHERE...Stevens Pass and Holden Village.
* WHEN...Until 10 AM PST this morning.
* IMPACTS...Plan on winter driving conditions on Highway 2 near
Stevens Pass.
* WHAT...Snow above 4500 feet. Additional snow accumulations between
2 and 7 inches. Winds gusting as high as 45 mph.
* WHERE...In Oregon, Northern Blue Mountains of Oregon. In
Washington, Northwest Blue Mountains.
* WHEN...Until 4 PM PST Tuesday.
* IMPACTS...Travel could be difficult due to periods of moderate to
heavy snow. Gusty winds could bring down tree branches.
* ADDITIONAL DETAILS...Snow rates will briefly decrease Monday
evening, but is expected to increased again through Tuesday
morning.
* WHAT...Snow above 4000 feet. Additional snow accumulations up to 6
inches. Winds gusting as high as 50 mph.
* WHERE...Upper Slopes of the Eastern Washington Cascades Crest.
* WHEN...Until 10 AM PST Tuesday.
* IMPACTS...Travel could be difficult due to periods of moderate to
heavy snow. Gusty winds could bring down tree branches.
* ADDITIONAL DETAILS...Snow rates may lessen notably on Monday after
the initial line of activity, but a deformation band could set up
and bring further locally heavy accumulations late Monday into
Tuesday.