* WHAT...For the Air Stagnation Advisory, light winds and limited
air movement will lead to a period of stagnant air conditions.
This scenario could result in the build up of air pollutants over
time. For the Freezing Fog Advisory, areas of fog and freezing
fog, with visibility one quarter mile or less at times.
* WHERE...Central and Southern Willamette Valley.
* WHEN...For the Air Stagnation Advisory, until 4 AM PST Thursday.
For the Freezing Fog Advisory, until noon PST today.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems. Low visibility could make driving
conditions hazardous. With freezing temperatures, moisture in the
fog could freeze on bridges and overpasses, making slick and icy
spots.
* WHAT...Visibility one quarter to one half mile in areas of dense
fog and freezing fog.
* WHERE...Hood Canal Area, Bellevue and Vicinity, Bremerton and
Vicinity, Everett and Vicinity, Seattle and Vicinity, Southwest
Interior, and Tacoma Area.
* WHEN...Until 10 AM PST this morning.
* IMPACTS...Areas of low visibility could make driving conditions
hazardous.
* ADDITIONAL DETAILS...Sub-freezing temperatures have caused areas
of freezing fog, which may cause black ice to form on roadways.
* 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 in valleys.
* WHERE...Portions of south central, southwest, and west central
Idaho and northeast and southeast Oregon.
* WHEN...Until 5 PM MST /4 PM PST/ Saturday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems.
* WHAT...For the Air Stagnation Advisory in valleys, 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. For the Dense Fog Advisory,
visibility one quarter mile or less in dense fog.
* WHERE...Lower Treasure Valley Zones.
* WHEN...For the Air Stagnation Advisory, until 5 PM MST Saturday.
For the Dense Fog Advisory, until 2 PM MST Thursday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems. Low visibility could make driving conditions
hazardous.
* WHAT...For the Air Stagnation Advisory in valleys, 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. For the Dense Fog Advisory,
visibility one quarter mile or less in dense fog.
* WHERE...Lower Treasure Valley Zones.
* WHEN...For the Air Stagnation Advisory, until 5 PM MST Saturday.
For the Dense Fog Advisory, until 2 PM MST Thursday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems. Low visibility could make driving conditions
hazardous.
* WHAT...A ridge of high pressure will lead to a strong inversion
and stagnant air conditions near the surface that will continue to
trap pollutants. This could worsen air quality over time.
* WHERE...Valley locations across southern Oregon. West of the
Cascades, this includes the Umpqua, Illinois, Applegate, and Rogue
valleys. East of the Cascades, this includes Klamath Falls,
Sprague River, Chiloquin, Chemult, Silver Lake, Paisley, and
surrounding areas.
* WHEN...Until 4 PM PST Friday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems.
Dense freezing fog has formed along Interstate 84 east of
Pendleton on Cabbage Hill, with visibilities less than one
quarter mile. Motorists are urged to use caution when traveling
this stretch of interstate tonight and be alert for patches of ice
on the roadways.
* WHAT...Visibility less than one quarter of a mile in freezing fog.
* WHERE...John Day Basin.
* WHEN...Until 11 AM PST Wednesday.
* IMPACTS...Low visibility and slick roads could make driving
conditions hazardous.
* WHAT...Visibility less than one quarter of a mile in freezing fog.
* WHERE...Central Oregon.
* WHEN...Until 11 AM PST Wednesday.
* IMPACTS...Low visibility and slick roads could make driving
conditions hazardous.
* WHAT...Visibility less than one quarter mile in freezing fog.
* WHERE...Foothills of the Southern Blue Mountains of Oregon and
North Central Oregon.
* WHEN...Until 11 AM PST Wednesday.
* IMPACTS...Low visibility and slick roads 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 in valleys.
* WHERE...Portions of south central, southwest, and west central
Idaho and northeast and southeast Oregon.
* WHEN...Until 5 PM MST /4 PM PST/ Saturday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems.
* WHAT...For the Air Stagnation Advisory in valleys, 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. For the Dense Fog Advisory,
visibility one quarter mile or less in dense fog.
* WHERE...Lower Treasure Valley Zones.
* WHEN...For the Air Stagnation Advisory, until 5 PM MST Saturday.
For the Dense Fog Advisory, until 2 PM MST Thursday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems. Low visibility could make driving conditions
hazardous.
* WHAT...For the Air Stagnation Advisory in valleys, 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. For the Dense Fog Advisory,
visibility one quarter mile or less in dense fog.
* WHERE...Lower Treasure Valley Zones.
* WHEN...For the Air Stagnation Advisory, until 5 PM MST Saturday.
For the Dense Fog Advisory, until 2 PM MST Thursday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems. Low visibility could make driving conditions
hazardous.
* WHAT...Light winds and limited air movement will lead to a period
of stagnant air conditions. This scenario could result in the
build up of air pollutants over time.
* WHERE...Foothills of the Northern and Central Oregon Cascades,
North and Central Coast Range Valleys of Oregon, Lower Columbia
River and Cowlitz River Valleys, Tualatin Valley, Outer Southeast
Portland Metro, Willapa and Wahkiakum Lowlands, North Clark County
Lowlands, and South Washington Cascade Foothills.
* WHEN...Until 4 AM PST Thursday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems.
* WHAT...Light winds and limited air movement will lead to a period
of stagnant air conditions. This scenario could result in the
build up of air pollutants over time.
* WHERE...Inner Vancouver Metro.
* WHEN...Until 4 AM PST Thursday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems.
* WHAT...Light winds and limited air movement will lead to a period
of stagnant air conditions. This scenario could result in the
build up of air pollutants over time.
* WHERE...Foothills of the Northern and Central Oregon Cascades,
North and Central Coast Range Valleys of Oregon, Lower Columbia
River and Cowlitz River Valleys, Tualatin Valley, Outer Southeast
Portland Metro, Willapa and Wahkiakum Lowlands, North Clark County
Lowlands, and South Washington Cascade Foothills.
* WHEN...Until 4 AM PST Thursday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems.
* WHAT...For the Freezing Fog Advisory, areas of fog and freezing
fog, with visibility one quarter mile or less. For the Air
Stagnation Advisory, poor air quality will continue. This is due
to an inversion and stagnant air conditions near the surface that
will continue to trap pollutants.
* WHERE...Central and Southern Willamette Valley.
* WHEN...For the Freezing Fog Advisory, until noon PST Wednesday.
For the Air Stagnation Advisory, until 4 AM PST Thursday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems. Fog will be reforming this evening. Low
visibility could make driving conditions hazardous. With freezing
temperatures, moisture in the fog could freeze on bridges and
overpasses, making slick and icy spots.
* WHAT...For the Freezing Fog Advisory, areas of fog and freezing
fog, with visibility one quarter mile or less. For the Air
Stagnation Advisory, poor air quality will continue. This is due
to an inversion and stagnant air conditions near the surface that
will continue to trap pollutants.
* WHERE...Central and Southern Willamette Valley.
* WHEN...For the Freezing Fog Advisory, until noon PST Wednesday.
For the Air Stagnation Advisory, until 4 AM PST Thursday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems. Fog will be reforming this evening. Low
visibility could make driving conditions hazardous. With freezing
temperatures, moisture in the fog could freeze on bridges and
overpasses, making slick and icy spots.
* WHAT...A ridge of high pressure will lead to a strong inversion
and stagnant air conditions near the surface that will continue to
trap pollutants. This could worsen air quality over time.
* WHERE...Valley locations across southern Oregon. West of the
Cascades, this includes the Umpqua, Illinois, Applegate, and Rogue
valleys. East of the Cascades, this includes Klamath Falls,
Sprague River, Chiloquin, Chemult, Silver Lake, Paisley, and
surrounding areas.
* WHEN...For the Cold Weather Advisory, from 2 AM to 8 AM PST Monday.
For the Air Stagnation Advisory, until 4 PM PST Wednesday.
* IMPACTS...Low visibility could make driving conditions hazardous.
Watch for icy spots on roads. Poor air quality may cause issues
for people with respiratory problems.
* 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 in valleys.
* WHERE...Portions of south central, southwest, and west central
Idaho and northeast and southeast Oregon.
* WHEN...Until 5 PM MST /4 PM PST/ Saturday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems.