* 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.
* WHAT...For the Dense Fog Advisory, visibility one quarter mile or
less in dense fog. 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.
* WHERE...Lower Treasure Valley Zones.
* WHEN...For the Dense Fog Advisory, until 2 PM MST Thursday. For
the Air Stagnation Advisory, until 5 PM MST Saturday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems. Low visibility could make driving conditions
hazardous.
* WHAT...For the Dense Fog Advisory, visibility one quarter mile or
less in dense fog. 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.
* WHERE...Lower Treasure Valley Zones.
* WHEN...For the Dense Fog Advisory, until 2 PM MST Thursday. For
the Air Stagnation Advisory, until 5 PM MST Saturday.
* 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...Central and Southern Willamette Valley, 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...Visibility less than one mile in freezing fog.
* WHERE...Central Oregon.
* WHEN...Until 11 AM PST Wednesday.
* IMPACTS...Low visibility could make driving conditions hazardous.
* ADDITIONAL DETAILS...Visibilities are expected to improve in parts
of central Oregon this afternoon, before fog redevelops this
evening.
* WHAT...Visibility less than one 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 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 to one half mile 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 this afternoon.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems. 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 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 to one half mile 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 this afternoon.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems. Low visibility could make driving conditions
hazardous.
* WHAT...Visibility less than one quarter mile in freezing fog.
* WHERE...Central Oregon.
* WHEN...Until 11 AM PST this morning.
* IMPACTS...Low visibility and slick roadways will 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 this morning.
* IMPACTS...Low visibility and slick roadways will make driving
conditions hazardous.
* 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, visibility one quarter mile
or less at times in areas of dense freezing fog.
* WHERE...Central and Southern Willamette Valley.
* WHEN...For the Air Stagnation Advisory, until 4 AM PST Thursday.
For the Freezing Fog Advisory, until 11 AM PST this morning.
* IMPACTS...Deteriorating air quality may cause issues for people
with respiratory problems. Low visibility in areas of dense
freezing fog could make driving conditions hazardous.
* ADDITIONAL DETAILS...Frost is possible on elevated surfaces and
grassy surfaces, as well as bridges and overpasses.
* 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...Deteriorating air quality may cause issues for people
with respiratory problems.
* 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, visibility one quarter mile
or less at times in areas of dense freezing fog.
* WHERE...Central and Southern Willamette Valley.
* WHEN...For the Air Stagnation Advisory, until 4 AM PST Thursday.
For the Freezing Fog Advisory, until 11 AM PST this morning.
* IMPACTS...Deteriorating air quality may cause issues for people
with respiratory problems. Low visibility in areas of dense
freezing fog could make driving conditions hazardous.
* ADDITIONAL DETAILS...Frost is possible on elevated surfaces and
grassy surfaces, as well as bridges and overpasses.
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...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...Deteriorating air quality may cause issues for people
with respiratory problems.
* WHAT...For the Freezing Fog Advisory, visibility one quarter mile
or less in areas of dense freezing fog. 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.
* WHERE...South Willamette Valley, and East Central Willamette
Valley.
* WHEN...For the Air Stagnation Advisory, until 4 AM PST Thursday.
For the Freezing Fog Advisory, until 11 AM PST Tuesday.
* IMPACTS...Deteriorating air quality may cause issues for people
with respiratory problems. Low visibility in areas of dense
freezing fog could make driving conditions hazardous.
* ADDITIONAL DETAILS...Dense fog will impact portions of the I-5
corridor from Salem to Eugene. Frost is possible on elevated
surfaces and grassy surfaces, as well as bridges and overpasses.
* WHAT...For the Freezing Fog Advisory, visibility one quarter mile
or less in areas of dense freezing fog. 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.
* WHERE...West Central Willamette Valley.
* WHEN...For the Freezing Fog Advisory, until 11 AM PST Tuesday. For
the Air Stagnation Advisory, until 4 AM PST Thursday.
* IMPACTS...Deteriorating air quality may cause issues for people
with respiratory problems. Low visibility in areas of dense
freezing fog could make driving conditions hazardous.
* ADDITIONAL DETAILS...Frost is possible on elevated surfaces and
grassy surfaces, as well as bridges and overpasses.
* WHAT...For the Freezing Fog Advisory, visibility one quarter mile
or less in areas of dense freezing fog. 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.
* WHERE...South Willamette Valley, and East Central Willamette
Valley.
* WHEN...For the Air Stagnation Advisory, until 4 AM PST Thursday.
For the Freezing Fog Advisory, until 11 AM PST Tuesday.
* IMPACTS...Deteriorating air quality may cause issues for people
with respiratory problems. Low visibility in areas of dense
freezing fog could make driving conditions hazardous.
* ADDITIONAL DETAILS...Dense fog will impact portions of the I-5
corridor from Salem to Eugene. Frost is possible on elevated
surfaces and grassy surfaces, as well as bridges and overpasses.
