* WHAT...Visibilities one-quarter mile or less in freezing fog.
* WHERE...Foothills of the Southern Blue Mountains of Oregon and
North Central Oregon.
* WHEN...Until 11 AM PST Tuesday.
* 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 in valleys.
* WHERE...Portions of south central, southwest, and west central
Idaho and northeast and southeast Oregon.
* WHEN...Until 9 PM MST /8 PM PST/ Friday.
* IMPACTS...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.
Dense fog has decreased this afternoon, but will likely increase
again this evening through Tuesday.
* WHERE...Lower Treasure Valley Zones.
* WHEN...Until 9 PM MST Friday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems.
* WHAT...Visibilities one-quarter mile or less in freezing fog.
* WHERE...Foothills of the Southern Blue Mountains of Oregon and
North Central Oregon.
* WHEN...Until 3 PM PST this afternoon.
* IMPACTS...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.
* 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...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.
* WHEN...Until 4 AM PST Thursday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems.
* WHAT...Visibilities one-quarter mile or less in freezing fog.
* WHERE...Foothills of the Southern Blue Mountains of Oregon and
North Central Oregon.
* WHEN...Until 3 PM PST this afternoon.
* IMPACTS...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...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...For the Dense Fog Advisory, visibility less than one mile
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 in Idaho and Oregon.
* WHEN...For the Dense Fog Advisory, until 2 PM MST this afternoon.
For the Air Stagnation Advisory, until 9 PM MST Friday.
* 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 9 PM MST /8 PM PST/ Friday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems.
* WHAT...For the Dense Fog Advisory, visibility less than one mile
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 in Idaho and Oregon.
* WHEN...For the Dense Fog Advisory, until 2 PM MST this afternoon.
For the Air Stagnation Advisory, until 9 PM MST Friday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems. Low visibility could make driving conditions
hazardous.
* WHAT...Temperatures will continue warming this morning, allowing
the cold weather advisory to expire. 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...For the Air Stagnation Advisory, the Rogue, Applegate and
Sams valleys in Jackson County, including Medford, Talent,
Phoenix, Eagle Point, Central Point, Jacksonville, Applegate and
Shady Cove.
* WHEN...Until 4 PM PST Wednesday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems.
* 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, including Grants Pass, Sunny Valley, Galice, Murphy,
Selma, Cave Junction and O'Briend. East of the Cascades, this
includes Klamath Falls, Sprague River, Chiloquin, Chemult, Silver
Lake, Paisley, and surrounding areas.
* WHEN...Until 4 PM PST Wednesday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems.
* WHAT...Temperatures of 33 to 36 will result in frost formation.
* WHERE...South Central Oregon Coast, including all coastal areas
from Port Orford north to around Reedsport as well as the Coquille
Valley.
* WHEN...Until 9 AM PST this morning.
* IMPACTS...Frost could harm sensitive outdoor vegetation. Sensitive
outdoor plants may be killed if left uncovered.
* ADDITIONAL DETAILS...A few of the typically colder locations could
fall to freezing.
* WHAT...Temperatures will continue warming this morning, allowing
the cold weather advisory to expire. 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...For the Air Stagnation Advisory, the Rogue, Applegate and
Sams valleys in Jackson County, including Medford, Talent,
Phoenix, Eagle Point, Central Point, Jacksonville, Applegate and
Shady Cove.
* WHEN...Until 4 PM PST Wednesday.
* IMPACTS...Poor air quality may cause issues for people with
respiratory problems.
* WHAT...Visibility less than one half mile locally less than one
quarter mile.
* WHERE...Central Oregon, Foothills of the Southern Blue Mountains
of Oregon, and North Central Oregon.
* WHEN...Until 11 AM PST this morning.
* IMPACTS...Low visibility will make driving conditions hazardous.
Slick road conditions may also develop especially on bridges and
overpasses.
* 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 Dense Fog Advisory, visibility one quarter mile or
less in dense fog.
* WHERE...Central Willamette Valley.
* WHEN...For the Air Stagnation Advisory, until 4 AM PST Thursday.
For the Dense Fog Advisory, until 11 AM PST this morning.
* IMPACTS...Deteriorating 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...Deteriorating 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, 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.
* WHEN...For the Air Stagnation Advisory, until 4 AM PST Thursday.
For the Dense Fog Advisory, until 11 AM PST this morning.
* IMPACTS...Deteriorating air quality may cause issues for people
with respiratory problems. Low visibility could make driving
conditions hazardous.
