Aggregator

* WHAT...Visibility one quarter of a mile or less in freezing fog. * WHERE...Foothills of the Southern Blue Mountains of Oregon and North Central Oregon. * WHEN...Until 11 AM PST Friday. * IMPACTS...Low visibility and slick roads 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, Central Willamette Valley, Tualatin Valley, Outer Southeast Portland Metro, Willapa and Wahkiakum Lowlands, North Clark County Lowlands, and South Washington Cascade Foothills. * WHEN...Until 4 AM PST Saturday. * 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 Saturday. * 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, Central Willamette Valley, Tualatin Valley, Outer Southeast Portland Metro, Willapa and Wahkiakum Lowlands, North Clark County Lowlands, and South Washington Cascade Foothills. * WHEN...Until 4 AM PST Saturday. * IMPACTS...Poor 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 Dense Fog Advisory, visibility frequently below one quarter mile in dense fog and areas of freezing fog. * WHERE...South Willamette Valley. * WHEN...For the Air Stagnation Advisory, until 4 AM PST Saturday. For the Dense Fog Advisory, until 11 AM PST Friday. * IMPACTS...Poor air quality may cause issues for people with respiratory problems. Low visibility could make driving conditions hazardous. * ADDITIONAL DETAILS...Fog will reform and increase across the south Willamette Valley this evening. Overall, temperatures will hold at or just above freezing overnight. But, a few spots will drop back below freezing. As such, motorists should be prepared for potentially icy or slick spots, especially on less-traveled rural roadways and bridges.

* 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 frequently below one quarter mile in dense fog and areas of freezing fog. * WHERE...South Willamette Valley. * WHEN...For the Air Stagnation Advisory, until 4 AM PST Saturday. For the Dense Fog Advisory, until 11 AM PST Friday. * IMPACTS...Poor air quality may cause issues for people with respiratory problems. Low visibility could make driving conditions hazardous. * ADDITIONAL DETAILS...Fog will reform and increase across the south Willamette Valley this evening. Overall, temperatures will hold at or just above freezing overnight. But, a few spots will drop back below freezing. As such, motorists should be prepared for potentially icy or slick spots, especially on less-traveled rural roadways and bridges.

* 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 AM PST Saturday. * 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.

Dense freezing fog will continue along Interstate 84 east of Pendleton towards Cabbage Hill, with visibilities less than one quarter mile. Motorists are urged to use caution when traveling this stretch of interstate this afternoon tonight and be alert for patches of ice on the roadway.

* 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 Saturday. * IMPACTS...Deteriorating 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, Central Willamette Valley, Tualatin Valley, Outer Southeast Portland Metro, Willapa and Wahkiakum Lowlands, North Clark County Lowlands, and South Washington Cascade Foothills. * WHEN...Until 4 AM PST Saturday. * IMPACTS...Deteriorating 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...South Willamette Valley. * WHEN...Until 4 AM PST Saturday. * 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, Central Willamette Valley, Tualatin Valley, Outer Southeast Portland Metro, Willapa and Wahkiakum Lowlands, North Clark County Lowlands, and South Washington Cascade Foothills. * WHEN...Until 4 AM PST Saturday. * IMPACTS...Deteriorating air quality may cause issues for people with respiratory problems.

If you are located in this coastal area, move inland to higher ground. Tsunami warnings mean that a tsunami with significant inundation is possible or is already occurring. Tsunamis are a series of waves dangerous many hours after initial arrival time. The first wave may not be the largest. At 1044 AM Pacific Standard Time on December 5 an earthquake with preliminary magnitude 7.3 occurred 45 miles southwest of Eureka California. Estimated tsunami start times for selected sites are; Fort Bragg California 1110 AM. PST. December 5. Crescent City California 1120 AM. PST. December 5. Port Orford Oregon 1120 AM. PST. December 5. Brookings Oregon 1125 AM. PST. December 5. Charleston Oregon 1140 AM. PST. December 5. San Francisco California 1210 PM. PST. December 5. The tsunami warning will remain in effect until further notice. Refer to the internet site tsunami.gov for more information.

* WHAT...Visibility less than one quarter mile in freezing fog. Although there will be some improvement in the visibility this afternoon, dense freezing fog will return tonight. * WHERE...Foothills of the Southern Blue Mountains of Oregon and North Central Oregon. * WHEN...Until 11 AM PST Friday. * IMPACTS...Low visibility and slick roads could make driving conditions hazardous. * ADDITIONAL DETAILS...Periods of light snow flurries or light freezing drizzle may be observed as well.

ESFSEW A stronger storm system will move though the area over much of the weekend that could produce enough rainfall to drive the Skokomish River above flood stage. There is still a fair amount of uncertainty regarding flooding since the precipitation forecasts have been quite variable. On the low end, it would not produce a flood, but on the high end minor flooding would be likely. Snow levels will remain quite high during the bulk of the heavy precipitation, ranging between 7000 and 9000 feet. Please monitor the latest river forecasts from the National Weather Service for additional information.

ESFSEW A stronger storm system will bring heavier rainfall to the northern and central portions of the Cascades in Washington this weekend. While uncertainty with respect to flood potential at individual river points remains high, confidence in heavier rainfall setting up across the mountains of Whatcom, Skagit, and Snohomish counties has increased. If the middle to high end forecast rainfall amounts occur, minor flooding is possible on rivers draining from the Cascades in these areas. Snow levels will remain quite high during the bulk of the heavy precipitation, ranging between 7000 and 9000 feet. Please monitor the latest river forecasts from the National Weather Service for additional information.

* 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...Treasure Valley Zones. * WHEN...For the Air Stagnation Advisory, until 5 PM MST Saturday. For the Dense Fog Advisory, until 2 PM MST Friday. * IMPACTS...Low visibility could make driving conditions hazardous especially for the morning commute. Poor air quality may cause issues for people with respiratory problems. Low visibility could make driving conditions hazardous. * ADDITIONAL DETAILS...Fog could produce patchy black ice and slick roads.

* 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...Treasure Valley Zones. * WHEN...For the Air Stagnation Advisory, until 5 PM MST Saturday. For the Dense Fog Advisory, until 2 PM MST Friday. * IMPACTS...Low visibility could make driving conditions hazardous especially for the morning commute. Poor air quality may cause issues for people with respiratory problems. Low visibility could make driving conditions hazardous. * ADDITIONAL DETAILS...Fog could produce patchy black ice and slick roads.

* WHAT...Valley locations may see poor air quality. This is due to an inversion and stagnant air conditions near the surface that will continue to trap pollutants. * WHERE...Valleys in Douglas, Josephine, and Jackson County. This includes the Umpqua, Illinois, Applegate, and Rogue valleys. * WHEN...Until 4 AM PST Saturday. * IMPACTS...Poor air quality may cause issues for people with respiratory problems.