HAZARDOUS WEATHER OUTLOOK
Issue Date: 1023 AM PST SAT DEC 26 2009
Expiration: 515 AM PST SUN DEC 27 2009

Expires:200912271315;;
FLUS46 KPDT 261822 AAA
HWOPDT
HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
1022 AM PST SAT DEC 26 2009
UPDATED DAY ONE DISCUSSION AND DAYS TWO THROUGH SEVEN DISCUSSION.
ORZ041>044-049-050-501>506-WAZ024-026>030-501-502-271315-
EASTERN COLUMBIA RIVER GORGE OF OREGON-NORTH CENTRAL OREGON-
CENTRAL OREGON-LOWER COLUMBIA BASIN OF OREGON-GRANDE RONDE VALLEY-
WALLOWA COUNTY-FOOTHILLS OF THE BLUE MOUNTAINS OF OREGON-
NORTHERN BLUE MOUNTAINS OF OREGON-
SOUTHERN BLUE MOUNTAINS OF OREGON-
NORTHERN WHEELER AND SOUTHERN GILLIAM COUNTIES-JOHN DAY BASIN-
OCHOCO-JOHN DAY HIGHLANDS-
EASTERN COLUMBIA RIVER GORGE OF WASHINGTON-KITTITAS VALLEY-
YAKIMA VALLEY-LOWER COLUMBIA BASIN OF WASHINGTON-
FOOTHILLS OF THE BLUE MOUNTAINS OF WASHINGTON-
NORTHWEST BLUE MOUNTAINS-
EAST SLOPES OF THE CENTRAL CASCADES OF WASHINGTON-
EAST SLOPES OF THE SOUTHERN CASCADES OF WASHINGTON-
1022 AM PST SAT DEC 26 2009
THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL...NORTH CENTRAL AND
NORTHEAST OREGON AS WELL AS SOUTH CENTRAL AND SOUTHEAST WASHINGTON.
.DAY ONE...TODAY AND TONIGHT
AIR STAGNATION ADVISORY
     EAST SLOPES OF THE CENTRAL CASCADES OF WASHINGTON, EAST SLOPES
     OF THE SOUTHERN CASCADES OF WASHINGTON, EASTERN COLUMBIA RIVER
     GORGE OF WASHINGTON, KITTITAS VALLEY, YAKIMA VALLEY, LOWER
     COLUMBIA BASIN OF WASHINGTON, FOOTHILLS OF THE BLUE MOUNTAINS
     OF WASHINGTON, EASTERN COLUMBIA RIVER GORGE OF OREGON, NORTH
     CENTRAL OREGON, CENTRAL OREGON, LOWER COLUMBIA BASIN OF
     OREGON, GRANDE RONDE VALLEY, FOOTHILLS OF THE BLUE MOUNTAINS
     OF OREGON, NORTHERN WHEELER AND SOUTHERN GILLIAM COUNTIES,
     JOHN DAY BASIN
THE COMBINATION OF A STRONG HIGH PRESSURE RIDGE ALOFT WITH VERY
LIGHT OR CALM SURFACE WINDS AND STRONG SURFACE BASED TEMPERATURE
INVERSIONS IN THE LOWEST 10000 FEET ABOVE MSL WILL MAINTAIN A STABLE
AIRMASS AND STAGNANT AIR CONDITIONS RESULTING IN LOW MIXING HEIGHTS
WHICH WILL TRAP AIR POLLUTANTS IN THE BOUNDARY LAYER IN THE AREAS
LISTED ABOVE. AS SUCH AN AIR STAGNATION ADVISORY IS IN EFFECT FOR
THESE AREAS. PLEASE REFER TO PDXNPWPDT FOR MORE DETAILS.
.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY
AIR STAGNATION ADVISORY UNTIL 4 PM PST MONDAY
     EAST SLOPES OF THE CENTRAL CASCADES OF WASHINGTON, EAST SLOPES
     OF THE SOUTHERN CASCADES OF WASHINGTON, EASTERN COLUMBIA RIVER
     GORGE OF WASHINGTON, KITTITAS VALLEY, YAKIMA VALLEY, LOWER
     COLUMBIA BASIN OF WASHINGTON, FOOTHILLS OF THE BLUE MOUNTAINS
     OF WASHINGTON, EASTERN COLUMBIA RIVER GORGE OF OREGON, NORTH
     CENTRAL OREGON, CENTRAL OREGON, LOWER COLUMBIA BASIN OF
     OREGON, GRANDE RONDE VALLEY, FOOTHILLS OF THE BLUE MOUNTAINS
     OF OREGON, NORTHERN WHEELER AND SOUTHERN GILLIAM COUNTIES,
     JOHN DAY BASIN
STRONG TEMPERATURE INVERSIONS WILL CAUSE STABLE CONDITIONS...LOW
MIXING HEIGHTS AND VERY LIGHT OR CALM WINDS TO PERSIST THROUGH
MONDAY. AS A RESULT THE AIR STAGNATION ADVISORY IS NOW IN EFFECT
UNTIL 4 PM PST MONDAY. PLEASE REFER TO PDXNPWPDT FOR MORE DETAILS.
STRONG TEMPERATURE INVERSIONS WILL CAUSE STABLE CONDITIONS AND LOW
MIXING HEIGHTS TO CONTINUE MONDAY NIGHT AND TUESDAY THUS PRODUCING
WIDESPREAD LOW CLOUDS AND PATCHY FOG OVER MUCH OF THE AREA THROUGH
TUESDAY.
MULTIPLE WEATHER SYSTEMS ARE EXPECTED TO MOVE THROUGH THE REGION
LATER THIS WEEK...WITH INCREASING PRECIPITATION CHANCES TUESDAY
THROUGH FRIDAY.
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME.
WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
GRAPHICAL FORECASTS OF WEATHER HAZARDS OUT TO SEVEN DAYS
ARE DISPLAYED ON THE WORLD WIDE WEB AT:
WWW.WRH.NOAA.GOV/PDT/CURRENTHAZARDS/HWO.HTML
ALL LETTERS IN THE ABOVE URL ARE LOWER CASE...EXCEPT THE H IN
CURRENTHAZARDS.
$$

AIR STAGNATION ADVISORY
Issue Date: 929 AM PST SAT DEC 26 2009
Expiration: 400 PM PST MON DEC 28 2009

...AIR STAGNATION ADVISORY NOW IN EFFECT UNTIL 4 PM PST MONDAY...
THE AIR STAGNATION ADVISORY IS NOW IN EFFECT UNTIL 4 PM PST
MONDAY.
* AIR QUALITY MAY DETERIORATE AS A RESULT OF INCREASING AIR
POLLUTION LEVELS IN VALLEYS AND BASINS DUE TO STABLE CONDITIONS
AND VERY LIGHT WINDS LIMITING MIXING HEIGHTS AND AIR MOVEMENT.
* AIR STAGNATION WILL CAUSE THE ACCUMULATION OF PARTICULATE
MATTER IN VALLEYS AND BASINS BELOW 3500 FEET.
* POOR AIR QUALITY MAY AFFECT PERSONS WITH RESPIRATORY PROBLEMS
AND PERSONS ENGAGED IN STRENUOUS OUTDOOR ACTIVITIES.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
AN AIR STAGNATION ADVISORY INDICATES THAT DUE TO LIMITED MOVEMENT
OF AN AIR MASS ACROSS THE ADVISORY AREA...POLLUTION WILL
INCREASE. CHECK WITH YOUR LOCAL AIR QUALITY AGENCY FOR POSSIBLE
RESTRICTIONS IN YOUR AREA. FOR ADDITIONAL WEATHER INFORMATION...
CHECK OUR WEBSITE AT WWW.WEATHER.GOV/PENDLETON.
$$

AIR STAGNATION ADVISORY
Issue Date: 225 PM PST WED DEC 23 2009
Expiration: 400 PM PST SAT DEC 26 2009

...AIR STAGNATION ADVISORY IN EFFECT FROM 4 AM THURSDAY TO 4 PM
PST SATURDAY...
THE NATIONAL WEATHER SERVICE IN PENDLETON HAS ISSUED AN AIR
STAGNATION ADVISORY...WHICH IS IN EFFECT FROM 4 AM THURSDAY TO
4 PM PST SATURDAY.
* AIR QUALITY: WILL DETERIORATE IN VALLEYS AND BASINS DUE TO HIGH
PRESSURE LIMITING AIR MOVEMENT. THIS WILL CAUSE THE ACCUMULATION
OF PARTICULATE MATTER IN VALLEYS AND BASINS MAINLY BELOW 3500
FEET.
* IMPACTS: POOR AIR QUALITY WILL AFFECT PERSONS WITH RESPIRATORY
PROBLEMS AND PERSONS ENGAGED IN STRENUOUS OUTDOOR ACTIVITIES.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
AN AIR STAGNATION ADVISORY INDICATES THAT DUE TO LIMITED MOVEMENT
OF AN AIR MASS ACROSS THE ADVISORY AREA...POLLUTION WILL INCREASE.
CHECK WITH YOUR LOCAL AIR QUALITY AGENCY FOR POSSIBLE
RESTRICTIONS IN YOUR AREA. FOR ADDITIONAL WEATHER INFORMATION...
CHECK OUR WEBSITE AT WWW.WEATHER.GOV/PENDLETON.
$$