HAZARDOUS WEATHER OUTLOOK
Issue Date: 545 AM PST THU DEC 24 2009
Expiration: 545 AM PST FRI DEC 25 2009

Expires:200912251345;;
FLUS46 KPQR 241344
HWOPQR
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PORTLAND OR
544 AM PST THU DEC 24 2009
ORZ001>004-009>014-WAZ019>021-023-040-251345-
NORTH OREGON COAST-CENTRAL OREGON COAST-
COAST RANGE OF NORTHWEST OREGON-
CENTRAL COAST RANGE OF WESTERN OREGON-
WESTERN COLUMBIA RIVER GORGE-NORTHERN OREGON CASCADE FOOTHILLS-
NORTHERN OREGON CASCADES-CASCADE FOOTHILLS IN LANE COUNTY-
CASCADES IN LANE COUNTY-UPPER HOOD RIVER VALLEY-
SOUTH WASHINGTON CASCADES-WILLAPA HILLS-SOUTH WASHINGTON COAST-
SOUTH WASHINGTON CASCADE FOOTHILLS-
544 AM PST THU DEC 24 2009
THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST
OREGON AND SOUTHWEST WASHINGTON.
.DAY ONE...TODAY AND TONIGHT
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL NOT BE NEEDED.
$$

DENSE FOG ADVISORY
Issue Date: 417 AM PST THU DEC 24 2009
Expiration: 1000 AM PST THU DEC 24 2009

...DENSE FOG ADVISORY REMAINS IN EFFECT UNTIL 10 AM PST THIS
MORNING...
...AIR STAGNATION ADVISORY REMAINS IN EFFECT UNTIL 6 PM PST
SATURDAY FOR THE I-5 CORRIDOR IN COWLITZ COUNTY AND GREATER
VANCOUVER AREA...
A DENSE FOG ADVISORY REMAINS IN EFFECT UNTIL 10 AM PST THIS
MORNING. AN AIR STAGNATION ADVISORY REMAINS IN EFFECT UNTIL 6 PM
PST SATURDAY.
* IMPACTS...DENSE FOG WILL LOWER VISIBILITIES TO ONE QUARTER OF
  A MILE OR LESS. FREEZING TEMPERATURES WILL ALLOW THE FOG TO
  FREEZE TO SURFACES MAKING THEM SLIPPERY.
* TIMING...THROUGH 10 AM THURSDAY.
OFFSHORE FLOW OVER THE REGION WILL STRENGTHEN LATER TONIGHT AND
CONTINUE FOR THE REST OF THE WEEK INTO THE COMING WEEKEND.
HOWEVER...STRONG LOW LEVEL INVERSIONS WILL KEEP AREAS BELOW
1500 FEET FROM MIXING WELL. THIS WILL LEAD TO AIR QUALITY THAT
WILL GRADUALLY BECOME MORE POOR WITH TIME.
EAST WINDS OVER SOUTHERN CLARK COUNTY WILL BE STRONG ENOUGH TO
KEEP AREAS MIXED...WITH NO SIGNIFICANT AIR QUALITY CHANGE.
* AREAS AFFECTED...ACROSS NORTHERN CLARK COUNTY...EXTENDING
  NORTH THROUGH THE COWLITZ VALLEY.
* TIMING...THURSDAY THROUGH SATURDAY.
* AIR QUALITY...EXPECT SLOWLY DEGRADING AIR QUALITY.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
AN AIR STAGNATION ADVISORY IS ISSUED WHEN LOCALLY ESTABLISHED
CRITICAL VALUES OF TRANSPORT WINDS...MIXING HEIGHT...AND
VENTILATION ARE EXPECTED TO PERSIST FOR AT LEAST 72 HOURS. THIS
PRODUCT WILL BE UPDATED AT LEAST EVERY 24 HOURS WHEN CONDITIONS
EXIST OR ARE EXPECTED TO CONTINUE.
A DENSE FOG ADVISORY MEANS VISIBILITIES WILL FREQUENTLY BE
REDUCED TO LESS THAN ONE QUARTER MILE. IF DRIVING...SLOW DOWN...
USE YOUR HEADLIGHTS...AND LEAVE PLENTY OF DISTANCE AHEAD OF YOU.
&&
$$

AIR STAGNATION ADVISORY
Issue Date: 1105 PM PST WED DEC 23 2009
Expiration: 600 PM PST SAT DEC 26 2009

...DENSE FOG ADVISORY IN EFFECT UNTIL 10 AM PST THURSDAY...
...AIR STAGNATION ADVISORY REMAINS IN EFFECT FROM 4 AM THURSDAY
TO 6 PM PST SATURDAY...
THE NATIONAL WEATHER SERVICE IN PORTLAND HAS ISSUED A DENSE FOG
ADVISORY...WHICH IS IN EFFECT UNTIL 10 AM PST THURSDAY. AN AIR
STAGNATION ADVISORY REMAINS IN EFFECT FROM 4 AM THURSDAY TO 6 PM
PST SATURDAY.
* IMPACTS...DENSE FOG WILL LOWER VISIBILITIES TO ONE QUARTER OF A
MILE OR LESS. FREEZING TEMPERATURES WILL ALLOW THE FOG TO FREEZE
TO SURFACES MAKING THEM SLIPPERY.
* TIMING...THROUGH 10 AM THURSDAY.
OFFSHORE FLOW OVER THE REGION WILL STRENGTHEN LATER TONIGHT AND
CONTINUE FOR THE REST OF THE WEEK INTO THE COMING WEEKEND.
HOWEVER...STRONG LOW LEVEL INVERSIONS WILL KEEP AREAS BELOW
1500 FEET FROM MIXING WELL. THIS WILL LEAD TO AIR QUALITY THAT
WILL GRADUALLY BECOME MORE POOR WITH TIME.
EAST WINDS OVER SOUTHERN CLARK COUNTY WILL BE STRONG ENOUGH TO
KEEP AREAS MIXED...WITH NO SIGNIFICANT AIR QUALITY CHANGE.
* AREAS AFFECTED...ACROSS NORTHERN CLARK COUNTY...EXTENDING
NORTH THROUGH THE COWLITZ VALLEY.
* TIMING...THURSDAY THROUGH SATURDAY.
* AIR QUALITY...EXPECT SLOWLY DEGRADING AIR QUALITY.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
AN AIR STAGNATION ADVISORY IS ISSUED WHEN LOCALLY ESTABLISHED
CRITICAL VALUES OF TRANSPORT WINDS...MIXING HEIGHT...AND
VENTILATION ARE EXPECTED TO PERSIST FOR AT LEAST 72 HOURS. THIS
PRODUCT WILL BE UPDATED AT LEAST EVERY 24 HOURS WHEN CONDITIONS
EXIST OR ARE EXPECTED TO CONTINUE.
A DENSE FOG ADVISORY MEANS VISIBILITIES WILL FREQUENTLY BE
REDUCED TO LESS THAN ONE QUARTER MILE. IF DRIVING...SLOW DOWN...
USE YOUR HEADLIGHTS...AND LEAVE PLENTY OF DISTANCE AHEAD OF YOU.
$$