AIR STAGNATION ADVISORY
Issue Date: 917 PM PST FRI DEC 25 2009
Expiration: 1000 AM PST SAT DEC 26 2009

...AIR STAGNATION ADVISORY REMAINS IN EFFECT FOR MUCH OF THE
INTERIOR LOWLANDS UNTIL 10 AM PST SATURDAY...
AN AIR STAGNATION ADVISORY REMAINS IN EFFECT UNTIL 10 AM PST
SATURDAY.
* STRONG HIGH PRESSURE ALOFT WILL PERSIST OVER THE REGION THROUGH
  SATURDAY.. THIS WILL TRAP COLD AIR NEAR THE SURFACE UNDER WARM
  AIR ALOFT.
* THE RESULTING LACK OF MIXING WILL ALLOW POLLUTANTS SUCH AS WOOD
  SMOKE AND INDUSTRIAL EMISSIONS TO ACCUMULATE AND REDUCE AIR
  QUALITY.
* THE MOST LIKELY PLACES TO EXPERIENCE REDUCED AIR QUALITY ARE
  ALONG THE I-5 CORRIDOR OF SNOHOMISH...THURSTON...AND PIERCE
  COUNTIES.
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. CHECK
WITH YOUR LOCAL AIR QUALITY AGENCY FOR POSSIBLE RESTRICTIONS IN
YOUR AREA.
$$