HAZARDOUS WEATHER OUTLOOK
Issue Date: 648 AM PST SUN DEC 20 2009
Expiration: 600 AM PST MON DEC 21 2009
THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL AND NORTHEAST OREGON
AS WELL AS SOUTH CENTRAL AND SOUTHEAST WASHINGTON.
.DAY ONE...TODAY AND TONIGHT
DENSE FOG THIS MORNING
KITTITAS VALLEY, YAKIMA VALLEY
STRONG WIND THROUGH THIS AFTERNOON
GRANDE RONDE VALLEY
LOW CLOUDS WILL CONTINUE ACROSS THE LOWER COLUMBIA BASIN...THE
KITTITAS AND YAKIMA VALLEYS AND THE FOOTHILLS OF THE BLUE MOUNTAINS
TODAY. AREAS OF DENSE FOG WITH VISIBILITIES AT ONE QUARTER OF A MILE
OR LESS WILL OCCUR WHERE THE LOW CLOUD DECK BANKS UP AGAINST HIGHER
TERRAIN. A DENSE FOG ADVISORY IS IN EFFECT FOR THE AREAS LISTED
ABOVE. PLEASE REFER TO PRODUCT PDXNPWPDT FOR FURTHER DETAILS.
SURFACE HIGH PRESSURE OVER SOUTHEAST OREGON WILL PRODUCE TIGHT
PRESSURE GRADIENTS IN THE GRANDE RONDE VALLEY TODAY RESULTING IN
VERY WINDY CONDITIONS ACROSS THE SOUTHERN GRANDE RONDE VALLEY. A
WIND ADVISORY REMAINS IN EFFECT TODAY FOR THE GRANDE RONDE VALLEY.
THE HIGHEST WINDS WILL OCCUR IN THE LADD AND PYLES CANYONS AND AREAS
ADJACENT TO THESE CANYONS. PLEASE REFER TO PRODUCT PDXNPWPDT FOR
FURTHER DETAILS.
A MID/UPPER LEVEL SHORT WAVE WILL MOVE INLAND THIS AFTERNOON AND
THEN ACROSS THE FORECAST AREA TONIGHT. THE WAVE WILL PUSH A WEAK
COLD FRONT INTO THE FORECAST AREA TODAY AND THEN MOVE INTO THE
FORECAST AREA THIS EVENING AND THEN EXIT OVERNIGHT. SNOW LEVELS WILL
CONTINUE ABOVE 7000 FEET THROUGH TONIGHT.
.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY
THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.
A MID/UPPER LEVEL TROUGH WILL MOVE INLAND ON MONDAY AND USHER IN
ANOTHER...STRONGER COLD FRONT LATE MONDAY AFTERNOON...WHICH THEN
MOVES THROUGH THE REGION MONDAY NIGHT AND TUESDAY. THE COLD FRONT
WILL LOWER SNOW LEVELS DOWN TO THE COLUMBIA BASIN FLOOR BY EARLY
TUESDAY MORNING. THE MID/UPPER LEVEL TROUGH MOVES ACROSS THE
FORECAST AREA ON TUESDAY. HIGH PRESSURE THEN BUILDS OVER THE
FORECAST AREA TUESDAY NIGHT AND WEDNESDAY AND THEN PERSIST OVER THE
PACIFIC NORTHWEST THROUGH SATURDAY FOR DRIER CONDITIONS.
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE REQUIRED TODAY FOR WINDY CONDITIONS IN THE
GRANDE RONDE VALLEY AND THIS MORNING FOR DENSE FOG IN THE KITTITAS
AND YAKIMA VALLEYS.
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.
|
|
|
