FXUS66 KPDT 262334
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
333 PM PST THU NOV 26 2009
.SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...THE COLD FRONT HAS
BEGUN TO MOVE SLOWLY INTO EASTERN OREGON THIS AFTERNOON. THE FRONT
IS DRAPED ACROSS SOUTH CENTRAL WASHINGTON SOUTHWEST ACROSS WESTERN
OREGON. A COUPLE HUNDREDTHS OF AN INCH OF RAIN HAS FALLEN AT YAKIMA
IN THE LAST HOUR OR SO AND EXPECT RAIN TO BEGIN IN THE DALLES IN THE
NEXT HOUR. THIS FRONT WILL GRADUALLY MAKE ITS WAY ACROSS EASTERN
OREGON AND WASHINGTON TONIGHT...REACHING THE FAR NORTHEAST MOUNTAINS
BY EARLY FRIDAY MORNING. SNOW LEVELS WILL BE HIGH AHEAD AND WITH THE
FRONT THEREFORE EXPECT ONLY RAIN SHOWERS AT THE START. AS COOLER AIR
FILTERS IN BEHIND THE FRONT...SNOW LEVELS WILL LOWER TO AROUND 4000
FEET IN THE NORTHEAST MOUNTAINS BY FRIDAY AFTERNOON. NO SIGNIFICANT
SNOW ACCUMULATIONS ARE EXPECTED WITH THIS SYSTEM AS THE GREATEST
PRECIPITATION AMOUNTS WILL BE BEFORE THE COLDER AIR MOVES IN.
SOUTHERLY WINDS IN THE GRANDE RONDE VALLEY WILL CONTINUE TO BE VERY
WINDY THIS AFTERNOON AND EVENING. WILL LET THE WIND ADVISORY
CONTINUE UNTIL 7 PM AS PRESSURE GRADIENTS ARE FORECASTED TO DECREASE
GRADUALLY THIS EVENING. THERE MAY BE LOCALIZED VERY WINDY CONDITIONS
CONTINUING BEYOND 7 PM IN THE LADD AND PYLES CANYONS...AND WILL LET
THE NEXT SHIFT ANALYZE THE SITUATION TO SEE IF THE ADVISORY WILL
NEED TO BE EXTENDED OR ALLOWED TO EXPIRE.
A RIDGE OF HIGH PRESSURE WILL BEGIN TO BUILD OFF THE PACIFIC
NORTHWEST COAST WITH DRYING CONDITIONS FRIDAY NIGHT AND SATURDAY.
MODELS INDICATE A WARM FRONT MOVING OVER THE RIDGE AND MAY BRING
SOME SHOWERS ALONG THE CENTRAL WASHINGTON CASCADE CRESTS. WITH
CLEARING SKIES AND LIGHTER WINDS SATURDAY NIGHT...GOOD RADIATIONAL
COOLING WILL LEAD TO THE DEVELOPMENT OF PATCHY FOG AND FREEZING FOG
ALONG THE COLUMBIA...YAKIMA AND WALLA WALLA RIVERS. DMH
.LONG TERM...SUNDAY THROUGH THURSDAY. AN UPPER LEVEL RIDGE WILL
BUILD INTO THE REGION ON SUNDAY. MID AND HIGH LEVEL CLOUDS WILL BE
MOVING THROUGH THE RIDGE WITH PARTLY CLOUDY SKIES OTHERWISE DRY
WEATHER EXPECTED. THE RIDGE WILL WEAKEN ON MONDAY AS AN UPPER LEVEL
TROUGH APPROACHES THE PACIFIC NORTHWEST. SHOULD REMAIN DRY THROUGH
MOST OF THE DAY. THE UPPER TROUGH AND SURFACE COLD FRONT WILL MOVE
THROUGH MONDAY NIGHT WITH A CHANCE OF RAIN AND MOUNTAIN SNOW. THE
UPPER RIDGE WILL REBUILD INTO THE REGION TUESDAY WITH CLEARING
SKIES. NORTHWEST FLOW WILL KEEP A FEW SNOW SHOWERS GOING OVER THE
BLUES. THE RIDGE WILL REMAIN OVER THE NORTHWEST WEDNESDAY AND
THURSDAY WITH FAIR WEATHER. PATCHY FOG IS POSSIBLE IN THE COLUMBIA
BASIN AND ADJACENT VALLEYS SUNDAY NIGHT AND AGAIN WEDNESDAY NIGHT
UNDER HIGH PRESSURE. MONDAY NIGHTS COLD FRONT WILL HELP MIX THE
ATMOSPHERE AND KEEP FOG TO A MINIMUM FOR A FEW DAYS. TEMPERATURES
WILL BE PRETTY CLOSE TO NORMAL LEVELS THROUGH THE PERIOD. 94
&&
.AVIATION...00Z TAFS. IFR/MVFR CONDITIONS TONIGHT AND FRIDAY
MORNING. FRONTAL BOUNDARY MOVING SLOWLY ACROSS THE REGION TONIGHT
WILL RESULT IN RAIN FOR ALL TAF SITES. CEILINGS WILL LOWER INTO THE
020-040 RANGE WITH VISIBILITY 2-5 MILES. STEADY RAIN WILL TAPER OFF
TO SHOWERS FRIDAY MORNING ENDING BY EARLY AFTERNOON. CEILINGS WILL
INCREASE TO 030-060 AND WESTERLY WINDS WILL INCREASE BY AFTERNOON.
94
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 36 48 31 44 / 60 30 10 10
ALW 41 50 33 45 / 60 40 10 10
PSC 37 52 28 46 / 50 20 10 10
YKM 33 49 22 44 / 70 20 0 10
HRI 37 51 26 45 / 50 20 10 0
ELN 33 46 26 44 / 70 20 0 10
RDM 33 43 21 42 / 50 20 10 0
LGD 37 41 27 39 / 40 60 20 10
GCD 37 40 28 38 / 40 60 10 10
DLS 38 50 33 48 / 70 20 10 10
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...WIND ADVISORY UNTIL 7 PM PST THIS EVENING FOR ORZ049.
WA...NONE.
&&
THREAT INDEX
FRIDAY : GREEN
SATURDAY : GREEN
SUNDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
84/94/94
