High Wind in Oregon, December 18, 2005

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
900 AM PST SUN DEC 18 2005

.SYNOPSIS...HIGH PRESSURE ALOFT OVER THE PACIFIC NORTHWEST WILL
WEAKEN AS A SYSTEM MOVES INTO THE AREA TODAY AND IS EXPECTED TO
IMPACT THE AREA LATE THIS AFTERNOON INTO MON. THIS SYSTEM COULD BRING
FREEZING RAIN TO THE NORTH HALF OF THE FORECAST AREA...ESPECIALLY THE
COLUMBIA GORGE. FREEZING RAIN WILL REMAIN A THREAT IN THE COLUMBIA
GORGE THROUGH THE MIDDLE OF NEXT WEEK.
&&

.SHORT TERM...STRONG EAST WINDS CONTINUE TO BLOW THROUGH THE GORGE
AND ACROSS THE CASCADES TODAY. PRESSURE GRADIENTS THROUGH THE GORGE
HAVE INCREASED TO AROUND 13MB BETWEEN PORTLAND AND THE DALLES. WIND
GUSTS OF 55 TO 65 MPH REPORTED EARLIER IN CORBETT NEAR THE GORGE
OUTLET. STRONG WINDS ALSO AFFECTED THE PORTLAND/VANCOUVER METRO AREA
AND FOOTHILLS IN CLARK AND CLACKAMAS COUNTIES WITH GUSTS OF 45 TO 55
MPH ALREADY REPORTED THIS MORNING. EXPECT WIND IN THE GORGE AND METRO
AREA TO PEAK LATER TODAY AS GRADIENT THROUGH THE GORGE INCREASES
WITH THE APPROACH OF LOW PRES SYSTEM. NEXT CONCERN IS FOR LATER TODAY
INTO MON AS STRONG FRONTAL SYSTEM APPROACHING FROM THE SOUTH BRINGS
MOISTURE AND THREAT OF FREEZING PRECIPITATION TO THE AREA. CURRENT
INDICATIONS ARE FREEZING PRECIPITATION THREAT WILL BE IN THE
GORGE...FOOTHILLS...CENTRAL AND NORTHERN WILLAMETTE VALLEY...NORTH
COAST RANGE...AND CLARK AND COWLITZ COUNTIES. WARM FRONT REACHES THE
SOUTHERN AREAS BY 22Z SUN...THEN UP TO THE NORTH AROUND 03Z. WILL
NEED TO MONITOR TEMPERATURE PROFILE IN THE SOUTHERN WILLAMETTE VALLEY
CLOSELY THIS AFTERNOON FOR THREAT OF FREEZING PRECIP THERE AS
MOISTURE REACHES THIS AREA. ETA BUFR SOUNDING FOR KPDX IMPLIES A
MIXTURE OF PRECIP TYPES THIS EVENING AND TONIGHT. MAY GET A BURST OF
SNOW OR SLEET IN THE GORGE AND AREAS NEAR GORGE OUTLET BEFORE
SWITCHING TO FREEZING RAIN. THE GORGE WILL LIKELY BE TREACHEROUS
TONIGHT. BY MON AFTERNOON...MOST AREAS EXCEPT GORGE AND PDX/VANCOUVER
METRO AREAS SHOULD BE TURNED TO RAIN. GORGE AND EASTERN MULTNOMAH
COUNTY WILL BE LAST TO SWITCH OVER. TW

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
12Z GFS SOLUTION TRENDING MORE TOWARDS BETTER PERFORMING ECMWF WITH
SIGNIFICANT SHORTWAVE ON THURS PUSHING NORTHWARD OVER THE RIDGE
RATHER THAN SPLITTING INTO A SOUTHERN STREAM. SOME SPREAD IN
ENSEMBLES WITH MOST MEMBERS IN AGREEMENT WITH EC SOLUTION...HOWEVER
HAVE NOT TOTALLY ELIMINATED THE POSSIBILITY OF A SPLITTING SYSTEM
GIVEN STRONG NORTHWESTERLY UPPER JET PUSHING TOWARDS THE CENTRAL
CALIF COAST. THUS...MADE ONLY MINOR CHANGES IN GRIDS...MAINLY A
SLIGHT BUMP UP IN TEMPERATURES AND SNOW LEVELS GIVEN THE LIKELIHOOD
OF 558+ THICKNESSES BY MID/LATE NEXT WEEK. ONLY EXCEPTION TO THIS
WOULD BE IN THE COLUMBIA GORGE WHERE LOW LEVEL EASTERLIES WILL LIKELY
CONTINUE TO PULL CONTINENTAL AIR WESTWARD UNTIL A MORE SIGNIFICANT
SURFACE WARM FRONT VEERS THE FLOW MORE SOUTHERLY ON THURS.

&&

.AVIATION...MAIN CONCERN THIS TAF PERIOD WILL BE CONTINUED VERY
STRONG EAST WIND IN THE GORGE...AND EVEN IN THE PORTLAND METRO AREA.
WILL ALSO NEED TO MONITOR FOR LLWS AT KTTD AND POSSIBLY KPDX AFTER
00Z MON AS ETA BUFR SOUNDINGS INDICATE SOUTHEAST TO SOUTH WIND FLOW
DEVELOPING NEAR 2K FEET MSL. THE OTHER FORECAST DILEMMA AFTER 00Z MON
WILL BE PRECIP TYPE. COULD START AS SNOW...ESPECIALLY IN THE
GORGE...THEN SWITCH TO FREEZING RAIN AFTER 06Z.
&&

.PRELIMINARY POINT POPS
AST 16673  PDX 17773  SLE 36663  EUG 46643
&&

.PQR WATCHES/WARNINGS/ADVISORIES

.OR/WA...WINTER STORM WARNING TONIGHT THROUGH TUES MORNING FOR
          NORTHERN WILLAMETTE VALLEY...COLUMBIA RIVER
          GORGE...NORTH COAST RANGE...CLARK COUNTY...I-5
          CORRIDOR IN COWLITZ COUNTY.
         WINTER STORM WARNING SUN AFTERNOON THROUGH MON MORNING FOR
          CENTRAL WILLAMETTE VALLEY...CASCADES AND FOOTHILLS.
         HIGH WIND WARNING WA CASCADE FOOTHILLS AND EAST
          PORTLAND/VANCOUVER METRO AREA TODAY.
         GALE WARNING CAPE SHOALWATER TO FLORENCE THROUGH MONDAY.
         SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA BAR THROUGH TODAY.
&&

MORE WEATHER INFORMATION ONLINE AT...
http://weather.gov/portland

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PORTLAND OR
602 AM PST SUN DEC 18 2005

ORZ003-005>007-009>013-WAZ019-022-023-039-040-191415-
COAST RANGE OF NORTHWEST OREGON-LOWER COLUMBIA-
GREATER PORTLAND METRO AREA-CENTRAL WILLAMETTE VALLEY-
WESTERN COLUMBIA RIVER GORGE-NORTHERN OREGON CASCADE FOOTHILLS-
NORTHERN OREGON CASCADES-CASCADE FOOTHILLS IN LANE COUNTY-
CASCADES IN LANE COUNTY-SOUTH WASHINGTON CASCADES-I-
5 CORRIDOR IN COWLITZ COUNTY-GREATER VANCOUVER AREA-
SOUTH WASHINGTON CASCADE FOOTHILLS-
602 AM PST SUN DEC 18 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST
OREGON AND SOUTHWEST WASHINGTON.

.DAY ONE...TODAY AND TONIGHT

WINTER STORM WARNING FOR FREEZING RAIN...SLEET AND SNOW FOR PARTS
OF THE CENTRAL WILLAMETTE VALLEY, THE NORTH AND CENTRAL OREGON
CASCADES AND FOOTHILLS, THE COAST RANGE OF NORTHWEST OREGON, THE
GREATER PORTLAND AND VANCOUVER METRO AREA, LOWER COLUMIBIA AND I-5
CORRIDOR IN COWLITZ COUNTY IN SOUTHWEST WASHINGTON, AND THE
COLUMBIA RIVER GORGE.

HIGH WIND WARNING TODAY FOR THE PORTLAND AND VANCOUVER METRO AREA
AND THE SOUTH WASHINGTON CASCADE FOOTHILLS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

WINTER STORM WARNING CONTINUES THROUGH TUE FOR THE COAST RANGE OF
NORTHWEST OREGON, THE GREATER PORTLAND AND VANCOUVER METRO AREA, LOWER
COLUMIBIA AND I-5 CORRIDOR IN COWLITZ COUNTY IN SOUTHWEST
WASHINGTON, AND THE COLUMBIA RIVER GORGE.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

ORZ001-002-004-008-WAZ020-021-191415-
NORTH OREGON COAST-CENTRAL OREGON COAST-
CENTRAL COAST RANGE OF WESTERN OREGON-SOUTH WILLAMETTE VALLEY-
WILLAPA HILLS-SOUTH WASHINGTON COAST-
602 AM PST SUN DEC 18 2005

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...MONDAY THROUGH SATURDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER REPORTS ARE NOT LIKELY TO BE NEEDED TODAY.