High Wind in Oregon, December 10, 2014

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
909 PM PST TUE DEC 9 2014

.SYNOPSIS...BROAD UPPER LEVEL LOW PRES OVER THE GULF OF ALASKA WILL
BRING TWO ADDITIONAL STRONG SYSTEMS INTO THE REGION THROUGH THU. THE
FIRST FRONTAL SYSTEM WILL AFFECT THE REGION OVERNIGHT AND MUCH OF
WED. THE NEXT AND POTENTIALLY STRONGEST SYSTEM IS EXPECTED TO RUN
NORTH ALONG THE COAST THURSDAY BUT WITH CONSIDERABLE UNCERTAINTY AS
TO LOCATION AND TIMING. THE MAIN UPPER LOW WILL OPEN UP AND MOVE
ACROSS THE PACIFIC NORTHWEST LATE IN THE WEEK BRINGING COOLER AND
SHOWERY WEATHER THURSDAY NIGHT AND FRIDAY. UPPER LEVEL RIDGING MAY
BRING A PERIOD OF DRY WEATHER OVER THE WEEKEND BEFORE A PROGRESSIVE
TROUGHING PATTERN RETURNS FOR NEXT WEEK.

&&

.EVENING UPDATE...THE OCCLUDED FRONT THAT MOVED ONSHORE THIS MORNING
STALLED OVER THE REGION. AFTER A RELATIVE LULL IN THE WEATHER FOR
MUCH OF THE AFTERNOON AND EARLY EVENING...WE ARE BEGINNING TO SEE THE
EFFECTS OF THE NEXT APPROACHING SYSTEM. ANOTHER SURFACE LOW HAS
FORMED OUT NEAR 45N 138W...WHICH HAS REACTIVATED THE STALLED
BAROCLINIC ZONE AND IS CURRENTLY LIFTING IT BACK NORTHWARD AS A WARM
FRONT. A BAND OF MODERATE RAIN ASSOCIATED WITH ISENTROPIC LIFT AHEAD
OF THE WARM FRONT MOVED THROUGH THE REGION OVER THE PAST SEVERAL HRS.
MUCH OF THE N OR COAST RANGE AND WILLAPA HILLS SAW 0.25 TO 0.5 INCH
OUT OF THIS BAND. IR SATELLITE SHOWS A BROADER AREA OF MOISTURE WITH
COLDER CLOUD TOPS NOW MOVING ONSHORE. RADAR IS ALSO SHOWING MORE
WIDESPREAD MOISTURE STREAMING IN FROM THE SW. EXPECT STEADIER RAIN TO
DEVELOP LATER THIS EVENING AND OVERNIGHT. HOWEVER...WITH THE WARM
FRONT LIFTING NORTH...THE FOCUS WILL SHIFT PRIMARILY OVER THE N OR
COAST AND COAST RANGE AND WILLAPA HILLS AFTER MIDNIGHT. BY EARLY
TOMORROW MORNING...THE MOISTURE TAP WILL BE FOCUSED ON THE OLYMPIC
PENINSULA AND VANCOUVER ISLAND...WITH VERY LITTLE RAIN EXPECTED OVER
OUR AREA FROM ABOUT 3 AM TO 10 AM.

WHILE RAINFALL AMOUNTS WILL BE FAIRLY MODEST THROUGH MID MORNING
WED...EXPECT SOUTHERLY WINDS TO PICK UP SIGNIFICANTLY OVERNIGHT IN
THE WARM SECTOR OF THIS FRONTAL SYSTEM. THE LOCATION AND ORIENTATION
OF THE SYSTEM IS ACTUALLY FAIRLY SIMILAR TO THE ONE WE SAW LAST
NIGHT. HOWEVER...THE FCST MODELS CONTINUE TO INDICATE THAT THE LOW
LEVEL WINDS WILL BE STRONGER WITH THIS ONE. DID NOT MAKE ANY MAJOR
CHANGES THE PREVIOUS WIND FCST...KEEPING WIND GUSTS OF 65 TO 75 MPH
FOR THE COASTAL BEACHES AND HEADLANDS AND THE ELEVATED TERRAIN OF THE
COAST RANGE. THIS TIME...THE COASTAL COMMUNITIES WILL ALSO LIKELY
EXPERIENCE HIGH WIND CRITERIA WINDS...WITH GUSTS OF 55 TO 65 MPH
EXPECTED. THE ONE SIGNIFICANT CHANGE TO THE FCST THIS EVENING WAS
WARMING THE OVERNIGHT LOW TEMPERATURES. CURRENT OBSERVED TEMPERATURES
ARE NOTABLY MILD...WITH UPPER 50S AND EVEN SOME LOW 60S STILL ALONG
THE COAST AND THROUGH MUCH OF THE INTERIOR LOWLANDS. WITH THE WARM
FRONT LIFTING NORTHWARD THIS EVENING AND SOUTHERLY WINDS EXPECTED TO
INCREASE OVERNIGHT...DO NOT THINK THAT TEMPS WILL COOL ALL THAT MUCH
FROM WHERE THE ARE AT NOW.

THE 00Z RUNS OF THE NAM AND GFS DID NOT HELP MUCH WITH SORTING OUT
THE POTENTIAL VERY STRONG THU SYSTEM. THE GFS MAINTAINED GOOD
CONTINUITY WITH ITS PREVIOUS SEVERAL RUNS...WITH THE NEW NAM DID NOT
CHANGE ALL THAT MUCH EITHER OTHER THAN SLOWING THE TIMING SYSTEM DOWN
JUST A BIT MORE. PYLE

.PREV DISC.../ISSUED 418 PM PST TUE DEC 9 2014/

.SHORT TERM...TONIGHT THROUGH FRIDAY...LITTLE CHANGE IN THE BIG
PICTURE FOR THE AFTERNOON PACKAGE WITH THE MOST INTERESTING IMPACTS
COMING FROM EVOLUTION OF THE SURFACE PATTERN DETAILS OVER THE NEXT
COUPLE DAYS. WILL ADDRESS WINDS LATER IN THE DISCUSSION.

THE BROAD UPPER LOW IS SLOWLY MOVING SOUTHEAST AND IS LARGELY
DRAGGING THE BAROCLINIC ZONE WITH IT. THE UPPER SHORTWAVE/LOW
CROSSING TO THE WEST TONIGHT AND WEDNESDAY WILL AGAIN TILT THE
OVERALL FLOW MORE SOUTHERLY AND SOMEWHAT SIMILAR TO LAST NIGHT. AS
IT EXITS...WILL SEE ANOTHER ROUND OF MODERATE TO HEAVY RAIN CROSS
THE REGION TOMORROW. ADDITIONALLY...THE COASTAL WATERS AND IMMEDIATE
COASTLINE WILL BE UNDER A THREAT FOR THUNDERSTORMS. AGAIN...THE
PRIMARY CONCERN WILL BE FOR SOME LOCALLY GUSTY OUTFLOW WINDS. FOR
WEDNESDAY NIGHT...LARGE SCALE FLOW BECOMES FAR MORE SPLITTY AND
SHUNTS THE HEAVIER RAIN MAINLY TO THE SOUTH BUT STILL DRAGS SOME
MODERATE RAIN PERIODS ACROSS THE AREA. AT THE SAME TIME...MODELS
HAVE SOME CONSENSUS REGARDING DEVELOPING UPPER LOW PRESSURE MOVING
FROM SOUTH TO NORTH ACROSS THE REGION THURSDAY. THE GFS IS BY FAR
THE MOST CONSISTENTLY AGGRESSIVE WITH RAPID CYCLOGENESIS AND A CLOSED

LOW SWINGING TOWARD THE SOUTH OREGON COAST WEDNESDAY NIGHT AND THEN
NORTH FOR THURSDAY. THE NAM SUPPORTS BUT IS INITIALLY ABOUT 6 TO 9
HOURS SLOWER. THE ECMWF KEEPS UPPER FLOW AS A WEAKER OPEN WAVE.
AGAIN REGARDLESS OF WHICH SOLUTION EVOLVES...THE BULK OF THE RAIN
WILL AFFECT SOUTHERN OREGON AND NORTHERN CALIFORNIA WITH MOST OF THE
OREGON MOISTURE RUNNING INTO THE SISKIYOUS AND SHADOWED LEFTOVERS
AFFECTING OUR AREA. THIS SETUP IN GENERAL STILL APPEARS TO KEEP
RIVERS WITHIN THEIR BANKS BUT SOME COAST RANGE RIVERS STILL BEAR
WATCHING.

NOW TO THE WINDS...ANOTHER SYSTEM SOMEWHAT SIMILAR TO LAST NIGHT
WILL CROSS THE REGION LATE TONIGHT AND TOMORROW. THIS TIME...EXPECT
WINDS TO BE JUST A BIT STRONGER WITH THIS ONE. THE MAIN DIFFERENCE
WILL BE A BETTER POTENTIAL FOR THE INLAND COASTAL COMMUNITIES TO
CATCH MORE OF THE WINDS AS WELL AS THE EXPOSED COAST RANGE TERRAIN.
GUSTS UP TO 65 MPH FOR THE INLAND COASTAL COMMUNITIES AND UP TO 75
MPH FOR THE BEACHES...HEADLANDS...AND COAST RANGE.

THE AFOREMENTIONED THURSDAY UPPER DEVELOPMENT HAVE A SIGNIFICANT
SURFACE REFLECTION TO GO WITH IT. MODELS ARE IN GOOD AGREEMENT
SHOWING A CLOSED SURFACE LOW DEVELOPING. TIMING AND LOCATION ARE
STILL HIGHLY IN QUESTION BUT THE OPERATIONAL GFS REALLY HASN'T
BUDGED ALL THAT MUCH OVER THE LAST COUPLE DAYS. THE LATEST 18Z RUN
HAS THE CENTRAL LOW PRESSURE DOWN TO 973 MB ABOUT 110 MILES OFF THE
SOUTHERN OREGON COAST AT 12Z THURSDAY THEN FILLING AS IT MOVES NORTH
SITTING ABOUT 70 MILES OFF OF LINCOLN CITY  AT 18Z THEN ABOUT 10
MILES OFF OF QUILLAYUTE AT 00Z FRIDAY. TOOK A LOOK AT THE PARALLEL
HIGH RESOLUTION GFS13 RUN FIELDS AND THEY GENERALLY SHOW A SIMILAR
PICTURE BUT WITH SIMILAR STRENGTH BUT FURTHER OFFSHORE. THE 18Z NAM
AND THE 12Z ECMWF HAVE A SIMILAR STRUCTURE OF STRETCHING THE SURFACE
LOW OUT WITH 2 LOBES...ONE OFFSHORE THE MOUTH OF THE COLUMBIA AND
ONE OFF THE COOS BAY COAST. THE ECMWF IS AROUND 984MB FOR BOTH LOBES
AT 18Z. SIMILAR TO THE UPPER LEVEL TIMING...THE NAM IS ABOUT 3 TO 5
HOURS SLOWER AND DEEPER AT THE 21Z TIME STEP. DECIDED TO GENERALLY
FOLLOW THE MORE CONSISTENT GFS APPROACH BUT RAMP UP SPEEDS SIMILAR
TO WHAT WE MIGHT HAVE SEEN HAD THE CLOSER/SLOWER NAM12 CAME TO
FRUITION. IN BOTH CASES...WOULD EXPECT THE STRONGEST WINDS TO
DEVELOP UNDER THE RAPID PRESSURE RISES AS THE LOW PUSHES NORTH...OR
IN OTHER WORDS...TRAILING THE SOUTH SIDE OF THE LOW. WOULD NOT BE
SURPRISED TO SEE 3 HOURLY RISES OF 10 TO 12 MB AND THIS TYPICALLY
COULD PRODUCE WARNING LEVEL WINDS. FEELING MORE CONFIDENT THE COAST
AND COAST RANGE WILL SEE STRONG WINDS THURSDAY GIVEN THE TRACK OF
THE GFS IS MORE OFFSHORE BUT CANNOT COMPLETELY RULE OUT SOME STRONG
GUST POTENTIAL FOR THE INLAND AREAS AS WELL. HAVE ISSUED A HIGH WIND
WATCH FOR THE CASCADE FOOTHILLS WESTWARD WITH GUSTS MAINLY 65 TO 75
FOR THE CAST RANGE WESTWARD AND...FOR NOW...45 TO 55 MPH FOR THE
VALLEY AND FOOTHILLS. WOULD REALLY LIKE TO SEE THE HIGHER TEMPORAL
AND SPATIAL RESOLUTION MODELS COME INTO LINE HAVE LOOKED AT THE UW
WRF/GFS SOLUTIONS BUT FEEL THEY MAY BE A BIT OVERDONE AS THE LOW IS
FILLING AS IT CROSSES OUT AREA...BUT PERHAPS NOT BY TOO MUCH. JUST
LOOKING FOR A SECOND OR MORE CONSENSUS OPINIONS.

FINALLY...WILL CONTINUE TO SEE HIGH SURF GIVEN THE PERSISTENT FETCH
FROM WELL OFFSHORE CREATING DANGEROUS CONDITIONS ALONG THE COAST.
HAVE EXTENDED THE HIGH SURF ADVISORY WELL INTO THURSDAY TO COVER
ALTHOUGH SEAS AND HIGHER SURF MAY PERSIST A BIT LONGER. /JBONK

.LONG TERM...FRIDAY NIGHT THROUGH MONDAY NIGHT...AN UPPER LEVEL
TROUGH WILL MAINTAIN SHOWERS FRIDAY EVENING BEFORE AN UPPER RIDGE
RESULTS IN DRIER WEATHER FOR THE WEEKEND. OFFSHORE WINDS ARE
POSSIBLE LATE IN THE WEEKEND AS SURFACE HIGH PRESSURE BUILDS EAST OF
THE CASCADES AND A FRONT APPROACHES FROM THE WEST. THE FRONT WILL
BRING RAIN AND GUSTY WINDS SOMETIME ON MONDAY. HOWEVER...MODELS HINT
THAT THE UPPER TROUGH ASSOCIATED WITH THIS FRONT MAY SPLIT BEFORE IT
REACHES THE COAST WHICH WOULD RESULT IN MOST OF THE RAIN MOVING
SOUTH INTO CALIFORNIA. AN ACTIVE WEATHER PATTERN WILL CONTINUE NEXT
WEEK. TJ

&&

.AVIATION...MOSTLY VFR AS OF 03Z...BUT AREAS OF MVFR AND LOCALIZED
IFR...PRIMARILY ALONG THE COAST. EXPECT MAINLY VFR OVERNIGHT
THROUGH AT LEAST WED MORNING...WITH AREAS OF MVFR ALONG THE COAST.
LATEST MODEL RUNS HOLD THE NEXT FRONTAL BOUNDARY OFFSHORE UNTIL
WED AFTERNOON. THUS...WITH STRONG WIND ALOFT PROMOTING GOOD
MIXING...WOULD EXPECT VFR TO BE THE DOMINANT FLIGHT CATEGORY.
CONDITIONS SHOULD LOWER INTO MVFR OR WORSE WED AFTERNOON. WIND
WILL BE A MAJOR ISSUE LATE TONIGHT THROUGH MUCH OF WED FOR THE
COASTAL TAF SITES WITH GUSTS TO 60 KT POSSIBLE. EAST WIND WILL
PERSIST IN THE WEST COLUMBIA RIVER GORGE THROUGH WED MORNING WITH
LLWS A CONCERN.

KPDX AND APPROACHES...VFR SHOULD PREVAIL THROUGH AT LEAST WED
AFTERNOON. MAY STILL GET SOME BRIEF PERIODS OF MVFR THROUGH 10Z OR
SO DUE TO SHOWER ACTIVITY. EAST WIND TO CONTINUE AT THE WEST END
OF THE COLUMBIA GORGE THROUGH WED MORNING. WILL INDICATE LLWS AT
KPDX AND KTTD DUE TO POTENTIAL S WIND OF 35-45 KT AT FL015 TO 020.
SOUTH WIND DIRECTION EXPECTED AT THE TERMINAL WED AFTERNOON.
WEISHAAR

&&

.MARINE...NO CHANGES TO ON-GOING MARINE HAZARDS. LATEST GFS
CONTINUES ITS TREND OF DEPICTING STRONGER BOUNDARY LAYER WIND OVER
THE WATERS TONIGHT AND WED MORNING COMPARED TO THE 00Z NAM. THE
LATEST NAM SHOWS 65-70 KT 950 MB WIND OVER THE WATERS WED MORNING.
THE GFS HAS A CORE OF 75-85 KT 925 MB WIND OVER THE WATERS WED
MORNING WITH COASTAL BARRIER JET DEVELOPMENT LIKELY. WILL MAINTAIN
GUSTS UP TO 65 KT BUT STAY JUST SHY OF HURRICANE FORCE LEVELS.
STRONGEST GUSTS LOOK TO BE 12Z-20Z WED AND OVER THE OUTER WATERS.

THE WIND DROPS OFF PRETTY QUICK WED AFTERNOON AND EVENING THEN ALL
ATTENTION TURNS TO THE THU SYSTEM. 00Z NAM AND GFS MAINTAINED
THEIR RESPECTIVE MODEL TRENDS...WITH THE GFS MUCH FASTER WITH THE
DEEPENING SURFACE LOW. CENTRAL PRESSURES HAVE GOTTEN CLOSER SO
CONFIDENCE IS GROWING THAT A SHORT-LIVED STORM FORCE WIND EVENT
WILL DEVELOP OVER THE WATERS THU. GFS CONTINUES TO ADVERTISE HUGE
6-HR PRESSURE RISES BEHIND THE LOW...ON THE ORDER OF NEARLY 20 MB
IN 6 HRS OVER THE CENTRAL WATERS THU AFTERNOON. THE WIND QUICKLY
DROPS TO 15-25 KT BY LATE THU AFTERNOON OVER THE SRN WATERS BUT
NOT TIL THU EVENING FOR THE N.

SEAS RUNNING CLOSE TO LATEST ENP GUIDANCE VALID 06Z WED. WILL KEEP
SEAS A COUPLE FEET HIGHER THAN ENP GUIDANCE WED...PUSHING INTO THE
MID 20S. SEAS EASE UNDER 20 FT LATE WED EVENING...BUT WILL QUICKLY
RAMP UP THU DUE TO THE BOMBING LOW PRESSURE MOVING THROUGH THE
WATERS. WAVE HEIGHTS DIMINISH THU EVENING...FALLING TO AROUND 15
FT BY 12Z FRI. WEISHAAR

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...HIGH WIND WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
     EVENING FOR CASCADE FOOTHILLS IN LANE COUNTY-CENTRAL COAST
     RANGE OF WESTERN OREGON-CENTRAL OREGON COAST-CENTRAL
     WILLAMETTE VALLEY-COAST RANGE OF NORTHWEST OREGON-GREATER
     PORTLAND METRO AREA-LOWER COLUMBIA-NORTH OREGON COAST-
     NORTHERN OREGON CASCADE FOOTHILLS-SOUTH WILLAMETTE VALLEY.

     HIGH WIND WARNING FROM 1 AM TO 2 PM PST WEDNESDAY FOR CENTRAL
     COAST RANGE OF WESTERN OREGON-CENTRAL OREGON COAST-COAST
     RANGE OF NORTHWEST OREGON-NORTH OREGON COAST.

     HIGH SURF ADVISORY UNTIL NOON PST WEDNESDAY FOR CENTRAL OREGON
     COAST-NORTH OREGON COAST.

     HIGH SURF ADVISORY FROM 4 AM TO 10 PM PST THURSDAY FOR CENTRAL
     OREGON COAST-NORTH OREGON COAST.

WA...HIGH WIND WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
     EVENING FOR GREATER VANCOUVER AREA-I-5 CORRIDOR IN COWLITZ
     COUNTY-SOUTH WASHINGTON CASCADE FOOTHILLS-SOUTH WASHINGTON
     COAST-WILLAPA HILLS.

     HIGH WIND WARNING FROM 1 AM TO 2 PM PST WEDNESDAY FOR SOUTH
     WASHINGTON COAST-WILLAPA HILLS.

     HIGH SURF ADVISORY UNTIL NOON PST WEDNESDAY FOR SOUTH WASHINGTON

     COAST.

     HIGH SURF ADVISORY FROM 4 AM TO 10 PM PST THURSDAY FOR SOUTH
     WASHINGTON COAST.

PZ...STORM WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY EVENING
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60
NM.

     STORM WARNING UNTIL NOON PST WEDNESDAY FOR COASTAL WATERS FROM
     CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 10 PM
PST
     THURSDAY.

&&

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...HIGH WIND WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
     EVENING FOR CASCADE FOOTHILLS IN LANE COUNTY-CENTRAL COAST
     RANGE OF WESTERN OREGON-CENTRAL OREGON COAST-CENTRAL
     WILLAMETTE VALLEY-COAST RANGE OF NORTHWEST OREGON-GREATER
     PORTLAND METRO AREA-LOWER COLUMBIA-NORTH OREGON COAST-
     NORTHERN OREGON CASCADE FOOTHILLS-SOUTH WILLAMETTE VALLEY.

     HIGH WIND WARNING FROM 1 AM TO 2 PM PST WEDNESDAY FOR CENTRAL
     COAST RANGE OF WESTERN OREGON-CENTRAL OREGON COAST-COAST
     RANGE OF NORTHWEST OREGON-NORTH OREGON COAST.

     HIGH SURF ADVISORY UNTIL NOON PST WEDNESDAY FOR CENTRAL OREGON
     COAST-NORTH OREGON COAST.

     HIGH SURF ADVISORY FROM 4 AM TO 10 PM PST THURSDAY FOR CENTRAL
     OREGON COAST-NORTH OREGON COAST.

WA...HIGH WIND WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
     EVENING FOR GREATER VANCOUVER AREA-I-5 CORRIDOR IN COWLITZ
     COUNTY-SOUTH WASHINGTON CASCADE FOOTHILLS-SOUTH WASHINGTON
     COAST-WILLAPA HILLS.

     HIGH WIND WARNING FROM 1 AM TO 2 PM PST WEDNESDAY FOR SOUTH
     WASHINGTON COAST-WILLAPA HILLS.

     HIGH SURF ADVISORY UNTIL NOON PST WEDNESDAY FOR SOUTH WASHINGTON

     COAST.

     HIGH SURF ADVISORY FROM 4 AM TO 10 PM PST THURSDAY FOR SOUTH
     WASHINGTON COAST.

PZ...STORM WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
     EVENING FOR COASTAL WATERS FROM CAPE SHOALWATER TO FLORENCE
     OUT 60 NM.

     STORM WARNING FROM 10 PM THIS EVENING TO NOON PST WEDNESDAY
     FOR COASTAL WATERS FROM CAPE SHOALWATER TO FLORENCE OUT 60
     NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 10
     PM PST THURSDAY.

&&

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

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.