087
FXUS66 KPQR 201804
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
1004 AM PST WED NOV 20 2024
UPDATED THE AVIATION DISCUSSION
SYNOPSIS
SHOWERS CONTINUE TODAY INTO THURSDAY. ANOTHER
WEATHER SYSTEM MAY BRING ANOTHER ROUND OF WIND IMPACTS AS WELL
AS WIDESPREAD RAIN LATE THURSDAY INTO FRIDAY, BUT FORECAST
CONFIDENCE REMAINS LOW AT THIS TIME. SHOWERY WEATHER CONTINUES
THROUGH THE WEEKEND INTO EARLY NEXT WEEK WITH LIMITED MOUNTAIN
SNOW IMPACTS AFTER THIS MORNING.
DISCUSSION...WEDNESDAY THROUGH TUESDAY
SATELLITE IMAGERY
AS OF 2 AM WEDNESDAY MORNING IS STILL A SIGHT TO BEHOLD. THE
STRONG LOW PRESSURE SYSTEM REMAINS SPINNING WITH THE CENTER OF
THE LOW AROUND 48N/130W WHILE THE STRONG MOISTURE PLUME
ASSOCIATED WITH THE ATMOSPHERIC RIVER IS PUSHING SOUTH OF OUR
AREA INTO SOUTHERN OREGON AND NORTHERN CALIFORNIA. ALSO VISIBLE
ON SATELLITE IMAGERY AS WELL AS THROUGH OBSERVATIONS IS THE
OCCLUDED FRONT THAT HAS FINALLY BEGUN TO PUSH INLAND IN THE
PAST COUPLE OF HOURS, STRETCHING FROM AROUND THE PUGET SOUND TO
AROUND THE NEWPORT AREA. THE FRONT HAS BEEN SLOWLY WEAKENING AS
IT SLOWLY MOVES EAST, WHICH WILL CONTINUE TO HAPPEN AS IT MOVES
EAST THROUGH THE MORNING, REACHING THE CASCADES AROUND MIDDAY.
STRATIFORM RAIN REMAINS ALONG AND EAST OF THE FRONT WITH SHOWERS
IN THE WAKE OF THE FRONT, CONTINUING THROUGH THE DAY. WINDS
HAVE ALREADY BEEN DIMINISHING FROM THE STRONGEST GUSTS OVER THE
PAST FEW HOURS, SO THE HIGH WIND WARNING AND WIND ADVISORY ARE
NO LONGER IN EFFECT. GUSTY WINDS WILL CONTINUE THROUGH THE
MORNING HOURS WITH GUSTS UP TO 25 MPH INLAND, OCCASIONALLY UP TO
30 MPH AT TIME, AND UP TO 30-40 MPH ALONG THE COAST. ALSO COULD
SEE A FEW RUMBLES OF THUNDER ALONG THE COAST AND OVER THE
COASTAL WATERS. A WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR
THE CASCADES THROUGH 10 AM WHERE SNOW LEVELS WILL RESIDE AROUND
4000-4500 FEET THROUGH THIS EVENING. ADDITIONAL SNOW AMOUNTS UP
TO 5 INCHES ARE POSSIBLE AT THE PASSES THROUGH 10 AM WITH THE
STRATIFORM PRECIPITATION, WITH MINIMAL ADDITIONAL ACCUMULATIONS
AFTER THIS IN THE SHOWERY REGIME.
SHOWERY WEATHER CONTINUES INTO THURSDAY, BEFORE ATTENTION
QUICKLY TURNS TO THE NEXT SYSTEM TO POTENTIALLY IMPACT THE AREA
THURSDAY NIGHT INTO FRIDAY. MODELS ARE COMING INTO BETTER
AGREEMENT ON DEPICTING ANOTHER LOW DEVELOPING OFF THE NORTHERN
CALIFORNIA COAST THURSDAY NIGHT AND TRACKING RAPIDLY NORTHWARD
TOWARDS THE WASHINGTON COAST ON FRIDAY. FROM A CONCEPTUAL
STANDPOINT, THIS WOULD BE A MORE FAVORABLE TRACK FOR BRINGING
WIND TO THE INTERIOR VALLEYS ON FRIDAY, BUT THE PRECISE TRACK
AND INTENSITY OF THE LOW WILL HAVE LARGE IMPLICATIONS ON THE
FORECAST. THERE IS STILL QUITE A BIT OF MODEL SPREAD WITH REGARD
TO THESE DETAILS, WHICH WILL OBVIOUSLY BEAR CLOSE WATCHING OVER
THE NEXT 24-48 HOURS. FOR NOW, NBM PROBABILISTIC GUIDANCE
DEPICTS A 50-70 PERCENT CHANCE FOR 50 MPH WIND GUSTS ALONG THE
COAST AND A 20-40 PERCENT CHANCE FOR 40 MPH WIND GUSTS IN THE
WILLAMETTE VALLEY ON FRIDAY.
THE GFS AND EURO ENSEMBLES ARE COMING INTO MUCH BETTER
AGREEMENT OF THE AMOUNT OF PACIFIC MOISTURE THIS WEATHER SYSTEM
WILL PULL BACK NORTH INTO NW OREGON AND SW WASHINGTON. THE 00Z
RUNS OF ENSEMBLES SUGGEST THE IVT PLUME WILL PEAK AROUND 500
KG/MS FOR LESS THAN 24 HOURS ON FRIDAY, INDICATIVE OF A WEAKER
MOISTURE PLUME THAN THE ONE THAT JUST IMPACTED THE AREA. MODEL
QPF REMAINS IN LINE WITH PREVIOUS THINKING WITH 48 HOUR RAIN
AMOUNTS ENDING 4 AM SATURDAY RANGING FROM 1.25-2.5" ALONG THE
COAST, 1.5-2.5" OVER THE MOUNTAINS, AND 0.75-1.25" INLAND. HYDRO
IMPACTS CONTINUE TO APPEAR RATHER MINIMAL AS A RESULT, WITH
LATEST HEFS GUIDANCE OF PROBABILITIES OF REACHING MINOR FLOOD
STAGE ON THE MORE RESPONSIVE RIVERS DRAINING THE COAST RANGE
LOWERING TO 5-10%. WINTER WEATHER IMPACTS WILL ALSO BE MINIMAL
AS SNOW LEVELS RISE ABOVE 7000 FEET ON THURSDAY. OTHERWISE,
SHOWERY CONDITIONS LOOK TO PERSIST INTO THIS WEEKEND AND BEYOND
AS MEDIUM RANGE GUIDANCE CONTINUES TO DEPICT UPPER LEVEL
TROUGHING LINGERING OVER THE NE PACIFIC THROUGH THE WEEKEND AND
INTO EARLY NEXT WEEK. /CB/HEC
AVIATION
THUNDERSTORMS ARE IMPACTING THE COAST, MAINLY KAST AND
NORTHWARD THIS MORNING. LIGHTNING, RAIN AND HAIL HAVE BEEN
REPORTED WITH THESE THUNDERSTORMS. SHOWERS ARE TAPERING OFF INLAND
THIS MORNING, EXCEPT FOR NEAR THE CASCADES OF LANE COUNTY. THE
THREAT FOR SHOWERS WILL CONTINUE THROUGH THE DAY, BUT EXPECT
MOSTLY VFR FLIGHT CONDITIONS WITH SOUTHEAST TO SOUTH WINDS.
ANOTHER WAVE OF LOW PRESSURE WILL APPROACH FROM THE SW TONIGHT,
INCREASING RAIN CHANCES FROM SOUTH TO NORTH TONIGHT. EXPECT
PREDOMINATELY MVFR CONDITIONS WITH RAIN TONIGHT INTO THURSDAY
MORNING.
PDX APPROACHES...VFR CONDITIONS WITH MOSTLY CLEAR SKIES THIS
MORNING WITH SOUTHEAST WINDS AROUND 10 KT. THERE IS A 20-40
PERCENT CHANCE FOR SHOWERS LATE THIS AFTERNOON. BRIEF MVFR
CONDITIONS CAN BE EXPECTED WITH ANY DEVELOPING AFTERNOON SHOWERS.
DRY CONDITIONS TONIGHT WITH MVFR CIGS BETWEEN 2500-3500.
PREDOMINATELY SE WINDS FOR THE NEXT 24 HRS MOSTLY 10 KT OR LESS.
~TJ
MARINE
STRONG GALES ACROSS ALL WATERS THROUGH TONIGHT WITH SEAS
AROUND 20 TO 26 FT. WINDS WILL FALL BELOW GALES BY TONIGHT, BUT
SEAS WILL TAKE A MUCH LONGER TIME TO FALL BELOW 20 FT. SEAS WILL
SLOWLY SUBSIDE THROUGH THURSDAY TOWARDS 17 TO 19 FT. AS A RESULT
HAVE ISSUED A FOLLOW ON HAZARDOUS SEAS WARNING FOR ALL WATERS
STARTING TONIGHT.
THERE IS LITTLE REPRIEVE THIS WEEK AS THE NEXT SYSTEM IS EXPECTED
TO BRING ANOTHER ROUND OF ELEVATED WINDS AND SEAS THURSDAY NIGHT
INTO FRIDAY. THERE STILL SOME UNCERTAINTY WITH THE FRIDAY SYSTEM
AND MODELS ARE VARIED IN STRENGTH AND TRACK OF THE LOW. AS A
RESULT AM PUTTING MODERATE GALES ACROSS ALL WATERS. SEAS WILL ALSO
BUILD WITH THIS SYSTEM AND WILL RESULT IN A 40-60% PROBABILITY
FOR SEAS TO BUILD TOWARDS 19 TO 21 FT. /42-BATZ
BEACH HAZARDS
LARGE WAVES AND HAZARDOUS SURF CONDITIONS
THROUGH WEDNESDAY AFTERNOON, WITH BREAKERS OF 23 TO 28 FT
EXPECTED.
DESTRUCTIVE WAVES MAY WASH OVER BEACHES, JETTIES, AND OTHER
STRUCTURES UNEXPECTEDLY. PEOPLE CAN BE SWEPT OFF ROCKS AND JETTIES
AND DROWN WHILE OBSERVING HIGH SURF. MINOR BEACH EROSION MAY
DAMAGE COASTAL PROPERTIES AND BUILDINGS. HIGHER THAN NORMAL WATER
RUN-UP IS EXPECTED ON BEACHES AND LOW-LYING SHORELINE.
PQR WATCHES/WARNINGS/ADVISORIES
OR...HIGH SURF ADVISORY UNTIL 7 PM PST THIS EVENING FOR ORZ101>103.
WINTER WEATHER ADVISORY UNTIL 10 AM PST THIS MORNING FOR
ORZ126>128.
WA...HIGH SURF ADVISORY UNTIL 7 PM PST THIS EVENING FOR WAZ201.
WINTER WEATHER ADVISORY UNTIL 10 AM PST THIS MORNING FOR WAZ211.
PZ...GALE WARNING UNTIL 7 PM PST THIS EVENING FOR PZZ210-251>253-
271>273.
HAZARDOUS SEAS WARNING FROM 7 PM THIS EVENING TO 4 AM PST
THURSDAY FOR PZZ210-251>253-271>273.
PQR WATCHES/WARNINGS/ADVISORIES
OR...HIGH SURF ADVISORY UNTIL 7 PM PST THIS EVENING FOR ORZ101>103.
WINTER WEATHER ADVISORY UNTIL 10 AM PST THIS MORNING FOR
ORZ126>128.
WA...HIGH SURF ADVISORY UNTIL 7 PM PST THIS EVENING FOR WAZ201.
WINTER WEATHER ADVISORY UNTIL 10 AM PST THIS MORNING FOR WAZ211.
PZ...GALE WARNING UNTIL 7 PM PST THIS EVENING FOR PZZ210-251>253-
271>273.
HAZARDOUS SEAS WARNING FROM 7 PM THIS EVENING TO 4 AM PST
THURSDAY FOR PZZ210-251>253-271>273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page