082
FXUS66 KPQR 202305
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
305 PM PST SAT DEC 20 2025
SYNOPSIS
A COOL AND UNSETTLED PATTERN REMAINS IN PLACE ACROSS NORTHWEST
OREGON AND SOUTHWEST WASHINGTON THIS AFTERNOON AND EVENING.
SCATTERED SHOWERS AND MOUNTAIN SNOW CONTINUE MAINLY IN
SOUTHWEST WASHINGTON. A FEW SLOWER RESPONDING RIVERS CONTINUE TO
HAVE RIVER FLOODING IMPACTS. WINTER TRAVEL CONDITIONS MAY
LINGER ACROSS THE CASCADE PASSES WITH OCCASIONAL MOUNTAIN SNOW
EXPECTED BEYOND THIS WEEKEND. AN ACTIVE AND PROGRESSIVE PATTERN
CONTINUES INTO NEXT WEEK, WITH PERIODIC CHANCES FOR RAIN AND
BREEZY CONDITIONS, AND A VERY LOW CHANCE FOR LOWLAND SNOW AT THE
END OF NEXT WEEK.
DISCUSSION...NOW THROUGH FRIDAY
SCATTERED SHOWERS CONTINUE ACROSS SOUTHWEST WASHINGTON AND NORTH
OREGON COAST AND COAST RANGE THIS AFTERNOON AS THE AREA REMAINS
WITHIN A COOL POST-FRONTAL AIRMASS. SNOW LEVELS REMAIN ROUGHLY
2,500 TO 3500 FEET. SNOW SHOWERS ARE ONGOING ACROSS THE
SOUTHWEST WASHINGTON CASCADES, KEEPING WINTER DRIVING CONDITIONS
IN PLACE AT PASS ELEVATIONS. WITH THAT SAID, THE WINTER WEATHER
ADVISORY HAS ENDED DUE TO REDUCED SNOW AMOUNTS. TRAVELERS
SHOULD REMAIN PREPARED FOR CHANGING CONDITIONS THROUGH THE
EVENING AND OVERNIGHT HOURS.
SHOWER COVERAGE CONTINUES TO DECREASE THROUGH THE DAY AND INTO
TONIGHT AS A WEAK RIDGE ALOFT MOVES THROUGH THE AREA.
INTERMITTENT SHOWERS MAY STILL LINGER OVERNIGHT ACROSS
SOUTHWEST WASHINGTON AND HIGHER TERRAIN. RAINFALL AMOUNTS AT
LOWER ELEVATIONS WILL GENERALLY REMAIN LIGHT, LIMITING THE
POTENTIAL FOR ADDITIONAL HYDROLOGIC IMPACTS. HOWEVER, RIVER
LEVELS WILL STAY ELEVATED AS RUNOFF FROM EARLIER SYSTEMS
CONTINUES TO DRAIN THROUGH AREA WATERSHEDS. ADDITIONAL
INFORMATION ON RIVER CONDITIONS CAN BE FOUND IN THE HYDROLOGY
SECTION BELOW.
BY SUNDAY, FLOW ALOFT TURNS MORE SOUTHWESTERLY AHEAD OF AN
APPROACHING PACIFIC TROUGH. THIS WILL BRING AN INCREASE IN
SHOWER COVERAGE DURING THE DAY, WITH THE MOST ORGANIZED
PRECIPITATION EXPECTED SUNDAY EVENING INTO SUNDAY NIGHT AS THE
TROUGH MOVES INLAND. WHILE THIS SYSTEM IS NOT EXPECTED TO
PRODUCE WIDESPREAD LOWLAND IMPACTS, RENEWED SNOWFALL ACROSS THE
CASCADE PASSES IS LIKELY TO CREATE ADDITIONAL TRAVEL CHALLENGES.
WITH CURRENT GUIDANCE INDICATING DECENT SNOW ACCUMULATION
POSSIBLE AT PASS ELEVATIONS (50-60% CHANCE FOR MORE THAN 6
INCHES OF SNOW OVER 24 HOURS), A WINTER WEATHER ADVISORY HAS
BEEN ISSUED FROM 4 AM SUNDAY TO 4 AM MONDAY. ADDITIONALLY,
GUIDANCE SUGGESTS A 5-15% CHANCE FOR MORE THAN 12 INCHES OF
SNOW OVER 24 HOURS FROM 4 AM SUNDAY TO 4 AM MONDAY.
AN ACTIVE PATTERN CONTINUES INTO EARLY NEXT WEEK AS BROAD
UPPER-LEVEL TROUGHING REMAINS ANCHORED OVER THE NORTHEASTERN
PACIFIC. EMBEDDED SHORTWAVE DISTURBANCES WILL MOVE THROUGH THE
REGION IN SUCCESSION WITH BRIEF BREAKS BETWEEN EACH, MAINTAINING
PERIODIC CHANCES FOR SHOWERS ACROSS NORTHWEST OREGON AND
SOUTHWEST WASHINGTON. ONE OF THESE DISTURBANCES IS EXPECTED TO
ARRIVE AROUND MONDAY, ACCOMPANIED BY INCREASING SOUTH WINDS AND
LOCALLY BREEZY CONDITIONS. ENSEMBLE GUIDANCE SUGGESTS COASTAL
AREAS WILL BE MOST SUSCEPTIBLE TO STRONGER WIND GUSTS WITH THIS
SYSTEM (5-20% CHANCE OF GUSTS ABOVE 50 MPH), WHILE INLAND
LOCATIONS SHOULD GENERALLY SEE MORE MODEST WINDS (20-40% CHANCE
OF GUSTS ABOVE 35 MPH). GIVEN SATURATED SOILS, EVEN MODERATE
WIND GUSTS MAY BE ENOUGH TO RESULT IN ISOLATED TREE DAMAGE,
PARTICULARLY ALONG THE COAST AND IN EXPOSED AREAS.
FORECAST UNCERTAINTY INCREASES BY THE MIDDLE OF THE WEEK AS
ENSEMBLE GUIDANCE DIVERGES ON THE EVOLUTION OF A CLOSED LOW TO
THE SOUTH. MOST ENSEMBLE SOLUTIONS KEEP THE STRONGEST WINDS AND
HEAVIEST PRECIPITATION DISPLACED WELL TO THE SOUTH. HOWEVER, A
SMALLER SUBSET OF ENSEMBLE MEMBERS SUGGESTS THE LOW WILL SWING
FARTHER NORTH, BRINGING ADDITIONAL RAIN AND WIND IMPACTS INTO
THE AREA. ADDITIONALLY, SNOW LEVELS MAY LOWER TOWARDS THE END OF
NEXT WEEK, BRINGING THE POTENTIAL FOR LOWLAND SNOW. SPECIFICALLY,
GUIDANCE SUGGESTS A 1-5% CHANCE FOR 0.1 INCH OF SNOW OVER 24
HOUR ON FRIDAY FOR LOWLAND LOCATIONS NORTH OF SALEM. WHILE
CHANCES FOR SNOW ARE LOW, A SNOW/RAIN MIX IS FORECASTED FOR
FRIDAY TO REFLECT THE UNCERTAINTY BETWEEN MODELS WHILE BRINGING
AWARENESS TO THIS POSSIBILITY. WHILE CONFIDENCE IN SPECIFIC
IMPACTS NEXT WEEK REMAINS LOW AT THIS TIME, THE OVERALL PATTERN
FAVORS CONTINUED UNSETTLED CONDITIONS BEFORE A POTENTIAL DRYING
TREND DEVELOPS LATE NEXT WEEK AND INTO NEXT WEEKEND.
~12
HYDROLOGY
WHILE HEAVY RAIN HAS ENDED OVER THE AREA AND WE HAVE
TRANSITIONED TO SHOWERS MAINLY OVER SOUTHWEST WASHINGTON,
MINOR RIVER FLOODING CONTINUES FOR A FEW RIVERS. AS OF THIS
AFTERNOON, THE LUCKIAMUTE RIVER NEAR SUVER AND PUDDING RIVER AT
AURORA REMAINS AT MINOR FLOOD STAGE. THE COWLITZ RIVER AT KELSO
AND SOUTH YAMHILL RIVER AT MCMINNVILLE ARE FORECASTED TO BRIEFLY
REACH MINOR FLOOD STAGE TONIGHT AND WILL CONTINUE TO BE
MONITORED. EXPECT MOST RIVERS TO FALL BELOW FLOOD STAGE TONIGHT
AND SUNDAY MORNING, WITH THE PUDDING RIVER AT AURORA EXPECTED TO
FALL BELOW FLOOD STAGE ON TUESDAY. THE LATEST RIVER FORECASTS
ACROSS THE REGION CAN BE FOUND AT: WWW.WATER.NOAA.GOV/WFO/PQR.
BE SURE TO NEVER DRIVE THROUGH A FLOODED ROAD AND HEED ANY
REMAINING ROAD CLOSURES.
AVIATION
RADAR IMAGERY AS OF SATURDAY AFTERNOON DEPICTS
LINGERING SHOWERS ACROSS NORTHWEST OREGON WITH PREDOMINATELY LOW-
END VFR CIGS. THIS TREND CONTINUES THROUGH 06Z SUN WITH GUIDANCE
SUGGESTING A 20-30% CHANCE OF INTERMITTENT MVFR CIGS AT ANY GIVEN
TERMINAL. THERE IS ALSO A 10-20% CHANCE FOR THUNDERSTORMS THROUGH
12Z SUN ALONG THE COAST. ANY PASSING THUNDERSTORMS MAY BRING
LIGHTNING, HEAVY RAIN, ERRATIC GUSTY WINDS, AND SMALL HAIL. HEAVY
RAIN COULD BRIEFLY DROP VIS/CIGS TO IFR THRESHOLDS OR LOWER.
TONIGHT, ANOTHER SYSTEM FROM THE SOUTH WILL PUSH SHOWERS FROM
SOUTH TO NORTH AFTER 06-09Z SUN. THIS WILL ALSO BRING A 20-40%
CHANCE FOR MVFR CIGS ACROSS WILLAMETTE VALLEY AND COASTAL
TERMINALS BETWEEN 12-18Z SUN, INCREASING TO A 40-60% CHANCE AFTER
18Z SUN. SOUTHWESTERLY WINDS WILL GRADUALLY WEAKEN BELOW 10 KT
ACROSS THE AREA TONIGHT.
KPDX AND APPROACHES...PREDOMINATELY LOW-END VFR CIGS WITH A 20-30%
CHANCE FOR MVFR CIGS THROUGH 06Z SUN. SOUTHWESTERLY WEAKEN AND
TURN MORE SOUTHEASTERLY UNDER 10 KT TONIGHT INTO EARLY SUNDAY
MORNING. 40-50% CHANCE FOR MVFR CIGS AFTER 18Z SUN. -10
MARINE
BUOY OBSERVATIONS AS OF LATE SATURDAY AFTERNOON DEPICT
SOUTHWESTERLY WINDS ACROSS THE WATERS WITH GUSTS UP TO 25 KT AND
SEAS AROUND 9-10 FT AT 9-10 SEC. A WEAK FRONT WILL MAINTAIN
BREEZY CONDITIONS THROUGH TOMORROW, BUT WINDS SHOULD BEGIN TO
WEAKEN FOR THE WATERS SOUTH OF CAPE FOULWEATHER TONIGHT INTO
SUNDAY MORNING AS THIS FRONT IS PROGRESSING FURTHER NORTH. SMALL
CRAFT ADVISORIES REMAIN IN EFFECT FOR THE WATERS INCLUDING
COLUMBIA RIVER BAR THROUGH 1 PM SUNDAY, EXCEPT UNTIL 10 PM
SATURDAY FOR THE WATERS SOUTH OF CAPE FOULWEATHER. SEAS SUBSIDE TO
7-9 FT AT 10 SEC ON SUNDAY. THERE IS ALSO A 15-20% CHANCE FOR
THUNDERSTORMS ACROSS THE WATERS INCLUDING THE COLUMBIA RIVER BAR
THROUGH SUNDAY AFTERNOON. ANY THUNDERSTORMS MAY PRODUCE LIGHTNING,
BRIEF ERRATIC WINDS, AND HEAVY RAIN WHICH COULD REDUCE
VISIBILITY.
THE NEXT ROBUST FRONTAL SYSTEM ARRIVES ON MONDAY, RETURNING BREEZY
SOUTHWESTERLY WINDS AND BUILDING SEAS. A GALE WATCH HAS BEEN
ISSUED FOR ALL WATERS INCLUDING THE COLUMBIA RIVER BAR BETWEEN 7
AM TO 7 PM MONDAY FOR SOUTHWESTERLY WIND GUSTS UP 40 KT. GUIDANCE
CURRENTLY SHOWS A 40-60% CHANCE FOR GALE FORCE WIND GUSTS ON
MONDAY, WITH THE HIGHEST CHANCES ACROSS THE INNER WATERS OUT 10
NM. SEAS ALSO BUILD TO 12-14 FT AT 10-11 SEC ON MONDAY AS A
WESTERLY SWELL MOVES IN. GUIDANCE SUGGESTS A 20-40% CHANCE THAT
SEAS RISE ABOVE 15 FT. MARINE CONDITIONS BRIEFLY SETTLE DOWN
TUESDAY TO WEDNESDAY BEFORE MORE ACTIVE WEATHER RETURNS AT THE END
OF THE WEEK. -10
PQR WATCHES/WARNINGS/ADVISORIES
OR...WINTER WEATHER ADVISORY FROM 4 AM SUNDAY TO 4 AM PST MONDAY FOR
ORZ126>128.
WA...WINTER WEATHER ADVISORY FROM 4 AM SUNDAY TO 4 AM PST MONDAY FOR
WAZ211.
PZ...SMALL CRAFT ADVISORY UNTIL 1 PM PST SUNDAY FOR PZZ210-251-252-
271-272.
GALE WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR PZZ210-
251>253-271>273.
SMALL CRAFT ADVISORY UNTIL 10 PM PST THIS EVENING FOR PZZ253-273.
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