566
FXUS66 KPQR 210435 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
835 PM PST SAT DEC 20 2025
UPDATED AVIATION, MARINE AND HYDRO DISCUSSIONS
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
AVIATION
SHOWERS CONTINUE TO DISSIPATE ACROSS THE AIRSPACE AND
IS RESULTING IN VFR CONDITIONS ACROSS THE AIRSPACE. WHILE SHOWERS
WILL CONTINUE TO SLOW DIMINISH, THERE REMAINS 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.
ANOTHER SYSTEM APPROACHING FROM THE SOUTH WILL PUSH SHOWERS FROM
SOUTH TO NORTH STARTING AROUND 09Z SUN. THIS WILL BRING SHOWERY
PRECIPITATION AS WELL AS A 25-45% CHANCE FOR MVFR CIGS ACROSS
WILLAMETTE VALLEY AND COASTAL TERMINALS BETWEEN 12Z-18Z SUNDAY,
INCREASING TO A 45-70% CHANCE AFTER 18Z SUNDAY. SOUTHWESTERLY
WINDS WILL GRADUALLY WEAKEN BELOW 10 KT ACROSS THE AREA TONIGHT.
KPDX AND APPROACHES...PREDOMINATELY VFR CONDITIONS THROUGH AROUND
17Z SUNDAY. SHOWERS ARE EXPECTED TO APPROACH FROM THE SOUTH AND
WILL BRING MVFR CONDITIONS AROUND 20Z SUNDAY. SOUTHWESTERLY WINDS
UNDER 10 KT. /42
MARINE
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 ZONES PZZ271, PZZ251, PZZ272, PZZ152 AND THE COLUMBIA RIVER
BAR THROUGH 1 PM SUNDAY. SEAS SUBSIDE TOWARDS 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. /42-10
HYDROLOGY
WHILE HEAVY RAIN HAS ENDED OVER THE AREA AND WE
HAVE TRANSITIONED TO SHOWERS, 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. EXPECT MOST RIVERS TO FALL BELOW FLOOD STAGE BY 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.
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 6 PM PST SUNDAY FOR PZZ210.
GALE WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR PZZ210-
251>253-271>273.
SMALL CRAFT ADVISORY UNTIL 1 PM PST SUNDAY FOR PZZ251-252-271-
272.
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