485
FXUS66 KPQR 220437
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
837 PM PST SUN DEC 21 2025
SYNOPSIS
A COOL AND UNSETTLED PATTERN REMAINS IN PLACE
ACROSS NORTHWEST OREGON AND SOUTHWEST WASHINGTON AS A SERIES OF
PACIFIC DISTURBANCES CONTINUE TO MOVE INLAND. PERIODS OF SHOWERS
AND MOUNTAIN SNOW PERSIST INTO EARLY NEXT WEEK, WITH WINTER
TRAVEL IMPACTS ONGOING AT THE CASCADE PASSES. WHILE A BRIEF
REDUCTION IN PRECIPITATION IS EXPECTED EARLY NEXT WEEK, FORECAST
UNCERTAINTY INCREASES BY MIDWEEK AS A LOW-PROBABILITY BUT
POTENTIALLY HIGH-IMPACT WIND SCENARIO CONTINUES TO GAIN SOME
ENSEMBLE SUPPORT. A MORE STABLE AND DRIER PATTERN MAY ATTEMPT TO
DEVELOP TOWARD THE END OF THE WEEK.
DISCUSSION...NOW THROUGH SATURDAY
SHOWERY CONDITIONS CONTINUE
THIS AFTERNOON AS A PACIFIC SHORTWAVE AND ASSOCIATED FRONTAL
BOUNDARY MOVE THROUGH THE REGION WITHIN BROAD SOUTHWEST FLOW
ALOFT. AS OF 2 PM, PRECIPITATION IS MOSTLY LOCATED OVER
SOUTHWEST WASHINGTON AND NORTHERN PORTIONS OF NORTHWEST OREGON.
PRECIPITATION COVERAGE IS EXPECTED TO INCREASE AND BECOME MORE
ORGANIZED AGAIN THIS EVENING AND TONIGHT. LOWLAND IMPACTS REMAIN
LIMITED, BUT RENEWED SNOWFALL ACROSS THE CASCADE PASSES WILL
MAINTAIN WINTER TRAVEL CONCERNS. SNOW LEVELS REMAIN NEAR PASS
ELEVATIONS (2500 TO 5000 FEET), AND ADDITIONAL SNOW
ACCUMULATIONS OF 4 TO 10 INCHES ARE LIKELY, ESPECIALLY FROM
SANTIAM PASS SOUTHWARD WHERE CONFIDENCE REMAINS MODERATE FOR
IMPACTFUL SNOW TOTALS.
AS THE FRONTAL SYSTEM MOVES EAST OVERNIGHT, SHOWERS PERSIST
INTO MONDAY, ALTHOUGH WITH A MORE SCATTERED CHARACTER. THE
BROADER SYNOPTIC PATTERN REMAINS PROGRESSIVE, AND ANOTHER UPPER-
LEVEL DISTURBANCE IS EXPECTED TO APPROACH LATER MONDAY INTO
MONDAY NIGHT. THIS SYSTEM WILL BRING ANOTHER UPTICK IN SHOWER
COVERAGE ALONG WITH STRENGTHENING SOUTHERLY WINDS. COASTAL AREAS
AND EXPOSED HEADLANDS ARE FAVORED FOR STRONGER GUSTS (35-45
MPH GUSTS, WITH ISOLATED GUSTS UP TO 50 MPH), WHILE INLAND
VALLEYS ARE EXPECTED TO SEE BREEZY CONDITIONS (25-35 MPH GUSTS,
WITH ISOLATED GUSTS UP TO 40 MPH). GIVEN SATURATED SOILS FROM
RECENT RAINFALL, EVEN MODERATE WIND GUSTS MAY RESULT IN ISOLATED
TREE DAMAGE OR LOCALIZED POWER DISRUPTIONS.
BY TUESDAY, THE DEPARTING DISTURBANCE ALLOWS HEIGHTS ALOFT TO
GRADUALLY RISE AS WEAK RIDGING BRIEFLY DEVELOPS, HELPING CONFINE
LINGERING SHOWERS MORE TOWARD THE COAST RANGE AND CASCADES,
WITH INLAND VALLEYS SEEING DRIER CONDITIONS. WINDS ARE EXPECTED
TO EASE DURING THIS TIME, PROVIDING A RELATIVE LULL BEFORE THE
NEXT POTENTIAL SYSTEM.
FORECAST CONFIDENCE DECREASES NOTABLY BY MIDWEEK AS ENSEMBLE
GUIDANCE DIVERGES ON THE EVOLUTION OF A CLOSED LOW TO THE SOUTH
AND THE TRAJECTORY OF EMBEDDED SHORTWAVES. MOST ENSEMBLE
SOLUTIONS CONTINUE TO FAVOR THE STRONGEST WINDS AND HEAVIEST
PRECIPITATION REMAINING DISPLACED WELL SOUTH AND EAST OF THE
FORECAST AREA. HOWEVER, A GROWING SUBSET OF ENSEMBLE MEMBERS
(PRIMARILY FROM THE EPS) DEPICTS A COMPACT SURFACE LOW LIFTING
NORTHWARD THROUGH WESTERN OREGON, A SCENARIO THAT WOULD FAVOR A
BRIEF PERIOD (4-6 HOURS) OF STRONG SOUTHERLY WINDS (45-65 MPH
WITH ISOLATED GUSTS UP TO 70 MPH). WHILE THIS OUTCOME REMAINS A
LOWER-PROBABILITY SOLUTION (5-15% CHANCE, SLIGHTLY LESS THAN
THIS MORNINGS PROBABILITY) AND IS NOT REFLECTED IN THE OFFICIAL
FORECAST AT THIS TIME, THE SCENARIO BEARS CLOSE MONITORING GIVEN
THE POTENTIAL FOR HIGH-IMPACT WINDS.
BEYOND MIDWEEK, CONFIDENCE REMAINS LOW REGARDING THE EXACT
PLACEMENT AND TIMING OF ADDITIONAL DISTURBANCES. PERIODIC SHOWER
CHANCES ARE LIKELY TO PERSIST, ALTHOUGH COVERAGE AND INTENSITY
REMAIN UNCERTAIN. TOWARD THE LATTER PART OF THE WEEK, ENSEMBLE
AGREEMENT INCREASES FOR SOME DEGREE OF UPPER-LEVEL RIDGING
BUILDING INTO THE PACIFIC NORTHWEST, WHICH COULD SUPPORT A
TEMPORARY TREND TOWARD DRIER AND CALMER CONDITIONS. THE DURATION
AND ROBUSTNESS OF THIS POTENTIAL BREAK REMAIN UNCERTAIN, BUT IT
REPRESENTS THE MOST LIKELY WINDOW FOR IMPROVED WEATHER BEYOND
THE MIDDLE OF THE WEEK. ~12
AVIATION
RADAR IMAGERY SUNDAY EVENING SHOWING SHOWERS ACROSS
ACROSS THE AIRSPACE AS A WEAK FRONT CONTINUES TO TRACK NORTHEASTWARD.
THIS IS RESULTING IN A MIXTURE OF MVFR/VFR CONDITIONS WITH
INTERMITTENT IFR CONDITIONS THROUGH THE TAF PERIOD. SOUTH/SOUTHWEST
WINDS UNDER 10 KT THROUGH AROUND 10Z-12Z MONDAY ALONG THE COAST
AND 18Z-20Z MONDAY FOR INLAND LOCATIONS. WINDS INCREASE TOMORROW
AS A STRONGER FRONT ENTERS THE AREA, WITH GUSTS UP TO 30 KT AFTER
15Z MONDAY ALONG THE COAST AND GUSTS UP TO 25 KT FOR INLAND
LOCATIONS AFTER 18Z MONDAY. WINDS EXPECTED TO FALL BELOW 10 KT
AROUND 00Z TUESDAY.
KPDX AND APPROACHES...MIXTURE OF MVFR/VFR CONDITIONS AS SHOWERS
MOVE NORTHEASTWARD THROUGH THE TAF PERIOD. SOUTH/SOUTHWEST WINDS
UNDER 10 KT THROUGH AROUND 18Z MONDAY. AFTERWARDS, EXPECT GUSTS UP
TO 25 KT THROUGH AROUND 00Z TUESDAY. /42
MARINE
BUOY OBSERVATIONS AS OF SUNDAY EVENING SHOW WINDS
HAVE FALLEN BELOW 20 KT ACROSS THE WATERS WITH SEAS AROUND 7-9
FT AT 10-11 SEC. WILL MAINTAIN THIS BRIEF BREAK THROUGH THE
EVENING, BEFORE CONDITIONS START TO RAMP UP AGAIN OVERNIGHT.
THE NEXT ROBUST FRONTAL SYSTEM ARRIVES ON MONDAY, RETURNING
BREEZY SOUTHWESTERLY WINDS AND BUILDING SEAS. THE PREVIOUS GALE
WATCH HAS BEEN UPGRADED TO A GALE WARNING ACROSS ALL WATERS
INCLUDING THE COLUMBIA RIVER BAR BETWEEN 7 AM TO 7 PM MONDAY FOR
SOUTHWESTERLY WIND GUSTS UP 40 KT. WILL NOTE THAT THERE IS A
10-15% CHANCE FOR BRIEF, ISOLATED WIND GUSTS UP TO 50 KT DURING
THIS TIME. SEAS ALSO BUILD TO 12-14 FT AT 10-11 SEC ON MONDAY AS
A WESTERLY SWELL MOVES IN. GUIDANCE SUGGESTS A 20-30% CHANCE THAT
SEAS RISE ABOVE 15 FT. MARINE CONDITIONS BRIEFLY SETTLE DOWN
TUESDAY TO WEDNESDAY WITH POTENTIAL FOR EASTERLY WINDS DUE TO A
LOW PRESSURE SYSTEM SPINNING OFFSHORE OF NORTHERN CALIFORNIA. BY
THE END OF THE WEEK, A SOUTHERLY SWELL PRODUCED BY THIS SYSTEM
WILL ENTER OUR WATERS AND RE-BUILD SEAS. -10
HYDROLOGY
PAST HEAVY RAIN CONTINUES TO DRAIN INTO SLOWER
RESPONDING RIVERS, RESULTING IN CONTINUED MINOR RIVER FLOODING
FOR THE PUDDING RIVER AT AURORA. EXPECT THE PUDDING RIVER AT
AURORA TO FALL BELOW FLOOD STAGE BY TUESDAY MORNING. 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 UNTIL 4 AM PST MONDAY FOR ORZ126>128.
WA...WINTER WEATHER ADVISORY UNTIL 4 AM PST MONDAY FOR WAZ211.
PZ...SMALL CRAFT ADVISORY FROM 1 AM TO 7 AM PST MONDAY FOR PZZ210-
251>253-271>273.
GALE WARNING FROM 7 AM TO 7 PM PST MONDAY 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