961
FXUS66 KPQR 221512
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
710 AM PST MON DEC 22 2025
UPDATED WWA PRODUCTS...
SYNOPSIS
PERIODS OF LOWLAND RAIN AND MOUNTAIN SNOW PERSIST
THE NEXT COUPLE OF DAYS AS THE REGION REMAINS UNDER THE
INFLUENCE OF AN ACTIVE AND UNSETTLED WEATHER PATTERN.
ALARMINGLY, MODEL GUIDANCE CONTINUES TRENDING TOWARDS A
POTENTIAL REGION-WIDE HIGH WIND SCENARIO WEDNESDAY WITH
ADDITIONAL ENSEMBLE SUPPORT COMING IN WITH LATEST SUITE OF
GUIDANCE. UNCERTAINTY REGARDING THE EXACT DETAILS OF THIS EVENT
REMAIN HOWEVER. AT LEAST A MORE STABLE AND DRIER PATTERN WILL
ATTEMPT TO DEVELOP TOWARD THE END OF THE WEEK INTO THE WEEKEND.
DISCUSSION...NOW THROUGH SUNDAY
AS ONE SHORTWAVE DEPARTS,
ANOTHER APPROACHES THANKS TO A BROAD TROUGH OF LOW PRESSURE PARKED
OVER THE NORTHEASTERN PACIFIC. THIS FEATURE CONTINUES TO STEER
WEATHER DISTURBANCES INTO THE PACIFIC NORTHWEST, DRIVING OUR
IMPACTS THROUGH MOST OF THE WEEK. HIGH RESOLUTION MODEL GUIDANCE
IS IN GOOD AGREEMENT THIS MORNING FOR THE CONTINUATION OF
SHOWERS THROUGH MUCH OF TODAY ALTHOUGH AS ALLUDED TO AN UPPER-
LEVEL SHORTWAVE AND ACCOMPANYING FRONTAL BOUNDARY IS EXPECTED TO
SWING INTO THE REGION THIS AFTERNOON INTO THE EVENING. THIS
SYSTEM WILL BRING ANOTHER UPTICK IN SHOWER COVERAGE ALONG WITH
STRENGTHENING SOUTHERLY WINDS, ESPECIALLY ALONG THE COAST.
COASTAL AREAS AND EXPOSED BEACHES/HEADLANDS ARE FAVORED FOR
DECENT WIND GUSTS (35-45 MPH GUSTS, WITH ISOLATED GUSTS UP TO 50
MPH), WHILE INLAND VALLEYS ARE EXPECTED TO STILL SEE BREEZY
CONDITIONS (20-30 MPH GUSTS, WITH ISOLATED GUSTS UP TO 35-40
MPH). GIVEN SATURATED SOILS FROM RECENT RAINFALL, IMPACTS MAY BE
SLIGHTLY EXACERBATED FROM WHAT WE WOULD NORMALLY FROM WINDS OF
THIS MAGNITUDE. FORTUNATELY, THESE WINDS ARE EXPECTED TO EASE
BY MONDAY NIGHT.
ON TUESDAY, THE DEPARTING DISTURBANCE COUPLED WITH AN A LARGE-
SCALE AMPLIFICATION OF THE LONG WAVE PATTERN ALLOWS FOR SOME
WEAK RIDGING AND BUILDING HEIGHTS ALOFT THROUGH THE DAY -
GENERALLY A GOOD THING IF YOU FAVOR DRY WEATHER. THUS, MODELS
SHOW LINGERING SHOWER ACTIVITY LARGELY CONSOLIDATING TOWARDS
THE COAST, COAST RANGE AND CASCADES/CASCADE FOOTHILLS FOR THE
AFTERNOON HOURS WITH THE CENTRAL WILLAMETTE VALLEY THROUGH THE
PORTLAND METRO DRYING OUT, ALBEIT ONLY FOR A SHORT REPRIEVE.
ALL EYES ARE STILL LASER FOCUSED ON WEDNESDAY IN REGARDS TO YET
ANOTHER DISTURBANCE ROTATING IN TO THE REGION. IT'S WORTH
MENTION FROM THIS POINT ONWARD THERE IS DEGRADED FORECAST
CONFIDENCE DUE TO THE COMPLEXITY OF THE EVOLVING UPPER-LEVEL
PATTERN AS THE TROUGH PREVIOUSLY PARKED OVER THE NORTHEAST
PACIFIC TRANSITIONS TEMPORARILY INTO A CLOSED LOW WHILE DROPPING
SOUTHWARD AND AMPLIFYING THE PATTERN. THIS PROGRESSION IN OF
AND ITSELF IS NOT PARTICULARLY TROUBLESOME, BUT THE MID TO
UPPER- LEVEL SHORTWAVES STILL ROTATING AROUND THIS EVOLVING
FEATURE ARE, AND GLOBAL MODELS (PARTICULARLY THE GFS/GEFS IN THE
PAST) NOTORIOUSLY STRUGGLE TO FULLY RESOLVE THE THEM WELL.
THIS BRINGS US TO OUR POTENTIAL CHRISTMAS-EVE TROUBLEMAKER, AN
UPPER-LEVEL SHORTWAVE AND COUPLED RAPIDLY DEVELOPING SURFACE LOW
PRESSURE SLING-SHOTTING NORTHWARD RIGHT ALONG COASTLINE; AN
IDEAL TRACK FOR A GOOD OLE FASHION PACIFIC NORTHWEST WINDSTORM.
THE ECMWF AND A FEW SELECT EPS MEMBERS HAVE BEEN THE STANDARD
BEARERS FOR A "WORSE CASE" SCENARIO THE PAST 24-48 HOURS AND
IT'S ALARMING TO SEE AN EVEN LARGER CONTINGENT OF EPS ENSEMBLE
MEMBERS SUPPORTING THIS ADVERSE OUTCOME AS OF THE 00Z/06Z MODEL
RUNS (NOT TO MENTION THE 00Z UW-WRF AS WELL). SHOULD THIS
SCENARIO COME TO FRUITION, A STRONG SURFACE PRESSURE GRADIENT
SUPPORTED BY A "STING JET" JUST ABOVE THE SURFACE WOULD PROVIDE
A BRIEF PERIOD (4-6 HOURS) OF STRONG SOUTH TO SOUTHWEST WINDS
WITH GUSTS 45-65+ MPH DURING THE DAY WEDNESDAY, AND NOT JUST FOR
THE ELEVATED TERRAIN FEATURES OR COAST, THE I-5 CORRIDOR WOULD
BE IN PLAY FOR THESE WINDS AS WELL. WINDS OF THIS MAGNITUDE
WOULD PRODUCE SIGNIFICANT IMPACTS LIKE WIDESPREAD POWER OUTAGES,
TREE DAMAGE, ETC. STILL, IN THE CONTEXT OF THE BROADER
AVAILABLE ENSEMBLE SOLUTIONS (GEFS AND GEPS) IT IS DEFINITELY
NOT A SURE THING JUST YET. WHILE THE LATEST EPS HAS LARGELY
BOUGHT INTO THE ABOVE SCENARIO WOULD LIKE SEE A BIT MORE RUN TO
RUN CONSISTENCY FROM THE BROADER FIELD OF EPS MEMBERS BEFORE
SIGNIFICANTLY CRANKING UP WINDS/GUSTS IN THE FORECAST - WHAT IS
IN THIS MORNING'S FORECAST IS NOT REFLECTIVE OF THE OUTCOME
MENTIONED ABOVE. IF (YES BIG IF) THE 12Z/18Z EPS MAINTAIN THE
SAME ENTHUSIASM FOR THIS SET-UP THROUGH TODAY WITH LITTLE
DEVIATION, HIGH WIND WATCHES/WARNINGS MAY BE NECESSARY ACROSS
MUCH OF WESTERN OREGON AND SOUTHWEST WASHINGTON. PLEASE CONTINUE
TO CLOSELY MONITOR THE FORECAST! THIS TIME OF YEAR IT'S AWAYS A
GOOD IDEA TO MAKE SURE YOU HAVE AN EMERGENCY KIT WITH FOOD,
WATER, AND BATTERIES AT YOUR PLACE OF RESIDENCE AND IN YOUR
VEHICLE.
BEYOND THE MIDWEEK, CONFIDENCE REMAINS LOW TO MODERATE REGARDING
THE TIMING OF ADDITIONAL WEATHER DISTURBANCES AS DETERMINISTIC AND
ENSEMBLE GUIDANCE STRUGGLE WITH THE LONGITUDINAL
PLACEMENT/PROGRESSION OF THE AMPLIFIED TROUGH OVER THE EASTERN
PACIFIC. THAT SAID, AROUND 70% OF LREF ENSEMBLE MEMBERS
EVENTUALLY MOVE THE AXIS OF THE TROUGH INTO WESTERN CONUS AROUND
FRIDAY INTO SATURDAY. UNTIL THEN, PERIODIC SHOWER CHANCES ARE
LIKELY TO PERSIST, MOST LIKELY ALONG THE COAST, COAST RANGE, AND
IN THE CASCADE. OVER THE COMING WEEKEND MODELS ARE STILL IN
DECENT AGREEMENT INCREASING 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 IN THE
NEXT 7 TO 10 DAYS. -99
AVIATION
CONDITIONS ARE A MIX OF IFR TO VFR ACROSS THE REGION
THIS MORNING AS ISOLATED TO SCATTERED SHOWERS CONTINUE TO
STREAM SOUTHWEST TO NORTHEAST OVERHEAD. WHILE SHOWERS GENERALLY
WANE FOR INLAND TERMINALS LATER THIS MORNING, WINDS BEGIN TO
INCREASE AS A FRONT ENTERS THE AREA. AT THE COAST GUST BETWEEN
30-40 KNOTS ARE LIKELY INTO THE AFTERNOON WITH GUSTS UP TO 20-25
KT FOR INLAND LOCATIONS AFTER 18-20Z MONDAY. WINDS EXPECTED TO
FALL BELOW 10 KT AROUND 03-06Z TUESDAY.
KPDX AND APPROACHES...IT'LL REMAIN A MIXTURE OF MVFR/VFR
CONDITIONS THIS MORNING AS SHOWERS MOVE NORTHEASTWARD THROUGH
THE AREA. THAT SAID, VFR PREVAILING CONDITIONS ARE FAVORED
THROUGH 22-23Z. AT THIS POINT, THE FRONTAL BOUNDARY ARRIVES WITH
THE CHANCE FOR MVFR CONDITIONS INCREASING TO 50-60%. -99
MARINE
THE NEXT ROBUST FRONTAL SYSTEM ARRIVES TODAY USHERING
IN BREEZY/GUSTY SOUTHWESTERLY WINDS AND BUILDING SEAS. A GALE
WARNING REMAINS IN EFFECT ACROSS ALL WATERS INCLUDING THE
COLUMBIA RIVER BAR UNTIL 7PM FOR WIND GUSTS AROUND 40 KNOTS.
WILL NOTE THAT THERE IS A 10-25% CHANCE FOR BRIEF, ISOLATED
WIND GUSTS UP TO 50 KT DURING THIS TIME AS WELL. SEAS ALSO
BUILD TO 13-15 FT AT 10-11 SEC THIS AFTERNOON AND EVENING AS A
WESTERLY SWELL MOVES IN. GUIDANCE SUGGESTS A 20-35% CHANCE THAT
SEAS RISE ABOVE 15 FT. MARINE CONDITIONS BRIEFLY SETTLE DOWN
TUESDAY WITH POTENTIAL FOR EASTERLY WINDS INTO TUESDAY NIGHT DUE
TO A LOW PRESSURE SYSTEM SPINNING OFFSHORE OF NORTHERN
CALIFORNIA. HOWEVER, GUIDANCE IS BEGINNING TO SUGGEST A STRONG
QUICK-HITTING SYSTEMS COULD (30-40%) BRING A PERIOD OF STORM-
FORCE WINDS (GUSTS >48 KNOTS) THROUGH THE AREA ON WEDNESDAY. BY
THE END OF THE WEEK, A SOUTHERLY SWELL PRODUCED BY THIS SYSTEM
WILL ENTER OUR WATERS AND RE-BUILD SEAS. -99/10
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. PLEASE BE SURE TO NEVER DRIVE
THROUGH A FLOODED ROAD AND HEED ANY REMAINING ROAD CLOSURES.
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...GALE WARNING UNTIL 7 PM PST THIS EVENING FOR PZZ210-251>253-
271>273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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