151
FXUS66 KPQR 251155
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
355 AM PST THU DEC 25 2025
SYNOPSIS
THE ACTIVE WEATHER CONTINUES FOR JUST A COUPLE MORE
DAYS AS ANOTHER LOW PRESSURE SYSTEM SPINS OFF OF THE COAST
USHERING IN MORE RAIN AND LOCALLY BREEZY WINDS INTO THE REGION
FOR CHRISTMAS DAY. THEN ON FRIDAY IMPACTS SWITCH TO CASCADE
SNOWFALL FOLLOWED BY A RIDGE OF HIGH PRESSURE AND DRIER
CONDITIONS THE REMAINDER OF THE FORECAST PERIOD. COLDER
OVERNIGHT TEMPERATURES AND PATCHY FOG EXPECTED OVER THE WEEKEND
INTO EARLY NEXT WEEK.
SHORT TERM...NOW THROUGH SATURDAY
TODAY A CLOSED LOW
PRESSURE SYSTEM OVER THE EASTERN PACIFIC WILL NUDGE CLOSER TO
THE SOUTHERN OREGON COAST WHILE DEEPENING BEFORE BECOMING
NEARLY STATIONARY. THIS PROGRESSION IS EXPECTED TO INCREASE THE
PRESSURE GRADIENT ACROSS THE AREA WHICH IS ALREADY BEING FELT
THROUGH THE CASCADE GAPS AND COLUMBIA RIVER GORGE. COME THE
AFTERNOON HOURS MODELS, PARTICULARLY HIGH RESOLUTION GUIDANCE,
SUGGEST A PERIOD OF BREEZY SOUTH WINDS EXTENDING OUTWARD FROM
THE LOW INTO THE OREGON COAST AND PORTIONS OF THE SOUTHERN
WILLAMETTE VALLEY. THAT SAID, THE OVERALL SET-UP IS NOT
PARTICULARLY FAVORABLE FOR ABNORMALLY HIGH WINDS, ESPECIALLY FOR
THE LATTER LOCATION, SO NO HEADLINES APPEAR NECESSARY FOR
EITHER AREA.
BY FRIDAY, THIS LOW WILL BEGIN TO TRANSITION TO MORE OF AN OPEN
WAVE WHILE MAKE ITS LEAP INLAND WITH STRONG ONSHORE FLOW
DEVELOPING. THANKS IN-PART TO THE AXIS OF THIS FEATURE PASSING
OVERHEAD IN ADDITION TO A SECONDARY SHORTWAVE AND COLD FRONTAL
BOUNDARY RACING INTO THE REGION FROM OFF THE BRITISH COLUMBIA
COASTLINE SHOWER ACTIVITY WILL BE REINVIGORATED ACROSS THE
PACIFIC NORTHWEST. GIVEN THE COOLER TEMPERATURES, LOWERING SNOW
LEVELS, AND ADDED PRECIPITATION, WE CONTINUE TO ANTICIPATE
ADVISORY LEVEL SNOWFALL IN THE OREGON AND WASHINGTON CASCADES
WITH 6-11 INCHES OF SNOWFALL ABOVE 3000-4000 FT. SNOW WILL
BEGIN TO DECREASE LATE INTO SATURDAY MORNING WITH LINGERING
ACTIVITY ENDING IN THE AFTERNOON HOURS. IF YOU PLAN ON
TRAVELING ACROSS THE CASCADES FRIDAY THROUGH SATURDAY MORNING
PREPARE FOR WINTER DRIVING CONDITIONS. -99/27
LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
HIGH PRESSURE
CONTINUES TO STRENGTHEN THE LATTER HALF OF THE WEEKEND WITH
CLEARER SKIES CAUSING TEMPERATURES TO DROP. OVERNIGHT SATURDAY
INTO SUNDAY, TEMPERATURES WILL FALL AROUND OR BELOW FREEZING FOR
MANY OF THE INLAND VALLEYS. CURRENTLY THERE IS AROUND A 90-95%
CHANCE OF TEMPERATURES BELOW FREEZING WITHIN THE SOUTHERN
WILLAMETTE VALLEY, NEAR 60-70% IN THE NORTHERN WILLAMETTE
VALLEY AND AROUND 15-25% IN THE PORTLAND-VANCOUVER METRO AREA.
THE COAST ALSO HAS A NON-ZERO CHANCE OF SEEING FREEZING
TEMPERATURES SUNDAY MORNING AS WELL. THE PROBABILITY OF 25
DEGREES OR LESS IS A MUCH LOWER PROBABILITY WITH A 25-30%
CHANCE WITHIN THE SOUTHERN WILLAMETTE VALLEY AND LESS THAN 5%
CHANCE ELSEWHERE. DURING THE DAY, CONDITIONS WILL BE DRY AND
MOSTLY CLEAR, HOWEVER, WE WILL LIKELY HAVE TO DEAL WITH PATCHY
OVERNIGHT/MORNING FOG WHICH CAN STRUGGLE TO BURN OFF THIS TIME
OF YEAR. SIMILAR CONDITIONS EXPECTED ON MONDAY AND TUESDAY
MORNINGS WITH A SLIGHT WARMING TREND EACH DAY. SOME UNCERTAINTY
REMAINS REGARDING THE EXACT BREAKDOWN OF THIS RIDGE FEATURE WITH
AROUND 45% OF LREF ENSEMBLE MEMBERS BRINGING PRECIPITATION BACK
TO THE REGION BY WEDNESDAY AFTERNOON, WITH ANOTHER 45% SHIFTING
THE TIMING BACK TO THURSDAY - THE LAST 10% OF ENSEMBLES KEEP THE
RIDGE IN PLACE THROUGH THE END OF NEXT WEEK. -99/27
AVIATION
EARLY THIS MORNING SATELLITE AND RADAR IMAGERY SHOW
OUR NEXT BAND OF RAIN SHOWERS MOVING SOUTH TO NORTH ACROSS THE
REGION. WHILE SEVERAL SITES IN THE CENTRAL/NORTHERN WILLAMETTE
VALLEY AND PORTLAND METRO WERE EXPERIENCING LIFR CONDITIONS
EARLIER DUE TO FOG, THESE CONDITIONS HAVE LIFTED (EXCLUDING
KEUG AS OF 12Z). AFTER TWO PRIMARY WAVES OF SHOWER ACTIVITY
THIS MORNING, DRIER CONDITIONS RETURN TO INLAND SITES FOR THE
AFTERNOON HOURS AS VFR CIGS PERSIST. THAT SAID, GUIDANCE DOES
SUGGESTS A 20-40% CHANCE FOR MVFR CIGS THROUGHOUT THE DAY,
MAINLY FOR THE VALLEY. EXPECT BREEZY EAST WINDS THROUGH THE
GORGE WITH GUSTS AT KTTD AROUND 20-30 KNOTS MOST OF THE FORECAST
PERIOD.
KPDX AND APPROACHES...LIFR CONDITIONS HAVE IMPROVED BACK TO VFR
WITH PREDOMINATELY VFR CONDITIONS THROUGH THE END OF THE TAF
PERIOD. STILL MODELS PROJECT A 20-35% CHANCE FOR MVFR CIGS
BETWEEN 18Z THU-00Z FRI. VARIABLE WINDS SHIFT EASTERLY THIS
MORNING AROUND 5-10 KT, ALTHOUGH THERE'S A CHANCE FOR A GUST OR
TWO NEAR 15-20 KNOTS BETWEEN 15-20Z. -99/10
MARINE
EASTERLY WINDS WILL INCREASE OVER THE WATERS TO START
THE MORNING AS A LOW PRESSURE SYSTEM APPROACHES FROM THE
SOUTHWEST. THE EAST WINDS WILL GUST UP TO 25 KT BEYOND 10 NM.
THEN WINDS WILL TURN SOUTHEASTERLY AND STRENGTHEN MIDDAY INTO
THE AFTERNOON AS THE LOW GETS CLEAR. A GALE WARNING IN IN EFFECT
FOR THE WATERS SOUTH OF CAPE FALCON AND BEYOND 10 NM FOR
SOUTHEASTERLY WIND GUSTS UP TO 40 KT. ELSEWHERE, SMALL CRAFT
ADVISORIES REMAIN IN EFFECT FOR WIND GUSTS UP TO 30 KT. SEAS
ALSO BUILD TODAY DUE TO A COMBINATION OF WIND WAVES AND A
SOUTHERLY SWELL. SEAS WITHIN THE GALE WARNING MAY BUILD TO 17-22
FT AT 10-12 SEC, WHILE OTHER LOCATIONS BUILD TO 13-16 FT AT
11-12 SEC. HAZARDOUS SEAS AND SMALL CRAFT CONDITIONS CONTINUE
INTO FRIDAY BEFORE MARINE CONDITIONS SETTLE DOWN THIS WEEKEND
THANKS TO A RIDGE OF HIGH PRESSURE BUILDING OVERHEAD. BY SUNDAY
WAVE HEIGHTS LIKELY SETTLE IN THE 4-6FT RANGE. -99/11
PQR WATCHES/WARNINGS/ADVISORIES
OR...WINTER WEATHER ADVISORY FROM 4 AM FRIDAY TO 4 PM PST SATURDAY
FOR ORZ126>128.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 4 AM PST
FRIDAY FOR PZZ251>253.
SMALL CRAFT ADVISORY UNTIL 7 PM PST THIS EVENING FOR PZZ271.
HAZARDOUS SEAS WARNING FROM 7 PM THIS EVENING TO 4 AM PST
FRIDAY FOR PZZ271.
SMALL CRAFT ADVISORY UNTIL 10 AM PST THIS MORNING FOR PZZ272-
273.
GALE WARNING FROM 10 AM THIS MORNING TO 10 PM PST THIS EVENING
FOR PZZ272-273.
HAZARDOUS SEAS WARNING FROM 10 PM THIS EVENING TO 4 AM PST
FRIDAY FOR PZZ272-273.
WWW.WEATHER.GOV/PORTLAND
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X.COM/NWSPORTLAND
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