086
FXUS66 KPQR 270548 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
946 PM PST FRI DEC 26 2025
..UPDATED AVIATION DISCUSSION
SYNOPSIS
THE LOW PRESSURE SYSTEM THAT HAS BROUGHT SCATTERED
SHOWERS TODAY CONTINUES TO SPIN OVER THE OR/CA BORDER. A FRONTAL
SYSTEM IS TRAVERSING NORTHERN OREGON BRINGING RAIN TO THE
LOWLANDS AND SNOW TO THE MOUNTAINS. HIGH PRESSURE BUILDS ON
SATURDAY WHICH WILL LEAD TO CLEAR AND DRY WEATHER THROUGH MUCH
OF NEXT WEEK.
SHORT TERM...NOW THROUGH MONDAY NIGHT
SATELLITE IMAGERY SHOWS
A WEAK LOW PRESSURE SYSTEM SPINNING OVER THE OREGON/CALIFORNIA
BORDER. THIS LOW IS COLD AIR WRAPPED WHICH MEANS THAT WE WILL
SEE A DROP IN DAYTIME AND OVERNIGHT TEMPERATURES. FOR THOSE
WANTING TO HIT THE SLOPES THOUGH, THE MOUNTAINS ARE RECEIVING
SNOW. CURRENT OBSERVATIONS AT THE MT HOOD SNOTEL SHOW AROUND 5-6
INCHES IN THE LAST 24 HOURS, AND BEAR GRASS CLOSER TO 8 INCHES
IN 24 HOURS. OBSERVATIONS IN THE WILLAMETTE NATL FOREST HAVE
SEEN LESS PRECIPITATION IN GENERAL, MOSTLY BECAUSE THE FRONT
CONTINUES TO BE SLIGHTLY NORTH OF THE AREA. WILL ADD THAT THE
FRONT HAS MOVED VERY SLOWLY AND THE WARM AIR HAS LINGERED IN THE
SOUTH. PRECIPITATION TOTAL WISE, THE COAST, COAST RANGE AND THE
CASCADES HAVE SEEN THE MOST PRECIPITATION WHILE THE INTERIOR
VALLEYS HAVE BEEN RAIN SHADOWED.
AS THE FRONT SHIFTS EASTWARD, THE COLD AIR WILL FILL IN BEHIND
IT AND ANOTHER WAVE OF MOISTURE WILL MOVE IN FROM THE SOUTH.
HIGHER RESOLUTION MODELS SHOWING THIS PRECIPITATION HITTING LATE
THIS AFTERNOON AND EARLY EVENING, MAINLY IMPACTING THE SOUTHERN
PORTIONS OF THE FORECAST AREA. SHOWERS WILL PERSIST THROUGH THE
DAY ON SATURDAY. THE COMBINATION OF THESE FEATURES WILL LEAD TO
SEVERAL INCHES OF SNOW WITHIN THE CASCADES THROUGH SATURDAY
AFTERNOON. THE LOCATIONS THAT WILL SEE THE HIGHEST ACCUMULATION
WILL BE ABOVE 4500 FT WITHIN THE MT HOOD NATL FOREST AND
NORTHWARD WITH UP TO 11 INCHES EXPECTED. FURTHER SOUTH,
ACCUMULATION WILL BE LESS WITH AROUND 6-8 INCHES OF SNOW AROUND
THE PASSES. FOR THOSE TRAVELING ACROSS THE CASCADES, PREPARE FOR
WINTER DRIVING - ESPECIALLY THOSE DRIVING AT NIGHT AS THAT IS
WHEN THE SNOW WILL BE THE HEAVIEST. CONDITIONS WILL ALSO BE
BREEZY AT THAT TIME SO DURING HEAVIER SNOW SHOWERS, VISIBILITY
MAY BE REDUCED AT TIMES. SNOW WILL ALSO FALL WITHIN THE UPPER
HOOD RIVER VALLEY THOUGH ACCUMULATION WILL BE MINIMAL BELOW 2000
FT.
AS THE FRONTS EXIT, THERE IS HIGH CONFIDENCE IN A HIGH PRESSURE
RIDGE BUILDING OVER THE REGION. THIS RIDGE WILL LEAD TO DRY, AND
COLD CONDITIONS THROUGH EARLY NEXT WEEK. THERE ARE TWO FORECAST
CHALLENGES TO ADDRESS THERE THOUGH. THE FIRST IS THE OVERNIGHT
TEMPERATURES. MODELS CONTINUE TO LOWER THE OVERNIGHT
TEMPERATURES WITH INCREASING PROBABILITY IN TEMPERATURES BELOW
FREEZING WITHIN THE LOWLANDS. THE COLDEST AREAS WILL BE THE
SOUTHERN WILLAMETTE VALLEY AND THE RURAL AREAS OF THE INTERIOR
LOWLANDS. COASTAL SITES THOUGH WILL STILL BE IN THE RUNNING FOR
NEAR FREEZING OVERNIGHT TEMPERATURES WITH AROUND A 10-25%
CHANCE OF OVERNIGHT TEMPERATURES BELOW FREEZING ON SUNDAY AND
MONDAY MORNING. WITHIN THE INTERIOR LOWLANDS, THE COLDEST NIGHT
WILL BE SUNDAY NIGHT INTO MONDAY MORNING WITH AROUND A 50%
CHANCE OF OVERNIGHT MINIMUM TEMPERATURES LESS THAN 29 DEGREES F,
AND AROUND 15% CHANCE TO THE NORTH.
THE SECOND FACTOR TO CONSIDER WILL BE THE PRESENCE OF FOG AND OR
FROST. AT THIS POINT, FROST APPEARS TO BE THE MOST LIKELY
SCENARIO DUE TO THE LACK OF SATURATION BUT CANNOT RULE OUT AREAS
OF FOG. -27
LONG TERM...TUESDAY THROUGH FRIDAY
COLD WEATHER PERSISTS
THROUGH AT LEAST WEDNESDAY AS HIGH PRESSURE LINGERS.
TRANSITIONING INTO THURSDAY IS WHEN CONDITIONS GET A BIT MORE
COMPLICATED. THE UPPER AIR PATTERN SUGGESTS A DIRTY RIDGE
CONTINUING OVER THE AREA, WHILE SOME OF THE ENSEMBLES SUGGEST A
LONG WAVE TROUGH MOVING IN BRINGING PRECIPITATION AND SLIGHTLY
WARMER AIR. WHILE AT THE MID-LEVELS THE TROUGH LOOKS MORE
LIKELY, ALOFT THE RIDGE IS BETTER SUPPORTED. GIVEN THE LACK OF
VERTICAL SUPPORT, THE CHANGE IN THE PATTERN WILL BE HARDER TO
SUPPORT. GIVEN THE PERVASIVE NATURE OF THE RIDGE, THE LOW MUST
BE ROBUST ENOUGH TO ERODE IT COMPLETELY ON THURSDAY. AT THIS
POINT, THAT DOES NOT LOOK TO BE THE CASE BUT THERE IS STILL
AMPLE TIME FOR CONSENSUS TO FORM. -27
AVIATION
RADAR IMAGERY AND TERMINAL OBSERVATIONS AS OF LATE
FRIDAY EVENING DEPICTS SCATTERED SHOWERS WITH VFR CONDITIONS ACROSS
NORTHWEST OREGON AS A WEAK FRONT MOVES THROUGH. EXPECT PREDOMINATELY
VFR THRESHOLDS THROUGH THE TAF PERIOD, EXCEPT FOR A 20-40% CHANCE
FOR MVFR CIGS BETWEEN 12-21Z SAT ACROSS THE WILLAMETTE VALLEY AS.
SHOWERS WILL GRADUALLY DECREASE SATURDAY AFTERNOON AS THE FRONT
EXITS THE REGION. WEST-NORTHWESTERLY WINDS WITH GUSTS UP TO 20 KT
CONTINUE ALONG THE COAST THROUGH 12-15Z SAT, THEN WEAKENING UNDER 10
KT. ACROSS THE VALLEY, SOUTHWESTERLY WINDS PREVAIL UNDER 10 KT. WITH
TEMPERATURES NEARING THE MID TO LOW 30S, FROST DEVELOPMENT IS
POSSIBLE ON METAL SURFACES.
KPDX AND APPROACHES...PREDOMINATELY VFR CONDITIONS THROUGH THE TAF
PERIOD WITH A 30-40% CHANCE FOR MVFR CIGS BETWEEN 12-21Z SAT.
SOUTHWESTERLY WINDS UNDER 10 KT. -10
MARINE
A FRONT CONTINUES MOVING THROUGH THE WATERS THIS
AFTERNOON WITH WINDS SHIFTING NORTHWESTERLY BEHIND IT. WINDS
CONTINUE INCREASING WITH GUSTS UP TO 25-30 KTS NORTH OF DEPOE
BAY. SEAS ALSO BUILD TO 11-15 FT AT 10 TO 12 SEC ACROSS ALL
WATERS, HIGHEST NORTH OF CASCADE HEAD. A HAZARDOUS SEAS WARNING
REMAINS IN EFFECT FOR ALL OUTER WATER ZONES AND A SMALL CRAFT
ADVISORY FOR ALL INNER WATERS AND THE COLUMBIA RIVER BAR THROUGH
AT LEAST SATURDAY AFTERNOON FOR A COMBINATION OF WINDS AND SEAS.
WINDS BEGIN DECREASING EARLY SATURDAY MORNING, ALONG WITH SEAS
SLOWLY SUBSIDING THROUGH THE DAY SATURDAY, WITH CONDITIONS
FALLING BELOW HAZARDOUS SEAS AND SMALL CRAFT THRESHOLDS BY LATE
SATURDAY AFTERNOON. A RIDGE OF HIGH PRESSURE BUILDS OVERHEAD LATE
SATURDAY INTO SUNDAY. WINDS DECREASE TO LESS THAN 15 KTS BY
SATURDAY NIGHT AND SEAS SETTLE IN THE 4-6 FT RANGE, CONTINUING
INTO SUNDAY. -03
PQR WATCHES/WARNINGS/ADVISORIES
OR...WINTER WEATHER ADVISORY UNTIL 4 PM PST SATURDAY FOR ORZ126>128.
WA...WINTER WEATHER ADVISORY UNTIL 4 PM PST SATURDAY FOR WAZ211.
PZ...SMALL CRAFT ADVISORY UNTIL 3 PM PST SATURDAY FOR PZZ210-251>253.
HAZARDOUS SEAS WARNING UNTIL 3 PM PST SATURDAY FOR PZZ271>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