902
FXUS66 KPQR 161225
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
425 AM PST MON FEB 16 2026
SYNOPSIS
A DEEP, UPPER LEVEL TROUGH DROPPING SOUTH OUT OF CANADA
WILL BRING COOLER TEMPERATURES, SCATTERED TO WIDESPREAD SHOWERS AND
THE POTENTIAL FOR LOWLAND SNOW. MODIFIED ARCTIC AIR IS EXPECTED TO
MAINTAIN TEMPERATURES AROUND 5-10 DEGREES COOLER THAN AVERAGE, WHILE
LOWERING SNOW LEVELS TO AT LEAST 1000 FT. UNSETTLED AND SHOWERY
WEATHER CONDITIONS WILL LIKELY CONTINUE THROUGH MUCH OF THE WEEK,
WITH MIXED RAIN/SNOW SHOWERS POSSIBLE DOWN TO SEA LEVEL STARTING
LATE TONIGHT/TUESDAY MORNING. WHILE NOT THE MOST LIKELY SOLUTION,
THERE IS POTENTIAL (10-20% CHANCE) FOR 1 TO 2 INCHES OF SNOWFALL
OCCURRING SOMEWHERE IN NW OREGON/SW WASHINGTON WED NIGHT INTO
THURSDAY MORNING. SNOW LEVELS SLOWLY RISE AGAIN THROUGH THE WEEKEND.
DISCUSSION...NOW THROUGH SUNDAY
WATER VAPOR SATELLITE IMAGERY
EARLY MONDAY MORNING SHOWS AN UPPER LEVEL TROUGH DROPPING SOUTH FROM
THE GULF OF ALASKA WHICH IS ACTING TO STRETCH AND SQUEEZE THE LOW
PRESSURE SYSTEM OFF THE CALIFORNIA COAST. THIS IS PUSHING AN INITIAL
BAND OF MOISTURE FROM OVER SOUTHWEST OREGON NORTHWARD ACROSS THE
SOUTHERN WILLAMETTE VALLEY UP TO THE NORTH OREGON CASCADES THIS
MORNING. SNOW LEVELS IN THE CASCADES ARE STILL RELATIVELY HIGH, NEAR
PASS LEVEL AT AROUND 4000 TO 4500 FT, WHILE TEMPERATURES NEAR
GOVERNMENT CAMP AND AT THE SANTIAM AND WILLAMETTE PASSES ARE
HOVERING AROUND 32-33 DEGREES. THIS WILL LIMIT EARLY ACCUMULATIONS
TO THE HIGHER CASCADES, BUT COLDER AIR WILL STEADILY FILTER INTO THE
REGION THROUGH THE DAY.
BY THIS AFTERNOON, A COLD FRONT PUSHING THROUGH THE AREA WILL USHER
IN MORE UNSTABLE, COOLER AIR ALOFT WITH SHOWERS BECOMING MORE
WIDESPREAD. SNOW LEVELS WILL CONTINUE TO LOWER TO AROUND 1000-1500
FT BY THIS EVENING AS THE UPPER LEVEL TROUGH CONTINUES TO DEEPEN
OFFSHORE. THIS TROUGH IS DRIVEN BY A STRENGTHENING JET STREAK, UP TO
170 KT AT 300 MB, EXTENDING FROM THE CHUKCHI SEA INTO THE NE
PACIFIC. SNOW LEVELS OVERNIGHT CONTINUE TO DROP, DOWN TO AROUND 500-
750 FT, LOWEST OVER SOUTHWEST WASHINGTON. THE CURRENT WINTER WEATHER
ADVISORY FOR THE COAST RANGE, CASCADES AND CASCADE FOOTHILLS LOOKS
TO REMAIN ON TRACK, WITH AT LEAST A 60-70% CHANCE OF EXCEEDING 6
INCHES AT PASS LEVEL THROUGH TUESDAY MORNING, WITH SIMILAR
PROBABILITIES OF AT LEAST 2 INCHES OF SNOWFALL FOR THE COAST RANGE
AND CASCADE FOOTHILLS.
BY TUESDAY, A DEEP UPPER LOW WILL BE POSITIONED OVER THE PACIFIC NW,
WHILE 850 MB TEMPERATURES ARE EXPECTED TO SETTLE AROUND -5 TO -6 C.
SURFACE LOW PRESSURE WILL LIKELY REMAIN OFFSHORE NEAR THE WASHINGTON
OR NORTH OREGON COAST. THIS WILL SUPPORT AN UNSTABLE AND SHOWERY
PATTERN AS SOUTHWEST FLOW MAINTAINS MARGINAL TEMPERATURES FOR SNOW
TO RIVER LEVEL. SO, SNOW ACCUMULATIONS WILL BE UNLIKELY WITHIN THE
LOWLANDS, WITH A DUSTING OF SNOW POSSIBLE ABOVE 500 FT. LOCALLY
HEAVIER SHOWERS COULD BRIEFLY ENHANCE SNOWFALL RATES, BUT WOULD
LIKELY MELT ON CONTACT. THE CONVECTIVE NATURE OF THE AIR MASS WILL
ALSO MAINTAIN A 10-20% CHANCE OF THUNDER, MAINLY AT THE COAST LATER
THIS MORNING THROUGH TUESDAY AFTERNOON. ANY THUNDERSTORMS THAT DO
FORM WOULD HAVE THE POTENTIAL FOR SMALL HAIL OR GRAUPEL, ALONG WITH
GUSTY OUTFLOW WINDS.
ENSEMBLES AND HI-RES MODELS SUGGEST A BIT OF A LULL IN SHOWER
ACTIVITY TUESDAY NIGHT INTO WEDNESDAY MORNING. OVERNIGHT
TEMPERATURES ARE EXPECTED TO FALL BELOW FREEZING ACROSS MOST OF THE
FORECAST AREA. ANY SHOWERS THAT DO OCCUR EARLY WEDNESDAY WOULD
LIKELY PRODUCE SNOW SHOWERS, BUT SHOULD BE LIGHT AND WIDELY
SCATTERED. ANOTHER CONCERN WOULD BE ANY WET ROADS FROM PRECIPITATION
ON TUESDAY WOULD HAVE THE CHANCE TO FREEZE AND BECOME ICY BY
WEDNESDAY MORNING.
WEDNESDAY NIGHT INTO THURSDAY MORNING BECOMES A BIT MORE INTERESTING
AS A FEW MODELS AND ENSEMBLE MEMBERS ARE HINTING AT A SCENARIO THAT
COULD PRODUCE ACCUMULATING SNOW FOR THE LOWLANDS, PARTICULARLY
DURING THE MORNING COMMUTE. THIS WOULD DEPEND ON THE LOCATION OF A
SURFACE LOW NEAR THE NORTHERN OR CENTRAL OREGON COAST, AND IF MORE
EASTERLY FLOW DRAWS IN COOLER AIR EAST OF THE CASCADES. A TRUE
ARCTIC AIR MASS IS NOT EXPECTED TO BE IN PLACE, BUT COOLER MORNING
TEMPERATURES COULD ALLOW FOR BRIEF ACCUMULATIONS. THE PROBABILITIES
FOR AT LEAST A TRACE OF SNOW HAS INCREASED FOR THURSDAY MORNING TO
AROUND 50-70% (HIGHEST IN THE PORTLAND/VANCOUVER METRO AND ACROSS
THE SOUTHERN WILLAMETTE VALLEY NEAR EUGENE). WHILE MOST GUIDANCE
STILL FAVORS LITTLE TO NO ACCUMULATION AT ANY ONE LOCATION WITHIN
THE LOWLANDS, THERE IS A 10-20% CHANCE OF 1 TO 2 INCHES OF SNOWFALL
THURSDAY MORNING SHOULD AN ORGANIZED MESOSCALE BAND FORM UNDER THE
RIGHT CONDITIONS; PARTICULARLY IN SOUTHWEST WASHINGTON, THE TUALATIN
VALLEY, AND PORTIONS OF THE PORTLAND METRO INTO THE COLUMBIA RIVER
GORGE. CONFIDENCE IN THIS SCENARIO REMAINS LOW.
LATER IN THE WEEK, TROUGHING PERSISTS BUT GRADUALLY MODERATES. SNOW
LEVELS ARE LIKELY TO NUDGE UPWARD THIS WEEKEND, THOUGH COOL AND
UNSETTLED CONDITIONS MAY LINGER AND MAINTAIN LIGHT SNOW FOR THE
MOUNTAINS. DH/12
AVIATION
MOIST SOUTHWEST FLOW ALOFT CONTINUES AHEAD OF A
DEEPENING UPPER LEVEL TROUGH OFFSHORE. PREDOMINATELY MVFR
CONDITIONS ARE IN PLACE ACROSS THE WILLAMETTE VALLEY, EXCEPT IFR
CIGS AT KEUG. AS OF 09Z, VFR CONDITIONS PERSIST ACROSS SOUTHWEST
WASHINGTON AND AT KAST. A FRONTAL BAND OVER SOUTHWEST OREGON WILL
LIFT NORTH SPREADING RAIN NORTHWARD THIS MORNING. A SECONDARY
SYSTEM WILL APPROACH THE COAST LATER THIS MORNING AS A COLD FRONT
PUSHES ONSHORE BY THIS AFTERNOON. MORE UNSTABLE CONDITIONS ARE
EXPECTED BEHIND THIS FRONT AS COOLER AIR ALOFT FILTERS IN, WITH
SCATTERED TO WIDESPREAD SHOWERS SPREADING ACROSS THE AREA FROM
WEST TO EAST. GUIDANCE DECREASES PROBS FOR MVFR CONDITIONS DURING
THE AFTERNOON HOURS AS THE TRANSITION TO THIS SHOWERY AIR MASS
OCCURS, HOWEVER CONFIDENCE IS LOW REGARDING THE TIMING OF DEFINED
PERIODS OF VFR, AS SHOWERS WILL HAVE THE POTENTIAL TO BRING
REDUCED CIGS OR VIS AT TERMINALS. THERE IS ALSO A 10-20% CHANCE OF
THUNDERSTORMS, MAINLY AT THE COAST LATER THIS MORNING AND
AFTERNOON. SMALL HAIL, GRAUPEL, OR EVEN A FEW SNOW FLAKES WILL BE
POSSIBLE WITH STRONGER SHOWERS OR THUNDERSTORMS, AS WELL AS GUSTY
AND ERRATIC OUTFLOW WIND GUSTS UP TO 25-30 KT.
KPDX AND APPROACHES...CONDITIONS LIKELY BOUNCE BETWEEN MVFR AND
VFR AS THERE IS A 40-60% CHANCE OF EITHER FLIGHT CONDITIONS
THROUGH 18Z. PROBS FOR MVFR INCREASE LATER THIS MORNING THROUGH
THE AFTERNOON WITH CIGS LIKELY FALLING TO AROUND 1500 FT. CHANCES
FOR VFR INCREASE AFTER 00Z TUESDAY. STARTING 12-14Z, LIGHT RAIN
IS EXPECTED TO INCREASE OVER THE TERMINAL FROM THE SOUTH BEFORE
TRANSITIONING TO SHOWERS DURING THE AFTERNOON HOURS. LIGHT
NORTHWEST WINDS BECOME MORE VARIABLE THIS MORNING BEFORE BECOMING
SOUTHERLY 6-8 KT BY 20Z. /DH
MARINE
NORTHERLY WINDS ARE EXPECTED TO BECOME WESTERLY AS A
COLD FRONT MOVES ACROSS THE WATERS THIS MORNING AND QUICKLY
PUSHES INLAND BY THIS AFTERNOON. EXPECT INCREASING WESTERLY WINDS
BEHIND THIS FRONT WITH GUSTS GENERALLY UP TO 20 KT. HOWEVER,
STRONGER SHOWERS THAT DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE
OUTFLOW WIND GUSTS UP TO 30 KT.
SURFACE LOW PRESSURE DROPS SOUTH ALONG THE WASHINGTON COAST LATE
MONDAY INTO TUESDAY, BRINGING MORE SOUTH TO SOUTHWESTERLY WINDS
ACROSS THE WATERS ON TUESDAY. THE LOW PRESSURE LIKELY WEAKENS AS
IT CONTINUES TO DRIFT SOUTH THROUGH THE OREGON COASTAL WATERS
RESULTING IN EASING WIND SPEEDS.
A MID-PERIOD WEST-NORTHWESTERLY SWELL WILL PUSH INTO THE COASTAL
WATERS MONDAY NIGHT, BUILDING SEAS TO AROUND 13 TO 15 FT ON
TUESDAY, LIKELY HIGHEST OVER THE CENTRAL AND SOUTHERN WATERS,
WHERE THERE IS A 10% CHANCE OF SEAS REACHING 16 TO 17 FT. HAVE
EXTENDED THE SMALL CRAFT ADVISORY FOR ALL COASTAL WATERS THROUGH
TUESDAY NIGHT.
SEAS GRADUALLY SUBSIDE WEDNESDAY INTO THURSDAY WITH WIND GUSTS
MOST LIKELY RANGING BETWEEN 15-25 KT AND SEAS FALLING TO AROUND 10
FT OR LESS. WINDS AND SEAS WILL LIKELY INCREASE NEXT WEEKEND AS
THERE IS POTENTIAL FOR A STRONGER SYSTEM NEAR THE WATERS. THERE
IS CURRENTLY A 50-70% CHANCE FOR GALE FORCE WIND GUSTS OVER 34 KT
FEBRUARY 21-22 WITH A 50% CHANCE FOR SEAS OF 12 TO 15 FT AND A
5-10% CHANCE FOR SEAS AS HIGH AS 17-20 FT. DH/23
BEACH HAZARDS
A HIGH THREAT FOR SNEAKER PERSISTS THROUGH
SUNDAY EVENING DUE TO A LONG PERIOD WESTERLY SWELL. ALTHOUGH THE
THREAT FOR SNEAKER WAVES DECREASES ON MONDAY, ANOTHER LONG PERIOD
WESTERLY SWELL ARRIVES ON TUESDAY, BRINGING A HIGH SNEAKER WAVE
THREAT ONCE AGAIN. SNEAKER WAVES CAN RUN UP SIGNIFICANTLY FARTHER
ON A BEACH THAN NORMAL, INCLUDING OVER ROCKS AND JETTIES. THESE
WAVES CAN SUDDENLY KNOCK PEOPLE OFF OF THEIR FEET AND QUICKLY
PULL THEM INTO THE FRIGID OCEAN WHICH MAY LEAD TO SERIOUS INJURY
OR DROWNING. CAUTION SHOULD BE USED WHEN IN OR NEAR THE WATER,
ESPECIALLY THOSE WHO WILL BE RAZOR CLAMMING. KEEP CHILDREN AND
PETS AWAY FROM THE SURF ZONE. KEEP OFF OF JETTIES, ROCKS AND LOGS
NEAR THE SURF ZONE. IF YOU SEE SOMEONE SWEPT INTO THE SEA, DO NOT
SWIM IN AFTER THEM. INSTEAD , CALL 911 AND KEEP AN EYE ON THEM
UNTIL HELP ARRIVES.
PQR WATCHES/WARNINGS/ADVISORIES
OR...WINTER WEATHER ADVISORY FROM 4 AM EARLY THIS MORNING TO 4 AM PST
THURSDAY FOR ORZ106-107-123>128.
WA...WINTER WEATHER ADVISORY FROM 4 AM EARLY THIS MORNING TO 4 AM PST
THURSDAY FOR WAZ203-208-211.
PZ...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM PST
WEDNESDAY FOR PZZ210-251>253.
SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 4 AM PST
WEDNESDAY FOR PZZ271>273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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