999
FXUS66 KPQR 120525
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
925 PM PST SUN JAN 11 2026
UPDATED HAZARDS AND AVIATION AND MARINE DISCUSSIONS.
SYNOPSIS
A SLOW-MOVING FRONTAL BOUNDARY WILL BRING PERIODS
OF LIGHT RAIN TO SOUTHWEST WASHINGTON AND ALONG THE FAR NORTH
OREGON COAST NOW THROUGH MONDAY MORNING, WHILE THE REST OF
WESTERN OREGON STAYS DRY WITH LIGHT WINDS AND HIGH CLOUDS. A
VERY STRONG HIGH PRESSURE SYSTEM WILL STRENGTHEN AND REMAIN
ANCHORED OVER THE PACIFIC NORTHWEST TUESDAY THROUGH NEXT
WEEKEND. THIS WILL RESULT IN A PROLONGED STRETCH OF DRY WEATHER
WITH ABNORMALLY MILD TEMPERATURES AND LIGHT WINDS. EXPECT AT
LEAST 6 TO 8 CONSECUTIVE DRY DAYS IN A ROW.
DISCUSSION...NOW THROUGH SATURDAY NIGHT
ASIDE FROM PERIODS OF
LIGHT RAIN OVER PORTIONS OF SOUTHWEST WASHINGTON AND THE FAR NORTH
OREGON COAST THROUGH SUNDAY NIGHT/MONDAY MORNING, THE WEATHER
FORECAST OVER THE NEXT 6 TO 8 DAYS IS DOMINATED BY A PROLONGED
STRETCH OF DRY AND CALM CONDITIONS WITH ABOVE NORMAL TEMPERATURES
FOR THIS TIME OF YEAR. THE PRIMARY CAUSE OF THESE CONDITIONS IS
AN ANOMALOUSLY STRONG HIGH PRESSURE SYSTEM THAT MODELS AND
THEIR ENSEMBLES CONTINUE TO SHOW A BROAD AREA OF HIGH PRESSURE
ANCHORED OVER THE PAC NW/ NE PACIFIC THROUGH THIS WEEK AND INTO
NEXT WEEKEND. MODELS ALSO SHOW THAT THE RIDGE WILL AMPLIFY OVER
WESTERN OR AND WA MONDAY THROUGH WEDNESDAY. THE OVERALL SYNOPTIC
PATTERS HAS A WELL ESTABLISHED, UPPER LEVEL RIDGE THAT
TRANSITIONS INTO A REX BLOCKING PATTERN TOWARDS THE LATTER PART
OF THIS WEEK. IT SHOULD BE NOTED THAT MODELS ARE SHOWING THE
RIDGE FLATTENING AS ALASKAN LOWS RIDE THE CREST OF THE RIDGE,
BUT THESE SYSTEMS ARE NOT EXPECTED TO BREAK THE OVERALL BLOCKING
PATTERN. 500 MB HEIGHTS LOOK TO PEAK NEAR 590 DM OVER NORTHERN
CALIFORNIA AND SOUTHERN OREGON, AND NEAR 585 DM OVER NORTHERN
OREGON. NOTE THESE VALUES ARE AROUND THE 95TH-99TH PERCENTILE
COMPARED TO CLIMATOLOGY, WHICH MEANS HIGH PRESSURE OF THIS
MAGNITUDE IS QUITE RARE THIS TIME OF YEAR, ESPECIALLY GIVEN THE
EXTENDED DURATION.
AT THIS TIME, IT IS NOT CLEAR EXACTLY WHEN THE RIDGE/BLOCKING
PATTERN WILL BREAK DOWN AND PRECIPITATION WILL RETURN, HOWEVER
SOME MODEL GUIDANCE IS SUGGESTING THAT A PATTERN CHANGE COULD
OCCUR AROUND JAN. 21-23 WITH PRECIPITATION COMING BACK INTO THE
CONVERSATION. STILL, CONFIDENCE ON THIS OCCURRING IS VERY LOW
GIVEN THAT WE ARE LOOKING AT MODEL SOLUTIONS AROUND 10 DAYS IN
THE FUTURE. ALSO, BLOCKING PATTERNS (VIA FORECASTER PATTERN
RECOGNITION) WILL TYPICALLY LAST 7-8 DAYS OR 10-11 DAYS. UNTIL
THEN, EXPECT MORE OF THE SAME EACH DAY WITH VARYING DEGREES OF
CLOUD COVER, LIGHT WINDS, AND MILD TEMPERATURES WITH AFTERNOON
HIGHS RUNNING ANYWHERE FROM 5-15 DEGREES ABOVE NORMAL FOR THIS
TIME OF YEAR AS DAYTIME HIGHS ARE EXPECTED TO BE GENERALLY IN
THE 50S TO 60S. THE NBM SUGGESTS HIGHS WILL RANGE IN THE LOW TO
UPPER 50S LOWLANDS, MID 50S TO MID 60S IN THE CASCADE FOOTHILLS
AND LOW TO UPPER 50S ALONG THE COAST. CURRENTLY, THE WARMEST
DAYS IN THE FORECAST ARE THURSDAY AND FRIDAY.
THE COOLEST DAYTIME TEMPERATURES WILL OCCUR IN PORTIONS OF THE
CENTRAL AND SOUTHERN WILLAMETTE VALLEY WHERE CHANCES FOR FOG AND
LOW CLOUDS EACH NIGHT/MORNING MAY LIMIT DAYTIME HEATING AND
KEEP HIGHS CLOSER TO 50 DEGREES. THE REASON THE OREGON CASCADE
FOOTHILLS WILL LIKELY BE WARMEST IS DUE TO A COMBINATION OF MORE
HOURS OF SUNSHINE AND THE FACT THAT THESE ELEVATIONS ARE HIGH
ENOUGH TO POKE ABOVE A STRONG LOW-LEVEL TEMPERATURE INVERSION
THAT WILL REMAIN IN PLACE THROUGH THE WEEK, THUS TAPPING INTO
RELATIVELY WARMER AIR ALOFT. LOCATIONS SUCH AS OAKRIDGE WILL
FEEL MORE SPRING LIKE RATHER THAN TYPICAL MID JANUARY DAYTIME
HIGHS.
IT SHOULD BE NOTED THAT A HIGH PRESSURE ALOFT WILL RESULT IN A
RATHER STABLE ATMOSPHERE IE...MINIMAL AIR MIXING AND MOVEMENT.
THIS WILL LEAD TO THE POTENTIAL FOR DEGRADED AIR QUALITY AS THIS
PATTERN IS EXPECTED TO PERSIST. SO, PROLONGED MULTI-DAY STRETCH
OF VERY LOW VERTICAL MIXING HEIGHTS, WHICH HELPS TRAP AIR
POLLUTANTS NEAR THE SURFACE, WILL BRING ABOUT STAGNANT AIR.
AS A RESULT OF THESE CONDITIONS, WE HAVE ISSUED A AIR
STAGNATION ADVISORY FOR THE MAJORITY OF THE WILLAMETTE VALLEY
AND IT COULD EXPAND AS THE WEEK PROGRESSES. STATE AIR QUALITY
AGENCIES HIGHLY RECOMMEND THAT NO OUTDOOR BURNING OCCUR AND THAT
RESIDENTIAL WOOD BURNING DEVICES BE LIMITED AS MUCH AS
POSSIBLE. ACCORDING TO STATE AIR QUALITY AGENCIES, PROLONGED
PERIODS OF STAGNANT AIR CAN HOLD POLLUTANTS CLOSE TO THE GROUND
WHERE PEOPLE LIVE AND BREATHE. CHECK WITH YOUR LOCAL BURN AGENCY
FOR ANY CURRENT RESTRICTIONS IN YOUR AREA.
ALSO, PEOPLE WITH RESPIRATORY ILLNESS SHOULD FOLLOW THEIR
PHYSICIAN'S ADVICE FOR DEALING WITH HIGH LEVELS OF AIR POLLUTION
DURING PERIODS OF STAGNANT AIR, ESPECIALLY IF AN AIR QUALITY
ALERT IS IN EFFECT FOR YOUR AREA. TO SEE IF AN AIR QUALITY ALERT
IS IN EFFECT FOR YOUR AREA, GO TO WWW.WEATHER.GOV/PQR AND LEFT-
CLICK YOUR LOCATION ON THE HOMEPAGE MAP DISPLAY. ALTERNATIVELY,
YOU COULD ALSO TYPE YOUR LOCATION INTO THE SEARCH BAR FOUND ON
THE TOP-LEFT HAND SIDE OF THE HOMEPAGE. FROM THERE, YOU WILL SEE
AN AIR QUALITY ALERT LISTED AT THE TOP IF ONE IS IN EFFECT FOR
YOUR LOCATION; YOU CAN CLICK THE ALERT TO READ MORE DETAILS IF
APPLICABLE. YOU CAN ALSO FIND THE CURRENT AIR QUALITY INDEX
(AQI) FOR YOUR LOCATION AT WWW.AIRNOW.GOV. /42-23
AVIATION
VFR CONDITIONS PREVAIL ACROSS THE REGION OUTSIDE OF
KAST WHERE THE SOUTHERN EDGE OF A FRONTAL BOUNDARY HAS KEPT
OCCASIONAL LIGHT RAIN AND MVFR CIGS IN PLACE. HEADED THROUGH TONIGHT
THE PRIMARY FLIGHT IMPACTS WILL BE ASSOCIATED WITH THE POTENTIAL FOR
PATCHY FOG WITHIN PORTIONS OF THE WILLAMETTE VALLEY AND TUALATIN
VALLEY. CONFIDENCE IS STILL RATHER LOW REGARDING EXACTLY WHERE AND
WHEN FOG WILL DEVELOP - IF IT EVEN DEVELOPS AT ALL. SIMILAR TO THE
PAST COUPLE OF NIGHTS, BROKEN HIGH CLOUDS WILL LARGELY WORK AGAINST
WIDESPREAD FOG FORMATION, BUT THIS SETUP HAS GENERALLY RESULTED IN
PATCHY FOG AND FLUCTUATING VISIBILITIES AT KHIO, KSLE, AND KUAO.
KHIO HAS THE HIGHEST CHANGE FOR FOG OF ANY TAF SITE, WITH
PROBABILITIES REACHING 30-50% FOR SURFACE VISIBILITIES BELOW 1 SM
BETWEEN 09-18Z MONDAY. PROBABILITIES FOR FOG RANGE BETWEEN 15-30% AT
KUAO, KSLE AND KEUG. ADDITIONALLY, A PUSH OF LOW CLOUDS FROM THE
WEST WILL CAUSE MVFR CONDITIONS AT KONP. OTHERWISE, VFR CONDITIONS
ARE FAVORED TO PERSIST AT KPDX AND KTTD. IT'S WORTH NOTING JUST
OUTSIDE OF THE TAF PERIOD (MONDAY NIGHT INTO TUESDAY MORNING)
PROBABILITIES FOR FOG AND LIFR/IFR CONDITIONS ACROSS THE INLAND
VALLEYS INCREASE SIGNIFICANTLY.
KPDX AND APPROACHES...EXPECT VFR FLIGHT CONDITIONS TO PREVAIL
THROUGH THE TAF PERIOD AS HIGH CLOUDS STREAM OVERHEAD. LIGHT ESE
WINDS CONTINUE AS WELL HELPING TO PREVENT ANY FOG FORMATION LOCALLY.
-99/03
MARINE..A LONG PERIOD SOUTHWESTERLY SWELL CONTINUES THROUGH MONDAY.
AS OF 9 PM PST, OBSERVATIONS FOR BUOYS 46089 AND 46029 HAVE BEEN
LOWER THAN PREVIOUS GUIDANCE SUGGESTED, ONLY PEAKING AROUND 13-15 FT
INSTEAD OF AROUND 16-17 FT. LATEST GUIDANCE HAS ADJUSTED TO MATCH
OBSERVATIONS, AND AS SUCH, FORECAST HAS BEEN UPDATED TO MATCH. SEAS
ARE EXPECTED TO REMAIN AROUND 13-15 FEET INTO MONDAY, HIGHEST OVER
THE NORTHERN WATERS TO THE NORTH OF CAPE FALCON WHERE SOUTHERLY
WINDS WILL BE STRONGEST, GUSTING AS HIGH AS 28-35 KT. THIS INCLUDES
THE MAIN CHANNEL OF THE COLUMBIA RIVER BAR. NOTE THAT GALE FORCE
WIND GUSTS OF 34-35 KT ARE EXPECTED TO BE ISOLATED AND INFREQUENT
TONIGHT, BUT STILL SOMETHING TO KEEP IN MIND BEFORE WINDS SLOWLY
DECREASE ON MONDAY.
A HAZARDOUS SEAS WARNING REMAINS IN EFFECT FOR MARINE ZONES PZZ271,
272, 251, 252, AND 210 THROUGH MONDAY AFTERNOON WITH SMALL CRAFT
ADVISORIES FOR ZONES PZZ273 AND 253. ONCE WE GET INTO MONDAY NIGHT,
SEAS GRADUALLY DECREASE, TRANSITIONING TO A BRIEF PERIOD OF SMALL
CRAFT ADVISORY CONDITIONS. BY TUESDAY AFTERNOON, CONFIDENCE IS
MODERATE TO HIGH SEAS FALL BACK INTO THE 8-9 FT RANGE ACROSS THE
INNER AND OUTER WATERS. HEADED THROUGH THE REST OF THE WEEK, A RIDGE
OF HIGH PRESSURE AMPLIFIES OVERHEAD RESULTING IN RATHER CALM
CONDITIONS BY WINTER-TIME STANDARDS. COME FRIDAY, SEAS LIKELY BOTTOM
OUT AROUND 4-6FT AT 11-12 SECONDS. -99/03
BEACH HAZARDS
THERE IS A HIGH THREAT OF SNEAKER WAVES AT THE COAST
THROUGH MONDAY DUE TO A CONTINUED LONG-PERIOD SOUTHWESTERLY TO
WESTERLY SWELL. SNEAKER WAVES CAN CREATE POTENTIALLY LIFE-
THREATENING CONDITIONS AS WAVES MAY RUN FARTHER UP THE BEACH THAN
EXPECTED. THESE WAVES CAN EASILY CATCH PEOPLE OFF GUARD AND CAUSE
BEACHGOERS TO BE KNOCKED OFF THEIR FEET AND PULLED OUT INTO COLD
OCEAN WATERS. NEVER TURN YOUR BACK TO THE OCEAN. CAUTION SHOULD BE
USED WHEN IN OR NEAR THE WATER, AND THOSE WITH CHILDREN SHOULD BE
ESPECIALLY WATCHFUL. SNEAKER WAVES CAN LIFT OR ROLL LARGE, HEAVY
LOGS OR ROCKS WHICH CAN LEAD TO SERIOUS DEATH OR INJURY. KEEP OFF
ROCKS, LOGS, AND JETTIES NEAR THE WATERLINE ON BEACHES. -23
PQR WATCHES/WARNINGS/ADVISORIES
OR...AIR STAGNATION ADVISORY UNTIL 4 AM PST FRIDAY FOR ORZ109>111-
114>118.
WA...AIR STAGNATION ADVISORY UNTIL 4 AM PST FRIDAY FOR WAZ205-206.
PZ...HAZARDOUS SEAS WARNING UNTIL 4 PM PST MONDAY FOR PZZ210-251-252-
271-272.
SMALL CRAFT ADVISORY FROM 4 PM MONDAY TO 10 AM PST TUESDAY FOR
PZZ251-252-271-272.
SMALL CRAFT ADVISORY UNTIL 4 AM PST TUESDAY FOR PZZ253-273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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