081
FXUS66 KPQR 140455 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
955 PM PDT TUE OCT 13 2026
UPDATED AVIATION DISCUSSION.
SYNOPSIS
HIGH PRESSURE WILL MAINTAIN DRY WEATHER THROUGH
FRIDAY. OFFSHORE FLOW WILL BRING UNUSUALLY WARM TEMPERATURES
THURSDAY AND FRIDAY ALONG WITH GUSTY EASTERLY WINDS IN THE
CASCADES, FOOTHILLS, AND WESTERN COLUMBIA RIVER GORGE. A WEAK
PACIFIC COLD FRONT WILL BRING CHANCES FOR LIGHT RAIN FRIDAY
NIGHT INTO SATURDAY, BEFORE HIGH PRESSURE BRINGS A QUICK RETURN
TO DRY WEATHER SATURDAY NIGHT INTO SUNDAY. WIDESPREAD RAIN IS
LIKELY (75-85% CHANCE) ON MONDAY WITH AN APPROACHING LOW
PRESSURE SYSTEM.
SHORT TERM...NOW THROUGH FRIDAY
THE SHORT TERM FORECAST IS
HIGHLIGHTED BY A WARMING TREND AND CONTINUED DRY WEATHER. AN
UPPER-LEVEL SHORTWAVE RIDGE IS CURRENTLY MOVING OVERHEAD, BUT
WILL SHIFT EAST LATE TODAY WITH 500 MB FLOW BECOME WEST-
NORTHWEST. A WEAK UPPER-LEVEL IMPULSE EMBEDDED WITHIN THE WEST-
NORTHWEST FLOW AND A DECAYING SURFACE COOL FRONT WILL BRING A
10-15% CHANCE OF LIGHT RAIN TO THE LONG BEACH PENINSULA AND
WILLAPA HILLS WEDNESDAY MORNING, RESULTING IN TRACE AMOUNTS OF
RAIN IF ANY AT ALL. OTHERWISE, THE REST OF SOUTHWEST WA AND ALL
OF NORTHWEST OR SHOULD REMAIN DRY.
TEMPERATURES WILL PEAK THURSDAY AND FRIDAY AS A SECONDARY
UPPER-LEVEL RIDGE AMPLIFIES OVER THE REGION AND LOW-LEVEL
OFFSHORE FLOW DEVELOPS. MODEL GUIDANCE IS IN GOOD AGREEMENT FOR
WIDESPREAD HIGH TEMPERATURES RANGING BETWEEN 75-80 DEGREES ON
BOTH DAYS FOR INLAND VALLEYS, AND AROUND 70 DEGREES AT THE
COAST. ALTHOUGH THIS IS AROUND 10-15 DEGREES ABOVE NORMAL FOR
MID-OCTOBER, RECORD HIGH TEMPERATURES SHOULD BE OUT OF REACH FOR
MOST LOCATIONS. EUGENE IS THE ONLY LOCATION THAT HAS A CHANCE
TO TIE OR BREAK THE CURRENT RECORD OF 81 DEGREES IN 2002, AS
THIS SITE HAS A 30% CHANCE OF REACHING 81 DEGREES OR WARMER
ACCORDING TO THE 13Z/OCT. 13 ITERATION OF THE NBM.
IN ADDITION TO THE WARMER TEMPERATURES, WINDS WILL BECOME GUSTY
OUT OF THE EAST IN THE CASCADES, CASCADE FOOTHILLS, AND WESTERN
COLUMBIA RIVER GORGE. CORBETT, TROUTDALE, WOOD VILLAGE,
WASHOUGAL, AND CAMAS WILL ALSO BECOME QUITE BREEZY, ESPECIALLY
LATE THURSDAY THROUGH FRIDAY MORNING. THIS IS IN RESPONSE TO A
STRENGTHENING SURFACE PRESSURE GRADIENT; THE NAM AND GFS BOTH
SUGGEST THE PRESSURE GRADIENT BETWEEN TROUTDALE AND THE DALLES
WILL PEAK AROUND -4 TO -5 MB ON THURSDAY. AS SUCH, THE
AFOREMENTIONED AREAS SHOULD EXPECT MAX WIND GUSTS AS HIGH AS
25-35 MPH, EXCEPT UP TO APPROXIMATELY 45 MPH ON WIND-PRONE
EXPOSED RIDGETOPS AND IN THE WESTERN GORGE. SIMILAR PRESSURE
GRADIENTS AND WIND SPEEDS ARE ANTICIPATED ON FRIDAY. BEYOND A
FEW SMALL DOWNED TREE BRANCHES WHERE WIND GUSTS ARE STRONGEST,
IMPACTS ARE NOT EXPECTED. FOR THE REST OF NORTHWEST OR AND
SOUTHWEST WA, WINDS SHOULD REMAIN UNDER 10-15 MPH. OFFSHORE
WINDS SHOULD DISSIPATE FRIDAY NIGHT AS LOW-LEVEL FLOW
TRANSITIONS BACK TO AN ONSHORE FLOW REGIME AHEAD OF AN INCOMING
PACIFIC COLD FRONT. THIS FRONT WILL BRING CHANCES FOR LIGHT RAIN
TO THE AREA FRIDAY NIGHT INTO SATURDAY, WHICH IS DISCUSSED
BELOW IN THE LONG TERM DISCUSSION. -23
LONG TERM...FRIDAY NIGHT THROUGH MONDAY NIGHT
A WEAK
PACIFIC COLD FRONT IS SET TO MOVE INLAND FRIDAY NIGHT INTO
SATURDAY, WHICH WILL BRING COOLER TEMPERATURES THIS UPCOMING
WEEKEND AND CHANCES FOR LIGHT RAIN. RAIN CHANCES BEGIN AT THE
COAST FRIDAY NIGHT (15-35%, EXCEPT 40-50% FROM SEASIDE NORTHWARD
TO ASTORIA AND THE LONG BEACH PENINSULA). RAIN CHANCES THEN
SPREAD INLAND TO THE CASCADES SATURDAY MORNING (20-40%, EXCEPT
45-65% OVER THE WESTERN COLUMBIA RIVER GORGE, SOUTH WA/NORTH OR
CASCADES AND ADJACENT FOOTHILLS). LOCATIONS THAT DO OBSERVE RAIN
CAN EXPECT LIGHT AMOUNTS RANGING ANYWHERE FROM A TRACE TO 0.15
INCHES, RESULTING IN NO IMPACTS.
CHANCES FOR RAIN DECREASE SATURDAY AFTERNOON INTO SATURDAY
NIGHT WITH THE RETURN OF HIGH PRESSURE. MODEL ENSEMBLE GUIDANCE
IS IN AGREEMENT FOR THE CONTINUATION OF HIGH PRESSURE THROUGH
LATE SUNDAY AFTERNOON, RESULTING IN A DRY DAY WITH SEASONABLE
TEMPERATURES IN THE 60S, EXCEPT 50S AT THE COAST AND IN THE
CASCADES. HOWEVER, A DEVELOPING LOW PRESSURE SYSTEM OFFSHORE
WILL APPROACH THE REGION SUNDAY NIGHT INTO MONDAY, BRINGING A
75-85% CHANCE OF RAIN TO ALL OF NORTHWEST OR AND SOUTHWEST WA
FROM THE COAST TO THE CASCADES BETWEEN EARLY MONDAY MORNING AND
EARLY TUESDAY MORNING. RAIN COULD BEGIN AS EARLY AS SUNDAY
EVENING, HOWEVER THE VAST MAJORITY OF ENSEMBLE GUIDANCE HOLDS
RAIN OFF UNTIL SUNDAY NIGHT OR MONDAY MORNING. THIS SYSTEM HAS
THE POTENTIAL TO BRING A MORE MEANINGFUL AMOUNT OF RAIN
CONSIDERING HOW DRY CONDITIONS HAVE BEEN THUS FAR THIS OCTOBER,
AND THE NBM CURRENTLY SHOWS A 45-65% CHANCE FOR AT LEAST 0.25
INCHES OF RAIN BETWEEN 5 AM PDT MONDAY AND 5 AM PDT TUESDAY.
FORTUNATELY, THIS IS NOT ENOUGH RAIN TO CAUSE FLOODING. CHANCES
FOR IMPACTFUL WIND GUSTS OVER 40 MPH ARE CURRENTLY LESS THAN 10%
WITH THIS SYSTEM. -23
AVIATION...THROUGH 06Z THURSDAY
MID AND HIGH LEVEL CLOUDS
CONTINUE TO FILTER IN AS A WEAK SYSTEM PASSES WELL NORTH OF THE
AREA. PRECIPITATION IS NOT EXPECTED WITH THIS SYSTEM BUT A
SPRINKLE OR TWO IS POSSIBLE AROUND THE LONG BEACH PENINSULA IN WA
AND MAYBE AROUND KAST. AS THE SYSTEM PASSES, SCT TO BKN MID LEVEL
CLOUDS ARE EXPECTED FOR MOST TERMINALS. SEVERAL TERMINALS ARE
REPORTING INCREASING CLOUD COVER IN THE 5-7 KFT RANGE. KAST HAS
THE BEST CHANCE OF SEEING MVFR CIGS AS THE SYSTEM PASSES WITH A
50-70% CHANCE BETWEEN 8-15Z. WINDS WILL BE LIGHT OVERNIGHT,
INCREASING FROM THE NORTH TO 5-10 KT WEDNESDAY AFTERNOON.
KPDX AND APPROACHES...VFR WITH MID TO HIGH LEVEL CLOUDS THROUGH
THE TAF PERIOD. VARIABLE WINDS UNDER 5 KT OVERNIGHT, BECOMING
NORTH AROUND 5 KT WEDNESDAY AFTERNOON. -19/03
MARINE
BENIGN MARINE CONDITIONS EXPECTED THIS WEEK.
SOUTHERLY WINDS CONTINUE THROUGH WEDNESDAY DUE TO A WEAK FRONT,
THEN RETURN NORTHERLY BY THE END OF THE WEEK. SEAS REMAIN AROUND
4-6 FT THIS WEEK WITH PERIODS OF 13-14 SECONDS THROUGH
WEDNESDAY AND 11-13 SECONDS LATE THIS WEEK. A STEEPER
NORTHWESTERLY SWELL ARRIVES THIS WEEKEND, BUILDING SEAS TO 7-9
FT BY SUNDAY AND 11-13 FT EARLY NEXT WEEK. THERE IS A 20-35%
CHANCE FOR SEAS EXCEEDING 15 FT ON MONDAY FOR THE WATERS NORTH
OF CAPE FOULWEATHER AND BEYOND 10 NM, AND A 10-20% CHANCE
ELSEWHERE. WILL ALSO NOTE THAT THE LONG PERIODS FROM THE SWELLS
WILL RESULT IN A MODERATE SNEAKER WAVE THREAT THIS WEEK. CAUTION
SHOULD BE USED WHEN IN OR NEAR THE WATER. -03/10
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
WWW.WEATHER.GOV/PORTLAND
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