935
FXUS66 KPQR 031757 AAB
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
1056 AM PDT FRI OCT 3 2025
UPDATED SHORT TERM DISCUSSION, AVIATION DISCUSSION, AND SYNOPSIS.
UPDATED PQR WATCHES/WARNINGS/ADVISORIES.
SYNOPSIS
SEASONABLE TEMPERATURES ON FRIDAY WITH NORTHERLY
FLOW ALOFT. VERY LIGHT RAIN SHOWERS LIKELY FRIDAY NIGHT INTO EARLY
SATURDAY MORNING, BECOMING MORE ISOLATED IN THE AFTERNOON. LOW-LEVEL
OFFSHORE FLOW DEVELOPS SUNDAY AND CONTINUES THROUGH AT LEAST TUESDAY,
BRINGING AN EXTENDED PERIOD OF DRY WEATHER WITH DAYTIME HIGH
TEMPERATURES IN THE 70S ACROSS THE LOWLANDS.
UPDATE
AREAS OF FOG HAVE LIFTED ACROSS THE LOWLANDS THIS MORNING,
WITH SURFACE VISIBILITIES CONTINUING TO IMPROVE. THEREFORE, THE DENSE
FOG ADVISORY THAT WAS PREVIOUSLY IN EFFECT UNTIL 11 AM PDT THIS
MORNING HAS BEEN CANCELLED. LOCATIONS IN THE WILLAMETTE VALLEY THAT
ARE STILL OBSERVING LOW CLOUDS SHOULD EXPECT CLOUD COVER TO SCATTER
OUT BY 1-2 PM, GIVING WAY TO MOSTLY SUNNY SKIES. THIS WILL ALLOW
TEMPERATURES TO QUICKLY WARM INTO THE 60S. -59
DISCUSSION...FRIDAY THROUGH THURSDAY
NORTHERLY FLOW ALOFT
AND HIGH PRESSURE AT THE SURFACE WILL RESULT IN RELATIVELY DRY
WEATHER WITH SEASONABLE HIGH TEMPERATURES IN THE UPPER 60S TO
LOW 70S THROUGH SUNDAY. MODELS ARE SHOWING A WEAK PERTURBATION
WITHIN THE UPPER LEVEL FLOW, WHICH IS RESULTING IN A MODERATE TO
HIGH POP/LOW QPF PATTERN WHICH COULD RESULT IN SOME VERY LIGHT
SHOWERS THROUGH FRIDAY EVENING. HOWEVER, MOST LOCATIONS WILL
LIKELY NOT SEE ANY PRECIPITATION TODAY. WINDS ALSO, LOOK FAIRLY
LIGHT WITH SPEEDS LESS THAN 10 MPH.
CHANCES FOR RAIN REMAIN ELEVATED ON SATURDAY AS A SET OF UPPER
LEVEL PERTURBATIONS WITHIN THE OVERALL NORTHERLY FLOW WILL MOVE
SOUTHWARD ACROSS THE CWA. THE FIRST IMPULSE MOVES THROUGH
DURING THE EARLY MORNING HOURS, WHILE THE SECOND IMPULSE MOVES
THROUGH DURING THE AFTERNOON AND EARLY EVENING. BOTH OF THESE
IMPULSES ARE SHOWING HIGH POPS, BUT LOW QPF. SO, DON'T EXPECT
MUCH BEYOND A FEW HUNDREDTHS OF AN INCH.
AS THE WEEKEND PROGRESSES, THE FORECAST REMAINS DRY SUNDAY
THROUGH WEDNESDAY IN RESPONSE TO A BUILDING UPPER LEVEL
SHORTWAVE RIDGE COMBINED WITH A PROLONGED PERIOD OF OFFSHORE
FLOW. THIS PATTERN CHANGE WILL RESULT IN MOSTLY SUNNY AND BREEZY
CONDITIONS WITH TEMPERATURES BECOMING NOTICEABLY WARMER. EXPECT
HIGHS TEMPERATURES IN THE 70S EACH DAY ACROSS THE LOWLANDS, WITH
EVEN THE COAST LIKELY WARMING INTO THE 70S ON MONDAY AND
TUESDAY. TUESDAY IS STILL SHAPING UP TO BE THE WARMEST DAY OF
THE WEEK WITH HIGHS WELL INTO THE 70S. PROBABILITIES FOR HIGHS
OF 80 DEGREES OR WARMER ARE LOW, RANGING BETWEEN 5-10%. AS THE
LATTER PART OF NEXT WEEK APPROACHES, THE PATTERN BECOMES MORE
PROGRESSIVE. LOOKING AT WPC 500 MB CLUSTER, AROUND 70% OF THE
MODELS SHOW A TROUGHING PATTERN DEVELOPING AROUND THE PAC NW,
WHILE 20% OF THE MODELS SHOW A BROAD RIDGE OVER THE WESTERN PART
OF CONUS AND THE REMAINING 10% HAVE A MORE ZONAL REGIME SETTING
UP. AS A RESULT, THE MULTI-MODEL ENSEMBLE IS GENERALLY SHOWING A
WEAK TROUGH DEVELOPING FOR THE LATTER PART OF NEXT WEEK, WHICH
WOULD BRING MORE SEASONABLE CONDITIONS TO THE PAC NW. /42-59
AVIATION
SATELLITE IMAGERY AS OF LATE FRIDAY MORNING DEPICTS
WIDESPREAD LIFR/IFR STRATUS ALONG THE COAST AND ACROSS THE
WILLAMETTE VALLEY. LATEST GUIDANCE AND KNOWN CLIMATOLOGY SUGGESTS
THAT THIS STRATUS SHOULD BEGIN TO BREAK OUT AS DAYTIME HEATING
PROGRESSES AROUND 20-21Z FRI. ONCE STRATUS BREAKS OUT, CONDITIONS
SHOULD IMPROVE TO VFR ACROSS ALL TERMINALS WITH MID-LEVEL CLOUDS
AND PERSIST THROUGH THE EVENING. TONIGHT, A WEAK SHORTWAVE TROUGH
WILL BRUSH THE REGION, RETURNING LOWER CIGS AND ISOLATED TO
SCATTERED SHOWERS. HIGH CONFIDENCE (60-80% CHANCE) THAT IFR/MVFR
CIGS RETURN ALONG THE COAST AROUND 02-04Z SAT, WITH MODERATE
CONFIDENCE (40-70% CHANCE) ACROSS VALLEY TERMINALS AFTER 07-09Z
SAT. THE HIGHEST CHANCES FOR MVFR CIGS IN THE VALLEY ARE AROUND
THE PORTLAND/VANCOUVER METRO AREA. IT LOOKS LIKE ONSHORE FLOW WILL
FAVOR STRATUS DEVELOPING ALONG THE CASCADE FOOTHILLS AND BACK-
BUILDING INTO THE VALLEY. WINDS GENERALLY WEST-SOUTHWESTERLY UNDER
5 KT ACROSS THE AREA, BECOMING VARIABLE AND UNDER 5 KT OVERNIGHT.
KPDX AND APPROACHES...60-80% CHANCE THAT CIGS IMPROVE TO VFR AFTER
20Z FRI. VFR CONDITIONS WITH MID TO HIGH LEVEL CLOUDS PREVAIL
THROUGH LATE TONIGHT. 50-70% CHANCE FOR MVFR CIGS RETURNING AROUND
09-12Z SAT. WEST WINDS TODAY AROUND 5 KT, BECOMING VARIABLE UNDER
5 KT OVERNIGHT. -10
MARINE
A VERY WEAK FRONTAL SYSTEM WILL KEEP SOUTHERLY WINDS
ACROSS ALL WATERS THROUGH THIS EVENING. RELATIVELY BENIGN
CONDITION WILL SLOWLY SPREAD ACROSS ALL WATERS THIS WEEKEND AS
HIGH PRESSURE ALOFT SLOWLY BUILDS IN. SATURDAY, EXPECT
NORTHWESTERLY WINDS AS WELL AS ANOTHER WEAK FRONT MOVES INTO THE
AREA SATURDAY AFTERNOON. SEAS 5-7 FT BY MID FRIDAY AND ARE
EXPECTED TO PERSIST THROUGH AT LEAST THE START OF NEXT WEEK.
AS HIGH PRESSURE CONTINUE TO DEVELOP ON SUNDAY, EXPECT MORE
NORTHERLY WINDS WITH A HIGH PROBABILITY (GREATER THAN 50% CHANCE)
OF SMALL CRAFT ADVISORY CONDITIONS DEVELOPING. TIMING, STRENGTH
AND LOCATION ARE STILL UNCERTAIN SO WILL REFRAIN FROM ISSUING ANY
HEADLINES AT THIS TIME. AS LATE SUNDAY/EARLY MONDAY APPROACHES,
EXPECT WINDS TO BECOME SLIGHTLY OFFSHORE BEFORE RETURNING TO AN
ONSHORE FLOW PATTERN BY TUESDAY. /42
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
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