993
FXUS66 KPQR 020435
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
935 PM PDT WED OCT 1 2025
UPDATED AVIATION & MARINE DISCUSSIONS AND WATCH/WARNING/ADVISORIES
SYNOPSIS
CONDITIONS WILL REMAIN COOL AND SHOWERY THROUGH
THURSDAY AS A LOW PRESSURE SYSTEM CURRENTLY CENTERED AROUND 250
MILES WEST OF VANCOUVER ISLAND SLOWLY MOVES SOUTHWARD AND
WEAKENS. FRIDAY AND SATURDAY WILL BE SEASONABLE WITH MAINLY DRY
CONDITIONS ASIDE FROM A FEW STRAY SHOWERS. LOW-LEVEL OFFSHORE
FLOW DEVELOPS SUNDAY AND CONTINUES INTO EARLY NEXT WEEK,
BRINGING AN EXTENDED PERIOD OF DRY WEATHER WITH HIGH
TEMPERATURES IN THE 70S FOR MOST INLAND VALLEY LOCATIONS.
DISCUSSION...NOW THROUGH TUESDAY NIGHT
RADAR, SATELLITE AND
SURFACE WEATHER OBSERVATIONS FROM EARLY WEDNESDAY AFTERNOON
DEPICTED A BAND OF LIGHT TO MODERATE RAIN EXTENDING ACROSS THE
WILLAMETTE VALLEY, COLUMBIA RIVER GORGE, AND CASCADES. THIS
BAND OF RAIN WAS OCCURRING ALONG AN OCCLUDED FRONT THAT EXTENDED
FROM A VERTICALLY-STACKED CLOSED LOW PRESSURE SYSTEM CENTERED
AROUND 250 MILES WEST OF VANCOUVER ISLAND. MODELS ARE IN GENERAL
AGREEMENT THIS LOW WILL GRADUALLY SHIFT SOUTHWARD OVER THE
COASTAL WATERS THROUGH FRIDAY MORNING WHILE WEAKENING
SIMULTANEOUSLY. UNTIL THEN, SCATTERED RAIN SHOWERS WILL REMAIN
IN THE AREA. SHOWERS WILL BE MOST PREVALENT DURING THE AFTERNOON
AND EVENING HOURS WEDNESDAY AND THURSDAY, WITH MOST SHOWERS
DISSIPATING DURING THE OVERNIGHT HOURS. THE STRONGEST AFTERNOON
SHOWERS WILL HAVE THE POTENTIAL TO PRODUCE A FLASH OR TWO OF
LIGHTNING WITH BRIEF GUSTY OUTFLOW WINDS AND/OR SMALL HAIL UNDER
THE SIZE OF PEAS. THAT SAID, THE PROBABILITY FOR THUNDERSTORMS
AT ANY GIVEN LOCATION IS VERY LOW AT 5-15%. THE VAST MAJORITY OF
THE AREA WILL NOT OBSERVE THUNDERSTORMS.
FROM FRIDAY AFTERNOON ONWARD, THE FORECAST IS TRENDING MAINLY DRY
WITH NORTHERLY FLOW ALOFT. IN ADDITION, TEMPERATURES WILL BECOME
NOTICEABLY WARMER SUNDAY THROUGH TUESDAY AS LOW-LEVEL OFFSHORE
DEVELOPS. MODELS AND THEIR ENSEMBLES DEPICT MINIMAL TEMPERATURE
SPREAD, SUGGESTING CONFIDENCE IS HIGH THE WARMER TEMPERATURES
WILL MATERIALIZE. THE NBM CONTINUES TO SUGGEST WIDESPREAD
HIGHS IN THE 70S ACROSS INLAND VALLEYS ON ALL THREE DAYS,
WARMEST ON TUESDAY WHEN HIGHS ARE EXPECTED TO RISE INTO THE MID
TO UPPER 70S.
THE ONLY OTHER THING WORTH MENTIONING IS OVERNIGHT LOWS IN THE
UPPER HOOD RIVER VALLEY NEAR THE PARKDALE AREA. THIS AREA WILL
LIKELY SEE MORNING LOWS NEAR 40 DEGREES THURSDAY MORNING AND
UPPER 30S FRIDAY MORNING. CANNOT COMPLETELY RULE OUT PATCHY
FROST FRIDAY MORNING GIVEN THE CLEAR SKIES AND LIGHT WINDS IN
PLACE, HOWEVER THE PROBABILITY FOR THIS TO OCCUR IS AT 20-40%.
PROBABILITIES DROP TO NEAR 0% IN ODELL AND HOOD RIVER. GIVEN THE
MARGINAL TEMPERATURES IN PLACE AND THE FACT THAT TEMPERATURES
WILL MOST LIKELY STAY ABOVE 36-37 DEGREES, HAVE DECIDED NOT TO
ISSUE A FROST ADVISORY FOR THIS ZONE. -TK
AVIATION
SHOWERY CONDITIONS CONTINUE THIS EVENING, PRIMARILY
ALONG THE COAST. SOUTHERLY-SOUTHEASTERLY WINDS CONTINUE, WITH
WINDS AROUND 5-10 KT INLAND AND 8-12 KT WITH GUSTS UP TO 20-25
KT ALONG THE COAST. SHOWERS AND INCREASED WINDS WEAKEN INTO THE
EVENING, EXPECTED TO END AROUND 06-12Z THURSDAY (MAINLY FOR
INLAND, AS SHOWERS WILL CONTINUE ALONG THE COAST). THEREAFTER,
WINDS WILL LIKELY REMAIN SOUTHERLY-SOUTHEASTERLY AND UNDER 10 KT
THROUGH 18Z THURSDAY. AFTER 18Z THURSDAY, WINDS THROUGHOUT THE
AIRSPACE WILL SHIFT MORE SOUTHERLY-SOUTHWESTERLY. COASTAL WIND
GUSTS UP TO 20 KT WILL BE POSSIBLE BETWEEN 18-22Z THURSDAY.
FOR AVIATION CONDITIONS, EXPECT PRIMARILY VFR CONDITIONS THROUGH
THE TAF PERIOD. PROBABILISTIC GUIDANCE SUGGESTS A 10% CHANCE FOR
MVFR CIGS INLAND AND A 20-30% CHANCE ALONG THE COAST. WITH
SHOWERS EXPECTED TO CONTINUE ALONG THE COAST, BRIEF MVFR CIGS
FOR COASTAL TERMINALS WOULD NOT BE OUT OF QUESTION. STILL, WITH
KEEP SUCH CONDITIONS OUT OF THE TAF AT THE MOMENT DUE TO LOW
CONFIDENCE.
KPDX AND APPROACHES...VFR CONDITIONS THROUGH THE TAF PERIOD,
WITH PROBABILISTIC GUIDANCE SUGGESTING A 10% CHANCE OF MVFR
CIGS OVERNIGHT BEFORE 17Z THURSDAY. OTHERWISE, EXPECT 5-8 KT
SOUTHEASTERLY WINDS UNTIL 18Z THURSDAY, THEN SHIFTING SOUTHERLY
TO SOUTHWESTERLY. ~HALL
MARINE
A DEEP AREA OF SURFACE LOW PRESSURE WILL LINGER WEST OF
VANCOUVER ISLAND, STEADILY WEAKENING IN PLACE BEFORE MOVING
INLAND FRIDAY INTO FRIDAY NIGHT. THE PRESSURE GRADIENT ACROSS
THE WATERS WILL THEREFORE SLOWLY SLACKEN THROUGH THE WORKWEEK,
ALLOWING WINDS TO EASE THROUGH THE PERIOD.
WINDS HAVE FALLEN BELOW GALE-FORCE, AND THE GALE WARNING FOR
THE INNER WATERS NORTH OF CAPE FALCON HAS THEREFORE BEEN
CANCELED. SEAS REMAIN ELEVATED WITH BUOY OBSERVATIONS OF 14-18
FT ACROSS MUCH OF THE WATERS. AS WINDS CONTINUE TO EASE, SEAS
WILL SIMILARLY SUBSIDE. EXPECT SEAS TO FALL BELOW 10 FT BY
THURSDAY AFTERNOON TO EVENING. A HAZARDOUS SEAS WARNING WILL
THEREFORE REMAIN IN EFFECT UNTIL THURSDAY MORNING, FOLLOWED BY A
SMALL CRAFT ADVISORY UNTIL ROUGH SEAS AND GUSTY WINDS END
THURSDAY AFTERNOON. AFTERNOON AND EVENING THUNDERSTORMS WILL
POSE LESS OF A THREAT ON THURSDAY.
AS A MORE SEASONABLE PATTERN OF OFFSHORE HIGH PRESSURE REBUILDS
LATE IN THE WEEK AND THROUGH THE WEEKEND, WINDS WILL TURN BACK
OUT OF THE NORTH. -HALL/PICARD
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...HAZARDOUS SEAS WARNING UNTIL 8 AM PDT THURSDAY FOR PZZ210-251-
252-271-272.
SMALL CRAFT ADVISORY FROM 8 AM TO 5 PM PDT THURSDAY FOR PZZ210-
251-252-271-272.
HAZARDOUS SEAS WARNING UNTIL 2 AM PDT THURSDAY FOR PZZ253-273.
SMALL CRAFT ADVISORY FROM 2 AM TO 5 PM PDT THURSDAY FOR PZZ253-
273.
WWW.WEATHER.GOV/PORTLAND
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