268
FXUS66 KPQR 232115
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
215 PM PDT FRI OCT 23 2026
SYNOPSIS
DRY WEATHER IS EXPECTED THROUGH SATURDAY WITH
OVERNIGHT AND EARLY MORNING FROST/FREEZE CONDITIONS ACROSS
MUCH OF THE REGION. RAIN CHANCES INCREASE EARLY SUNDAY MORNING,
THEN LINGER INTO THE BEGINNING OF THE WORKWEEK. THE ACTIVE
PATTERN CONTINUES WITH ADDITIONAL RAIN CHANCES MIDWEEK.
DISCUSSION...NOW THROUGH FRIDAY
TRANSIENT UPPER-LEVEL RIDGING
CONTINUES TO BUILD OVERHEAD, BRINGING CLEARING SKIES TO THE
REGION. COOL TEMPERATURES ALOFT WILL SUPPORT SEASONABLE DAYTIME
HIGHS IN THE 50S ON THE COAST AND IN TERRAIN AND IN THE LOW TO
MID 60S WITHIN INLAND VALLEYS. AS THE RIDGE AXIS SHIFTS INLAND,
LIGHT OFFSHORE FLOW WILL PEAK OVERNIGHT IN THE CASCADES AND
COAST RANGE. CLEAR AND CALMER VALLEY CONDITIONS WILL AGAIN YIELD
EFFICIENT NOCTURNAL RADIATIVE COOLING, WITH SATURDAY MORNING
LIKELY TO BE THE COLDEST. WIDESPREAD MORNING LOWS IN THE 30S ARE
EXPECTED, COLDEST IN SHELTERED VALLEYS INCLUDING THE SOUTHERN
WILLAMETTE AND NEIGHBORING PERIPHERAL VALLEYS, NORTHERN COAST
RANGE VALLEYS NEAR VERNONIA AND GRAND RONDE, AND THE UPPER HOOD
RIVER VALLEY, WHERE FREEZE WARNINGS ARE IN EFFECT FROM 11 PM PDT
THIS EVENING THROUGH 10 AM PDT SATURDAY. FROST ADVISORIES FOR
TEMPERATURES IN THE LOW TO MID 30S ARE IN EFFECT AT THE SAME
TIMES FOR MOST OTHER AREAS OUTSIDE OF THE SOUTH WASHINGTON COAST
AND COASTAL LOWLANDS. THOSE WITH EXPOSED OR UNINSULATED OUTDOOR
PIPES, AGRICULTURAL INTERESTS, OR SENSITIVE OUTDOOR PLANT
SHOULD TAKE ACTION TO PREVENT FROST/FREEZE DAMAGE TONIGHT.
SEASONABLE CONDITIONS WITH MILDER OVERNIGHT TEMPERATURES THEN
PERSIST THROUGH THE REMAINDER OF THE PERIOD AS THE WEATHER
PATTERN BECOMES MORE ACTIVE BY LATE THIS WEEKEND. MEAN UPPER
TROUGHING DEVELOPS OVER THE REGION FROM SUNDAY THROUGH MUCH OF
NEXT WEEK AS A SERIES OF UPPER LOWS DROP FROM THE GULF OF ALASKA
OVER THE PACIFIC NORTHWEST. THERE REMAINS GOOD AGREEMENT AMONG
MID-RANGE ENSEMBLES THAT AN INITIAL SYSTEM WILL MOVE INTO THE
REGION ON SUNDAY WITH RAIN BEGINNING AT THE COAST EARLY SUNDAY
MORNING AND REACHING INLAND THROUGH THE AFTERNOON, ALTHOUGH
THERE ARE MODEST, PERHAPS 10-20% CHANCES, THAT THE SYSTEM TRACKS
FARTHER TO THE SOUTH WITH LOWER RAIN CHANCES LOCALLY. AS THE LOW
SLOWLY EXITS EASTWARD, AT THIS POINT, THE CHANCES FOR 0.25
INCHES OF RAIN OR MORE FROM 5 AM SUNDAY THROUGH 5 AM TUESDAY ARE
75-85% ALONG THE COAST AND COAST RANGE, 60-75% ALONG THE I-5
CORRIDOR, AND 50-60% IN THE CASCADES AND FOOTHILLS.
FORECAST CONFIDENCE DECREASES BY MIDWEEK AS THIS LOW DEPARTS
EASTWARD, ALTHOUGH LONG-RANGE GUIDANCE DOES CONTINUE TO SUPPORT
ADDITIONAL CHANCES FOR RAIN, WITH 30-40% OF ENSEMBLE MEMBERS
BRINGING ANOTHER WEATHER SYSTEM TO THE NORTHEAST PACIFIC.
OTHERWISE, SEASONABLE TEMPERATURES ARE FAVORED TO CONTINUE INTO
THE FINAL WEEK OF OCTOBER. -36
AVIATION...THROUGH 00Z SUNDAY
WIDESPREAD VFR CONDITIONS
CONTINUE ACROSS NORTHWEST OR AND SOUTHWEST WA, INCLUDING COASTAL
AND INLAND TAF SITES. SKIES ARE EXPECTED TO REMAIN CLEAR TO
MOSTLY CLEAR NOW THROUGH AT LEAST 12Z SATURDAY, EXCEPT AT KTTD
AND KPDX WHERE SCATTERED TO BROKEN CEILINGS AROUND 4000-5000 FT
WILL CONTINUE THIS AFTERNOON BEFORE DISSIPATING SOMETIME THIS
EVENING. HIGH CLOUDS WITH CEILINGS ABOVE 15-20 KFT WILL INCREASE
OVER THE REGION BETWEEN 12-18Z SATURDAY.
THERE IS A 10-20% CHANCE FOR CEILINGS AROUND 1000 FT OR LOWER
DEVELOPING AT KUAO AND KSLE BETWEEN 11-18Z SATURDAY AND A 30-40%
CHANCE AT KAST AND KEUG. CONFIDENCE IS TOO LOW TO JUSTIFY
PUTTING A BROKEN OR OVERCAST LOW STRATUS DECK IN THE TAFS,
ESPECIALLY BECAUSE FROST FORMATION IS MORE LIKELY THAN FOG AND
LOW STRATUS TONIGHT AS TEMPERATURES DIP INTO THE LOW TO MID 30S
AT ALL TAF SITES. HOWEVER, SOME POCKETS OF FOG AND LOW STRATUS
CANNOT BE COMPLETELY RULED OUT, ESPECIALLY AT KEUG.
KPDX AND APPROACHES...VFR CONDITIONS WILL CONTINUE THROUGH 00Z
SUNDAY WITH LIGHT AND VARIABLE WINDS AROUND 3-5 KT. FROST
DEVELOPMENT IS POSSIBLE LATE TONIGHT INTO EARLY TOMORROW MORNING
AS TEMPERATURES DIP AS LOW AS 35-38 DEGREES. -23
MARINE
BUOY OBSERVATIONS AS OF 2 PM PDT FRIDAY SHOWED
NORTHERLY WINDS AROUND 5-15 KT WITH SEAS AROUND 7 TO 10 FT AT
9 TO 11 SECONDS, MAINLY DRIVEN BY A NORTHWEST SWELL. ALTHOUGH
WINDS HAVE WEAKENED SIGNIFICANTLY FRIDAY AFTERNOON, SEAS REMAIN
STEEP ENOUGH TO POSE A HAZARD FOR SMALL CRAFT THROUGH THE
REMAINDER OF THE AFTERNOON. THEREFORE, SMALL CRAFT ADVISORIES
REMAIN IN EFFECT FOR THE INNER AND OUTER WATERS THROUGH 5 PM PDT
FRIDAY. SEAS WILL DECREASE THIS EVENING INTO TONIGHT WITH WINDS
REMAINING WEAK, BRINGING IMPROVING CONDITIONS.
A SLOW-MOVING LOW WILL APPROACH THE OUTER WATERS LATE SATURDAY
INTO SUNDAY, BRINGING A TRANSITION TO SOUTHERLY WINDS WITH SEAS
INCREASING AGAIN SATURDAY NIGHT INTO SUNDAY. CONDITIONS WILL BE
HAZARDOUS FOR SMALL CRAFT DURING THAT TIME, BEFORE WINDS AND
SEAS DECREASE EARLY NEXT WEEK. THERE IS STILL UNCERTAINTY ON
THE EXACT STRENGTH AND TRACK OF THIS LOW, HOWEVER PROBABILITIES
FOR GALE FORCE WIND GUSTS REMAIN LOW AT 5-15%, EXCEPT 25-35%
NEAR BUOY 029. CHANCES FOR SEAS OVER 10 FT PEAK BETWEEN 15-35%
SUNDAY MORNING, WITH THE HIGHEST PROBABILITIES BEYOND 20-30 NM
OFFSHORE. -23
PQR WATCHES/WARNINGS/ADVISORIES
OR...FROST ADVISORY FROM 11 PM THIS EVENING TO 10 AM PDT SATURDAY
FOR ORZ101>103-105-107>109-111>113-119-123.
FREEZE WARNING FROM 11 PM THIS EVENING TO 10 AM PDT SATURDAY
FOR ORZ104-106-114>118-124-125.
WA...FROST ADVISORY FROM 11 PM THIS EVENING TO 10 AM PDT SATURDAY
FOR WAZ203>208.
PZ...SMALL CRAFT ADVISORY UNTIL 5 PM PDT THIS AFTERNOON FOR
PZZ251>253-271>273.
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