016
FXUS66 KPQR 290515
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
1015 PM PDT TUE APR 28 2026
SYNOPSIS
HIGH PRESSURE STRENGTHENS OVER THE REGION WEDNESDAY
AND THURSDAY, DELIVERING THE WARMEST WEATHER OF THE WEEK. A
WEAK, MOISTURE-LIMITED TROUGH BRUSHES THE PACIFIC NORTHWEST
FRIDAY INTO SATURDAY, BRINGING A SLIGHT COOL-DOWN AND LOW-END
CASCADE SHOWER CHANCES. WITH WARM AND DRY CONDITIONS RETURNING
SUNDAY AND MONDAY, CONTINUE TO KEEP COLD WATER SAFETY IN MIND AS
LOCAL RIVERS REMAIN COLD ENOUGH FOR COLD WATER SHOCK.
DISCUSSION...NOW THROUGH MONDAY
TONIGHT INTO WEDNESDAY, A
FROST ADVISORY IS IN EFFECT FOR THE UPPER HOOD RIVER VALLEY
(NOTABLY ABOVE 1000 FT IN ELEVATION) FROM 1 AM TO 8 AM
WEDNESDAY. LOWS THERE ARE EXPECTED TO DROP INTO THE 33 TO 36
DEGREE RANGE, WHICH IS COLD ENOUGH FOR FROST DEVELOPMENT. FROST
MAY HARM SENSITIVE OUTDOOR VEGETATION; PROTECT OR BRING IN
SENSITIVE PLANTS.
WEDNESDAY AND THURSDAY BRING A SHARP TURN TOWARD WARMER,
SUNNIER WEATHER AS HIGH PRESSURE BUILDS OVERHEAD AND A DRIER AIR
MASS SETTLES IN. CONFIDENCE IS MODERATE TO HIGH (GREATER THAN
60%) THAT INLAND HIGHS REACH THE UPPER 60S TO LOW 70S WEDNESDAY,
THEN CLIMB INTO THE UPPER 70S TO NEAR 80 THURSDAY. THE GREATER
PORTLAND METRO DOWN TO AURORA STILL HAS THE BEST ODDS OF HITTING
80 ON THURSDAY (ABOUT 50-80%), WHILE THE REMAINDER OF THE I-5
CORRIDOR IS LOWER (ROUGHLY 20-40%). OVERNIGHT LOWS SHOULD
CONTINUE TO DROP COMFORTABLY, KEEPING HEAT-RELATED IMPACTS
LIMITED.
FRIDAY INTO SATURDAY, MODEL AND ENSEMBLE GUIDANCE REMAINS
CONSISTENT IN SHOWING THE RIDGE WEAKENING AS A WEAK TROUGH DROPS
IN FROM CANADA. MOISTURE WITH THIS FEATURE APPEARS LIMITED, SO
MOST AREAS SHOULD STAY DRY. THE ONLY LOCATION WITH A MEANINGFUL
PRECIPITATION SIGNAL REMAINS THE CASCADES (INCLUDING THE CASCADE
FOOTHILLS), WHERE CHANCES FOR LIGHT SHOWERS ARE AROUND 20-40%;
ELSEWHERE PROBABILITIES REMAIN BELOW 15%. TEMPERATURES EASE BACK
A FEW DEGREES BUT REMAIN SEASONABLY WARM.
SUNDAY INTO MONDAY, MANY ENSEMBLE SOLUTIONS DEPICT A CLOSED LOW
SHIFTING SOUTHEAST TOWARDS CALIFORNIA WHILE HIGH PRESSURE
REBUILDS ACROSS THE PACIFIC NORTHWEST. THAT FAVORS ANOTHER WARM-
UP LOCALLY WITH DRY WEATHER FOR MOST LOWER ELEVATIONS; THE
CASCADES COULD STILL SEE OCCASIONAL LIGHT SHOWERS IF ANY
MOISTURE WRAPS NORTH. GUIDANCE CONTINUES TO SUPPORT HIGH
CONFIDENCE (>90%) FOR GREATER THAN 80 DEGREES ALONG THE I-5
CORRIDOR SUNDAY, WITH MONDAY MAINTAINING A 50-80% CHANCE, AGAIN
HIGHEST NEAR THE GREATER PORTLAND METRO.
DURING LATE-WEEK WARMTH, THOSE RECREATING ON AREA RIVERS SHOULD
REMAIN AWARE OF WATER TEMPERATURES, WHICH REMAIN COLD ENOUGH
FOR COLD WATER SHOCK, EVEN ON HOT AFTERNOONS. WEAR A PERSONAL
FLOATATION DEVICE AND USE EXTRA CAUTION AROUND FAST, COLD WATER.
~12
AVIATION
MODERATE TO HIGH CONFIDENCE IN PERSISTENT VFR FLYING
CONDITIONS ACROSS THE REGION THROUGHOUT THE PERIOD. FEW-SCT LOW
CLOUDS AT 3-5 KFT EXPECTED OVERNIGHT BENEATH HIGH PRESSURE
OFFSHORE, WITH 30-50% CHANCES FOR MVFR CIGS AT COASTAL TERMINALS
AND 10-30% INLAND. ANY LOW CLOUDS WILL QUICKLY MIX OUT
WEDNESDAY MORNING, WITH CLEAR SKIES EXPECTED BY 18Z WED. LIGHT
NORTH WINDS WILL EASE BELOW 3 KT OVERNIGHT, THEN BUILD OUT OF
THE NORTHWEST TO 5-10 KT INLAND AND 10-15 KT WITH GUSTS TO 20 KT
ALONG THE COAST BY WEDNESDAY AFTERNOON.
KPDX AND APPROACHES...HIGH CONFIDENCE IN VFR FLYING CONDITIONS
THROUGHOUT THE PERIOD. FEW-SCT LOW CLOUDS AT 3-5 KFT EXPECTED
OVERNIGHT, WITH A 10-15% CHANCE OF MVFR CIGS IF CLOUD COVERAGE
EXCEEDS EXPECTATIONS. LOW CLOUDS WILL DISSIPATE QUICKLY THROUGH
WEDNESDAY MORNING WITH CLEAR SKIES EXPECTED BY 18Z WED. LIGHT
NORTHWEST FLOW OF 5 KT OR LESS OVERNIGHT WILL BUILD TO 5-10 KT
BY WEDNESDAY AFTERNOON. -36
MARINE
NORTHWESTERLY WINDS TODAY TURN NORTHERLY BY WEDNESDAY
AS HIGH PRESSURE PERSISTS OFFSHORE. NORTHERLIES STRENGTHEN EACH
AFTERNOON AND EVENING AS PRESSURE GRADIENTS TIGHTEN OVER THE
COASTAL WATERS DUE TO STRENGTHENING SURFACE THERMAL TROUGH NEAR
THE SOUTHERN OREGON COAST. WIND GUSTS ARE EXPECTED TO REMAIN
BELOW 20 KT THROUGH WEDNESDAY MORNING. FROM WEDNESDAY EVENING
THROUGH AT LEAST FRIDAY, THERE IS A 70-90% CHANCE FOR AT LEAST
ISOLATED SMALL CRAFT WIND GUSTS UP TO 20-25 KT. THE STRONGEST
GUSTS WOULD MAINLY BE SOUTH OF CAPE FALCON. THE HIGHEST
PROBABILITIES FOR SCA WINDS ARE FOR THURSDAY AND FRIDAY. SEAS OF
6 TO 8 FT ARE EXPECTED TO PERSIST THROUGH THE WEEK WITH A
NORTHWESTERLY SWELL. MID-PERIOD SWELLS OF 13-16 SECONDS WILL
ALSO RESULT IN A MODERATE SNEAKER WAVE THREAT AT BEACHES
WEDNESDAY AND THURSDAY. THOSE PARTICIPATING IN RAZOR CLAM DIGS
SHOULD TAKE EXTRA PRECAUTION. DH/10
PQR WATCHES/WARNINGS/ADVISORIES
OR...FROST ADVISORY UNTIL 8 AM PDT WEDNESDAY FOR ORZ121.
WA...NONE.
PZ...NONE.
WWW.WEATHER.GOV/PORTLAND
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