631
FXUS66 KPQR 041135
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
435 AM PDT MON MAY 4 2026
UPDATED AVIATION DISCUSSION.
SYNOPSIS
COOLER BUT STILL ABOVE-NORMAL TEMPERATURES WITH
LARGELY DRY WEATHER EXPECTED THROUGH MUCH OF THE WORKWEEK
BENEATH BROAD AND PERSISTENT UPPER-LEVEL RIDGING. CHANCES FOR
RAIN INCREASE FRIDAY INTO SATURDAY AS THE RIDGE DEAMPLIFIES, BUT
UNCERTAINTY IN TIMING AND COVERAGE OF PRECIPITATION CONTINUES.
DISCUSSION...NOW THROUGH SUNDAY
BROAD UPPER-LEVEL RIDGING
SPANNING THE NORTHEASTERN PACIFIC AND WESTERN CONUS IS FAVORED
TO REMAIN IN PLACE WITH A SLIGHT EASTWARD TENDENCY THROUGH THE
NEXT WEEK. AN UPPER CUTOFF LOW OVER CALIFORNIA WHICH SUPPORTED
OFFSHORE FLOW RESULTING IN RECORD HIGH TEMPERATURES ON SUNDAY
WILL EXIT EASTWARD MORE QUICKLY, FAVORING A RETURN TO MORE
SEASONABLE NORTHERLY TO NORTHWESTERLY FLOW ALOFT. DESPITE UPPER
HEIGHTS RISING IN THE WAKE OF THE DEPARTING LOW, TEMPERATURES
WILL ACTUALLY TREND COOLER WHILE ALSO REMAINING SEASONABLY WARM
THANKS TO THIS PATTERN CHANGE. THROUGH MIDWEEK, RENEWED ONSHORE
AND SOUTHERLY FLOW WILL MAINTAIN FAIRLY STEADY DAYTIME HIGH
TEMPERATURES IN THE 60S ALONG THE COAST AND IN HIGH TERRAIN AND
IN THE 70S TO NEAR 80 DEGREES WITHIN INLAND VALLEYS, SOME 10 OR
SO DEGREES ABOVE NORMAL. THIS SOUTHERLY SURGE WILL SEE MARINE
OVERCAST AND PERIODS OF MIST AND DRIZZLE ALONG THE COAST AND
CLOUDS REACHING INLAND THROUGH COASTAL GAPS EACH NIGHT, BEFORE
RETREATING BACK TOWARD THE COAST DURING THE DAY. AS SUCH,
LARGELY DRY AND TRANQUIL WEATHER IS EXPECTED FOR MOST.
BY THE END OF THE WORKWEEK, LONG-RANGE ENSEMBLES DEPICT A
SHORTWAVE TROUGH TRANSITING THE APEX OF THE RIDGE, BRINGING
COOLER TEMPERATURES CLOSER TO SEASONAL NORMS AS WELL AS THE MOST
WIDESPREAD CHANCES FOR RAINFALL TO THE REGION. THERE IS STILL
UNCERTAINTY IN THE TIMING AND DISTRIBUTION OF PRECIPITATION, BUT
THE ENSEMBLE CONSENSUS FAVORS RAIN OCCURRING SOME TIME BETWEEN
FRIDAY MORNING AND SATURDAY AFTERNOON, WITH THE HIGHEST CHANCES
TO THE NORTH AND IN AREAS OF HIGHER TERRAIN AND LOWER CHANCES
TO THE SOUTH AND FOR VALLEY LOCALES. AT THIS TIME, POTENTIAL
RAINFALL AMOUNTS LOOK TO BE LIGHT, GENERALLY 0.1 INCH OR LESS.
BEYOND THIS LATE-WEEK SYSTEM, RIDGING ALOFT WILL MOST LIKELY
REBUILD, FAVORING A RETURN TO DRY AND WARMER-THAN-NORMAL
CONDITIONS. THERE REMAINS UNCERTAINTY, HOWEVER, IN THE
POSITION, ORIENTATION, AND AMPLITUDE OF RIDGING, WHICH COULD
AFFECT THE SENSIBLE WEATHER ON THE GROUND. -36
AVIATION
A SOUTHERLY MARINE SURGE IS ONGOING WITH THE LATEST
SATELLITE IMAGERY DEPICTING LOW STRATUS ALONG THE OREGON AND
SOUTHWEST WASHINGTON COAST, AS WELL AS REACHING INLAND THROUGH
GAPS IN THE COASTAL TERRAIN, PARTICULARLY TOWARD THE SOUTHERN
WILLAMETTE VALLEY. THIS WILL RESULT IN PERSISTENT IFR/LIFR CIGS
FOR COASTAL TERMINALS THROUGH MUCH OF THE PERIOD. AS DIURNAL
MIXING INCREASES, CIGS MAY LIFT SLIGHTLY, WITH INCREASING
CHANCES OF REACHING MVFR LEVELS TO THE NORTH ALONG THE COAST
TOWARD KAST, WHILE TO THE SOUTH NEAR KONP, THE IMPROVEMENT WILL
MORE LIKELY BE FROM LIFR TO IFR. HIGH-END IFR TO MVFR VIS OF 2-5
SM IS ALSO CURRENTLY BEING OBSERVED AT COASTAL TERMINALS SOUTH
OF KTMK, THESE RESTRICTED VIS WILL TEND TO IMPROVE AFTER 15-16Z
MON. MEANWHILE, GUSTY SOUTH-SOUTHWESTERLY WINDS OF 8-12 KT WITH
GUSTS TO 20 KT ARE EXPECTED TO CONTINUE THROUGH AT LEAST 21-24Z
MON. REINVIGORATED MARINE STRATUS LATE IN THE PERIOD, AFTER
00-03Z TUE, WILL YIELD A DOWNWARD TREND IN VIS/CIGS TO IFR/LIFR
LATE IN THE PERIOD WHILE WINDS EASE TO AROUND 5 KT.
INLAND, COVERAGE OF LOW STRATUS REMAINS RELATIVELY LOW, WITH
MVFR CIGS LIMITED TO THE SOUTHERN WILLAMETTE VALLEY AS OF 12Z
MON, HOWEVER SOME ADDITIONAL INLAND EXPANSION IS EXPECTED
THROUGH 15Z MON. WHILE VFR CONDITIONS ARE MOST LIKELY, CHANCES
FOR MVFR CIGS PEAK AROUND 15Z MON, REACHING 20-40% AT TERMINALS
ALONG THE WILLAMETTE AND LOWER COLUMBIA VALLEYS. LOW CLOUDS WILL
TEND TO MIX OUT THROUGH THE MORNING, LARGELY CLEARING BY 20-22Z
MON. WINDS OUT OF THE SOUTH TO SOUTHEAST AT AROUND 5 KT AT
PORTLAND-AREA TERMINALS AND 5-10 KT ALONG THE WILLAMETTE VALLEY
WILL VEER OUT OF THE SOUTH TO SOUTHWEST AT 5-10 KT THROUGH THIS
AFTERNOON, BEFORE EASING BELOW 5 KT OUT OF THE SOUTH TO
SOUTHEAST AFTER 00-06Z TUE. RENEWED MARINE STRATUS WILL AGAIN BE
MOST LIKELY TO YIELD MVFR CIGS IN THE SOUTHERN WILLAMETTE
VALLEY INCLUDING AT KEUG AFTER 06Z TUE.
KPDX AND APPROACHES...VFR FLYING CONDITIONS FAVORED TO CONTINUE
THROUGH THE PERIOD. MARINE STRATUS WILL CONTINUE TO EXPAND
INLAND THROUGH 14-15Z MON, RESULTING IN 20-40% CHANCES FOR MVFR
CIGS THIS MORNING BEFORE TENDING TO DECREASE IN COVERAGE AS
MIXING INCREASES. LARGELY CLEAR SKIES EXPECTED BY 20-22Z MON AS
LIGHT SOUTHEAST FLOW VEERS OUT OF THE SOUTH AT 5-10 KT THIS
AFTERNOON. MARINE STRATUS MAY RETURN LATE, AFTER 06-09Z TUE, AS
WINDS EASE BACK OUT OF THE SOUTHEAST TONIGHT. -36
MARINE
A SOUTHERLY SURGE IS UNDERWAY THIS MORNING, BRINGING
GUSTY SOUTH WINDS UP TO 20 KT, MARINE OVERCAST, AND PATCHY MIST
AND DRIZZLE TO THE COASTAL WATERS, ESPECIALLY WITHIN 20-30 NM OF
SHORE. A DIURNAL TENDENCY WILL PERSIST THROUGH WEDNESDAY, WITH
INCREASING CLOUDS, WIND, AND CHANCES FOR DRIZZLE OR LIGHT RAIN
AT NIGHT BEFORE CLOUDS RECEDE AND WINDS EASE DURING THE DAY. A
LESSENING NORTHWEST SWELL WILL SEE SEAS FALL FROM 6-8 FT TODAY
TO 4-5 FT BY WEDNESDAY.
WINDS LOOK TO TURN NORTHERLY WEDNESDAY THROUGH THURSDAY NIGHT
WITH PERSISTENT SEAS OF 5-7 FT. A SYSTEM MOVING ONSHORE FRIDAY
INTO SATURDAY WILL FAVOR A RETURN OF SOUTHERLY FLOW AND
INCREASED CHANCES FOR RAIN SHOWERS, BEFORE HIGH PRESSURE
REBUILDS LATER THIS WEEKEND AND NORTHERLY FLOW STRENGTHENS.
CHANCES INCREASE LATE SATURDAY INTO SUNDAY FOR NORTHERLY GUSTS
OF 20 KT, CONDITIONS WHICH MAY BE HAZARDOUS TO SMALL CRAFT. -36
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
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