351
FXUS66 KPQR 152152
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
252 PM PDT SUN MAR 15 2026
SYNOPSIS
MOSTLY DRY WEATHER THROUGH MONDAY AS AN UPPER LEVEL
RIDGE BUILDS OVERHEAD. THIS RIDGE WILL ALSO RESULT IN SPRING-
LIKE TEMPERATURES THIS WEEK WITH HIGHS IN THE MID 60S TO LOW 70S
ACROSS INTERIOR VALLEYS. TUESDAY THROUGH THE END OF THE WEEK,
MOISTURE RIDING THE NORTHERN PERIPHERY OF THE RIDGE WILL RETURN
CHANCES FOR PRECIPITATION, WITH THE HIGHEST CHANCES ACROSS
SOUTHWEST WASHINGTON AND THE OREGON COAST NORTH OF TILLAMOOK.
THE BULK OF THE RAIN IS FORECAST TO TRACK TOWARD WESTERN BRITISH
COLUMBIA AND NORTHWEST WASHINGTON, WITH LIGHTER AMOUNTS OVER
OUR AREA.
DISCUSSION...NOW THROUGH SATURDAY
RADAR IMAGERY AS OF EARLY
SUNDAY AFTERNOON DEPICTS LIGHT RAIN OVER THE AREA. HOWEVER,
GIVEN THAT SOUNDING PROFILES ARE SHOWING A DRY LOW LEVEL
ATMOSPHERE AND SURFACE OBS INDICATE DEWPOINT DEPRESSIONS OF
15-20 DEGREES, MOST OF THIS RAIN IS COMING DOWN AS VIRGA
(EVAPORATING BEFORE HITTING THE GROUND). AN UPPER LEVEL RIDGE IS
BUILDING OFFSHORE OVER THE NORTHEAST PACIFIC OCEAN, AND MOISTURE
FROM AN ATMOSPHERIC RIVER (AR) IS RIDING THE NORTHERN PERIPHERY
OF THE RIDGE. THIS IS WHAT'S BRINGING THE OVERCAST CONDITIONS
AND VIRGA THIS AFTERNOON. THIS TREND CONTINUES THROUGH TONIGHT,
BUT AS THE LOW LEVEL ATMOSPHERE MOISTENS UP WE COULD COULD SEE
SOME LIGHT RAIN ACTUALLY REACHING THE GROUND, WITH THE HIGHEST
CHANCES (50-70%) ALONG THE NORTH OREGON AND SOUTH WASHINGTON
COAST.
THE UPPER LEVEL RIDGE WILL MOVE OVERHEAD BY MONDAY, BRINGING DRY
WEATHER AND DECREASING CLOUD COVER. THE FURTHER SOUTH YOU GO,
THE MORE SUNNY SKIES YOU'LL SEE. THE MOISTURE RIDING THE RIDGE
MAY KEEP SOME SCATTERED/BROKEN CLOUD COVER AROUND LONGER FOR
AREAS NORTH OF SALEM AND TILLAMOOK. ABOVE-AVERAGE 500 MB HEIGHTS
WILL ALSO SET-UP OVER THE AREA, RESULTING IN A WARMER AIR MASS
AND HIGH TEMPERATURES IN THE MID TO UPPER 60S ACROSS INTERIOR
VALLEYS. SOME PLACES LIKE THE SOUTHERN WILLAMETTE VALLEY MAY
EVEN EXCEED 70 DEGREES (60-80% CHANCE) GIVEN THE LACK OF CLOUD
COVER AND GREATER MAGNITUDE OF HIGH PRESSURE.
THE RIDGE WILL GRADUALLY SHIFT EASTWARD ON TUESDAY, AND AS IT
DOES THE AFOREMENTIONED AR THAT'S RIDING THE RIDGE WILL SHIFT A
BIT FURTHER SOUTH. WHILE THE BULK OF THE RAIN FROM THIS AR WILL
BE DIRECTED TOWARD NORTHWEST WASHINGTON AND WESTERN BRITISH
COLUMBIA, THE SOUTHERN PERIPHERY OF THE AR WILL RETURN
PRECIPITATION CHANCES OVER OUR AREA. THE HIGHEST CHANCES
(60-80%) FOR RAIN WILL BE ACROSS SOUTHWEST WASHINGTON AND THE
COAST FROM TILLAMOOK NORTHWARD. FROM WEDNESDAY TO FRIDAY, THE
UPPER RIDGE REMAINS SETTLED OVER THE GREAT BASIN/ROCKIES WITH
MINIMAL BREAK-DOWN OR EASTWARD MOVEMENT. THIS WILL MAINTAIN
PRECIPITATION CHANCES OVER SOUTHWEST WASHINGTON AND FAR
NORTHWEST OREGON THROUGH THE END OF THE WEEK AS MOISTURE
CONTINUES TO TREK ALONG THE BACKSIDE OF THE RIDGE.
PRECIPITATION AMOUNTS LOOK LIGHT, RESULTING IN NEGLIGIBLE
IMPACTS TO OUR AREA. CHANCES FOR 24 HOUR RAIN EXCEEDING 1 INCH
EACH DAY THIS WEEK ARE AROUND 20-40% ALONG THE NORTH OREGON AND
SOUTH WASHINGTON COASTS, AND LESS THAN 10% EVERYWHERE ELSE.
THUS, CHANCES FOR RIVER FLOODING OVER THE NEXT 10 DAYS REMAIN
UNDER 5%. IF THE AR ENDS UP PUSHING EVEN FURTHER SOUTH, THEN WE
COULD RECEIVE EVEN MORE RAIN. IN THIS CASE, THE WETTEST
SCENARIOS FOR 24 HOUR RAIN EACH DAY THIS WEEK (10% CHANCE OF
OCCURRING) WOULD BE AROUND 1.25-1.75 INCHES ALONG THE COAST AND
0.30-0.80 INCHES ALONG THE I-5 CORRIDOR, HIGHEST NORTH OF SALEM.
DESPITE THE RENEWED PRECIPITATION CHANCES THIS WEEK, SPRING-LIKE
TEMPERATURES IN THE 60S AND POTENTIALLY LOW 70S WILL CONTINUE
ACROSS INTERIOR VALLEYS THROUGH FRIDAY, WARMEST FURTHER SOUTH.
CHANCES FOR EUGENE EXCEEDING 75 DEGREES ARE AROUND 20-30% FROM
WEDNESDAY TO THE END OF THE WEEK. GIVEN THE WARMER, TEMPERATURES
WE COULD SEE SOME INCREASED SNOWMELT ACROSS THE CASCADES. SNOW
LEVELS WILL BE ABOVE 7000-8000 FEET, SO ANY PRECIPITATION THAT
FALLS OVER THE CASCADE PASSES WILL BE RAIN. BY SATURDAY, MOST
ENSEMBLE GUIDANCE (80%) SUGGESTS THE RIDGE WILL BEGIN TO BREAK
DOWN, RESULTING IN COOLER TEMPERATURES. -10
AVIATION
A BROAD UPPER LEVEL RIDGE WITH MID-LEVEL MOISTURE
WILL MAINTAIN WEST TO NORTHWEST FLOW ALOFT ALONG WITH MID TO
HIGH LEVEL CLOUDS STREAMING ACROSS THE AREA. EXPECT WIDESPREAD
VFR CONDITIONS TO CONTINUE THROUGH THE PERIOD AT MOST TERMINALS.
AS A WARM FRONT APPROACHES THE COAST THIS AFTERNOON, EXPECT CIGS
TO GRADUALLY LOWER WITH LOW CHANCES FOR LIGHT RAIN ACROSS
NORTHERN TERMINALS. CHANCES FOR MVFR CONDITIONS INCREASE ALONG
THE NORTH OREGON COAST AFTER 10Z MONDAY TO AROUND 50%, ALONG
WITH A 10-20% CHANCE OF CONDITIONS DETERIORATING TO IFR AT KAST.
GENERALLY LIGHT AND VARIABLE WINDS EXPECTED THROUGH TONIGHT.
KPDX AND APPROACHES...VFR WITH BROKEN TO OVERCAST MID AND HIGH
LEVEL CLOUDS EXPECTED THROUGH THE TAF PERIOD. GENERALLY LIGHT AND
VARIABLE WINDS BECOMING SOUTHEAST LESS THAN 7 KT. SLIGHT CHANCE
FOR LIGHT RAIN BETWEEN 21Z SUNDAY AND 03Z MONDAY. /DH
MARINE
OFFSHORE WINDS THIS AFTERNOON TURN MORE SOUTHERLY
LATER TODAY AND TONIGHT AS A WARM FRONT APPROACHES THE COAST.
FAIRLY BENIGN CONDITIONS CONTINUE THROUGH THIS EVENING WITH
WINDS GENERALLY 15 KT OR LESS AND SEAS OF AROUND 3 TO 5 FT.
SOUTHERLY WINDS ARE EXPECTED TO INCREASE ON MONDAY, STRONGEST
ACROSS THE NORTHERN COASTAL WATERS. BREEZY SOUTHERLY WINDS
CONTINUE THROUGH AT LEAST MID-WEEK AS A QUASI-STATIONARY FRONT
REMAINS OFFSHORE. WINDS ARE LIKELY TO GUST UP TO 20-25 KT, WITH
SMALL CRAFT ADVISORY THRESHOLDS EXPECTED NORTH OF CAPE
FOULWEATHER THROUGH AT LEAST WEDNESDAY. A WEST-SOUTHWEST SWELL
PUSHING INTO THE COASTAL WATERS ALONG WITH INCREASING SOUTHERLY
WIND WAVES WILL BUILD COMBINED SEAS TO AROUND 9 TO 11 FT BY
TUESDAY. THE FRONT WILL LIKELY PUSH INLAND LATE IN THE WEEK,
RETURNING NORTHERLY WINDS BY THE WEEKEND. /DH
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 5 PM MONDAY TO 5 AM PDT WEDNESDAY FOR
PZZ210-251-252-272.
SMALL CRAFT ADVISORY FROM 11 AM MONDAY TO 5 AM PDT WEDNESDAY FOR
PZZ271.
WWW.WEATHER.GOV/PORTLAND
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