690
FXUS66 KPQR 220920
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
220 AM PDT SUN MAR 22 2026
SYNOPSIS
DRY WEATHER AND NEAR NORMAL HIGH TEMPERATURES
THROUGH MONDAY WITH MORNING LOW TEMPERATURES IN THE 30S,
PRODUCING WIDESPREAD FROST. A WEATHER SYSTEM BRINGS WIDESPREAD
RAIN AND BREEZY WINDS TUESDAY INTO WEDNESDAY ALONG WITH LIGHT
CASCADES SNOW TUESDAY NIGHT INTO WEDNESDAY. NO SNOW OR FLOODING
IMPACTS EXPECTED. DRY WEATHER RETURNS THURSDAY INTO FRIDAY.
DISCUSSION...SUNDAY THROUGH SATURDAY
MOSTLY CLEAR SKIES ARE
BEING OBSERVED ON SATELLITE IMAGERY ACROSS NW OR AND SW WA EARLY
SUNDAY MORNING UNDER BUILDING SURFACE HIGH PRESSURE AND ZONAL
FLOW ALOFT. A WEAK COLD FRONT WILL GRAZE FAR NW OR AND SW WA
COAST LATER THIS MORNING WITH MID- LEVEL CLOUDS AND A 15-25%
CHANCE OF SCATTERED SHOWERS THROUGH AROUND 8-10 AM. TEMPERATURE
OBSERVATIONS AT 2 AM SHOW MOST LOCATIONS ACROSS THE INTERIOR
LOWLANDS HAVE FALLEN TO THE MID TO UPPER 30S, EXCEPT FOR LOW 40S
IN THE PORTLAND METRO AREA. TEMPERATURES WILL CONTINUE DROPPING
OVER THE NEXT FEW HOURS WITH LOW TEMPERATURES AT MOST LOCATIONS
REACHING THE LOW 30S. EXPECTING WIDESPREAD FROST WITH LIGHT
WINDS AND MOSTLY CLEAR SKIES THIS MORNING. PATCHY FOG IS ALSO A
POSSIBILITY FOR AREAS THAT REMAIN ABOVE 34 DEGREES. THIS PATTERN
CONTINUES INTO MONDAY WITH DAYTIME TEMPERATURES PEAKING IN THE
UPPER 50S AND ANOTHER ROUND OF COOLER LOW TEMPERATURES MONDAY
MORNING. HOWEVER, LOW TEMPERATURES WILL BE SLIGHTLY HIGHER THAN
THIS MORNING, IN THE MID TO UPPER 30S, LEADING TO LESS
WIDESPREAD FROST DEVELOPMENT. NOTE THAT NWS PORTLAND WILL NOT
BEGIN ISSUING FROST ADVISORIES AND FREEZE WATCHES/WARNINGS FOR
AGRICULTURAL PURPOSES UNTIL APRIL 1ST AS THIS IS WHEN THE
GROWING SEASON BEGINS TO RAMP UP AND IMPACTS FROM FROST AND
FREEZE CONDITIONS BECOME MORE SIGNIFICANT.
EXPECT INCREASING CLOUD COVER THROUGH THE DAY ON MONDAY AS THE
NEXT WEATHER SYSTEM APPROACHES THE PACNW. ENSEMBLE GUIDANCE
REMAINS IN EXCELLENT AGREEMENT THAT A SURFACE CLOSED LOW
PRESSURE SYSTEM WILL MOVE NORTHEAST INTO BRITISH COLUMBIA WITH
A TRAILING COLD FRONT MOVING EAST INTO WA AND OR TUESDAY INTO
WEDNESDAY. THIS COLD FRONT WILL BRING WIDESPREAD RAIN AND BREEZY
WINDS TO NW OR AND SW WA. THERE IS SOME UNCERTAINTY ON HOW LONG
RAIN WILL LAST INTO WEDNESDAY NIGHT OR THURSDAY MORNING AS SOME
ENSEMBLE MEMBERS INDICATE MOISTURE WILL CONTINUE INTO THURSDAY
MORNING WHILE OTHERS CUT OFF MOISTURE BY LATE WEDNESDAY NIGHT.
THE TERRAIN AND LOWLAND LOCATIONS ALONG AND NORTH OF THE
COLUMBIA RIVER HAVE BETTER CHANCES FOR SHOWERS CONTINUING INTO
THURSDAY MORNING, THOUGH QPF AMOUNTS ARE ON THE LOW END BY THIS
TIME. OVERALL, ALTHOUGH THIS SYSTEM WILL BRING WIDESPREAD RAIN,
IMPACTS ARE EXPECTED TO BE LIMITED. 48 HOUR QPF ENDING AT 5 AM
PDT THURSDAY IS AROUND 0.25-0.75 INCHES FOR THE INTERIOR
LOWLANDS, 0.5-1.5 INCH FOR THE COAST, COAST RANGE, AND WILLAPA
HILLS, 0.5-1.5 INCH FOR THE NORTH OREGON CASCADES, AND 0.75-2
INCHES FOR THE SW WASHINGTON CASCADES. FLOODING IMPACTS ARE NOT
EXPECTED FROM THIS SYSTEM.
IN TERMS OF CASCADE SNOW, THE HEAVIEST PRECIPITATION IS
EXPECTED TO FALL AHEAD OF AND ALONG THE COLD FRONT ON TUESDAY
WHEN SNOW LEVELS ARE GENERALLY HIGHER THAN PASS LEVEL. SNOW
LEVELS WILL FALL QUICKLY AFTER THE FRONT PASSES LATE TUESDAY
INTO WEDNESDAY TO AROUND 3500-4500 FT BY WEDNESDAY MORNING.
HOWEVER, THE LOWEST SNOW LEVELS WILL BE IN SW WA CASCADES WITH
SNOW LEVELS RISING MOVING SOUTH INTO THE CENTRAL OR CASCADES. AS
SHOWERS WILL CONTINUE INTO WEDNESDAY, THERE IS THE POTENTIAL
FOR SOME ACCUMULATING SNOW AT PASS LEVEL, THOUGH DUE TO THE
CURRENT SUN ANGLE ALONG WITH WARMER ROAD TEMPERATURES, IT MIGHT
BE DIFFICULT FOR MUCH ACCUMULATION IN SCATTERED SHOWERS. SNOW
LEVELS WILL CONTINUE FALLING THROUGH WEDNESDAY, ESPECIALLY
WEDNESDAY NIGHT, FALLING TO AROUND 1500-3000 FT BY THURSDAY
MORNING. THE 10TH PERCENTILE (ONLY 10% CHANCE OF SNOW LEVELS
THIS LOW) DOES INDICATE SNOW LEVELS COULD FALL AS LOW AS
500-1500 FT BY THURSDAY MORNING. HOWEVER, IF PRECIPITATION
REALLY IS DECREASING BY THIS TIME, THEN THERE WILL BE LIMITED
PRECIPITATION TO EVEN CAUSE SNOW. ONLY A FEW ENSEMBLE MEMBERS
SUGGEST ANY KIND OF ACCUMULATING SNOW IN THE INTERIOR LOWLANDS
NORTH OF PORTLAND, AND GENERALLY LESS THAN AN INCH. NBM
PROBABILITIES FOR 6 INCHES OF SNOW OR MORE IN A 48-HOUR PERIOD
ENDING AT 5 AM PDT THURSDAY CONTINUE TO BACK THIS EXPECTATION
UP, AS CHANCES ARE ONLY AROUND 5% AT WILLAMETTE AND SANTIAM
PASSES, AND 10-20% ALONG HIGHWAY 26 NEAR GOVERNMENT CAMP.
BREEZY SOUTHERLY WINDS ARE ALSO EXPECTED WITH THE FRONTAL
PASSAGE ON TUESDAY. STRONGEST WINDS WILL BE ALONG THE COAST,
COAST RANGE, AND WILLAPA HILLS WHERE THERE IS A 60-80% CHANCE
OF MAXIMUM WIND GUSTS EXCEEDING 40 MPH. INLAND, THIS PROBABILITY
DROPS TO ONLY A 10-20% CHANCE, HIGHEST IN THE CENTRAL WILLAMETTE
VALLEY SOUTH OF THE PORTLAND METRO AREA TO THE SALEM AREA.
CHANCES FOR MAXIMUM WIND GUSTS EXCEEDING 30 MPH FOR INLAND
AREAS INCREASE TO AROUND 50-75%, SO MOST LIKELY SCENARIO IS PEAK
WIND GUSTS OF 30-35 MPH FOR INLAND LOCATIONS AND 40-45 MPH ALONG
THE COAST AS THE FRONT PASSES.
BY THURSDAY AFTERNOON INTO FRIDAY, THE WEATHER SYSTEM IS
EXPECTED TO MOVE OUT OF THE AREA WITH UPPER LEVEL FLOW BECOMING
MORE ZONAL. EXPECTING DRY CONDITIONS WITH CLEARING SKIES BY
MIDDAY THURSDAY, WHICH COULD ALLOW FOR TEMPERATURES TO WARM INTO
THE UPPER 50S ON THURSDAY AND INTO THE LOW TO MID 60S FOR FRIDAY
AND SATURDAY FOR THE INTERIOR LOWLANDS. SATURDAY IS EXPECTED TO
BE THE PEAK DAY OF THE WARMING TREND, AND NBM INDICATES A 20-30%
CHANCE OF TEMPERATURES REACHING 70 DEGREES ACROSS THE WILLAMETTE
VALLEY. -03
AVIATION
DRY, WESTERLY FLOW ALOFT WITH PREDOMINATELY VFR
CONDITIONS THROUGH THE TAF PERIOD. A WEAK SURFACE FRONT IS SLATED
TO GRAZE THE SW WA AND FAR NW OR COAST AROUND 12-15Z SUNDAY,
CAUSING A 15-20% CHANCE OF ISOLATED SHOWERS AND AN INCREASE IN
MID-LEVEL CLOUDS WITH A 20-40% CHANCE OF MVFR CEILINGS BETWEEN
10-16Z SUN. WINDS REMAIN GENERALLY FROM THE NORTH AND UNDER 10 KT
THROUGH AROUND 17-20Z SUN, WHEN WINDS INCREASE TO AROUND 8-12 KT
AT INTERIOR TERMINALS AND 12 TO 15 KT WITH GUSTS UP TO 21 KT AT
COASTAL TERMINALS SOUTH OF CLATSOP COUNTY. INLAND WINDS DECREASE
BELOW 8-10 KTS AFTER 02Z MON AND COASTAL WINDS AFTER 04-06Z MON.
CLEAR SKIES AND LIGHT WINDS EARLY SATURDAY MORNING WILL SUPPORT
TEMPERATURES DROPPING TOWARDS THE LOW TO MID 30S, RESULTING IN
POTENTIAL FROST DEVELOPMENT OVER METAL SURFACES (GENERALLY AROUND
09-16Z SUN).
KPDX AND APPROACHES...VFR CONDITIONS THROUGH THE TAF PERIOD.
NORTHWESTERLY WINDS UNDER 8 KT UNTIL AROUND 18-20Z SUN, THEN
INCREASING TO AROUND 8-10 KT THROUGH AROUND 02Z MON. POTENTIAL FOR
WIDESPREAD FROST OVER METAL SURFACES BETWEEN 09-16Z SUN DUE TO
CLEAR SKIES AND CALM WINDS. -03
MARINE
HIGH PRESSURE OVER THE WATERS WILL MAINTAIN NORTHERLY
WINDS THROUGH MONDAY. THE NEXT VERY STRONG EBB WILL OCCUR AROUND
730 AM SUNDAY, SO A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE
THE COLUMBIA RIVER BAR BETWEEN 5-10 AM SUNDAY AS THE EBB BUILDS
SEAS TO AROUND 8 FT ALONG THE MAIN CHANNEL OF THE BAR.
A THERMAL TROUGH DEVELOPS ALONG THE SOUTHERN OREGON COAST SUNDAY
AFTERNOON THROUGH EARLY MONDAY MORNING, TIGHTENING PRESSURE
GRADIENTS ACROSS THE WATERS SOUTH OF CAPE FALCON. THIS WILL LEAD
TO BREEZIER NORTHERLY WINDS WITH GUSTS UP TO 25 KT. A SMALL CRAFT
ADVISORY REMAINS IN EFFECT FOR ALL WATERS SOUTH OF CAPE FALCON
FROM 2 PM SUNDAY THROUGH AT LEAST 5 AM MONDAY. NORTHERLY WINDS MAY
LAST LONGER FOR THE OUTER WATERS BEYOND 10 NM OFFSHORE, SO THE
SMALL CRAFT ADVISORY FOR THESE ZONES WILL GO THROUGH 8 AM MONDAY.
SEAS FALL TO 5-6 FT TONIGHT, RE-BUILDING TO 8-9 FT AT 11 SEC AS
WIND WAVES INCREASE FROM THE BREEZY NORTHERLY WINDS.
THE NEXT ROBUST WEATHER SYSTEM RETURNS TUESDAY INTO WEDNESDAY.
THIS SYSTEM WILL BRING A RETURN OF BREEZY SOUTHERLY WINDS ACROSS
ALL WATERS. CURRENT GUIDANCE SUGGESTS HIGH CONFIDENCE (90%+
CHANCE) FOR WIDESPREAD AND FREQUENT SMALL CRAFT WIND GUSTS OF 21
KT OR GREATER, AND A 35-55% CHANCE FOR WIDESPREAD AND FREQUENT
GALE FORCE WIND GUSTS OF 34 KT OR GREATER ON TUESDAY. CHANCES FOR
ISOLATED GALE FORCE WIND GUSTS ARE AROUND 75-90%, WITH THE HIGHEST
CHANCES BEYOND 20 NM OFFSHORE. LATEST GUIDANCE SUGGESTS THE
STRONGEST WINDS OCCUR BETWEEN 8 AM TO 5 PM TUESDAY. SEAS ON
TUESDAY AND WEDNESDAY ARE ALSO EXPECTED TO BUILD TO AROUND 13-16
FT IN RESPONSE TO INCREASING WIND WAVES ALONG WITH AN INCREASING
WESTERLY SWELL. THERE'S A 30-60% CHANCE SEAS COULD EXCEED 15 FT
WITH A 5-15% CHANCE FOR SEAS EXCEEDING 20 FT. CHANCES INCREASE
FROM SOUTH TO NORTH, PEAKING ACROSS THE WATERS NORTH OF CAPE
FALCON AND MAINLY BEYOND 40 NM OFFSHORE. -10/03
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 5 AM TO 10 AM PDT THIS MORNING FOR
PZZ210.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 5 AM PDT
MONDAY FOR PZZ252-253.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 8 AM PDT
MONDAY FOR PZZ272-273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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