972
FXUS66 KPQR 290424 AAA
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
924 PM PDT SAT MAR 28 2026
UPDATED AVIATION DISCUSSION AND SYNOPSIS.
SYNOPSIS
A WEAK SYSTEM IS SET TO BRING LIGHT PRECIPITATION TO
THE AREA SUNDAY MORNING INTO SUNDAY NIGHT. CONDITIONS DRY OUT MONDAY
MORNING THROUGH TUESDAY AS WEAK RIDGING DEVELOPS ALONG WITH A THERMAL
TROUGH AT THE SURFACE. A ROBUST SYSTEM IS EXPECTED TO DROP SOUTHEAST
OUT OF THE GULF OF ALASKA, SENDING A COLD FRONT TOWARD THE PACNW AND
SUPPORTING UNSETTLED WEATHER INTO EARLY FRIDAY. THE SYSTEM WILL BRING
WIDESPREAD RAIN, CASCADE SNOW, AND GUSTY WINDS.
DISCUSSION...NOW THROUGH FRIDAY
CONDITIONS REMAIN PLEASANT
TODAY WITH PARTLY CLOUDY CONDITIONS AND HIGHS WARMING INTO THE
LOW 60S INLAND AND 50S ALONG THE COAST. SATURDAY NIGHT LOWS ARE
MORE MILD, ONLY DROPPING INTO THE UPPER 30S TO LOW 40S. ISOLATED
FROST MAY DEVELOP IN THE HIGHER TERRAIN AND IN MORE SHELTERED
LOCATIONS.
THE PATTERN SHIFTS TOMORROW AS A SHORT WAVE TROUGH OVER THE GULF OF
ALASKA DROPS SOUTHEAST TOWARD THE PACNW, RETURNING PRECIPITATION
CHANCES TO THE AREA EARLY SUNDAY MORNING AT THE COAST AND LATE
MORNING/EARLY AFTERNOON INLAND. PRECIPITATION TOTALS FROM
SUNDAY MORNING THROUGH SUNDAY NIGHT WILL BE LIGHT WITH MOST
LOCATIONS SEEING LESS THAN 0.10 INCHES, WITH THE EXCEPTION OF THE
HIGHER TERRAIN OF THE CASCADES WHICH COULD SEE UP TO 0.25 INCHES.
SNOW LEVELS SUNDAY MORNING OVER THE CASCADES START OUT AROUND 4-6
KFT BUT DROP CLOSER TO 1-2 KFT SUNDAY NIGHT INTO MONDAY MORNING.
SNOWFALL FOR MOST OF THE CASCADES WILL BE MINIMAL WITH ONLY THE
CRESTS AND TOPS OF THE VOLCANOES RECEIVING 1-3 INCHES. COOLER
TEMPERATURES ARE EXPECTED SUNDAY NIGHT IN THE WAKE OF THE COLD
FRONT. NORTHWEST FLOW DEVELOPS LATE SUNDAY WITH CLOUD COVER THINNING
OVERNIGHT. THERE IS A 20-70% CHANCE THAT MONDAY MORNING LOWS DROP
BELOW FREEZING ACROSS THE WILLAMETTE VALLEY AND I-5 CORRIDOR IN SW
WA. THE LOWEST CHANCES ARE OVER THE SOUTHERN WILLAMETTE VALLEY WHERE
CLOUDS WILL THIN LATEST WHILE THE I-5 CORRIDOR IN SW WA HAS THE
HIGHEST PROBABILITY OF REACHING FREEZING. HOWEVER, NO SNOW IS
EXPECTED OVER THE LOWLANDS GIVEN MOISTURE WILL BE LIMITED DURING
THIS TIME.
SHOWERY PRECIPITATION IS EXPECTED TO TAPER OFF BY EARLY MONDAY
MORNING. ZONAL FLOW DEVELOPS ALOFT IN THE WAKE OF THE SHORTWAVE
TROUGH. HIGH PRESSURE AT THE SURFACE OFF THE OR/WA COAST WILL TRY TO
BUILD EASTWARD LATE MONDAY INTO TUESDAY. TUESDAY CONDITIONS CONTINUE
TO LOOK DRY AND MILD AS THE ZONAL FLOW AMPLIFIES SLIGHTLY OVER THE
PACNW. A WEAK THERMAL TROUGH WILL ALSO HELP SUPPORT WEAK OFFSHORE
FLOW ON THE WESTERN SLOPES OF THE CASCADES AND COAST RANGE. HIGHS
CREEP BACK INTO THE UPPER 50S TO LOW 60S INLAND AND LOW TO MID 50S
ALONG THE COAST.
A MORE ROBUST SYSTEM MAY DEVELOP OVER THE GULF OF ALASKA EARLY NEXT
WEEK. ANOTHER TROUGH IS EXPECTED TO DIG SOUTHEAST FROM THE GULF OF
ALASKA, SUPPORTING THE DEVELOPMENT OF A SURFACE LOW OFF THE CANADIAN
COAST. A COLD FRONT ASSOCIATED WITH THIS LOW WILL APPROACH THE PACNW
WEDNESDAY, REACHING THE COAST EARLY WEDNESDAY MORNING AND BRINGING
A DECENT SHOT OF RAIN WEST OF THE CASCADES AND A GOOD AMOUNT OF SNOW
TO THE CASCADES. 48 HOUR QPF TOTALS FROM WEDNESDAY TO FRIDAY MORNING
COULD ECLIPSE 1 INCH. PROBABILITIES FOR THE WILLAMETTE VALLEY ARE 30-
60% AND 50-80% ALONG THE COAST AND COAST RANGE. SNOWFALL TOTALS OVER
THE CASCADES DURING THE SAME TIMEFRAME HAVE A 70-80% CHANCE OF
REACHING GREATER THAN 6 INCHES AT PASS LEVEL. CASCADE PEAKS OVER
CENTRAL OREGON AND THE TOPS OF THE VOLCANOES HAVE A 50-70% CHANCE OF
SEEING A FOOT OF SNOW OR MORE. THERE IS ALSO A CHANCE FOR GUSTY
WINDS ASSOCIATED WITH THIS SYSTEM ON WEDNESDAY. THERE IS A 30-60%
CHANCE FOR WIND GUSTS TO REACH 40+ MPH ALONG THE COAST AND A 15-30%
35+ MPH GUSTS INLAND. DETAILS ARE STILL UNCERTAIN AT THIS TIME.
SHOWER ACTIVITY BEHIND THE COLD FRONT IS EXPECTED TO DECREASE
THROUGH THE DAY ON FRIDAY AS HIGH PRESSURE BUILDS INTO THE REGION.
CLUSTER ANALYSIS SHOWS GOOD AGREEMENT IN SOME DEGREE OF RIDGING
DEVELOPING OVER THE PACNW BY THE END OF NEXT WEEK. CONDITIONS SHOULD
TREND DRIER AND MORE MILD. -19
AVIATION
SOUTHWEST FLOW ALOFT WITH BROKEN MID TO HIGH LEVEL
CLOUDS STREAMING ACROSS THE AREA. VFR FLIGHT CONDITIONS CONTINUE,
EXCEPT AT KONP WHERE MVFR CIGS HAVE DEVELOPED. GENERALLY
NORTHWEST WINDS 10 KT OR LESS EXPECTED TO CONTINUE THROUGH LATE
THIS EVENING, THEN BECOMING LIGHT AND VARIABLE OVERNIGHT. A WEAK
FRONT WILL APPROACH THE COAST SUNDAY MORNING WITH LIGHT RAIN
LIKELY AT KAST BY 15Z, BEFORE SPREADING DOWN THE COAST TO KNOP BY
APPROXIMATELY 18Z, AND THEN OVER THE NORTHERN WILLAMETTE VALLEY
AND PORTLAND METRO AREA AROUND 20Z. KSLE TO KEUG WILL LIKELY STAY
DRY, ASIDE FROM A FEW POTENTIAL SPRINKLES. HIGH-END MVFR CIGS
WILL LIKELY BECOME MORE WIDESPREAD ALONG THE NORTH OR COAST,
NORTHERN WILLAMETTE VALLEY, AND PORTLAND METRO ONCE RAIN BEGINS
(50-60% CHANCE AT KAST, 30-50% CHANCE AT KHIO, KPDX, KTTD, 15-30%
CHANCE AT KUAO, KSLE, AND KEUG). CONFIDENCE WAS JUST HIGH ENOUGH
TO LOWER CIGS DOWN TO 3000 FT AT KAST, KHIO, KPDX, AND KTTD, BUT
CONFIDENCE IS NOT HIGH ENOUGH TO BRING CIGS THAT LOW AT KUAO,
KSLE, AND KEUG. FOR TAF SITES THAT DO WIND UP OBSERVING MVFR
CIGS, EXPECT CIGS TO QUICKLY LIFT BACK TO VFR MID TO LATE SUNDAY
AFTERNOON AS RAIN BEGINS TO DISSIPATE.
KPDX AND APPROACHES...EXPECT PREDOMINATELY VFR FLIGHT CONDITIONS
TO CONTINUE, EXCEPT BETWEEN 20Z SUNDAY AND 01Z MONDAY WHEN CIGS
MAY LOWER DOWN TO 3000-3500 FEET (30-50% CHANCE) WITH A PERIOD OF
LIGHT RAIN. CIGS SHOULD LIFT TO 4000 FT OR HIGHER AFTER 01Z
MONDAY AS RAIN DISSIPATES. -23
MARINE
HIGH PRESSURE CONTINUES TO WEAKEN OVER THE WATERS
THROUGH TONIGHT. NORTHWEST WINDS AROUND 10-15 KT EASE OVERNIGHT
WHILE SEAS FALL TO AROUND 5 FT. A WEAK FRONT WILL MOVE ACROSS THE
WATERS SUNDAY MORNING FOLLOWED BY BREEZY NORTHWEST WINDS.
NORTHERLY WINDS INCREASE LATE SUNDAY INTO MONDAY, AND REMAIN
ELEVATED THROUGH MONDAY NIGHT, AS HIGH PRESSURE REBUILDS OVER THE
WATERS. THIS WILL LIKELY LEAD TO A PERIOD OF SMALL CRAFT ADVISORY
WINDS.
A MORE ROBUST FRONTAL SYSTEM IS EXPECTED TO MOVE ACROSS THE WATERS
SOMETIME LATE TUESDAY THROUGH WEDNESDAY. GUIDANCE SUGGESTS THERE
IS AROUND A 80-90% CHANCE OF GALE FORCE WIND GUSTS EXCEEDING 34
KT WITH THIS SYSTEM. SEAS ARE EXPECTED TO RAPIDLY BUILD ON
WEDNESDAY BECOMING STEEP AND HAZARDOUS INTO THURSDAY, LIKELY
PEAKING IN THE MID-TEENS. /DH
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
WWW.WEATHER.GOV/PORTLAND
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