429
FXUS66 KPQR 182123
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
223 PM PDT SAT APR 18 2026
SYNOPSIS
HIGH PRESSURE OVERHEAD IS KEEPING NORTHWEST OREGON
AND SOUTHWEST WASHINGTON WARM AND DRY TODAY. OUT OVER THE
PACIFIC, A STORM SYSTEM IS ORGANIZING AND IS EXPECTED TO BECOME
A SLOW-MOVING CLOSED LOW LATE THIS WEEKEND INTO EARLY NEXT WEEK.
THAT WILL GRADUALLY BRING MORE CLOUDS ON MONDAY, THEN A BETTER
CHANCE FOR COOLER, WETTER WEATHER BY THE MIDDLE OF THE WEEK.
CONFIDENCE IS INCREASING THAT SHOWERS BECOME MORE LIKELY LATE
MONDAY INTO TUESDAY AS THE SYSTEM BEGINS TO SPREAD MOISTURE
INLAND. WEDNESDAY STILL LOOKS LIKE THE COOLEST AND MOST SHOWERY
DAY OVERALL.
SHORT TERM...NOW THROUGH SUNDAY NIGHT
THIN CLOUDS HIGH IN
THE SKY HAVE BEEN STREAMING ACROSS THE AREA AT TIMES TODAY
(MOST NOTICEABLE NEAR THE COAST AND INTO SOUTHWEST WASHINGTON),
BUT CONDITIONS REMAIN DRY AND TEMPERATURES ARE STILL WARMING UP
NICELY INLAND. EXPECT INLAND HIGHS MAINLY IN THE LOWER TO MID
70S TODAY, WHILE THE COAST STAYS COOLER, GENERALLY UPPER 50S TO
MID 60S.
LATER TODAY AND TONIGHT, A WEAKENING FRONT WILL APPROACH THE
COASTAL WATERS. MOST OF THE MOISTURE AND LIFT LOOK LIKE THEY
WILL REMAIN OFFSHORE, SO FOR MOST LOCATIONS THE MAIN CHANGE WILL
BE INCREASING CLOUDS THIS EVENING AND OVERNIGHT. WHILE LIGHT
SHOWERS WILL MOST LIKELY STAY OVER THE OCEAN, THERE IS A SMALL
CHANCE A BRIEF SHOWER COULD BRUSH THE IMMEDIATE NORTH COAST LATE
TONIGHT INTO SUNDAY MORNING. NO RAIN IS EXPECTED FOR INLAND
AREAS.
CLOUD COVER TONIGHT WILL KEEP TEMPERATURES MILDER THAN THIS
MORNING. LOWS SHOULD BE MOSTLY IN THE MID TO UPPER 40S INLAND (A
FEW COOLER VALLEYS COULD DIP A BIT LOWER), AND GENERALLY IN THE
40S NEAR THE COAST. WITH CLOUDS AND WARMER NIGHTTIME
TEMPERATURES, FROST IS NOT EXPECTED OVER AT LEAST THE NEXT
COUPLE MORNINGS.
SUNDAY LOOKS SIMILAR TO TODAY; WARM AND DRY FOR MOST AREAS,
WITH MORE THIN HIGH CLOUDS AROUND. INLAND HIGHS SHOULD AGAIN
REACH THE LOW TO MID 70S. PARTS OF THE PORTLAND/VANCOUVER METRO
AND NEARBY COMMUNITIES COULD STILL REACH 80 DEGREES IF CLOUDS
THIN ENOUGH DURING THE WARMEST PART OF THE DAY, BUT THAT WILL
DEPEND ON HOW QUICKLY CLOUD COVER THICKENS (30-60% CHANCE OF
DAYTIME TEMPERATURES EXCEEDING 80 DEGREES). THERE IS MODERATE TO
HIGH CONFIDENCE THAT THESE HIGH CLOUDS WILL REMAIN THIN,
ALLOWING FOR GOOD DAYTIME HEATING. COASTAL HIGHS STAY IN THE
UPPER 50S TO MID 60S. SUNDAY NIGHT REMAINS DRYS INLAND WITH LOWS
MAINLY IN THE 40S.
LONG TERM...MONDAY THROUGH FRIDAY
ON MONDAY, THE OFFSHORE
LOW PRESSURE SYSTEM WILL START TO HAVE MORE INFLUENCE ON OUR
WEATHER. EXPECT MORE CLOUD COVER AND SLIGHTLY COOLER
TEMPERATURES COMPARED TO THE WEEKEND. HIGHS SHOULD GENERALLY BE
IN THE UPPER 60S TO NEAR 70 INLAND, AND UPPER 50S TO LOW 60S
ALONG THE COAST. RAIN SHOWER CHANCES INCREASE LATE MONDAY INTO
TUESDAY AS THE SYSTEM BEGINS TO MOVE CLOSER AND SPREAD MOISTURE
INLAND, WITH THE FIRST STEADIER SHOWERS MOST LIKELY OVER THE
HIGHER TERRAIN AND THE SOUTHERN WILLAMETTE VALLEY. EVEN SO,
PRECIPITATION THROUGH MONDAY LOOKS LIGHT OVERALL, GENERALLY
AROUND 0.05 TO 0.15 INCH WHERE SHOWERS OCCUR.
TUESDAY IS STILL THE TRICKIEST DAY. WHILE EXACT TIMING STILL
NEEDS REFINEMENT, CONFIDENCE IS HIGHER THAT AT LEAST SCATTERED
SHOWERS WILL REACH MORE OF THE AREA SOMETIME LATE MONDAY INTO
TUESDAY, RATHER THAN STAYING LARGELY OFFSHORE. IF SHOWERS DO
BEGIN TUESDAY, THEY WOULD MOST LIKELY SHOW UP FIRST ALONG THE
COAST AND IN AREAS FARTHER SOUTH AND WEST, THEN SPREAD INLAND
LATER.
CONFIDENCE IS HIGHER FOR TUESDAY NIGHT INTO WEDNESDAY: THIS IS
THE MOST LIKELY PERIOD FOR A MORE WIDESPREAD COOLER, AND SHOWERY
PATTERN ACROSS THE AREA. THE COAST RANGE AND CASCADES WILL BE
FAVORED FOR MORE PERSISTENT SHOWERS DUE TO TERRAIN ENHANCEMENT.
WHILE RAIN AMOUNTS REMAIN UNCERTAIN, EXPECT AROUND 0.25 TO 0.75
INCHES IN THE LOWLANDS AND AROUND 1 TO 1.75 INCHES IN THE COAST
RANGE AND CASCADES FROM 5 PM TUESDAY TO 5 PM WEDNESDAY.
BY THURSDAY AND FRIDAY, THE PATTERN LOOKS LIKE IT WILL TREND
DRIER AGAIN WITH TEMPERATURES SLOWLY WARMING BACK UP INTO THE
MID 60S AND MAYBE 70S BY FRIDAY. A FEW LEFTOVER SHOWERS NEAR THE
MOUNTAINS ARE POSSIBLE EARLY IN THAT PERIOD, BUT OVERALL
CONDITIONS SHOULD IMPROVE LATE WEEK. ~12
AVIATION
HIGH PRESSURE WILL MAINTAIN WIDESPREAD VFR FLIGHT
CONDITIONS THROUGH 00Z MONDAY WITH SCATTERED TO BROKEN HIGH
CLOUDS AROUND 20-25 KFT. WINDS WILL REMAIN LIGHT AND VARIABLE LESS
THAN 5 KT, WITH ONE EXCEPTION. EASTERLY WINDS AT KTTD WILL REMAIN
BREEZY THROUGH AT LEAST 22Z SATURDAY WITH OCCASIONAL GUSTS UP TO
20-25 KT BEFORE EAST WINDS GRADUALLY DECREASE IN STRENGTH BETWEEN
22-00Z. EXPECT EASTERLY WINDS TO RESTRENGTHEN A BIT BETWEEN 12-18Z
SUNDAY.
KPDX AND APPROACHES...SCATTERED TO BROKEN HIGH CLOUDS WITH CIGS
ABOVE 20-25 KFT WILL MAINTAIN VFR FLIGHT CONDITIONS THROUGH 00Z
MONDAY. VARIABLE WINDS AROUND 5 KT OR LESS ARE EXPECTED TO BECOME
EASTERLY TOWARDS 17Z SUNDAY WITH SUSTAINED WIND SPEEDS APPROACHING
10 KT. -23
MARINE
BENIGN CONDITIONS CONTINUE THROUGH THE WEEKEND. SOUTHERLY
TO SOUTHWESTERLY WINDS BETWEEN 5-15 KT CONTINUE TODAY WITH SEAS
UNDER 5 FT. WINDS WILL WEAKEN AND BECOME EAST TO SOUTHEAST BY
EARLY SUNDAY MORNING. WINDS THEN REMAIN LIGHT THROUGH EARLY NEXT
WEEK WITH SEAS INCREASING BY A FEW FEET, BUT STAYING UNDER 10 FT.
AN AREA OF LOW PRESSURE SITTING OFF THE COAST WILL MOVE INLAND
DURING THE MIDDLE OF NEXT WEEK. THIS WILL BRING ONSHORE FLOW,
SHOWERS, AND INCREASING WINDS AND SEAS. HOWEVER, UNCERTAINTY
REMAINS REGARDING EXACT WIND SPEEDS AND WAVE HEIGHTS. THE
PLACEMENT OF THE LOW WILL DETERMINE WHAT CONDITIONS MATERIALIZE
ACROSS THE WATERS. THE CURRENT FORECAST FAVORS A PERIOD OF
INCREASING WEST TO NORTHWEST WINDS LATE TUESDAY INTO WEDNESDAY
WITH WIND GUSTS REACHING 20-25 KT OR STRONGER BY WEDNESDAY
AFTERNOON. IN FACT, THERE IS A 50-75% CHANCE FOR MAX WIND GUSTS
OVER 25 KT. THE HIGHEST PROBABILITIES ARE BEYOND 30 NM OFFSHORE.
SEAS ARE EXPECTED TO REACH AT LEAST 10-12 FT BY LATE WEDNESDAY,
HOWEVER THERE IS A 40-70% CHANCE SEAS WILL PEAK OVER 12 FT OVER
THE NORTHERN AND CENTRAL OUTER WATERS. THERE IS A 1-5% CHANCE SEAS
WILL PEAK AS HIGH AS 15 FT, WHICH REPRESENTS THE WORST CASE
SCENARIO.
VERY STRONG EBB CURRENTS WILL CONTINUE ACROSS THE COLUMBIA RIVER BAR
EACH MORNING THROUGH TUESDAY. WITH SEAS EXPECTED TO BUILD
SLIGHTLY BY EARLY NEXT WEEK, A STEEP EBB CHOP MAY NECESSITATE
SMALL CRAFT ADVISORIES IN THE HOURS AROUND PEAK FLOW EACH DAY. -23
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
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