332
FXUS66 KPQR 201751 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
1051 AM PDT MON APR 20 2026
UPDATED AVIATION DISCUSSION.
SYNOPSIS
CONDITIONS REMAIN MOSTLY DRY TODAY BUT TRANSITION
THIS EVENING AS THE UPPER LEVEL LOW SHIFTS EASTWARD. INCREASING
CLOUD COVER IS EXPECTED FROM SOUTH TO NORTH WITH INCREASING
PRECIPITATION CHANCES. THE BEST SIGNAL FOR THE COOLEST AND MOST
UNSETTLED STRETCH REMAINS TUESDAY INTO WEDNESDAY AS THE SYSTEM
MOVES INLAND. BEYOND THAT, GUIDANCE SUPPORTS A RETURN TO DRIER
WEATHER AND A WARMING TREND BEGINNING THURSDAY AND CONTINUING
INTO THE WEEKEND AS HIGH PRESSURE REBUILDS.
DISCUSSION...NOW THROUGH SUNDAY
HIGH AND MID LEVEL CLOUDS
CONTINUE TO STREAM IN ALONG SOUTHERLY FLOW SUPPORTED BY THE
LARGE CUT-OFF LOW POSITIONED OFF THE COAST. OVERNIGHT LOWS
REMAIN ON THE MILD SIDE AS CLOUD COVER KEEPS THE SURFACE
INSULATED. EXPECTING LOWS IN THE MID 40S TO LOW 50S.
CONDITIONS START OUT DRY FOR THE AREA BUT WILL BEGIN TO
TRANSITION DURING THE LATTER HALF OF THE DAY. THE UPPER LEVEL
RIDGE THAT HAS CONTROLLED THE REGION OVER THE LAST FEW DAYS WILL
SHIFT EASTWARD AS THE UPPER LEVEL LOW SWINGS INLAND. CLOUD COVER
WILL CONTINUE TO STREAM IN THROUGH THE DAY BUT COULD SEE SOME
BREAKS OR THINNING OVER THE NORTHERN HALF OF THE FORECAST AREA,
MAINLY OVER THE NORTHERN WILLAMETTE VALLEY AND
PORTLAND/VANCOUVER METRO. HIGHS ARE EXPECTED TO TOP OUT A FEW
DEGREES COOLER THAN YESTERDAY WITH HIGHS IN THE UPPER 60S TO
AROUND 70 THROUGH THE CENTRAL AND SOUTHERN WILLAMETTE VALLEY.
HIGHS IN THE LOW TO MID 70S AROUND THE METRO WITH A LOW
(10-30%) TO HIT 80. COASTAL AREAS SEE TEMPERATURES IN THE UPPER
50S TO LOW 60S. POPS INCREASE FROM SOUTH TO NORTH THROUGH THE
DAY AS THE TROUGH BEGINS MAKING AN EASTWARD PUSH. SLIGHT CHANCE
POPS ENTER THE FORECAST AREA EARLY IN THE AFTERNOON AND SPREAD
NORTHWARD TO THE METRO BY THE EVENING. PRECIPITATION WILL BE
SCATTERED AND LIGHT WITH MOST LOCATIONS RECEIVING 0.10 INCHES
OR LESS THROUGH TONIGHT. THERE IS A LOW (~10%) CHANCE FOR AN
ISOLATED POP-UP THUNDERSTORM OVER MAINLY OVER THE CASCADES THIS
EVENING. NOT EXPECTING ANYTHING WIDESPREAD OR IMPACTFUL BUT
INSTABILITY COULD INCREASE ENOUGH WHERE CLOUD COVER BREAKS.
TUESDAY CONTINUES TO LOOK LIKE A SHOWERY, COOL DAY WITH RAIN
SHOWERS EXPECTED TO BE AT THEIR GREATEST AREAL COVERAGE AND
HIGHS DROP BACK TO NEAR NORMAL. HIGHS IN THE LOW 60S INLAND AND
UPPER 50S CAN BE EXPECTED. ENSEMBLES HAVE SHIFTED TOWARD A LULL
IN PRECIPITATION TUESDAY NIGHT WITH POPS DROPPING TO AROUND
20-40% EAST OF THE CASCADES. HOWEVER, AN AREA OF LOW PRESSURE
AND ASSOCIATED COLD FRONT ARE EXPECTED TO BRING ANOTHER ROUND OF
LIGHT RAIN ON WEDNESDAY. RAINFALL TOTALS TUESDAY MORNING
THROUGH WEDNESDAY NIGHT HAVE COME DOWN SIGNIFICANTLY FOR ALL
AREAS. AREAS EAST OF THE CASCADES, INCLUDING LOWLANDS, COAST
RANGE AND COAST ARE EXPECTED TO TOP OUT IN THE 0.15-0.35 INCH
RANGE WHILE THE CASCADES COULD SEE 0.50-0.80 WITH LOCALIZED
AREAS REACHING 1.0 INCHES. CHANCES FOR 0.50 INCHES FOR THE
LOWLANDS IS AROUND 10-25% WITH SLIGHTLY BETTER CHANCES UP TO 40%
IN THE COAST RANGE. THE PROBABILITY OF 1 INCH OF RAIN FOR THE
CASCADES DURING THIS SAME TIME FRAME IS 20-40%.
CONDITIONS THURSDAY TROUGH SATURDAY TREND DRIER AND WARMER WITH
TEMPERATURES MODERATING BACK INTO THE LOW TO MID 60S ON
THURSDAY AND LOW 70S ON FRIDAY AND SATURDAY FOR INLAND LOCATIONS.
SHOWER ACTIVITY COULD LINGER OVER THE CASCADES THROUGH THURSDAY
BUT WOULD REMAIN VERY LIGHT. UNCERTAINTY INCREASES HEADING INTO
THE LATTER HALF OF NEXT WEEKEND WITH THE RETURN OF LIGHT
PRECIPITATION POSSIBLE. -19
AVIATION
HIGH CLOUDS PERSIST OVER THE AREA THIS MORNING,
MAINTAINING VFR FLIGHT CONDITIONS. WINDS REMAIN LIGHT AND VARIABLE
AROUND 5 KT OR LESS.
AFTER 18-21Z MONDAY, A WEAK FRONT ASSOCIATED WITH A LOW PRESSURE
SYSTEM OFFSHORE WILL LIFT NORTHWARD OVER THE AREA, BRINGING
INCREASING SOUTHWEST TO WEST WINDS, LOWER CIGS, AND INCREASING
CHANCES FOR RAIN SHOWERS. HOWEVER, CIGS ARE VERY LIKELY TO REMAIN
VFR AT ALL TERMINALS THROUGH AT LEAST 00-06Z TUESDAY. AFTER 06Z
TUESDAY, CHANCES FOR MVFR CIGS OF 2-3 KFT INCREASE AT ALL
TERMINALS. NOTE AN ISOLATED THUNDERSTORM OR TWO IS POSSIBLE
AROUND 00Z TUESDAY SOMEWHERE OVER THE CASCADES, FOOTHILLS AND/OR
WILLAMETTE VALLEY, HOWEVER THE PROBABILITY FOR THUNDERSTORMS AT
ANY GIVEN TAF SITE IS ONLY 5-15%.
KPDX AND APPROACHES...PREDOMINATELY VFR CONDITIONS CONTINUE TODAY
WITH CIGS BETWEEN 10-20 KFT. WEST-SOUTHWESTERLY WINDS INCREASE
LATE MONDAY AFTERNOON AS THE NEXT FRONT MOVES IN, BUT MOST LIKELY
REMAINING UNDER 10 KT ASIDE FROM INFREQUENT GUSTS UP TO 15 KT.
CIGS WILL MOST LIKELY LOWER TO AROUND 3000 FT OR LESS BY 08-09Z
TUESDAY AS LIGHT RAIN SHOWERS MOVE IN FROM THE SOUTH. THERE IS A
15% CHANCE OF THUNDERSTORMS AT THE KPDX TERMINAL BETWEEN 00-03Z
TUESDAY. -23
MARINE
BENIGN CONDITIONS CONTINUE TODAY AND TUESDAY. WINDS
SHIFT TO THE SOUTHWEST TODAY THEN SHIFT TO THE WEST ON TUESDAY,
REMAINING AT 10 KT OR LESS DURING THIS TIMEFRAME. SEAS 6 TO 7
FEET THROUGH TODAY AS A WESTERLY SWELL CONTINUES TO MOVE IN THEN
GRADUALLY DECREASING TONIGHT INTO TUESDAY TO LESS THEN 5 FEET.
AN UPPER LEVEL LOW OFF THE COAST WILL SUPPORT SCATTERED LIGHT
SHOWERS TODAY WITH INCREASING CHANCES THROUGH TUESDAY. A
NORTHWEST SWELL WILL ALSO MOVE INTO THE WATERS, PUSHING SEAS
BACK TOWARD THE 6 TO 8 FOOT MARK TUESDAY NIGHT. A COLD FRONT IS
EXPECTED TO MOVE OVER THE WATERS ON WEDNESDAY, BRINGING
INCREASING SEAS AND GUSTY WINDS. WIND GUSTS WILL APPROACH 20 KT
ON WEDNESDAY WITH A 30-50% CHANCE FOR GUSTS REACHING SMALL
CRAFT CRITERIA BEYOND 30 NM AND ONLY 10-30% WITHIN 30 NM FOR ALL
WATERS. THERE IS A 50-80% CHANCE SEAS PEAK ABOVE 10 FEET BEYOND
10 NM AND A 20-30% CHANCE FOR SEAS ABOVE 12 FEET BEYOND 30 NM.
WINDS DECREASE BY WEDNESDAY NIGHT AND SEAS LAG, DECREASING
THROUGH THURSDAY.
VERY STRONG EBB CURRENTS WILL CONTINUE ACROSS THE
COLUMBIA RIVER BAR EACH MORNING THROUGH TUESDAY. SEAS ARE
EXPECTED TO INCREASE AS A WESTERLY SWELL MOVES INTO THE WATERS
THIS MORNING. WAVE HEIGHTS WITHIN THE COLUMBIA RIVER BAR ARE
EXPECTED TO INCREASE TO AROUND 9 FEET WITH THE VERY STRONG EBB
CURRENT. THEREFORE, A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR
THE COLUMBIA RIVER BAR FROM 5 AM - NOON PDT MONDAY. -19/23
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL NOON PDT TODAY FOR PZZ210.
WWW.WEATHER.GOV/PORTLAND
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