533
FXUS66 KPQR 220406 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
906 PM PDT TUE APR 21 2026
UPDATED AVIATION DISCUSSION
SYNOPSIS
CONDITIONS REMAIN COOL AND WET THROUGH TOMORROW AS
AN UPPER LEVEL LOW AND SURFACE FRONTS MOVE OVER THE REGION. A
WARMING AND DRYING TREND IS EXPECTED THURSDAY AND THROUGH THE
START OF NEXT WEEK AS HIGH PRESSURE BUILDS OVER THE EASTERN
PACIFIC.
DISCUSSION...NOW THROUGH MONDAY NIGHT
CONDITIONS CONTINUE TO
TREND COOLER AND DRIER AS THE UPPER LEVEL LOW CONTINUES TO MOVE
INLAND. RAIN HAS BEEN A BIT MORE SCATTERED WITH WESTERLY FLOW AT
THE SURFACE AND SOUTHEASTERLY FLOW ALOFT. SEEING SHOWERS FORMING
ALONG THE WILLAMETTE VALLEY AND THE CASCADE FOOTHILLS THIS
EVENING, WHILE THE OVERALL FLOW IS SOUTHEASTERLY. THE
COMBINATION OF THESE TWO AIR MASSES IS ENCOURAGING HEAVIER AND
MORE PERSISTENT RAIN THAN HIGHER RESOLUTION MODELS WERE
LATCHING ONTO. THE MAIN LOW THAT BROUGHT THE RAIN TODAY WILL
CONTINUE TO SHIFT EAST, AND A SECOND SMALLER SYSTEM AND FRONTAL
BAND MOVES IN TONIGHT THROUGH WEDNESDAY. -27
THIS SECOND SYSTEM WILL BRING ABOUT A MORE WEST/NORTHWEST WIND
PATTERN AS WELL AS A SECOND ROUND OF RAIN AND CLOUDS TO THE
REGION THROUGH MID-DAY WEDNESDAY. CLOUD COVER AND RAIN WILL KEEP
OVERNIGHT TEMPERATURES IN THE UPPER 30S TO UPPER 40S, BUT
EXPECT SKIES TO SLOWLY CLEAR THROUGH THE EARLY AFTERNOON ON
WEDNESDAY. CLEARING SKIES WILL ENABLE DAYTIME TEMPERATURES TO
WARM INTO THE UPPER 30S TO MID 40S FOR THE CASCADES AND MID 40S
TO UPPER 50S ALONG THE COAST AND INLAND LOCATIONS. RAIN WILL BE
LIGHT, WITH PRECIPITATION TOTALS FROM THIS EVENING THROUGH MID-
DAY WEDNESDAY RANGING FROM 0.05 TO 0.50 INCHES FOR LOWER
ELEVATIONS. BETTER FORCING ALONG THE CASCADES WILL RESULT IN
PRECIPITATION TOTALS ABOVE 0.30 TO 1.40 INCHES FOR THE CASCADES
THROUGH THE SAME TIME PERIOD. THERE IS A 10% CHANCE OR LESS FOR
THUNDERSTORMS CONFINED TO THE SOUTHEASTERN PORTION OF LANE
COUNTY. IF ANY STORMS OR MORE CONVECTIVE PRECIPITATION DEVELOPS,
THIS COULD LEAD TO LOCALLY HIGHER RAINFALL TOTALS.
AS WE MOVE INTO THE LATTER PART OF THE WEEK, CONDITIONS TREND
DRY AND WARM, THOUGH LIGHT SHOWERS MAY LINGER OVER THE CASCADES
EARLY THURSDAY MORNING. HIGH PRESSURE LOOKS TO BUILD OVER THE
EASTERN PACIFIC, WHICH PLACES THE PACIFIC NW ON THE
EAST/NORTHEAST FLANK OF THE RIDGE. THIS WILL RESULT IN SKIES
CLEARING ALONG WITH DAYTIME HIGHS WARMING INTO THE UPPER 60S TO
LOW 70S ON FRIDAY WITH SIMILAR DAYTIME HIGHS EXPECTED THROUGH
AT LEAST THE START OF NEXT WEEK. OVERNIGHT LOWS IN THE 40S
EXPECTED DURING THIS TIME FRAME. GIVEN THAT THE REGION LOOKS TO
BE ON THE EASTERN FLANK OF THE PACIFIC RIDGE, WE WILL BE
SQUISHED BETWEEN THIS RIDGE AND A BROAD AREA OF LOW PRESSURE
THAT WILL BE ANCHORED OVER THE FAR NORTHERN PLANES AND SOUTHERN
SASKATCHEWAN. THIS IS LEADING TO SOME UNCERTAINTY AS WE MOVE
INTO THE WEEKEND. AS THE SASKATCHEWAN LOW MEANDERS INTO PLACE,
IT WILL SEND A SERIES OF SHORTWAVE TROUGHS THAT WILL RIDE THE
EASTERN FLANK OF THE RIDGE. GIVEN THAT THE SHORTWAVES,
ORIGINATE FROM A CONTINENTAL SYSTEM, THEY WILL LACK MOISTURE.
THIS IS GENERALLY SUPPORTED IN THE NBM, GFS AND ECMWF AS WELL AS
THE MAJORITY THEIR ENSEMBLES.-42
AVIATION
RADAR CONTINUES TO SHOW LIGHT RAIN THROUGHOUT THE
REGION WHICH IS BRINGING A MIXTURE OF CONDITIONS TO THE AREA.
SEEING WIDESPREAD VFR CIGS WITH NORTHWESTERLY FLOW AT THE
SURFACE. IN AREAS OF PASSING SHOWERS, VISIBILITY HAS BEEN
REDUCED TO MVFR, THOUGH THAT IS NOT THE WIDESPREAD TREND AND IS
FAIRLY ISOLATED. RAIN IS EXPECTED EASE UNTIL AROUND 12Z WED WHEN
RAIN PROBABILITIES INCREASE ONCE MORE WITH A WEAK MESOSCALE LOW
AND FRONTAL SYSTEM. AT THAT TIME, WILL SEE VARIABLE FLIGHT
CONDITIONS. WE WILL MORE PERSISTENT MVFR CIG/VIS WITH GUSTY WEST
WINDS ALONG THE COAST. IF THERE ARE AREAS WITH HEAVIER RAIN AND
WIND, IFR VIS IS NOT OUT OF THE QUESTION.
WITH THE SECONDARY FRONTAL SYSTEM, WIND IS GOING TO BE THE MAIN
THREAT IN THE AFTERNOON AFTER 12Z WED. WHILE RAIN AND HEAVIER
CLOUD COVER MOVES IN, THE EAST/WEST PRESSURE GRADIENT INCREASES IN
A WAY THAT WILL BRING AMPLIFIED WESTERLY WIND GUSTS. HIGHEST WIND
SPEEDS WILL BE WITHIN THE COLUMBIA RIVER GORGE, ESPECIALLY AROUND
K4S2 AND OTHER VALLEY ALIGNED TERMINALS. AS YOU MOVE UP IN
ELEVATION AROUND 2000 FT, WINDS WILL BE GUSTING UP TO 35 KT WITH A
30% CHANCE OF WIND GUSTS GREATER THAN 40 KT. WINDS ALL APPEAR TO
BE UNIDIRECTIONAL AND THEREFORE LLWS IS NOT A THREAT AT THIS TIME.
KPDX AND APPROACHES...MVFR CEILINGS CONTINUE AT THE KPDX TERMINAL
WITH LIGHT RAIN SHOWERS AND LIGHT WINDS. CONDITIONS HAVE BEGUN TO
BOUNCE BETWEEN MVFR AND VFR WITH A STRONGER TREND TOWARDS MVFR
CIGS THIS EVENING. WILL SEE A SLOW CLEARING TREND AS RAIN EASES
THROUGH 12Z WED BUT A FRONTAL SYSTEM MOVES IN AT THAT TIME. THIS
WILL ALSO BRING THE RETURN OF MVFR CEILINGS ALONG WITH BREEZY
SOUTHWESTERLY WINDS WITH GUSTS UP TO AROUND 20 KT. -27
MARINE
WINDS AND SEAS WILL INCREASE OVER THE COASTAL WATERS
TONIGHT INTO WEDNESDAY AHEAD OF AN APPROACHING COLD FRONT. BY
EARLY TO MID WEDNESDAY MORNING, A NORTHWEST SWELL WILL PUSH SEAS
UP TO 7 TO 8 FT WITH WESTERLY WINDS AROUND 15 TO 20 KT WITH GUSTS
UP TO 25 KT OVER THE CENTRAL AND NORTHERN WATERS. THE SOUTHERN
WATERS WILL SEE WINDS AND SEAS INCREASE A BIT LATER IN TIME,
BEGINNING WEDNESDAY AFTERNOON. SEAS PEAK BETWEEN 9-13 FT WEDNESDAY
EVENING INTO WEDNESDAY NIGHT AT 10 TO 12 SECONDS, BRINGING STEEP
AND HAZARDOUS SEAS. THE HIGHEST SEAS ARE EXPECTED OVER THE
NORTHERN OUTER WATERS BEYOND 20-30 NM. WINDS DECREASE WEDNESDAY NIGHT
BEHIND THE FRONTAL PASSAGE, HOWEVER SEAS WILL REMAIN ELEVATED
UNTIL SIGNIFICANT WAVE HEIGHTS FALL BELOW 10 FT BY LATE THURSDAY
AFTERNOON.
THEREFORE, A HAZARDOUS SEAS WARNING HAS BEEN ISSUED
FOR PZZ271 FROM 2 PM PDT WEDNESDAY THROUGH 5 AM PDT THURSDAY,
FOLLOWING A SMALL CRAFT ADVISORY THAT BEGINS AT 5 AM PDT
WEDNESDAY. THE REMAINING MARINE ZONES HAVE SMALL CRAFT ADVISORIES
IN EFFECT FROM 5 AM WEDNESDAY UNTIL 5 PM PDT THURSDAY, EXCEPT 5 PM
WEDNESDAY UNTIL 5 PM PDT THURSDAY FOR THE SOUTHERN WATERS AS
WINDS AND SEAS TAKE LONGER TO INCREASE SOUTH OF CAPE FOULWEATHER.
NOTE THERE IS A 10-25% CHANCE SEAS WILL PEAK NEAR 14-15 FT OVER
THE NORTHERN OUTER WATERS, WHICH REPRESENTS A REASONABLE WORST
CASE SCENARIO.
A STRONG EBB CURRENT WILL OCCUR OVER THE COLUMBIA RIVER BAR
WEDNESDAY MORNING, PUSHING SEAS UP TO 7 TO 8 FT WITH STEEP EBB
CHOP OVER THE MAIN CHANNEL. SEAS THEN INCREASE TO AROUND 9 TO 10
FT OVER THE MAIN CHANNEL LATE WEDNESDAY AND REMAIN ELEVATED
WEDNESDAY NIGHT INTO THURSDAY. IN ADDITION, WESTERLY WINDS WILL
INCREASE TO 15 TO 25 KT WITH GUSTS UP TO 25 KT. WINDS WILL BECOME
SOUTHWEST AROUND 10 KT WITH GUSTS UP TO 15 KT THURSDAY MORNING. A
SMALL CRAFT ADVISORY HAS BEEN ISSUED FROM 5 AM WEDNESDAY PDT TO 5
PM PDT THURSDAY FOR THE COLUMBIA RIVER BAR TO COVER THESE HAZARDS.
-23
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 5 AM WEDNESDAY TO 5 PM PDT THURSDAY
FOR PZZ210-251-252-272.
SMALL CRAFT ADVISORY FROM 5 PM WEDNESDAY TO 5 PM PDT THURSDAY
FOR PZZ253-273.
SMALL CRAFT ADVISORY FROM 5 AM TO 2 PM PDT WEDNESDAY FOR
PZZ271.
HAZARDOUS SEAS WARNING FROM 2 PM WEDNESDAY TO 5 AM PDT
THURSDAY FOR PZZ271.
WWW.WEATHER.GOV/PORTLAND
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