181
FXUS66 KPQR 170410 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
909 PM PDT FRI MAY 16 2025
..UPDATED AVIATION DISCUSSION
SYNOPSIS
A PROGRESSIVE WEATHER PATTERN WILL BRING PERIODS OF
LIGHT RAIN THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. EXPECT
TEMPERATURES TO REMAIN SLIGHTLY BELOW AVERAGE DURING THIS PERIOD.
RAIN SHOWERS INCREASE LATER TONIGHT THROUGH SATURDAY, ALONG WITH A
10-20% CHANCE OF THUNDERSTORMS SAT AFTERNOON. LINGERING SHOWERS INTO
SUNDAY, THOUGH MOST AREAS LIKELY DRIER. TEMPERATURES TRENDING
WARMER, UPPER 60S TO LOWER 70S, TOWARD THE END OF NEXT WEEK.
DISCUSSION...TONIGHT THROUGH FRIDAY
MOSTLY CLOUDY SKIES WITH
LIGHT RAIN SHOWERS, MAINLY ALONG THE NORTH COAST, WILL CONTINUE
THROUGH THIS EVENING. TEMPERATURES THIS AFTERNOON ARE WARMING INTO
THE MID-60S INLAND, STILL AROUND 5 DEGREES BELOW NORMAL FOR MID-MAY.
LATER TONIGHT, EXPECT SHOWERS TO INCREASE IN INTENSITY AND BECOME
MORE WIDESPREAD AS THE NEXT WEATHER SYSTEM APPROACHES. A SHORTWAVE
TROUGH RIDING ALONG THE NORTHERN PACIFIC JET SLIDES ACROSS THE
REGION, DIGGING TOWARD NORTHERN CALIFORNIA BY EARLY SATURDAY
MORNING. RAIN SHOWERS WILL LIKELY BE HEAVIEST THROUGH THE EARLY
MORNING HOURS AS THE ATMOSPHERIC MOISTURE IS AT ITS DEEPEST AND THE
UPPER TROUGH IS OVERHEAD. CHANCES FOR SHOWERS WILL CONTINUE THROUGH
THE REST OF THE DAY, WITH A SMALL (10-20%) CHANCE FOR A RUMBLE OF
THUNDER THROUGH SATURDAY AFTERNOON/EVENING. NO STRONG THUNDERSTORMS
EXPECTED. WITH CONTINUED ONSHORE WEST TO NORTHWESTERLY FLOW ALOFT,
RAIN WILL BE MOST PERSISTENT ALONG THE HIGHER TERRAIN, ESPECIALLY
THE WESTERN SLOPES OF THE CASCADES AND CASCADE FOOTHILLS. TOTAL
RAINFALL AMOUNTS FROM NOW THROUGH SATURDAY NIGHT ARE EXPECTED TO
RANGE FROM AROUND 0.10 TO 0.40 INCH FOR MUCH OF THE LOWLANDS, AND A
BIT MORE SUBSTANTIAL FOR THE HIGHER TERRAIN, AROUND 0.5 TO 1.0 INCH,
WITH A 20-30% CHANCE OF EXCEEDING AN INCH OF RAINFALL OVER 48-HOURS
FOR A FEW LOCATIONS IN THE CASCADES.
CONDITIONS TREND DRIER ON SUNDAY, THOUGH LIGHT SHOWERS PERSIST INTO
THE AFTERNOON AS TROUGHING ALONG THE BRITISH COLUMBIA COAST DROPS
SOUTH, DEVELOPING INTO A CUTOFF LOW EAST OF THE CASCADES BY SUNDAY
EVENING. TRANSIENT UPPER LEVEL RIDGING BUILDS OVER THE REGION SUNDAY
NIGHT WITH DECREASING CLOUDS, AND SOME SUNSHINE BY LATER SUNDAY
AFTERNOON INTO THE EVENING. TEMPERATURES REMAIN SLIGHTLY BELOW
AVERAGE INTO EARLY NEXT WEEK. ANOTHER ROUND OF LIGHT RAIN IS NOW
LIKELY ON MONDAY AS A WEAK FRONT CROSSES THE REGION. ZONAL FLOW WITH
EMBEDDED UPPER LEVEL DISTURBANCES COULD MAINTAIN LIGHT SHOWERS INTO
TUESDAY, AGAIN MAINLY OVER NORTHERN PORTIONS OF THE FORECAST AREA.
AGREEMENT AMONGST THE MODELS AND THEIR ENSEMBLES DEGRADES MIDDLE TO
END OF NEXT WEEK WITH CLUSTER ANALYSIS SHOWING SPLIT PRETTY EQUALLY
BETWEEN RIDGING AND TROUGHING. NBM GUIDANCE THOUGH CONTINUES TO
SUGGEST TEMPERATURES GRADUALLY WARM CLOSER TO AVERAGE TOWARD THE
LATTER PART OF NEXT WEEK, ALONG WITH PRECIPITATION PROBABILITIES
GENERALLY 15% OR LESS WEDNESDAY THROUGH FRIDAY. /DH
AVIATION
WEST TO SOUTHWEST WINDS ALOFT AS A WEATHER SYSTEM
APPROACHES AND MOVES THROUGH THE REGION, BECOMING WEST TO NORTHWEST
BY 12Z SATURDAY. VFR CONDITIONS CONTINUE INLAND THROUGH 08-10Z
SATURDAY. THE NEXT FRONT WILL PUSH THROUGH TONIGHT, LEADING TO
IFR/MVFR CIGS AND VIS ALONG THE COAST, AND MVFR CIGS INLAND. CIGS
GENERALLY IMPROVE TO VFR INLAND AFTER 21Z FRI, WHILE THE COAST
MAINTAINS MVFR CIGS. SOUTHERLY TO SOUTHWESTERLY WINDS LESS THAN 10
KT WILL CONTINUE AT ALL TERMINALS THROUGH SATURDAY MORNING, TURNING
MORE NORTHWESTERLY AFTER 21Z FRI WITH GUSTS UP TO 20 KT AT ANY GIVEN
TERMINAL.
NOTE THAT THERE IS A 15-20% CHANCE FOR THUNDERSTORMS ACROSS THE
WILLAMETTE VALLEY BETWEEN 18Z SAT TO 00Z SUN. ANY PASSING
THUNDERSTORMS MAY BRING LIGHTNING, SMALL HAIL, AND HEAVY RAIN WHICH
MAY REDUCE VISIBILITY AT TIMES TO IFR/MVFR THRESHOLDS.
PDX AND APPROACHES...VFR CIGS AROUND FL3500-5000 THROUGH 08-10Z SAT.
THE NEXT FRONT WILL RETURN SHOWERS AND MVFR CIGS AFTER 10Z SAT. CIGS
IMPROVE TO VFR AFTER 19-21Z SAT. WESTERLY TO SOUTHWESTERLY WINDS
GENERALLY UNDER 10 KT THROUGH EARLY SATURDAY AFTERNOON. WINDS
INCREASE AND SHIFT MORE NORTHWESTERLY AFTER 19-21Z SAT, WITH GUSTS
UP TO 20 KT. -ALVIZ/HEC
MARINE
SOUTHWESTERLY WINDS OVER THE WATERS FRIDAY AFTERNOON
WILL SHIFT NORTHWESTERLY TONIGHT INTO SATURDAY AS A FRONT PASSES
THROUGH THE REGION. WINDS THROUGH EARLY SATURDAY MORNING AROUND 8-15
KTS WITH GUSTS MAINLY BELOW 20 KTS. HOWEVER, A LOCALIZED AREA OF
WIND GUSTS UP TO 25 KTS EXISTS IN PORTIONS OF ZONES PZZ271 & PZZ251
THROUGH AROUND 5 PM PDT. WINDS INCREASE SATURDAY LATE MORNING BEHIND
THE FRONTAL PASSAGE TO 17-22 KTS WITH GUSTS UP TO 25-30 KTS THROUGH
SUNDAY MORNING. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR 11 AM
SATURDAY THROUGH 11 AM SUNDAY. SEAS REMAIN AROUND 5-9 FT AT 10-12
SECONDS THROUGH THE WEEKEND.
ANOTHER FRONTAL PASSAGE IS FORECAST ON MONDAY. WINDS SHIFT SOUTHERLY
WITH ANOTHER ROUND OF SMALL CRAFT WIND GUSTS 25-30 KTS EXPECTED (70-
90% CHANCE). SEAS DECREASE TO 5-7 FT AT 10 SECONDS MONDAY BEFORE AN
INCREASING WESTERLY SWELL BUILDS WAVES TO AROUND 9-10 FT AT 12-13
SECONDS ON TUESDAY. -HEC
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 11 AM SATURDAY TO 11 AM PDT SUNDAY
FOR PZZ210-251>253-271>273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
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X.COM/NWSPORTLAND
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