327
FXUS66 KPQR 161010
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
310 AM PDT FRI MAY 16 2025
SYNOPSIS
A PROGRESSIVE WEATHER PATTERN WILL BRING PERIODS OF
LIGHT RAIN THROUGH THE WEEKEND, AND POSSIBLY INTO EARLY NEXT
WEEK. EXPECT TEMPERATURES TO REMAIN SLIGHTLY BELOW AVERAGE
DURING THIS PERIOD. RAIN SHOWERS INCREASE LATE FRIDAY NIGHT
THROUGH SATURDAY, ALONG WITH A 10-20% CHANCE OF THUNDERSTORMS
SAT AFTERNOON. LINGERING SHOWERS INTO SUNDAY, THOUGH MOST AREAS
LIKELY DRIER. TEMPERATURES TRENDING WARMER TOWARD THE END OF
NEXT WEEK.
DISCUSSION...TONIGHT THROUGH THURSDAY
ZONAL FLOW ACROSS THE
PACNW WILL PERSIST THROUGH MUCH OF FRIDAY, SUPPORTING ONSHORE
FLOW AND LIGHT RAIN SHOWERS. SHOWER ACTIVITY WILL BE MAINLY
ACROSS SOUTHWEST WA AND THE NORTHWEST OREGON COAST RANGE WITH
TOTALS OF A FEW HUNDREDTHS. COOL TEMPS ARE EXPECTED AGAIN WITH
MID TO UPPER 60S INLAND AND UPPER 50S ALONG THE COAST. SLIGHTLY
WARMER TEMPS ARE EXPECTED ACROSS THE SOUTHERN PORTION OF THE
AREA DUE TO BREAKS IN CLOUD COVER AND LESS OF A CHANCE FOR
PRECIPITATION.
THE NEXT SYSTEM APPROACHES THE PACNW FROM THE NORTHWEST AS A
SHORTWAVE DIGS ALONG THE BRITISH COLUMBIA COAST TONIGHT INTO
SATURDAY. THIS WILL BRING ANOTHER ROUND OF WIDESPREAD SHOWERS
THROUGH SATURDAY NIGHT. ANOTHER, STRONGER SYSTEM WILL MOVE OVER
VANCOUVER ISLAND AND ACROSS WA DURING THE LATTER HALF OF SATURDAY,
SUPPORTING NORTHWEST FLOW IN THE UPPER LEVELS. THIS WILL ALSO BRING
A SLIGHT CHANCE (10-20%) OF THUNDERSTORMS TO THE AREA FOR SATURDAY
AFTERNOON/EVENING. PERSISTENT SHOWERS WILL LIKELY PRODUCE A BIT MORE
SUBSTANTIAL RAINFALL AMOUNTS, INCLUDING A 30-50% CHANCE OF EXCEEDING
0.25 INCH THROUGH SATURDAY NIGHT ACROSS MUCH OF THE FORECAST AREA.
SHOWERS WILL LIKELY PERSIST ALONG THE HIGHER TERRAIN, INCLUDING THE
CASCADE FOOTHILLS, WHERE AMOUNTS CLOSER TO 0.50-1.00 INCH OF TOTAL
(48-HR) RAINFALL THROUGH 5 PM SUNDAY.
CONDITIONS TREND DRIER ON SUNDAY, THOUGH LIGHT SHOWERS WILL PERSIST
INTO THE AFTERNOON. WEAK RIDGING WILL BUILD INTO THE REGION,
SUPPORTING PARTLY SUNNY SKIES THOUGH TEMPS WILL REMAIN 5-8 DEGREES
BELOW AVERAGE, TOPPING OUT IN THE LOW 60S INLAND. MODEL AGREEMENT IS
INCREASING FOR ANOTHER WEAK SYSTEM TO CROSS THE REGION ON MONDAY
WITH ANOTHER ROUND OF LIGHT RAIN SHOWERS EXPECTED. ZONAL FLOW WITH
ANOTHER EMBEDDED DISTURBANCE PASSING TO THE NORTH MAY MAINTAIN LIGHT
SHOWERS INTO TUESDAY. AGREEMENT DEGRADES MIDDLE TO END OF NEXT WEEK
WITH CLUSTER ANALYSIS SHOWING SPLIT PRETTY EQUALLY BETWEEN RIDGING
AND TROUGHING. -BATZ
AVIATION
MIXED VFR/MVFR CIGS LIKELY ACROSS MUCH OF THE REGION
AS A FRONT EXITS EASTWARD BEYOND THE CASCADES. RAIN SHOWERS WILL
CONTINUE TO DWINDLE THROUGH THE REMAINDER OF THE OVERNIGHT PERIOD,
ASIDE FROM THE NORTHERN OR/SOUTHERN WA COAST (INCLUDING AST) WHERE
MORE PERSISTENT LIGHT SHOWERS ARE EXPECTED. INLAND AND ACROSS THE
CENTRAL OR COAST, DRIER CONDITIONS ARE ANTICIPATED BUT CHANCES
FOR PERSISTENT MVFR CIGS ARE HIGHEST (40-60%) IN THE PORTLAND
AREA (PDX, HIO, TTD), AND DECREASE TO THE SOUTH WITH THE LOWEST
CHANCES (10-30%) NEAR EUG. CIGS WILL SUBSEQUENTLY LIFT BACK TO
WIDESPREAD VFR FROM SOUTH TO NORTH BY MIDDAY, 18-21Z FRI. AN
ADDITIONAL FRONTAL SYSTEM EXPECTED TO AFFECT THE REGION THIS
EVENING INTO TONIGHT WILL SEE SHOWERS AND MVFR CIGS RETURN ALONG
THE COAST BY 03-06Z SAT AND INLAND BY 06-09Z SAT. SOUTHERLY TO
SOUTHWESTERLY WINDS AT LESS THAN 10 KT WILL CONTINUE AT ALL
TERMINALS THROUGH MUCH OF THE PERIOD, TURNING OUT OF THE NORTH TO
NORTHWEST AT LESS THAN 5 KT INLAND BEHIND THE FRONTAL BOUNDARY.
PDX AND APPROACHES...LOW-VFR TO MVFR CIGS EXPECTED TO CONTINUE
INTO THE EARLY AFTERNOON, LIFTING BACK TO VFR BY 20-21Z FRI.
ISOLATED LIGHT RAIN SHOWERS BRIEFLY RESTRICTING VIS ARE POSSIBLE
THROUGH THE MORNING, BUT IMPACTS ARE UNLIKELY. ANOTHER FRONTAL
SYSTEM WILL BRING ADDITIONAL RAIN SHOWERS AND LIKELY MVFR CIGS
AFTER 06-09Z FRI. SOUTHERLY WINDS AROUND 5 KT CONTINUE INTO THE
EARLY AFTERNOON, BEFORE TURNING OUT OF THE NORTH TO NORTHWEST AT
AROUND 5 KT AFTER 21-24Z FRI. -PICARD
MARINE
SEAS OF 4-6 FT AT 10-12 SECONDS WILL BUILD THROUGH
SATURDAY AS NORTHWESTERLY SWELL RISES TO 6-8 FT AHEAD OF A
FRONTAL SYSTEM APPROACHING THE COAST. WINDS OF 10-15 KT WITH
GUSTS UP TO 20 KT OUT OF THE SOUTH TO SOUTHWEST THROUGH TODAY WILL
VEER OUT OF THE NORTHWEST TONIGHT BEHIND THE BOUNDARY AS RAIN
SHOWERS SPREAD ACROSS THE WATERS. STEADILY BUILDING NORTHWESTERLY
SWELL WILL SEE SEAS REACH 8-10 FT LATE SATURDAY INTO SUNDAY
MORNING, WHILE NORTHWEST WINDS OF 15-20 KT GUST AS HIGH AS 25 KT.
CHANCES FOR GUSTS REACHING GALE-FORCE SATURDAY INTO SUNDAY HAVE
DECREASED TO 10-20% BEYOND 30 NM AND 0-10% ELSEWHERE, HOWEVER
THERE REMAINS HIGH CONFIDENCE IN CONDITIONS MERITING AT LEAST
SMALL CRAFT ADVISORIES ACROSS THE WATERS THROUGH PARTS OF THE
WEEKEND. WINDS WILL TURN SOUTHERLY AGAIN AT 10-20 KT ON MONDAY
AHEAD OF THE NEXT APPROACHING SYSTEM, BEFORE VEERING OUT OF THE
WEST TO NORTHWEST MONDAY NIGHT THROUGH AT LEAST MIDWEEK. -PICARD
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
WWW.WEATHER.GOV/PORTLAND
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