446
FXUS66 KPQR 200923
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
223 AM PDT SAT JUN 20 2026
SYNOPSIS
ONSHORE FLOW WILL SUPPORT MORNING CLOUDS AND COOLER
TEMPERATURES TODAY. TEMPERATURES RE-BOUND SUNDAY AS HIGH
PRESSURE RE-BUILDS OFFSHORE. THE HOTTEST DAYS OF THE WEEK ARE
EXPECTED MONDAY AND TUESDAY, WITH WIDESPREAD MODERATE HEATRISK
AND LOCALIZED MAJOR HEATRISK FOR THE PORTLAND-VANCOUVER METRO
AREA. WARM LOW TEMPERATURES FOR INTERIOR VALLEYS WILL PROVIDE
LIMITED OVERNIGHT RELIEF, ESPECIALLY IN URBAN AREAS. THERE IS
SOME UNCERTAINTY ON WEDNESDAY WITH HOW QUICKLY THE HEAT
DIMINISHES, BUT CONFIDENCE IS INCREASING FOR COOLER TEMPERATURES
AND PRECIPITATION CHANCES BY THURSDAY-FRIDAY.
DISCUSSION...TODAY THROUGH FRIDAY
THE PACIFIC NORTHWEST
CURRENTLY REMAINS WITHIN THE SOUTHERN PERIPHERY OF AN UPPER-
LEVEL TROUGH DROPPING DOWN INTO SOUTHERN BRITISH COLUMBIA AND
ALBERTA. WHILE THIS SYSTEM REMAINS TOO FAR NORTH TO BRING US ANY
PRECIPITATION, WE'RE STILL GETTING INCREASING ONSHORE FLOW AND
MOISTURE. AS A RESULT, SATELLITE IMAGERY AND SURFACE
OBSERVATIONS AS OF EARLY SATURDAY MORNING DEPICT WIDESPREAD
MARINE STRATUS ALONG THE COAST WITH SOME STRATUS BEGINNING TO
DEVELOP ACROSS THE SOUTHERN WILLAMETTE VALLEY AND ADJACENT
CASCADE FOOTHILLS. AS THE LOW LEVEL ATMOSPHERE MOISTENS UP THIS
MORNING, STRATUS WILL GRADUALLY SPREAD ACROSS PARTS OF THE
WILLAMETTE VALLEY. MORNING CLOUD COVER AND ONSHORE FLOW WILL
SUPPORT COOLER TEMPERATURES TODAY WITH AFTERNOON HIGHS PEAKING
IN THE UPPER 70S TO NEAR 80 ACROSS INTERIOR VALLEYS AND 60S
ALONG THE COAST. WHILE STRATUS MAY LINGER ALONG THE COAST TODAY,
INLAND STRATUS SHOULD BREAK OUT BY LATE MORNING OR EARLY
AFTERNOON AS DAYTIME HEATING PROGRESSES.
IT'S WORTH NOTING THAT THE PASSING TROUGH TO THE NORTH WILL
TIGHTEN THE WEST TO EAST SURFACE PRESSURE GRADIENT ACROSS THE
CASCADES ON SATURDAY LEADING TO BREEZY CONDITIONS THROUGH
CENTRAL COLUMBIA RIVER GORGE AND UPPER HOOD RIVER VALLEY, WHERE
WESTERLY WINDS MAY GUST UP TO 30-40 MPH WITH A 25-35% CHANCE
FOR ISOLATED AND BRIEF WIND GUSTS EXCEEDING 45 MPH. THESE WINDS
NOTICEABLE DECREASE SATURDAY NIGHT.
THE SECOND HALF OF THE WEEKEND TEMPERATURES BEGIN TO REBOUND
INTO THE MID TO UPPER 80S ACROSS INTERIOR VALLEYS SUNDAY
AFTERNOON AS ENSEMBLE GUIDANCE SHOWS THE UPPER-TROUGH QUICKLY
SHIFTING EASTWARD AND UPPER-LEVEL RIDGING REBUILDING OFFSHORE
OVER THE NORTHEAST PACIFIC. THE HOTTEST DAYS OVER THE NEXT WEEK
ARE STILL EXPECTED MONDAY AND TUESDAY DURING WHICH THE VAST
MAJORITY OF ENSEMBLE MEMBERS SHOW THE RIDGE SLIDING RIGHT OVER-
TOP THE PACIFIC NORTHWEST. THERE IS HIGH CONFIDENCE (>90%
CHANCE) FOR HIGH TEMPERATURES EXCEEDING 90 DEGREES F ACROSS THE
WILLAMETTE VALLEY AND SOUTHWEST WASHINGTON LOWLANDS ON MONDAY
AND TUESDAY WITH A 20-40% CHANCE FOR TEMPERATURES EXCEEDING 100
DEGREES F FROM SALEM TO PORTLAND-VANCOUVER ON MONDAY, INCREASING
TO 40-60% ON TUESDAY. OVERNIGHT LOWS WILL ALSO BE WARM,
ESPECIALLY ACROSS THE CENTRAL WILLAMETTE VALLEY, COLUMBIA RIVER
GORGE, AND PORTLAND-VANCOUVER METRO AREA WHERE THERE IS A 30-50%
CHANCE FOR TUESDAY MORNING LOWS TO REMAIN ABOVE 65 DEGREES
(HIGHEST CHANCES ACROSS PORTLAND-VANCOUVER METRO DUE TO URBAN
HEAT ISLANDS EFFECTS). CHANCES FOR LOWS REMAINING ABOVE 65
DEGREES FALL TO 20-35% WEDNESDAY MORNING AS ONSHORE FLOW
INCREASES. OVERNIGHT LOWS NEAR OR ABOVE 65 DEGREES WOULD
PROVIDE LIMITED OVERNIGHT RELIEF FROM THE HEAT. AS A RESULT,
THERE WILL BE WIDESPREAD MODERATE HEATRISK ACROSS MUCH OF
NORTHWEST OREGON AND SOUTHWEST WASHINGTON DURING THIS PERIOD,
WITH LOCALIZED MAJOR HEATRISK ACROSS THE PORTLAND-VANCVOUER
METRO AREA THROUGH THE COLUMBIA RIVER GORGE FROM THE WARM
OVERNIGHT TEMPERATURES. THE EXTREME HEAT WATCH FOR THESE TWO
AREAS REMAIN IN EFFECT BEGINNING MONDAY MORNING AND CONTINUING
THROUGH TUESDAY EVENING. MAKE SURE TO PRACTICE HEAT SAFETY,
INCLUDING STAYING HYDRATED, WEARING LIGHT-COLORED AND LOOSE-
FITTED CLOTHING, WEARING SUN PROTECTION, AND TAKING FREQUENT
BREAKS FROM THE HEAT. IF POSSIBLE, SCHEDULE OUTDOOR PLANS DURING
THE EARLY MORNING OR LATE EVENING WHEN TEMPERATURES WILL BE
LESS INTENSE.
THERE STILL REMAINS FORECAST UNCERTAINTY WITH EXACT PROGRESSION
OF THE UPPER-LEVEL RIDGE ON WEDNESDAY, HOWEVER RECENT GUIDANCE
HAS TRENDED TEMPERATURES SLIGHTLY WARMER. MOST OF THE GLOBAL
ENSEMBLE MEMBERS (65%) SHOW THE RIDGE AXIS REMAINING OVER THE
PACIFIC NORTHWEST AND KEEPING TEMPERATURES INTO THE 90S ACROSS
INTERIOR VALLEYS. MEANWHILE, THE REMAINING 35% OF ENSEMBLE
MEMBERS HAVE THE RIDGE AXIS PUSHES FURTHER EAST INTO THE
INTERIOR NORTHWEST/GREAT BASIN, WHICH WOULD USHER IN A RETURN OF
WEAK ONSHORE FLOW AND "COOLER" TEMPERATURES (80S TO NEAR 90).
STILL, WITHIN THE LATEST NBM THERE IS CURRENTLY A 15-20 DEGREE
SPREAD BETWEEN THE NBM 10TH AND 90TH PERCENTILES ON WEDNESDAY
FOR THE WILLAMETTE VALLEY AND PORTLAND METRO, WITH THE COOLEST
SCENARIO BEING IN THE MID 80S WHILE THE WARMEST SCENARIO PUSHES
HIGHS NEAR 100 DEGREES F. SHOULD THE WARMING TREND ON WEDNESDAY
CONTINUE, HEAT RELATED IMPACTS MAY EXTEND YET ANOTHER DAY. AT
LEAST THERE IS MORE AGREEMENT AMONG GUIDANCE FOR THE RIDGE AXIS
TO NUDGING EASTWARD THURSDAY, ALLOWING TEMPERATURES TO DECREASE
BY STILL ABOVE NORMAL FOR JUNE. BY FRIDAY, NEARLY 70% OF
ENSEMBLE MEMBERS SUGGESTS TROUGHING APPROACHING THE PACIFIC
NORTHWEST, RETURNING CHANCES FOR LIGHT PRECIPITATION AND MUCH
COOLER TEMPERATURES. UNCERTAINTY REMAINS WITH EXACTLY HOW MUCH
PRECIPITATION WE COULD SEE BY THE END OF NEXT WEEK. -10/99
AVIATION
SATELLITE IMAGERY AS OF EARLY SATURDAY MORNING
DEPICTS WIDESPREAD MVFR STRATUS ALONG THE COAST AND SOUTHERN
WILLAMETTE VALLEY (KEUG). ONSHORE FLOW WILL CONTINUE TO SUPPORT
MVFR STRATUS BACKBUILDING AGAINST THE CASCADE FOOTHILLS AND
SPREADING ACROSS THE WILLAMETTE VALLEY THIS MORNING BETWEEN
12-18Z SAT AS THE LOW LEVEL ATMOSPHERE MOISTENS UP. GUIDANCE
SUGGESTS THAT MVFR CIGS LINGER AT ALONG THE NORTH OREGON COAST
(KAST) THROUGHOUT THE TAF PERIOD, WHILE THE CENTRAL OREGON COAST
(KONP) MAY GET BRIEF IMPROVEMENT TO VFR CONDITIONS BETWEEN 20Z
SAT-00Z SUN. WILLAMETTE VALLEY TERMINALS SHOULD IMPROVE TO VFR
AFTER 18Z SAT AS DAYTIME HEATING PROGRESSES AND INCREASES
MIXING. AFTER 00Z SUN, ANOTHER SURGE OF MARINE STRATUS WILL
FILTER INTO THE COAST BRINGING A RETURN OF WIDESPREAD IFR/MVFR
CIGS.
KPDX AND APPROACHES...GUIDANCE SUGGESTS A 35-55% CHANCE FOR MVFR
CIGS AT ANY GIVEN HOUR BETWEEN 12-17Z SAT. AFTER 17-18Z SAT,
CONDITIONS IMPROVE TO VFR WITH HIGH CLOUDS. WEST-NORTHWESTERLY
WINDS UNDER 10 KT. -10
MARINE
HIGH PRESSURE OFFSHORE CONTINUES TO MAINTAIN NORTHERLY
TO NORTHWESTERLY WINDS OVER THE NEXT SEVEN DAYS. A SMALL CRAFT
ADVISORY REMAINS IN EFFECT ACROSS THE OUTER WATERS (BEYOND 10 NM
OFFSHORE) THROUGH 11 PM SATURDAY. NORTHWESTERLY WINDS WILL
GRADUALLY WEAKEN BELOW 20 KT THIS MORNING AS PRESSURE GRADIENTS
EASE. STEEP AND CHOPPY SEAS WILL CONTINUE UNTIL LATE SATURDAY,
AROUND 8 TO 11 FT AT 9 TO 10 SECONDS. SEAS SUBSIDE TO 5 TO 7 FT
SATURDAY INTO SUNDAY. SEAS REMAIN AROUND 6 TO 8 FT OR LESS INTO
EARLY NEXT WEEK, WITH ONLY A 5% CHANCE FOR SEAS EXCEEDING 8 FT
AT ANY GIVEN HOUR MON-WED. -10/12
PQR WATCHES/WARNINGS/ADVISORIES
OR...EXTREME HEAT WATCH FROM MONDAY MORNING THROUGH TUESDAY EVENING
FOR ORZ109-111-112-120-122.
WA...EXTREME HEAT WATCH FROM MONDAY MORNING THROUGH TUESDAY EVENING
FOR WAZ206-207-209-210.
PZ...SMALL CRAFT ADVISORY UNTIL 11 PM PDT SATURDAY FOR PZZ271>273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page