708
FXUS66 KPQR 211018
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
318 AM PDT SUN JUN 21 2026
SYNOPSIS
TEMPERATURES RE-BOUND TODAY AS HIGH PRESSURE RE-
BUILDS OFFSHORE. THE HOTTEST DAYS OF THE WEEK ARE EXPECTED
ON MONDAY AND TUESDAY WITH WIDESPREAD MODERATE HEATRISK AND A
30-50% CHANCE FOR MAJOR HEATRISK ACROSS THE PORTLAND-VANCOUVER
METRO AREA AND COLUMBIA RIVER GORGE. A HEAT ADVISORY IS IN
EFFECT DURING THESE DAYS. FAIRLY WARM OVERNIGHT FOR INTERIOR
VALLEYS WILL PROVIDE LIMITED OVERNIGHT RELIEF, ESPECIALLY IN
URBAN AREAS. TEMPERATURES COOL DOWN SLIGHTLY WEDNESDAY WITH
INCREASING CONFIDENCE FOR A COOLER AND WETTER PATTERN BY THE END
OF THE WEEK.
DISCUSSION...TODAY THROUGH SATURDAY
SATELLITE IMAGERY AS OF
EARLY SUNDAY MORNING DEPICTS WIDESPREAD MARINE STRATUS ALONG
THE COAST WITH SOME ISOLATED AREAS OF STRATUS ACROSS INTERIOR
VALLEYS. AS DAYTIME HEATING PROGRESSES TODAY, WE'LL SEE
INCREASED MIXING AND STRATUS BREAKING OUT BY LATE MORNING.
TEMPERATURES BEGIN TO REBOUND TODAY THANKS TO AN UPPER-LEVEL
RIDGE OF HIGH PRESSURE AMPLIFYING OVER THE EASTERN PACIFIC WITH
BUILDING 500 MB HEIGHTS OVERHEAD. STILL, WE'LL MAINTAIN SOME
DEGREE OF ONSHORE FLOW WHICH KEEPS TEMPERATURES ACROSS WESTERN
OREGON AND SOUTHWEST WASHINGTON MORE MODERATED THAN THEY
OTHERWISE WOULD BE. EXPECT HIGHS IN THE LOW TO MID 80S ACROSS
INTERIOR VALLEYS THIS AFTERNOON. 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 (70-95%
CHANCE) FOR HIGH TEMPERATURES EXCEEDING 90 DEGREES F ACROSS THE
WILLAMETTE VALLEY AND SOUTHWEST WASHINGTON LOWLANDS ON MONDAY
AND TUESDAY WITH A 5-15% CHANCE FOR TEMPERATURES EXCEEDING 100
DEGREES F FROM SALEM TO PORTLAND-VANCOUVER ON MONDAY, INCREASING
TO 30-50% ON TUESDAY. OVERNIGHT LOWS WILL ALSO BE WARM (NEAR 60
TO MID 60S), ESPECIALLY FOR URBAN CENTERS AWAY FROM THE COAST.
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 A 30-50% CHANCE
FOR MAJOR HEATRISK ACROSS THE PORTLAND-VANCVOUER METRO AREA AND
COLUMBIA RIVER GORGE DUE TO THE WARM OVERNIGHT TEMPERATURES. A
HEAT ADVISORY REMAINS IN EFFECT FROM 11 AM MONDAY TO 11 PM
TUESDAY FOR MUCH OF THE SOUTHWESTERN WASHINGTON LOWLANDS THROUGH
INTERIOR VALLEYS OF WESTERN OREGON. 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.
ALL THAT SAID, THERE ARE A COUPLE FORECASTING CAVEATS WORTH
HIGHLIGHTING THAT MAY KEEP TEMPERATURES FOR SPOTS LIKE THE
PORTLAND METRO CLOSER TO THE LOW TO MID 90S MONDAY AND TUESDAY
COMPARED TO NBM 5.0 (AND THE CURRENT FORECAST) WHICH PROJECTS
HIGHS IN THE MID TO UPPER 90S TO NEAR 100 FOR TUESDAY. FIRST IS
A SLIGHT HIGH BIAS OCCASIONALLY OBSERVED IN MID TO LONG TERM
TEMPERATURE PROJECTIONS WITH THE LATEST 5.0 VERSION OF THE NBM
AND A FEATURE WE CONTINUE TO ASSESS HERE LOCALLY SINCE THIS IS
ONLY OUR SECOND HEATWAVE OF THE YEAR LEANING ON NBM 5.0. WE'RE
ALSO MONITORING THE PLACEMENT AND STRENGTH OF A THERMAL TROUGH
DURING THIS MON/TUE PERIOD. CURRENT DETERMINISTIC GUIDANCE IS
TRENDING THE THERMAL TROUGH FURTHER EAST NOW, ANYWHERE BETWEEN
THE I-5 CORRIDOR AND THE CASCADE CREST. THIS SHOULD HELP BRING
NORTHERLY-NORTHWESTERLY FLOW INTO INTERIOR VALLEYS AND KEEP
TEMPERATURES A FEW DEGREES COOLER. IF THE THERMAL TROUGH WERE TO
LIE ALONG THE COAST (WHICH IT DOESN'T APPEAR TO BE FOR THIS
HEAT EVENT), WE WOULD SEE INCREASED EASTERLY WINDS ACROSS THE
REGION WHICH WOULD MAKE CONDITIONS MUCH WARMER. GIVEN THE MORE
EASTWARD PLACEMENT OF THE TROUGH NOW, THE LACK OF STRONG
OFFSHORE FLOW IS SUPPORTING A TEMPERATURE FORECAST SLIGHTLY
COOLER ON MONDAY, WITH HIGHS PEAKING IN THE LOW TO MID 90S
ACROSS INTERIOR VALLEYS. AS WE GET CLOSER TO THE START OF THIS
HEAT EVENT, WE'LL SEE IF TUESDAY ENDS UP TAKING A DOWNWARD TREND
AS WELL. EITHER WAY, IT'S GOING TO BE ABNORMALLY HOT AND PEOPLE
SHOULD MAKE SURE TO PRACTICE HEAT SAFETY.
THE RIDGE OF HIGH PRESSURE OVERHEAD BEGINS TO GRADUALLY DRIFT TO
OUR EAST ON WEDNESDAY ALTHOUGH THERE STILL REMAINS FORECAST
UNCERTAINTY AS TO JUST HOW QUICKLY IT'LL PROGRESS. THE VAST
MAJORITY OF ENSEMBLE MEMBERS KICK THE RIDGE AXIS WELL EAST OF
THE CASCADE CREST-LINE BY WEDNESDAY WHICH WOULD ALLOW FOR
TEMPERATURES TO DECREASE INTO THE UPPER 80S TO LOW 90S ACROSS
THE INTERIOR LOWLANDS, IF NOT FURTHER. THE LATEST NBM STILL
GIVES A 20-40% CHANCE FOR HIGHS EXCEEDING 95 DEGREES WEDNESDAY
AFTERNOON FROM SALEM TO THE PORTLAND-VANCOUVER METRO. THURSDAY
THROUGH THE START OF THE WEEKEND, THE MAJORITY OF ENSEMBLE
MEMBERS ARE NOW SHOWING A TROUGH OF LOW PRESSURE MOVING INTO THE
PACIFIC NORTHWEST, RETURNING COOLER AND WETTER PATTERN. THERE
STILL REMAINS UNCERTAINTY WITH THE EXACT TIMING, PLACEMENT, AND
MAGNITUDE OF THE TROUGH, AND THUS THERE IS UNCERTAINTY WITH
EXACT PRECIPITATION AMOUNTS. HOWEVER, PRECIPITATION AT THE END
OF THE WEEK GENERALLY LOOKS LIGHT AND NON-IMPACTFUL AT THIS
POINT. -10/99
AVIATION
NORTHWEST FLOW ALOFT CONTINUES WITH WEAK UPPER LEVEL
TROUGHING HELPING TO DEEPEN THE MARINE LAYER ALONG THE COAST.
MARINE STRATUS WITH MVFR CIGS IS EXPECTED TO PERSIST AT COASTAL
TERMINALS THROUGH AT LEAST 17-18Z SUNDAY. CIGS ARE EXPECTED TO
LIFT WITH IMPROVEMENT TO VFR BECOMING LIKELY (80-90% CHANCE)
AFTER 18Z SUNDAY. STRATUS MAY MOVE ACROSS THE WILLAMETTE VALLEY
THIS MORNING, AS CHANCES FOR MVFR CIGS ACROSS INLAND TERMINALS
ARE AROUND 30-50% AT ANY GIVEN HOUR BETWEEN 12-17Z SUNDAY.
OTHERWISE, EXPECT PREDOMINATELY VFR CONDITIONS FOR INLAND
TERMINALS THROUGH THE TAF PERIOD HAS HIGH PRESSURE BUILDS. NORTH
TO NORTHWEST WINDS CONTINUE, STRONGEST DURING THE AFTERNOON/EARLY
EVENING WITH GUSTS UP TO 20 KT ALONG THE CENTRAL OREGON COAST.
KPDX AND APPROACHES...VFR WITH A FEW HIGH CLOUDS THROUGH THE TAF
PERIOD WITH A 30-50% CHANCE FOR MVFR CIGS AT ANY GIVEN HOUR
BETWEEN 11-16Z SUNDAY. LIGHT NORTHWESTERLY WINDS THIS MORNING,
INCREASING NEAR 10 KT IN THE AFTERNOON AS PRESSURE GRADIENTS
TIGHTEN. -10/DH
MARINE
HIGH PRESSURE OFFSHORE HAS WEAKENED, RESULTING IN
WEAKER NORTHWESTERLY WINDS UNDER 20 KT TODAY THROUGH MONDAY
MORNING WITH STEEP AND CHOPPY SEAS AROUND 5 TO 7 FT. HIGH
PRESSURE RE-BUILDS MONDAY AFTERNOON INTO TUESDAY, TIGHTENING
PRESSURE GRADIENTS AND INCREASING NORTH-NORTHWESTERLY WINDS WITH
GUSTS UP TO 25 KT. SEAS GENERALLY REMAIN AROUND 6 TO 7 FT MON-
TUE. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR THE OUTER WATERS
(BEYOND 10 NM OFFSHORE) FROM LATE THIS AFTERNOON TO 5 AM TUESDAY
FOR THE WATERS SOUTH OF CAPE FALCON. FOR THE OUTER WATERS NORTH
OF CAPE FALCON, THE SMALL CRAFT ADVISORY IS IN EFFECT THROUGH 5
AM MONDAY. THERE IS ONLY A 10-20% CHANCE FOR SEAS EXCEEDING 7
FEET AT ANY GIVEN HOUR FROM MONDAY TO WEDNESDAY. -10
PQR WATCHES/WARNINGS/ADVISORIES
OR...HEAT ADVISORY FROM 11 AM MONDAY TO 11 PM PDT TUESDAY FOR
ORZ108>123.
WA...HEAT ADVISORY FROM 11 AM MONDAY TO 11 PM PDT TUESDAY FOR
WAZ204>210.
PZ...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 5 AM PDT MONDAY
FOR PZZ271.
SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 5 AM PDT
TUESDAY FOR PZZ272.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 5 AM PDT
TUESDAY FOR PZZ273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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