401
FXUS66 KPQR 092155
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
255 PM PDT TUE JUN 9 2026
SYNOPSIS
WARM AND DRY BECOMES HOT AND DRY FOR THE REGION AS
AN UPPER LEVEL HIGH SLOWLY BUILDS INTO THE REGION OVER THE NEXT
24-48 HOURS. THIS WILL RESULT IN A MULTI- DAY HEAT EVENT FOCUSED
OVER THE WEEKEND AND INTO EARLY NEXT WEEK (JUNE 13-16TH). THIS
TIME PERIOD WILL PRESENT SOME OF THE HOTTEST TEMPERATURES WE'VE
SEEN SO FAR THIS YEAR. THERE IS AT LEAST GROWING CONFIDENCE IN A
RETURN OF COOLER, CLOSER TO NORMAL TEMPERATURES (70S/80S) BY
WEDNESDAY OF NEXT WEEK.
SHORT TERM...NOW THROUGH THURSDAY
THE CORE OF THE UPPER-
LEVEL TROUGH WHICH BROUGHT WIDESPREAD RAIN AND LOCALLY BREEZY
CONDITIONS TO MUCH OF THE REGION HAS MOVED NORTHEASTWARD OUT OF
OUR CWA AND INTO WASHINGTON STATE. MODEL GUIDANCE MAINTAINS
BROAD WNW FLOW ACROSS THE REGION TODAY WITH DIMINISHING SHOWER
ACTIVITY AND SLIGHTLY COOLER THAN NORMAL TEMPERATURES. WHILE
THIS PATTERN CAN BE FAVORABLE FOR WEAK THUNDERSTORM ACTIVITY,
AND THE NBM WHICH GENERALLY DRIVES THE BASE LAYER OF OUR
FORECAST SUGGESTS A 10-20% CHANCE FOR THUNDERSTORMS THIS
AFTERNOON, DETERMINISTIC CAM SOUNDINGS REVEAL CAPE VALUES OF
100-200 J/KG AND IS RATHER SHALLOW IN NATURE (SURFACE TO 8,000
FT) WITH THE CAPE POOL WELL BELOW CHARGE SEPARATION LEVEL WHICH
OCCURS AROUND -10 DEGREES C TO -20 DEGREES C.
WEDNESDAY IS THE START OF THE NEXT MAJOR PATTERN CHANGE. UPPER-
LEVEL TROUGHING WHICH HAS BEEN THE DOMINANT SYNOPTIC PATTERN TO
THE START OF THE WEEK WILL CONTINUE TO GET SLOWLY SHOVED
EASTWARD BY AN UPPER-LEVEL RIDGE AMPLIFYING OVER THE EASTERN
PACIFIC. AS THIS HIGH PRESSURE DEVELOPS AND BECOMES THE DOMINANT
SYNOPTIC FEATURE, DAYTIME HIGHS ARE EXPECTED TO WARM INTO THE
MID 60S TO LOW 70S ACROSS THE INLAND VALLEYS, LOW TO UPPER 50S
FOR THE CASCADES AND MID 50S TO LOW 60S ALONG THE COAST.
THURSDAY, LOOKS TO BE VERY SIMILAR TO WEDNESDAY WITH DRY
CONDITIONS PERSISTING, WITH DAYTIME HIGHS TO BE 5-10 DEGREES
WARMER THAN 24 HOURS PRIOR. /42
LONG TERM...FRIDAY THROUGH TUESDAY
HOT AND DRY CONDITIONS
WILL BE WELL ENTRENCHED ACROSS THE PAC NW. EXPECT DAYTIME HIGHS
TO BE THE HOTTEST OF THE YEAR SO FAR. THESE CONDITIONS ARE THE
MAIN DRIVER OF OUR WEATHER IMPACTS THROUGH THE REMAINDER OF THE
WEEK, OVER THE WEEKEND AND INTO THE START OF NEXT WEEK. FRIDAY
THROUGH EARLY NEXT WEEK, MODELS AND THEIR RESPECTIVE ENSEMBLES
ARE IN VERY GOOD AGREEMENT THAT AN UPPER LEVEL RIDGE WILL
CONTINUE TO STRENGTHEN OVER THE FAR NORTHEASTERN PACIFIC BEFORE
SHIFTING EASTWARD. THIS WILL RESULT IN DAYTIME HIGHS ABOUT 5-10
DEGREES WARMER THAN NORMAL (NORMAL THIS TIME OF YEAR IS IN THE
60S ALONG THE COAST AND CASCADES AND IN THE 70S FOR INLAND
VALLEYS). BY SATURDAY, JUNE 13TH, THE NBM PROBABILITIES FOR
DAYTIME HIGHS ABOVE 90 DEGREES F ARE 20-50% FOR THE WILLAMETTE
VALLEY. NBM PROBABILITIES FOR DAYTIME HIGHS AT OR ABOVE 100
DEGREES F ON SUNDAY JUNE 14TH ARE 15-40% AND 20-70% ON MONDAY
JUNE 15TH, WITH THE HIGHEST PROBABILITIES EACH DAY TOWARDS THE
NORTHERN PORTIONS (PORTLAND/VANCOUVER METRO) OF THE WILLAMETTE
VALLEY. ALSO, THERE IS A 5-15% CHANCE FOR DAYTIME HIGHS ON JUNE
14TH AND JUNE 15TH OF 105 DEGREES F OR HIGHER FOR LOCATIONS
BETWEEN SALEM, OR AND KALAMA, WA.
FOR REFERENCE, HEATRISK LEVELS ARE AS FOLLOWS:
LITTLE TO NONE, MINOR, MODERATE, HIGH AND EXTREME.
PROBABILITIES FOR A MODERATE HEATRISK OR HIGHER ON SATURDAY
JUNE 13TH ARE 85-95%, THEN ON SUNDAY/MONDAY (JUNE 14TH AND
15TH) 90-99% ACROSS ALMOST THE ENTIRE REGION. FOR MAJOR
HEATRISK, THERE IS A 55-80% PROBABILITY ON SUNDAY JUNE 14TH AND
25-80% PROBABILITY ON JUNE 15TH (HIGHEST PORTLAND METRO, LOWEST
NEAR EUGENE AND ALONG THE COAST). AT LEAST THROUGH THIS PERIOD
THE PROBABILITY FOR EXTREME HEATRISK ACROSS THE CWA IS 5-15% OR
LESS. ANYONE WHO IS SENSITIVE TO HEAT OR THOSE WHO HAVE OUTDOOR
PLANS SHOULD PREPARE FOR AND TAKES STEPS TO MITIGATE POTENTIAL
HEAT IMPACTS. FOR THOSE PLANNING TO SEEK RELIEF BY SWIMMING IN
LOCAL AREA RIVERS AND/OR LAKES TO COOL OFF, BE MINDFUL OF COLD
WATER TEMPERATURES AND SWIFT CURRENTS WHICH CAN BECOME LIFE
THREATENING IF PRECAUTIONS LIKE WEARING A LIFE PRESERVER IS NOT
TAKEN.
IT'S WORTH NOTING WITH THIS UPPER LEVEL PATTERN, A THERMALLY
INDUCED SURFACE TROUGH ALSO WILL ESTABLISH ITSELF SOMEWHERE WEST
OF THE CASCADE CREST-LINE WHICH COULD RESULT IN LOCALLY BREEZY
WINDS WITHIN THE CASCADES AND/OR WILLAMETTE VALLEY DEPENDING ON
ITS ORIENTATION. AS DAYTIME HIGHS INCREASE, RELATIVE HUMIDITIES
WILL ALSO DECREASE. THEREFORE, WITH CONDITIONS DRYING OUT AND
THE POTENTIAL FOR GUSTY WINDS, THERE ARE INCREASING FIRE WEATHER
CONCERNS FOR THE LATTER PART OF THIS WEEK THROUGH THE START OF
NEXT WEEK. SO, BE AWARE OF POTENTIAL IGNITION SOURCES SUCH AS
CHAINS DRAGGING ON THE PAVEMENT, HOT VEHICLE COMPONENTS, AS WELL
AS CIGARETTE BUTTS AS THESE COULD EASILY RESULT IN THE IGNITION
OF DRY, FINE FUELS. LARGER FUELS MAY NOT HAVE THE TIME TO DRY
OUT, BUT THIS IS A VARIABLE THAT IS BEING CLOSELY MONITORED BY
STATE AND FEDERAL FIRE PARTNERS.
BY JUNE 16/17TH (TUESDAY AND WEDNESDAY OF NEXT WEEK), ENSEMBLE
MODELING SYSTEMS DO HINT AT THE RIDGE FINALLY BREAKING DOWN AND
SHIFTING EASTWARD, BRINGING A RETURN OF RELATIVELY COOLER,
WESTERLY FLOW. HOWEVER, THERE'S A LARGE DEGREE OF UNCERTAINTY AS
TO WHETHER THIS TRANSITION TAKES PLACE ON TUESDAY OR WEDNESDAY,
BUT AT LEAST THE MAJORITY OF MODELS DO PUSH TEMPERATURES
DOWNWARD BACK INTO THE 70S AND 80S BY THE MIDDLE OF NEXT WEEK AS
IN GENERAL THE 25TH-75TH PERCENTILES FALL IN-BETWEEN THESE TWO
VALUES. THE LATEST NBM ONLY GIVES THE INLAND VALLEYS A 10-15%
CHANCE FOR HIGHS TO EXCEED 90 DEGREES F ON WEDNESDAY. SO,
CONFIDENCE IS MODERATE TO HIGH IN A RETURN CLOSER TO NORMAL
DAYTIME HIGHS BY THE MIDDLE OF NEXT WEEK. /42-99
AVIATION
MIXED MVFR/VFR CONDITIONS REMAIN IN PLACE THIS
MORNING AS ISOLATED TO WIDELY SCATTERED SHOWERS CONTINUE WITH
COVERAGE INCREASING TO THE NORTH. SHOWERS WILL BEING PERSISTENT
LOW TO MODERATE CHANCES (20-50%) FOR PERIODS OF MVFR CIGS/VIS,
BUT CONFIDENCE IN THE TIMING OF SPECIFIC TERMINAL IMPACTS
REMAINS LOW WHILE BACKGROUND CONDITIONS ARE EXPECTED TO TREND
TOWARD CATEGORICAL IMPROVEMENTS TO VFR THROUGH THIS EVENING.
WEST TO SOUTHWEST WINDS CONTINUE THROUGH MUCH THE PERIOD, WITH
GUSTS OF 15-20 KT CONTINUING AT MOST TERMINALS THROUGH 00-06Z
WED BEFORE EASING TO 5 KT OR LESS.
KPDX AND APPROACHES...PREDOMINANT VFR FLYING CONDITIONS EXPECTED
THROUGH THE PERIOD. CURRENTLY WIDELY SCATTERED RAIN SHOWERS MAY
BRIEFLY RESTRICT VIS/CIGS TO MVFR (25-35% CHANCE), BUT
CONFIDENCE IN SPECIFIC TIMING OF TERMINAL IMPACTS IS LOW. WEST-
SOUTHWEST WINDS NEAR 10 KT WITH GUSTS OF 15-20 KT CONTINUE
THROUGH THIS EVENING BEFORE EASING BELOW 5 KT AND TURNING MORE
SOUTHERLY. -36
MARINE
LINGERING SMALL CRAFT CONDITIONS THROUGH THE LATE
EVENING ACROSS ALL WATERS AS WINDS AND SEAS GRADUALLY SUBSIDE.
SEAS AROUND 8-10FT AT 9-10 SECONDS WILL SLOWLY SUBSIDE TOWARD 5-7
FEET BY WEDNESDAY MORNING AND REMAIN THERE THROUGH THE WEEKEND.
WESTERLY WINDS WITH GUSTS UP TO 25 KT WILL ALSO DECREASE THROUGH
TONIGHT AND FALL BELOW 15 KT GUSTS BY THE MIDDLE OF THE WEEK. FROM
HERE OUR FOCUS SHIFTS TO HIGH PRESSURE BUILDING OFFSHORE THROUGH
THE REMAINDER OF THE WEEK. WEST WINDS OF 10-15 KT ON WEDNESDAY
EVENING/THURSDAY WILL BECOME MORE NORTHERLY. TYPICAL SUMMERTIME
NORTHERLIES LOCK IN PLACE FROM THIS POINT FORWARD, WITH GUSTS UP
TO 25 KT EACH AFTERNOON AND EVENING FROM THURSDAY THROUGH THE
WEEKEND. THIS MAY NECESSITATE DAILY SMALL CRAFT ADVISORIES. /42
PQR WATCHES/WARNINGS/ADVISORIES
OR...EXTREME HEAT WATCH FROM SUNDAY MORNING THROUGH MONDAY EVENING
FOR ORZ109-111-112-120.
WA...EXTREME HEAT WATCH FROM SUNDAY MORNING THROUGH MONDAY EVENING
FOR WAZ206-207-209.
PZ...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR PZZ210-
251>253-271>273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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