955
FXUS66 KPQR 130908
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
208 AM PDT SUN JUL 13 2025
SYNOPSIS
A HEAT ADVISORY REMAINS IN PLACE TODAY FOR MOST
INTERIOR VALLEYS. EXPECT SUNNY SKIES ACROSS THE AREA WITH
MORNING MARINE STRATUS/FOG ALONG THE COAST. TEMPERATURES COOL
SLIGHTLY ON MONDAY, BUT STILL REMAIN WARM AND DRY. AN EXTREME
HEAT WATCH CONTINUES FOR SOME INTERIOR VALLEY LOCATIONS FROM
TUESDAY TO WEDNESDAY, AS AFTERNOON TEMPERATURES BETWEEN 90 TO
100 DEGREES AND LOW TEMPERATURES BETWEEN 65 AND 70 DEGREES ARE
POSSIBLE.
SHORT TERM...NOW THROUGH MONDAY NIGHT
TODAY'S TEMPS ARE
FORECAST TO JUMP UP A FEW DEGREES FROM SATURDAY AS THE UPPER
RIDGE PERSISTS AND THE OVERALL AIRMASS CONTINUES TO WARM- UP.
850 MB TEMPERATURES ARE EXPECTED TO INCREASE TO 20-23 C AND WILL
MIX DOWN TO THE SURFACE ON SUNDAY, LEADING TO HIGH TEMPERATURES
IN THE MID TO UPPER 90S FOR INTERIOR VALLEYS. THERE IS A 20-40%
CHANCE FOR A FEW LOCATIONS THROUGHOUT THE WILLAMETTE VALLEY TO
REACH 100. EXPECT WIDESPREAD MODERATE HEATRISK, WHICH MEANS THAT
THIS LEVEL OF HEAT AFFECTS MOST INDIVIDUALS SENSITIVE HEAT,
ESPECIALLY THOSE WITHOUT EFFECTIVE COOLING AND/OR ADEQUATE
HYDRATION. A HEAT ADVISORY IS IN EFFECT ACROSS THE WILLAMETTE
VALLEY, PORTLAND/VANCOUVER METRO AREA, COLUMBIA RIVER GORGE,
UPPER HOOD RIVER VALLEY, AND LOWER COLUMBIA-COWLITZ COUNTY
LOWLANDS FROM 11 AM SUNDAY TO 10 PM SUNDAY. TAKE NECESSARY HEAT
PRECAUTIONS AS HOT TEMPERATURES MAY LEAD TO HEAT ILLNESSES.
ONSHORE NORTHWEST TO NORTHERLY WINDS WILL AGAIN INCREASE DURING THE
AFTERNOON AS SURFACE HIGH PRESSURE OFFSHORE AND LOW PRESSURE EAST OF
THE CASCADES INCREASES THE PRESSURE GRADIENT. EXPECT WIND GUSTS UP
TO 20-25 MPH INLAND, WHILE GUSTS UP TO 30 MPH WILL BE POSSIBLE ALONG
THE CENTRAL OREGON COAST.
THE UPPER RIDGE AXIS RETROGRADES OVER THE PACIFIC AS AN UPPER LEVEL
TROUGH DROPS OUT OF BRITISH COLUMBIA INTO WASHINGTON ON MONDAY. THIS
WILL LIKELY PUSH 850 MB TEMPS BACK DOWN INTO THE MID-TEENS,
RESULTING IN SURFACE TEMPERATURES COOLING AROUND 10 DEGREES, TOWARD
NEAR NORMAL VALUES FOR JULY. COULD ALSO DEEPEN THE MARINE LAYER
ALONG THE COAST ENOUGH TO PUSH UP THE LOWER COLUMBIA INTO THE
PORTLAND METRO BY MONDAY MORNING. -BATZ/DH
LONG TERM...TUESDAY THROUGH SATURDAY
TUESDAY AND WEDNESDAY
REMAIN THE HOTTEST DAYS NEXT WEEK. DETERMINISTIC VALUES FOR
TUESDAY HAVE COME UP A BIT BUT THE 10TH- 90TH PERCENTILE SPREAD
FOR TUESDAY REMAINS AROUND 10 DEGREES ACROSS THE INLAND VALLEYS,
GENERALLY FROM LOW 90S TO AROUND 100. DETERMINISTIC HIGHS ON
WEDNESDAY REMAIN IN THE MID TO UPPER 90S INLAND. THE SPREAD
BETWEEN THE 10TH-90TH PERCENTILES HAS SHRUNK, RANGING FROM THE
LOW 90S TO LOW 100S.
THE LATEST GUIDANCE SUGGESTS A 20-50% CHANCE THAT TEMPERATURES REACH
100 DEGREES OR HOTTER ACROSS THE WILLAMETTE VALLEY ON TUESDAY.
TUESDAY NIGHT LOW TEMPERATURES BETWEEN 65 AND 70 DEGREES ARE
EXPECTED ESPECIALLY AROUND THE PORTLAND/VANCOUVER METRO AREA AND
COLUMBIA RIVER GORGE. GUIDANCE SUGGESTS A 40-70% CHANCE THAT TUESDAY
NIGHT LOWS REMAIN ABOVE 65 DEGREES AND A 20% CHANCE LOW TEMPERATURES
REMAIN ABOVE 70 DEGREES, WHICH WOULD LIMIT OVERNIGHT RELIEF. WILL
CONTINUE THE EXTREME HEAT WATCH FOR NOW, THOUGH NWS HEATRISK
CONTINUES TO TREND TOWARD WIDESPREAD MODERATE RISK RATHER THAN MAJOR
RISK.
DAYS 6 AND 7 IN THIS FORECAST CONTINUE THE LARGE UNCERTAINTY TREND
WITH POTENTIAL FOR A BIG COOL DOWN OR ANOTHER DAY OF HOT CONDITIONS
ON THURSDAY. DETERMINISTIC VALUES ARE SUGGESTING LOW TO MID 90S
THROUGHOUT THE INLAND VALLEYS BUT THE 10TH-90TH PERCENTILE SPREAD IS
SIGNIFICANT, RANGING FROM UPPER 70S TO LOW 100S. ENSEMBLE
GUIDANCE IS REALLY STRUGGLING WITH THE PATTERN FOR THE LATTER
HALF OF NEXT WEEK WITH A 50/50 SPLIT BETWEEN TROUGHING OR WEAK
RIDGING ACROSS THE PACNW. MODEL SPREAD SHOULD DECREASE AS THE
LEAD TIME BECOMES SHORTER. GUIDANCE DOES SHOW HIGHER CONFIDENCE
OF TEMPERATURES TRENDING INTO THE MID-80S BY NEXT SATURDAY WITH
DRY CONDITIONS PERSISTING. -BATZ
AVIATION
HIGH PRESSURE OVER THE AIRSPACE CONTINUES THROUGH THE
TAF PERIOD, LEADING TO INCREASING DAYTIME TEMPERATURES. EXPECT
VFR CONDITIONS TO CONTINUE THROUGH THE TAF PERIOD FOR INLAND
TERMINALS. COASTAL TERMINALS WILL EXPERIENCE DETERIORATED
CONDITIONS AS UPWELLING CONTINUES TO BRING COOLER TEMPERATURES
ALONG THE COAST, CAUSING IFR/LIFR CEILINGS AND FOG OVER THE OCEAN.
THESE CONDITIONS WILL AFFECT COASTAL TERMINALS ON AND OFF THROUGH
18Z SUNDAY. THE WARMER AND DRIER CONDITIONS WILL CAUSE CONDITIONS
TO BOUNCE BETWEEN LIFR AND IFR. NORTHWESTERLY WINDS LESS THAN 10
KTS THROUGH AROUND 18Z SUNDAY. THEN GUSTY NORTH WINDS RETURN
AFTER 18-21Z SUNDAY, WITH GUSTS UP TO 25-30 KTS ALONG THE COAST
AND UP TO 20-25 KTS IN THE WILLAMETTE VALLEY.
PDX AND APPROACHES...VFR CONDITIONS PERSIST THROUGH THE TAF
PERIOD. BETWEEN 09-18Z SUNDAY, EXPECT NORTHERLY TO NORTHEASTERLY
SURFACE WINDS LESS THAN 10 KTS WITH WIND GUSTS ALOFT ABOVE
FL015-FL025 UP TO 25-30 KT. ADDITIONALLY, AFTER 18Z SUNDAY,
EXPECT NORTHWESTERLY SURFACE WINDS AROUND 10-15 KT WITH GUSTS UP
TO 20-25 KT. -HALL/HEC
MARINE
UPWELLING ALONG THE COAST IS KEEPING MARINE STRATUS IN
PLACE WITH MARINE FOG EXPECTED THROUGH THIS MORNING. A DENSE FOG
ADVISORY REMAINS IN EFFECT FOR THE INNER WATERS AND COLUMBIA BAR
WITH VISIBILITY OF 1/2 NM OR LESS EXPECTED THROUGH SUNDAY MORNING.
STRONG HIGH PRESSURE OVER THE WATERS CONTINUES INTO MIDWEEK. A
STRENGTHENING THERMAL TROUGH OVER WESTERN CA AND OR IS TIGHTENING
PRESSURE GRADIENTS, CAUSING GUSTY NORTH WINDS INTO MONDAY.
STRONGEST WINDS WILL BE TODAY WITH GUSTS UP TO 25 KTS FOR THE
WATERS NORTH OF CAPE FALCON AND UP TO 30 KTS FOR THE WATERS SOUTH
OF CAPE FALCON. A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL
WATERS. SEAS REMAIN AROUND 7-9 FEET AT 10 SECONDS THROUGH MONDAY
AFTERNOON, THOUGH SEAS COULD BRIEFLY RAISE TO 10 FEET FOR THE
OUTER WATERS MONDAY NIGHT INTO TUESDAY MORNING. -HEC
PQR WATCHES/WARNINGS/ADVISORIES
OR...HEAT ADVISORY FROM 11 AM THIS MORNING TO 10 PM PDT THIS EVENING
FOR ORZ108-109-111-112-114>118-120>122.
EXTREME HEAT WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR ORZ108>115-119>122.
WA...HEAT ADVISORY FROM 11 AM THIS MORNING TO 10 PM PDT THIS EVENING
FOR WAZ204>207-209-210.
EXTREME HEAT WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR WAZ204>207-209-210.
PZ...DENSE FOG ADVISORY UNTIL 11 AM PDT THIS MORNING FOR PZZ210-
251>253.
SMALL CRAFT ADVISORY UNTIL 5 AM PDT MONDAY FOR PZZ251>253-
271>273.
WWW.WEATHER.GOV/PORTLAND
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