541
FXUS66 KPQR 181035
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
335 AM PDT SAT JUL 18 2026
SYNOPSIS
A STEADY WARMING TREND WILL CONTINUE THROUGH THE
WEEKEND AS HIGH PRESSURE STRENGTHENS ACROSS THE REGION. INLAND
TEMPERATURES WILL RISE INTO THE 80S THIS WEEKEND, THEN INTO THE
UPPER 80S TO MID 90S EARLY NEXT WEEK. HOT AND DRY WEATHER IS
EXPECTED TO PERSIST THROUGH AT LEAST MIDWEEK, WITH INCREASING
HEAT IMPACTS POSSIBLE ACROSS THE INTERIOR LOWLANDS.
DISCUSSION...NOW THROUGH FRIDAY
A LARGE-SCALE PATTERN EARLY
THIS MORNING CONTINUES TO FAVOR WARMING AND DRYING ACROSS
SOUTHWEST WASHINGTON AND NORTHWEST OREGON. UPPER-LEVEL RIDGING
IS BUILDING INLAND WHILE SURFACE ONSHORE FLOW LINGERS JUST
ENOUGH TO TEMPER THE RATE OF WARMING, ESPECIALLY NEAR THE
COAST. EVEN SO, HEIGHTS ALOFT WILL CONTINUE TO RISE THROUGH THE
WEEKEND AS THE RIDGE BECOMES MORE FIRMLY ESTABLISHED OVER THE
PACIFIC NORTHWEST. IN RESPONSE, INLAND TEMPERATURES WILL TREND
UPWARD DAY BY DAY, WHILE COASTAL AREAS REMAIN NOTICEABLY COOLER
UNDER CONTINUED MARINE INFLUENCE.
FOR TODAY, INLAND HIGHS SHOULD CLIMB INTO THE LOWER TO MID 80S,
WARMEST ACROSS THE INTERIOR VALLEYS. BY SUNDAY, MOST INLAND
LOCATIONS ARE EXPECTED TO REACH THE MID TO UPPER 80S. ALONG THE
COAST, HIGHS WILL REMAIN MUCH MORE SEASONABLE, GENERALLY IN THE
60S TO LOWER 70S TODAY AND SUNDAY. HIGHER TERRAIN WILL ALSO
WARM THROUGH THE WEEKEND, WITH AFTERNOON TEMPERATURES RISING
INTO THE UPPER 70S TO MID 80S.
ATTENTION THEN TURNS TO THE HOTTER PORTION OF THE FORECAST FROM
MONDAY THROUGH WEDNESDAY, WHEN THE RIDGE IS EXPECTED TO PEAK IN
STRENGTH. CONFIDENCE REMAINS HIGHEST IN MONDAY'S FORECAST, WITH
INTERIOR LOWLAND HIGHS GENERALLY IN THE UPPER 80S TO LOWER 90S.
BEYOND THAT, UNCERTAINTY GROWS FOR TUESDAY AND WEDNESDAY. MUCH
OF THE UNCERTAINTY APPEARS TIED TO HOW A LOW OFF THE CALIFORNIA
COAST EVOLVES AND WHETHER SOME MONSOONAL MOISTURE IS ABLE TO
LIFT NORTHWARD INTO THE REGION. EVEN MODEST INCREASES IN CLOUD
COVER OR MOISTURE COULD INFLUENCE AFTERNOON TEMPERATURES, AND
ENSEMBLE GUIDANCE REFLECTS THAT WITH A BROADER SPREAD IN THE
FORECAST BY MIDWEEK.
DESPITE THAT UNCERTAINTY, THE OVERALL MESSAGE REMAINS THE SAME:
TUESDAY AND WEDNESDAY STILL APPEAR LIKELY TO BE THE HOTTEST DAYS
OF THE PERIOD FOR MANY INLAND LOCATIONS. PROBABILISTIC GUIDANCE
CONTINUES TO SUPPORT A MODERATE TO HIGH CHANCE OF 90-DEGREE
TEMPERATURES ACROSS MUCH OF THE INTERIOR LOWLANDS, WITH THE
HIGHER ODDS ON TUESDAY AND WEDNESDAY. THERE IS ALSO A MEANINGFUL
CHANCE (20-30% CHANCE ON MONDAY, 30-50% CHANCE ON TUESDAY AND
WEDNESDAY) THAT SOME OF THE TRADITIONALLY WARMER VALLEYS PUSH
INTO THE MID 90S. WITH SEVERAL CONSECUTIVE HOT AFTERNOONS AND
ONLY LIMITED OVERNIGHT COOLING, MODERATE HEATRISK APPEARS
INCREASINGLY LIKELY FOR PORTIONS OF THE INTERIOR LOWLANDS,
ESPECIALLY FOR THOSE WITHOUT EFFECTIVE COOLING OR FOR ANYONE
SPENDING EXTENDED TIME OUTDOORS. THERE IS ALSO A LOWER-END
CHANCE (15-35%) FOR POCKETS OF MAJOR HEATRISK IF TEMPERATURES
END UP ON THE WARMER SIDE OF THE FORECAST ENVELOPE.
BY THURSDAY AND FRIDAY, GUIDANCE STILL FAVORS A SLIGHT EASING
OF THE HEAT AS A BROADER UPPER-LEVEL LOW BEGINS TO SHIFT EAST
INTO THE PACIFIC NORTHWEST. EVEN SO, TEMPERATURES MAY REMAIN
ABOVE NORMAL, AND CONFIDENCE IN THE EXACT MAGNITUDE OF COOLING
REMAINS LOWER THAN AVERAGE GIVEN THE SPREAD THAT DEVELOPS BY THE
MIDDLE OF THE WEEK. OVERALL, THE FORECAST CONTINUES TO SUPPORT
AN EXTENDED STRETCH OF DRY WEATHER WITH THE MOST NOTABLE HAZARD
BEING THE BUILDING HEAT INLAND.
~12
AVIATION
WEST TO SOUTHWESTERLY FLOW ALOFT CONTINUES THROUGH
THE TAF PERIOD AS AN UPPER LOW MOVES THROUGH BRITISH COLUMBIA.
EXPECT VFR CONDITIONS INLAND AND A MIX OF IFR/MVFR/VFR
CONDITIONS ALONG THE COAST THROUGH THE TAF PERIOD. FROM NOW
UNTIL 19-21Z SAT, EXPECT MVFR CIGS AT COASTAL TERMINALS WITH A
30-50% CHANCE OF IFR CIGS ANYTIME BEFORE 18Z SAT. ADDITIONALLY,
THERE IS A 10-20% CHANCE OF LIFR CIGS BEFORE 16Z SAT. WHILE
CONDITIONS AT COASTAL TERMINALS WILL LIKELY RETURN TO VFR BY
19-21Z SAT, EXPECT CONDITIONS TO ONCE AGAIN DETERIORATE TO
IFR/MVFR CIGS BY 04-07Z SUN AS MARINE STRATUS PUSHES BACK INTO
THE COAST. OTHERWISE, EXPECT LIGHT NORTHWESTERLY WINDS EARLY
THIS MORNING, THEN INCREASING IN THE LATE MORNING/AFTERNOON TO
AROUND 8-12 KT WITH GUSTS UP TO 20 KT INLAND AND 12-18 KT WITH
GUSTS UP TO 20-25 KT ALONG THE COAST.
KPDX AND APPROACHES...VFR WITH CLEAR SKIES THROUGH THE TAF
PERIOD. THERE IS A 10-15% CHANCE OF MVFR CIGS UNTIL 18Z SAT.
LIGHT NORTHWESTERLY WINDS EARLY THIS MORNING INCREASE TO AROUND
8-12 KT WITH GUSTS UP TO 20 KT BETWEEN 20Z SAT AND 05Z SUN.
~12
MARINE
A TYPICAL SUMMERTIME PATTERN WILL CONTINUE THROUGH
EARLY NEXT WEEK WITH PERSISTENT NORTH TO NORTHWEST WINDS OVER
THE COASTAL WATERS. WINDS WILL BE STRONGEST DURING THE AFTERNOON
AND EVENING HOURS EACH DAY, ESPECIALLY THROUGH WEEKEND FOR THE
WATERS SOUTH OF CAPE FALCON. EXPECT WIND GUSTS UP TO 25 KT OVER
THE CENTRAL AND SOUTHERN WATERS THIS WEEKEND, WITH SEAS BECOMING
STEEP ON SUNDAY DUE TO A FRESH NORTHWEST SWELL AROUND 6-7 FT AT
7-8 SECONDS. BY SUNDAY AFTERNOON, THESE GUSTY WINDS AND STEEP
SEAS WILL EXPAND INTO THE WATERS NORTH OF CAPE FALCON. BETWEEN
THE INCREASING WINDS AND STEEPENING SEAS, CONDITIONS WILL BECOME
HAZARDOUS TO SMALL CRAFT. AS SUCH, SMALL CRAFT ADVISORIES ARE
IN EFFECT FROM SATURDAY AFTERNOON THROUGH LATE SUNDAY.
STEEP SEAS EARLY MONDAY ARE EXPECTED TO BECOME LESS STEEP THROUGH
THE DAY AS NORTHERLY WINDS DECREASE. SEAS AND WINDS DECREASE EVEN
MORE ON TUESDAY, BRINGING BENIGN CONDITIONS. ~12/23
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 2 PM SUNDAY TO 2 AM PDT MONDAY FOR
PZZ251-271.
SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 2 AM PDT MONDAY
FOR PZZ252-272-273.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 2 AM PDT MONDAY
FOR PZZ253.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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