157
FXUS66 KPQR 181805
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
1105 AM PDT SAT JUL 18 2026
UPDATED AVIATION DISCUSSION.
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
SOUTHWEST TO WESTERLY FLOW ALOFT CONTINUES THROUGH
THE TAF PERIOD AS AN UPPER LOW MOVES THROUGH BRITISH COLUMBIA. AS
OF 17Z SAT, A SOLID MARINE STRATUS DECK WITH MVFR CIGS HAS PUSHED
INLAND ALONG THE COLUMBIA RIVER THIS MORNING TO AROUND KSPB WITH
A SCT TO OCCASIONALLY BKN DECK WITH MVFR CIGS REACHING TO KPDX.
EXPECT THESE CONDITIONS TO IMPROVE TO VFR BETWEEN 18-21Z SAT WITH
SURFACE HEATING. ELSEWHERE INLAND REMAINS VFR. ALONG THE COAST,
LOCATIONS NEAR AND NORTH OF KTMK REMAIN IN MVFR CIGS, ALSO
EXPECTED TO IMPROVE TO VFR BY 21Z SAT. ANOTHER MARINE PUSH IS
EXPECTED TONIGHT INTO TOMORROW MORNING. MVFR/IFR CIGS EXPECTED TO
FORM ALONG THE COAST AGAIN, INITIALLY NEAR KAST BY 04-06Z SUN,
SPREADING SOUTH TO KONP BY 08-12Z SUN. ADDITIONALLY, THERE'S A
35-45% CHANCE OF MVFR CEILINGS DEVELOPING BETWEEN 10-14Z SUN
INLAND STRETCHING FROM THE PORTLAND METRO TO KSLE, INCLUDING KPDX
AND KTTD. ANY LOWERED FLIGHT CONDITIONS ARE EXPECTED TO IMPROVE
TO VFR BY 18-21Z SUN. EXPECT NORTH TO NORTHWEST WINDS INCREASING
BETWEEN 18-21Z SAT TO 8-12 KTS INLAND, UP TO 15 KTS ALONG THE
COAST WITH GUSTS UP TO 20-25 KTS.
KPDX AND APPROACHES...PREDOMINATELY VFR CONDITIONS THROUGH THE
TAF PERIOD. THERE IS A 30-45% CHANCE OF MVFR CIGS 12-18Z SUN.
NORTHWEST WINDS AROUND 8-12 KT WITH OCCASIONAL GUSTS UP TO 20 KT
BETWEEN 20Z SAT AND 05Z SUN. -03
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 UNTIL 2 AM PDT MONDAY FOR PZZ253.
WWW.WEATHER.GOV/PORTLAND
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