487
FXUS66 KPQR 181757 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
1057 AM PDT THU JUN 18 2026
UPDATED AVIATION DISCUSSION...
SYNOPSIS
WARMER THAN NORMAL AND DRY CONDITIONS ARE EXPECTED
TO CONTINUE THROUGH THE MIDDLE OF NEXT WEEK. CONFIDENCE IS
INCREASING THAT HOT TEMPERATURES PEAKING MONDAY AND TUESDAY WILL
SUPPORT MODERATE TO MAJOR HEATRISK, HOWEVER THERE REMAINS
UNCERTAINTY IN THE TEMPERATURE FORECAST AT THIS LEAD TIME.
DISCUSSION...THURSDAY MORNING THROUGH WEDNESDAY
THERE HAS
BEEN VERY LITTLE CHANGE IN THE FORECAST SINCE THE LAST PACKAGE.
AN UPPER- LEVEL RIDGE AXIS CURRENTLY CENTERED OVER THE
NORTHEASTERN PACIFIC WILL SHIFT EASTWARD AND INLAND THROUGH THE
END OF THE WORKWEEK, BRINGING WARMER TEMPERATURES WITH A
TYPICAL SUMMERTIME NORTHERLY WIND PATTERN. TEMPERATURES WILL
PEAK ON THURSDAY AT THE COAST AND ON FRIDAY INLAND AS TROUGHING
ALOFT SUPPORTS A RETURN TO STRONGER ONSHORE FLOW FRIDAY INTO
SATURDAY. TEMPERATURES NEAR 70 DEGREES ON THE COAST WILL YIELD
MINOR HEATRISK ON THURSDAY, WHILE INLAND TEMPERATURES CLIMB INTO
THE 80S TO NEAR 90 DEGREES BOTH THURSDAY AND FRIDAY, YIELDING
WIDESPREAD MINOR HEATRISK AND LOCALLY MODERATE HEATRISK FROM
SALEM NORTH TO KELSO/LONGVIEW AND PORTLAND EAST THROUGH THE
COLUMBIA GORGE. THE CHANCES TO EXCEED 90 DEGREES ON THURSDAY ARE
ONLY AROUND 20-35% FROM HILLSBORO TO NORTHERN MARION COUNTY AND
5-15% ELSEWHERE FOR THE INTERIOR LOWLANDS. THESE CHANCES
INCREASE ON FRIDAY TO 35-55% FROM PORTLAND/VANCOUVER SOUTH TO
NORTHERN MARION COUNTY, 15-25% IN THE CENTRAL WILLAMETTE VALLEY,
AND 5-15% ELSEWHERE ALONG THE I-5 CORRIDOR. AFOREMENTIONED
TROUGHING AND ONSHORE FLOW WILL YIELD COOLER TEMPERATURES NEAR
60 DEGREES STARTING FRIDAY ON THE COAST, AND UPPER 70S TO LOW
80S WITHIN INLAND VALLEYS ON SATURDAY.
ENSEMBLE GUIDANCE REMAINS IN GOOD AGREEMENT THAT RENEWED RIDGING
WILL DEVELOP FROM SUNDAY INTO EARLY NEXT WEEK, RAISING THE
CHANCES FOR ANOTHER PERIOD OF HOT TEMPERATURES PEAKING MONDAY
AND TUESDAY. UNCERTAINTY IN THE POSITION AND AMPLITUDE OF THE
RIDGE AXIS REMAIN, LEADING TO UNCERTAINTY IN THE TEMPERATURE
FORECAST, BUT GIVEN THE MODEL CONSENSUS, THERE ARE 70-95%
CHANCES FOR TEMPERATURES TO EXCEED 90 DEGREES THROUGHOUT INLAND
VALLEYS ON MONDAY, AND SLIGHTLY LOWER CHANCES, 65-85%, ON
TUESDAY. THE CHANCES TO EXCEED 95 DEGREES SIMILARLY PEAK AT
GENERALLY 30-80% EACH OF MONDAY AND TUESDAY AFTERNOON, WHILE
THE CHANCES TO REACH 100 DEGREES REACH 15-35% ONLY FROM SALEM
NORTH TO VANCOUVER. THESE DAYTIME TEMPERATURES COMBINED WITH
OVERNIGHT LOWS IN THE UPPER 50S TO LOW 60S SUPPORT WIDESPREAD
MODERATE HEATRISK INLAND BOTH MONDAY AND TUESDAY, WITH THE
COVERAGE OF MAJOR HEATRISK LARGELY DEPENDENT ON THE OCCURRENCE
OF OVERNIGHT TEMPERATURES FALLING TO LOWS ONLY IN THE MID 60S.
THE CHANCES OF MAJOR HEATRISK VERY NEARLY MIRROR THOSE OF
NIGHTTIME LOWS OF 65 DEGREES OR WARMER MONDAY NIGHT: 15-20%
FOR THE CENTRAL WILLAMETTE VALLEY, INCREASING NORTHWARD TO 50%
IN THE INNER PORTLAND/VANCOUVER METRO, THEN DECREASING TO 20%
NEAR KELSO/LONGVIEW. LONG-RANGE GUIDANCE FAVORS A COOLING TREND
BEGINNING TUESDAY NIGHT AND CONTINUING INTO LATER NEXT WEEK,
BUT THERE'S STILL A 20-40% CHANCE FOR TEMPERATURES ABOVE 90
DEGREES TO PERSIST INTO A THIRD DAY ON WEDNESDAY. -36/03
AVIATION
EXPECT DRY CONDITIONS THROUGHOUT THE AIRSPACE OVER
THE NEXT 24 HOURS. WHILE INLAND TERMINALS WILL CONTINUE TO SEE VFR
CONDITIONS THROUGH THE TAF PERIOD, COASTAL TERMINALS WILL LIKELY
SEE A MIX MVFR/IFR/LIFR MARINE STRATUS DEVELOPMENT ALONG THE COAST
BEGINNING AROUND 10-12Z FRI. FROM 10Z ONWARD TO AT LEAST 18Z FRI,
THERE IS A 40-60% CHANCE OF MVFR, 30-40% CHANCE OF IFR, AND A
10-20% CHANCE OF LIFR CONDITIONS FOR COASTAL TERMINALS.
EXPECT ANOTHER BREEZY DAY WITH NORTHERLY TO NORTHWESTERLY WINDS,
WITH WIND GUSTS UP TO 25 KT ALONG THE COAST UNTIL 04Z FRI. WIND
THROUGH THE WILLAMETTE VALLEY WILL NOT BE AS GUSTY (THEREFORE HAVE
KEPT WIND GUSTS OUT OF THE TAFS FOR MOST TERMINALS), HOWEVER
INFREQUENT GUSTS UP TO 20 KT ARE POSSIBLE BETWEEN 20Z THU AND 02Z
FRI.
KPDX AND APPROACHES...VFR AND DRY CONDITIONS THROUGH THE NEXT 24
HOURS. NORTHWEST WINDS AROUND 8-12 KT WITH GUSTS UP TO 18-20 KT
EXPECTED BETWEEN 20Z THU AND 02Z FRI. ~12
MARINE
HIGH PRESSURE OFFSHORE WILL MAINTAIN A SUMMERTIME
PATTERN THROUGH THIS WEEK. DIURNALLY DRIVEN NORTHERLIES ARE
EXPECTED TO PEAK EACH AFTERNOON AND EVENING THROUGH AT LEAST
FRIDAY. WINDS ARE EXPECTED TO PEAK EACH AFTERNOON AND EVENING
WITH GUSTS TO 25-30 KTS, DECREASING A BIT IN THE LATE OVERNIGHT TO
MORNING HOURS. WINDS WILL LIKELY EASE OVER THE WEEKEND AS HIGH
PRESSURE WEAKENS AND LOW PRESSURE MOVES INTO NORTHWEST WA, TURNING
WINDS MORE NORTHWESTERLY ON SATURDAY. SEAS AROUND 7 TO 9 FT AT
8-9 SECONDS ARE EXPECTED TO BUILD TO 9 TO 11 FT AT 9-10 SECONDS
LATER THURSDAY INTO EARLY SATURDAY AS A FRESH NORTHWESTERLY SWELL
PERSISTS ACROSS THE COASTAL WATERS. SEAS ARE EXPECTED TO SUBSIDE
LATER SATURDAY INTO SUNDAY. /DH/03
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 5 AM PDT FRIDAY FOR PZZ251>253.
SMALL CRAFT ADVISORY UNTIL 5 AM PDT SATURDAY FOR PZZ271>273.
WWW.WEATHER.GOV/PORTLAND
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X.COM/NWSPORTLAND
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