368
FXUS66 KPQR 100926
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
225 AM PDT MON AUG 10 2026
SYNOPSIS
WARM AND DRY CONDITIONS CONTINUE THROUGH THE UPCOMING
WEEK AS TEMPERATURES MODERATE TOWARDS AUGUST NORMALS. ONSHORE FLOW
WILL KEEP SMOKE EAST OF THE CASCADES, WHILE PRECIPITATION CHANCES
REMAIN VERY LOW THROUGH THE END OF THE WEEK. TEMPERATURES MAY TREND
WARMER LATE THIS WEEK AS A RIDGE OF HIGH PRESSURE DEVELOPS OFFSHORE.
INCREASING POTENTIAL FOR AFTERNOON CONVECTION OVER THE CENTRAL OR
CASCADES FRIDAY INTO THE WEEKEND.
DISCUSSION...TODAY THROUGH SUNDAY
FAIRLY TYPICAL SUMMER WEATHER
WILL CONTINUE EARLY THIS WEEK AS NEAR AVERAGE TEMPERATURES ARE
EXPECTED TODAY AND TUESDAY. THIS IS IN PART DUE TO ZONAL FLOW ALOFT
AND ONSHORE FLOW IN THE LOWER LEVELS. RELATIVELY SHALLOW MARINE
STRATUS AT THE COAST WILL RETREAT, GIVING WAY TO MOSTLY SUNNY SKIES
THIS AFTERNOON, WHILE A BRIEF PERIOD OF CLOUDS WILL BE POSSIBLE THIS
MORNING UP THE LOWER COLUMBIA RIVER VALLEY INTO THE PORTLAND METRO
AREA. OTHERWISE, MOSTLY SUNNY SKIES WILL ALLOW AFTERNOON
TEMPERATURES TO WARM INTO THE LOWER TO MID-80S FOR INTERIOR
LOWLANDS, AND INTO THE MID-60S TO LOW 70S AT THE COAST. EXPECT
SIMILAR CONDITIONS ON TUESDAY.
BY WEDNESDAY, THERE IS INCREASING CONFIDENCE FOR UPPER LEVEL
TROUGHING DROPPING OUT OF BRITISH COLUMBIA INTO WASHINGTON AND
OREGON. MODEL FORECAST SOUNDINGS ARE SHOWING A DEEPENING OF THE
MARINE LAYER WHICH WOULD ALLOW FOR DEEPER STRATUS TO PUSH INTO SW
WASHINGTON AND THE NORTHERN WILLAMETTE VALLEY, AS WELL AS THE
POTENTIAL FOR SQUEEZING OUT SOME DRIZZLE AT THE COAST. THIS WOULD
ALSO ALLOW FOR AFTERNOON TEMPERATURES TO DROP A FEW DEGREES,
DEPENDING ON HOW LONG MORNING CLOUDS LINGER.
STILL SOME UNCERTAINTY LATE IN THE WEEK IN DAYTIME HIGH TEMPERATURES
AS MODEL SPREAD REMAINS RELATIVELY LARGE THURSDAY AND FRIDAY. IF
TROUGHING WERE TO LINGER AROUND, COOLER (OR NEAR AVERAGE)
TEMPERATURES WOULD BE MORE LIKELY, BUT A WARMING TREND IS ALSO
POSSIBLE WITH HIGHS RETURNING INTO THE MID TO UPPER 80S, WITH AT
LEAST A 25% CHANCE OF REACHING 90 DEGREES ON FRIDAY. CLUSTER
ANALYSIS OF THE ENSEMBLES INDICATES THE POTENTIAL FOR UPPER LEVEL
RIDGING TO BUILD OFFSHORE WITH VARYING DEGREES OF TROUGHING OR UPPER
LEVEL LOW PRESSURE DEVELOPING NEAR CENTRAL CALIFORNIA. THIS FEATURE
IS ALSO BRINGING THE POTENTIAL FOR MORE CONVECTIVE WEATHER
DEVELOPING NEAR THE CENTRAL OR CASCADE CREST BOTH FRIDAY AND
SATURDAY AFTERNOONS WITH THE NORTHWARD PUSH OF SOME MONSOONAL
MOISTURE. TEMPERATURES ARE LIKELY TO PERSIST NEAR TO SLIGHTLY ABOVE
NORMAL INTO NEXT WEEKEND, WITH WARM AND DRY CONDITIONS LIKELY. /DH
AVIATION...THROUGH 12Z TUE
DRY, WESTERLY FLOW ALOFT CONTINUES
WITH MARINE STRATUS FILLING IN ALONG THE COAST AND UP THE LOWER
COLUMBIA RIVER VALLEY. HIGH CONFIDENCE FOR LOW-END MVFR CIGS
THROUGH 20Z MONDAY, WITH CHANCES FOR IFR CIGS AT AROUND 40-50%
BETWEEN 12-18Z THIS MORNING. CONFIDENCE FOR STRATUS DEVELOPING AT
KONP INCREASES AFTER 10Z EARLY THIS MORNING WITH IFR CIGS LIKELY
BETWEEN 12-16Z, FOLLOWED BY IMPROVEMENT BACK TO VFR AS CLOUDS
SCATTER OUT BY 18Z.
GIVEN THAT STRATUS AS ALREADY REACHED THE KKLS AREA EARLY THIS
MORNING, PORTLAND METRO TERMINALS, INCLUDING KPDX AND KTTD, COULD
SEE MVFR CIGS BETWEEN 13-16Z MON. AS DAYTIME HEATING PROGRESSES,
STRATUS WILL GRADUALLY DISSIPATE, RETURNING VFR CONDITIONS TO THE
PORTLAND METRO AFTER 16Z MON AND AFTER 19-21Z MON ALONG THE
COAST. FOR THE REST OF THE TERMINALS IN THE WILLAMETTE VALLEY, VFR
CONDITIONS WITH CLEAR SKIES PREVAIL THROUGH THE TAF PERIOD. NORTH
TO NORTHWESTERLY WINDS INCREASE TO 10-15 KT IN THE AFTERNOON AND
EVENING WITH GUSTS UP TO 25 KT ALONG THE COAST AND UP TO 20 KT
INLAND.
KPDX AND APPROACHES...PREDOMINATELY VFR CONDITIONS WITH CLEAR
SKIES EXPECTED THROUGH THE TAF PERIOD, EXCEPT FOR A PERIOD OF
BRIEF STRATUS BETWEEN 13-16Z THIS MORNING. DURING THIS TIME,
THERE IS A 40-60% CHANCE FOR MVFR CIGS ACROSS THE EASTERN PORTLAND
METRO. NORTHWEST WINDS 4-6 KT INCREASE TO AROUND 10-12 KT WITH
GUSTS UP TO 20 KT BY 00Z TUE. /DH
MARINE
HIGH PRESSURE OFFSHORE WILL MAINTAIN NORTHERLY WINDS
THROUGH MUCH OF NEXT WEEK. SURFACE PRESSURE GRADIENTS TIGHTEN
AGAIN THIS AFTERNOON WITH GUSTS UP TO 25 KT POSSIBLE SOUTH OF CAPE
FOULWEATHER THROUGH THIS EVENING. WILL MAINTAIN THE SMALL CRAFT
ADVISORY IN EFFECT TODAY. WINDS LOOK TO EASE SLIGHTLY ON TUESDAY
WITH MUCH LOWER CHANCES (30%) OF WIND GUSTS EXCEEDING 21 KT.
SIMILAR CONDITIONS PERSIST THROUGH LATE IN THE WEEK. WIND DRIVEN
SEAS ARE EXPECTED TO REMAIN AROUND 3 TO 6 FT THROUGH THE WEEK. /DH
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM NOON TODAY TO 11 PM PDT THIS EVENING
FOR PZZ253.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 11 PM PDT THIS
EVENING FOR PZZ273.
WWW.WEATHER.GOV/PORTLAND
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