397
FXUS66 KPQR 050510
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
1010 PM PDT SAT JUL 4 2026
UPDATED AVIATION DISCUSSION.
SYNOPSIS
EXPECT WARM AND SUNNY CONDITIONS FOR THE 4TH OF
JULY. TEMPERATURES WARM UP SLIGHTLY TOMORROW AND MONDAY AS HIGH
PRESSURE BUILDS, LEADING TO LOCALIZED MODERATE HEATRISK. AN
UPPER-LEVEL TROUGH MOVING INTO BRITISH COLUMBIA TUESDAY TO
WEDNESDAY WILL COOL TEMPERATURES A FEW DEGREES AND BRING SLIGHT
CHANCES FOR PRECIPITATION ALONG THE SOUTH WASHINGTON COAST.
SEASONABLE TEMPERATURES RETURN THURSDAY TO FRIDAY WITH
PERSISTENT ONSHORE FLOW. MAKE SURE TO PRACTICE WATER SAFETY
WHEN SWIMMING IN LOCAL RIVERS.
SHORT TERM...NOW THROUGH MONDAY NIGHT
SATELLITE IMAGERY AND
SURFACE OBSERVATIONS AS OF EARLY SATURDAY AFTERNOON SHOW SUNNY
SKIES FOR MOST AREAS ACROSS NORTHWEST OREGON AND SOUTHWEST
WASHINGTON AS MORNING STRATUS HAS DISSIPATED FROM DAYTIME
HEATING. THERE IS STILL SOME LINGERING STRATUS ALONG THE COAST,
BUT THAT SHOULD GRADUALLY DISSIPATE THIS AFTERNOON AND BRING
MOSTLY SUNNY SKIES TO THE COAST. EXPECT SEASONABLE TEMPERATURES
FOR THE 4TH OF JULY HOLIDAY WITH AFTERNOON HIGHS PEAKING IN THE
UPPER 70S TO LOW 80S ACROSS INTERIOR VALLEYS AND 60S ALONG THE
COAST. WE STILL HAVE ONSHORE FLOW, SO CAN'T RULE OUT SOME MARINE
CLOUDS OFF THE COAST THIS AFTERNOON AND EVENING. BY TONIGHT,
HIGH RESOLUTION GUIDANCE SUGGESTS ANOTHER RETURN OF WIDESPREAD
MARINE STRATUS ALONG THE COAST.
SUNDAY TO MONDAY, ENSEMBLE GUIDANCE CONTINUES TO SUGGEST HIGH
PRESSURE BUILDING OVER THE PACIFIC NORTHWEST, RESULTING IN
WARMER TEMPERATURES ACROSS THE AREA. HIGH TEMPERATURES ACROSS
INTERIOR VALLEYS ARE FORECAST A FEW DEGREES WARMER TOMORROW IN
THE MID 80S, THEN PEAKING ON MONDAY IN THE UPPER 80S. CHANCES
FOR EXCEEDING 90 DEGREES HAVE DECREASED SINCE YESTERDAY - NOW
ONLY A 10-35% CHANCE ACROSS THE WILLAMETTE VALLEY, 40-50% CHANCE
ACROSS THE UPPER HOOD RIVER VALLEY, AND LESS THAN 10% FOR THE
REST OF THE INTERIOR VALLEYS. HOWEVER, WE'LL STILL HAVE SOME
LOCALIZED MODERATE HEATRISK ON MONDAY WITHIN THE INNER PORTLAND
METRO AND PARTS OF THE GORGE AND UPPER HOOD RIVER VALLEY. THIS
MEANS THIS LEVEL OF HEAT WILL AFFECT THOSE SENSITIVE TO HEAT,
ESPECIALLY THOSE WITHOUT ADEQUATE COOLING OR HYDRATION. LOW
TEMPERATURES IN THE 50S ACROSS THE ENTIRE AREA SHOULD PROVIDE
DECENT OVERNIGHT RELIEF FROM THE HEAT.
IT IS IMPORTANT TO REMEMBER THAT WHILE TEMPERATURES WILL BE
WARM THIS HOLIDAY WEEKEND AND NEXT WEEK, MANY LOCAL
LAKES AND RIVERS REMAIN VERY COLD AND CAN CAUSE COLD WATER
SHOCK. ALSO, RIVERS MAY STILL HAVE SWIFT CURRENTS IN SOME AREAS,
WHICH CAN QUICKLY SWEEP YOU AWAY. PLEASE PRACTICE WATER SAFETY
BY WEARING LIFE JACKETS, VISITING WITH A BUDDY, AND ALWAYS BEING
AWARE OF YOUR SURROUNDINGS. -10
LONG TERM...TUESDAY THROUGH FRIDAY
THE MAJORITY OF ENSEMBLE
MEMBERS CONTINUE TO SHOW AN UPPER-LEVEL TROUGH FROM THE GULF OF
ALASKA MOVING DOWN INTO BRITISH COLUMBIA AND AN UPPER-LEVEL
HIGH IN THE SOUTHWEST UNITED STATES, RESULTING IN ZONAL FLOW
OVER THE PACIFIC NORTHWEST. GIVEN THE MORE NORTHERN TRACK OF THE
INCOMING TROUGH, THE MAJORITY OF OUR AREA IS EXPECTED TO BE
DRY. AN EXCEPTION WOULD BE THE SOUTH WASHINGTON COAST WHERE THIS
SYSTEM FAVORS A SLIGHT CHANCE (15-25%) FOR LIGHT RAIN ON
WEDNESDAY. GIVEN HOW DRY OUR AIR MASS IS AND HOW WEAK THIS
SYSTEM WOULD BE AS IT PASSES THROUGH OUR AREA, FORECAST
PRECIPITATION AMOUNTS ARE MINIMAL (AROUND 0.01" OR LESS).
DESPITE THE LACK OF PRECIPITATION, ONSHORE FLOW WILL INCREASE
MID-WEEK AND SUPPORT TEMPERATURES COOLING A FEW DEGREES CLOSER
TO SEASONAL NORMALS FOR EARLY JULY. WEST-NORTHWESTERLY WINDS ARE
GENERALLY EXPECTED TO BE LIGHT FOR MOST AREAS DURING THIS TIME.
HOWEVER, WILL SEE LOCALLY BREEZIER WINDS ALONG THE CENTRAL
COLUMBIA RIVER GORGE AND UPPER HOOD RIVER VALLEY, WHERE THERE IS
A 25-45% CHANCE FOR AT LEAST ISOLATED WIND GUSTS EXCEEDING 40
MPH TUESDAY AND WEDNESDAY.
AT THE END OF NEXT WEEK, MOST ENSEMBLE MEMBERS SHOW THE
AFOREMENTIONED TROUGH WEAKENING AS IT MOVES EASTWARD THROUGH
BRITISH COLUMBIA. AT THE SAME TIME, ENSEMBLE MEMBERS ARE SHOWING
ADDITIONAL TROUGHING MOVING DOWN FROM THE GULF OF ALASKA INTO
THE NORTHEAST PACIFIC/BRITISH COLUMBIA. THERE STILL REMAINS
UNCERTAINTY WITH THE EXACT PLACEMENT AND MAGNITUDE OF THIS
ADDITIONAL TROUGHING, THUS UNCERTAINTY WITH ANY POTENTIAL
IMPACTS AT THIS TIME. IF THIS PATTERN DOES PAN OUT, THIS WOULD
SUPPORT CONTINUED ONSHORE FLOW WITH SEASONABLE TEMPERATURES.
-10/42
AVIATION
VFR CONDITIONS REMAIN IN PLACE ACROSS THE AIRSPACE
AS SURFACE HIGH PRESSURE CONTINUES TO BUILD OFFSHORE, BUT
CHANCES INCREASE FOR MVFR CIGS WITHIN MARINE STRATUS OVERNIGHT.
ALONG THE COAST, CONFIDENCE IN HIGHER (60-80% CHANCE) IN BKN-OVC
CIGS AT 1.5-2.5 KFT, ALTHOUGH THERE ARE 25-35% CHANCES CIGS
FALL TO IFR, HIGHEST CHANCES ALONG THE NORTH OR AND SOUTH WA
COAST NEAR KAST. GUSTY NORTH WINDS WILL EASE OVERNIGHT, BEFORE
RESTRENGTHENING SUNDAY MORNING TO NEAR 15 KT WITH GUSTS AROUND
25 KT THROUGH THE AFTERNOON AND EVENING.
INLAND, CONFIDENCE IN LOWER IN THE DEVELOPMENT OF MVFR CIGS WITH
35-55% CHANCES, GENERALLY INCREASING NORTHWARD ALONG THE
WILLAMETTE VALLEY AND TO THE EAST NEAR THE CASCADE FOOTHILLS.
HIGHEST CHANCES ARE IN THE PORTLAND AREA INCLUDING KPDX AND
KTTD, WITH CIGS AT 2-3 KFT MOST LIKELY FROM 12-16Z SUN. LOW
CLOUD COVERAGE IS LIKELY TO PEAK AT THE SAME TIME AT OTHER
TERMINALS, BUT CONFIDENCE IS TOO LOW TO INCLUDE EXPLICIT MVFR
CIGS AT THIS TIME. LOW CLOUDS WILL TEND TO MIX OUT BY 17-19Z
SUN, WITH WIDESPREAD VFR CONDITIONS VERY LIKELY THROUGH THE
AFTERNOON. NORTH WINDS ALONG THE WILLAMETTE VALLEY AND NORTHWEST
WINDS IN THE PORTLAND AREA WILL CONTINUE THROUGH THE PERIOD,
EASING TO AROUND 5 KT TONIGHT BEFORE STRENGTHENING TO 8-12 KT BY
SUNDAY AFTERNOON. GUSTS AROUND 20 KT ARE MOST LIKELY ALONG THE
WILLAMETTE VALLEY.
KPDX AND APPROACHES...VFR CONDITIONS EXPECTED TO PREVAIL INTO
TONIGHT BEFORE CHANCES FOR MVFR CIGS WITHIN LOW STRATUS INCREASE
TO 50-55% AFTER 10-12Z SUN. CONFIDENCE IS MARGINALLY HIGHER AT
KTTD, BUT HAVE INCLUDED EXPLICIT MVFR CIGS AT KPDX OVERNIGHT AS
WELL. LOW CLOUD COVERAGE WILL PEAK FROM 12-16Z SUN BEFORE MIXING
OUT THROUGH THE EARLY AFTERNOON, WITH A RETURN TO LARGELY CLEAR
SKIES AND VFR CONDITIONS BY 18-19Z SUN. NORTHWEST WINDS EASE TO
5 KT OR LESS THIS EVENING, THEN INCREASE TO AROUND 10 KT BY
SUNDAY AFTERNOON. -36
MARINE
HIGH PRESSURE OVER THE REGION RESULT IN INCREASING
WINDS AND BUILDING SEAS THROUGH MONDAY. NORTHERLY WINDS WILL
SLOWLY INCREASE THROUGH THIS AFTERNOON AND WILL RESULT IN GUSTS
UP TO 20 KT BY THIS EVENING. WINDS WILL CONTINUE TO STRENGTHEN
WITH GUSTS UP TO 30 KT BY SUNDAY. SEAS WILL ALSO BUILD FROM 4 TO
6 FT TOWARDS 6 TO 8 FT BY SUNDAY. HIGH PRESSURE WILL SLOWLY
BECOME DISPLACED TOWARDS THE START OF NEXT WEEK, THUS EASING
OVERALL CONDITIONS BY MONDAY NIGHT/TUESDAY WHICH IS EXPECTED TO
PERSIST THROUGH THE REMAINDER OF NEXT WEEK. -42
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 11 PM PDT SUNDAY FOR PZZ251-271.
SMALL CRAFT ADVISORY UNTIL 11 PM PDT SUNDAY FOR PZZ252-253-272-
273.
WWW.WEATHER.GOV/PORTLAND
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