244
FXUS66 KPQR 152030
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
130 PM PDT SAT AUG 15 2026
SYNOPSIS
SEASONABLY WARM AND DRY CONDITIONS EXPECTED THROUGH
THE NEXT WEEK WITH MORNING CLOUDS AND AFTERNOON CLEARING. LOW
CHANCES FOR CASCADE THUNDERSTORMS THIS AFTERNOON, WHICH MAY
RESULT IN LIGHTNING WITH BRIEFLY HEAVY RAIN AND ERRATIC WINDS.
DISCUSSION...NOW THROUGH FRIDAY
SEASONABLE CONDITIONS WITH NO
WEATHER IMPACTS EXPECTED THROUGH THE NEXT WEEK. THE LARGE-SCALE
PATTERN LOOKS TO REMAIN FAIRLY STAGNANT THROUGH THE PERIOD, WITH
BROAD AND RELATIVELY FLAT UPPER-LEVEL RIDGING OVER THE MAJORITY
OF CONUS AND WEAK POSITIVELY-TILTED UPPER TROUGHING OVER THE
NORTHEAST PACIFIC. THIS PATTERN WILL SUPPORT CONTINUED ONSHORE
FLOW, MAINTAINING NEAR-NORMAL DAILY HIGH TEMPERATURES IN THE
80S WITHIN INLAND VALLEYS AND 60S ALONG THE COAST, AND OVERNIGHT
LOWS IN THE 50S ACROSS THE REGION.
A TRANSIENT SHORTWAVE TRACKING OVERHEAD TODAY YIELDED ISOLATED
LIGHT RAIN SHOWERS THIS MORNING, HOWEVER DRY CONDITIONS ARE
EXPECTED THROUGH THE REMAINDER OF THE DAY WEST OF THE CASCADES
AS THE BEST FORCING SLIDES NORTHWARD INTO WASHINGTON. THE ROBUST
MARINE LAYER HAS THUS FAR SUPPORTED OVERCAST SKIES, BUT LATEST
SATELLITE IMAGERY DEPICTS CLOUD COVER BEGINNING TO ERODE, WITH
INCREASED SUNSHINE EXPECTED THROUGH THIS AFTERNOON. ABOVE THE
LOW-LEVEL INVERSION, THERE IS SOME AVAILABLE INSTABILITY TO
GENERATE HIGH-BASE SHOWERS OR THUNDERSTORMS, BUT THOSE LOW
CHANCES (15-25%) ARE RESTRICTED TO THE CASCADES WHERE SHOWERS OR
STORMS MAY INSTEAD BE SURFACE-BASED. ANY PASSING STORMS WILL BE
CAPABLE OF PRODUCING LIGHTNING AS WELL AS BRIEFLY HEAVY RAIN AND
ERRATIC WINDS. CHANCES FOR THUNDER FALL BELOW 5% THIS EVENING.
THE NEXT CHANCE FOR LIGHT SHOWERS OR CASCADE THUNDERSTORMS
APPEARS TO BE ON MONDAY WHEN THE NEXT WEAK SHORTWAVE PASSES
OVERHEAD, HOWEVER THE PROBABILITY OF ACCUMULATING RAIN IS LESS
THAN 5% AWAY FROM THE IMMEDIATE CASCADE CREST. THERE IS
INCREASING CONSENSUS THAT UPPER-LEVEL RIDGING OVER THE ROCKIES
AND GREAT BASIN WILL BUILD LATE IN THE WORKWEEK, WHICH COULD
FAVOR WARMER TEMPERATURES THURSDAY AND FRIDAY AFTERNOONS. A
POTENTIAL PASSING SYSTEM FRIDAY INTO NEXT WEEKEND WILL BRING
HIGHER CHANCES FOR RAINFALL, HOWEVER UNCERTAINTY REMAINS HIGH
AT THIS LEAD TIME. -36
AVIATION...THROUGH 18Z SUNDAY
WIDESPREAD MARINE STRATUS WEST
OF THE CASCADES CONTINUES TO SUPPORT LOW-END MVFR CIGS AT
1.5-2 KFT ACROSS THE AIRSPACE LATE THIS MORNING. MODEST CLEARING
WILL SEE A TREND TO VFR CIGS INLAND BY 19-21Z SAT AND HIGH-END
MVFR CIGS WITH A 40-50% CHANCE OF VFR CIGS AT COASTAL TERMINALS
BY 21-23Z SAT. ISOLATED RAIN SHOWERS HAVE LARGELY DISSIPATED
ASIDE FROM ALONG THE CASCADES, WITH THE CHANCES FOR RAIN OR
THUNDER NOW AT 10% OR LESS WEST OF THE MOUNTAINS. OTHERWISE,
HAZY SKIES MAY CONTINUE TO RESTRICT SLANTWISE VIS WHILE TERMINAL
OBSERVATIONS MAINTAIN 7-10 SM AT THE SURFACE. LIGHT WINDS THIS
MORNING WILL BUILD TO 5-10 KT OUT OF THE NORTHWEST THIS
AFTERNOON, THEN EASE BELOW 5 KT TONIGHT.
KPDX AND APPROACHES...LOW-END MVFR CIGS BELOW 2 KFT ARE EXPECTED
TO TREND TO VFR AS SKIES CLEAR AND CLOUD BASES LIFT, WITH A 50%
CHANCE OF VFR CONDITIONS BY 20Z SAT. WEST TO NORTHWEST WINDS
EXPECTED THROUGHOUT THE PERIOD, INCREASING TO AROUND 5 KT THIS
AFTERNOON, THEN EASING TONIGHT. -36
MARINE
A LARGELY STAGNANT PATTERN CONTINUES THROUGH MUCH OF
THE NEXT WEEK WITH HIGH PRESSURE OFFSHORE SUPPORTING NORTHERLY
TO NORTHWESTERLY WINDS OF 8-15 KT AND GUSTS UP TO 20 KT. BENIGN
SEAS OF 3-6 FT PERSIST THROUGH THE PERIOD. -36
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
WWW.WEATHER.GOV/PORTLAND
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