580
FXUS66 KPQR 140850
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
150 AM PDT FRI AUG 14 2026
SYNOPSIS
WARM AND DRY CONDITIONS EXPECTED THROUGH NEXT WEEK
WITH PERSISTENT ONSHORE FLOW. SLIGHT CHANCES (10-20%) FOR
THUNDERSTORMS OR SHOWERS OVER THE CASCADES THIS AFTERNOON AND
SATURDAY AFTERNOON, WITH THE HIGHEST CHANCES ALONG THE CREST OF
THE CASCADES.
DISCUSSION...TODAY THROUGH THURSDAY
SATELLITE IMAGERY AND
SURFACE OBSERVATIONS AS OF EARLY FRIDAY MORNING DEPICTS ONSHORE
FLOW SUPPORTING A SOLID MARINE LAYER ALONG THE COAST WITH
STRATUS CLOUDS PUSHING THROUGH THE GAPS OF THE COAST RANGE AND
THROUGH THE LOWER COLUMBIA RIVER INTO THE COWLITZ VALLEY. BY 5-7
AM FRIDAY, EXPECT STRATUS CLOUDS TO MAKE IT'S WAY INTO THE REST
OF THE I-5 CORRIDOR INCLUDING THE WILLAMETTE VALLEY. AFTER 9-11
AM FRIDAY, CLOUDS ACROSS INTERIOR VALLEYS SHOULD BEGIN CLEARING
OUT AS DAYTIME HEATING PROGRESSES AND INCREASES MIXING.
MEANWHILE, THERE REMAINS UNCERTAINTY WITH HOW MUCH CLEARING WILL
OCCUR AT THE COAST. THERE IS ABOUT A 50-60% CHANCE AT ANY GIVEN
HOUR BETWEEN 2-7 PM FOR MARINE STRATUS BREAKING OUT ALONG THE
NORTH OREGON COAST, BUT LOWER CONFIDENCE FOR CLEARING ALONG THE
CENTRAL OREGON COAST.
EXPECT DRY AND WARM CONDITIONS TODAY AND THROUGH THE WEEKEND FOR
THE MAJORITY OF LOCATIONS AS WEAK RIDGING BUILDS OVER THE
PACIFIC NORTHWEST AND AN UPPER LEVEL TROUGH ELONGATES WELL-
OFFSHORE OVER THE NORTHEAST PACIFIC OCEAN. AN EXCEPTION WOULD BE
THE CASCADES, WHERE THERE IS A 10-25% CHANCE FOR ISOLATED
THUNDERSTORMS THIS AFTERNOON AND SATURDAY AFTERNOON. AS
SHORTWAVES FROM THE BROAD PARENT TROUGH OFFSHORE BRINGS MORE
SOUTHERLY FLOW ALOFT OVER THE AREA, WILL SEE INCREASING
INSTABILITY AND MONSOONAL MOISTURE SUPPORTING THESE THUNDERSTORM
CHANCES. ANY THUNDERSTORMS THAT DEVELOP MAY BRING LIGHTNING,
BRIEF HEAVY RAIN, AND ERRATIC WINDS. OTHERWISE, THE GENERAL
AIRMASS REMAINS TOO DRY TO SUPPORT ANY WIDESPREAD PRECIPITATION
WEST OF THE CASCADES. GUIDANCE SUGGESTS HIGH CONFIDENCE FOR NEAR
TO SLIGHTLY ABOVE AVERAGE TEMPERATURES FOR MID-AUGUST THROUGH
THE WEEKEND, WITH AFTERNOON HIGHS WARMING INTO THE MID TO UPPER
80S ACROSS INTERIOR VALLEYS.
EARLY NEXT WEEK, CLUSTER ANALYSIS OF 500 MB HEIGHTS CONTINUE TO
SUGGEST DRY AND SEASONABLY WARM CONDITIONS AS BROAD UPPER LEVEL
TROUGHING REMAINS WELL-OFFSHORE AND AN UPPER LEVEL RIDGE AXIS
OVER THE ROCKIES TILTS INTO THE PACIFIC NORTHWEST. BY MID-WEEK,
ENSEMBLES DIVERGE INTO VARIOUS UPPER LEVEL PATTERNS. A LITTLE
OVER HALF OF ENSEMBLE MEMBERS ARE FAVORING A TROUGH ENTERING THE
PACIFIC NORTHWEST AND RETURNING COOLER TEMPERATURES, WHILE THE
OTHER HALF FAVORS WARMER CONDITIONS DUE TO ZONAL FLOW OR
AMPLIFIED RIDGING. EITHER WAY, NO PRECIPITATION IS FORECAST AS
WE MAINTAIN A DRY SUMMERTIME AIRMASS. -10
AVIATION...THROUGH 06Z SAT
WEST TO SOUTHWESTERLY FLOW ALOFT
AS AN UPPER LEVEL TROUGH REMAINS OVER THE AIRSPACE. MVFR/IFR
CONDITIONS HAVE DEVELOPED ALONG THE COAST IN MARINE STRATUS.
THESE CONDITIONS WILL CONTINUE THROUGH THE MAJORITY OF THE TAF
PERIOD WITH A 50-70% CHANCE OF LIFR CIGS AT ANY GIVEN HOUR
THROUGH 18Z FRI. THERE'S A 20-40% CHANCE THAT STRATUS COULD
BRIEFLY IMPROVE TO VFR ALONG THE COAST AT ANY POINT THROUGH 18Z
FRI THROUGH 02Z SAT, THOUGH THIS IMPROVEMENT WOULD NOT LAST
LONG. NORTHWEST TO WEST WINDS LESS THAN 8 KTS CONTINUE ALONG THE
COAST THROUGH THE TAF PERIOD.
PREDOMINATELY VFR CONDITIONS EXPECTED FOR INLAND TERMINALS
THROUGH THE TAF PERIOD. THERE'S THE POTENTIAL FOR MARINE
STRATUS TO PUSH INLAND IN THE EARLY MORNING HOURS WITH A 20-40%
CHANCE OF MVFR CIGS FOR MOST INLAND TERMINALS EXCEPT FOR A
50-70% CHANCE AT KEUG AT ANY HOUR BETWEEN 10-18Z FRI.
ADDITIONALLY, SMOKE ALOFT CONTINUES TO IMPACT NW OR AND SW WA
AND COULD MIX DOWN TO THE SURFACE AT TIMES. SMOKE COULD IMPACT
SLANT RANGE VISIBILITIES FOR INLAND LOCATIONS THROUGH FRIDAY
AFTERNOON. NORTH TO NORTHWEST WINDS BECOME LIGHT AND VARIABLE
OVERNIGHT THROUGH FRIDAY MORNING, BECOMING WESTERLY AFTER 18Z
FRI.
KPDX AND APPROACHES...GENERALLY VFR CONDITIONS THROUGH THE TAF
PERIOD. THERE'S A 30-50% CHANCE OF MVFR CIGS DEVELOPING AT ANY
HOUR BETWEEN 12-18Z FRI. SMOKE IN THE MID LEVELS COULD IMPACT
SLANT RANGE VISIBILITIES THROUGH FRIDAY AFTERNOON AND MIX TO THE
SURFACE AT TIMES. NORTHWEST WINDS LESS THAN 6 KTS BECOME
VARIABLE OVERNIGHT THROUGH FRIDAY AFTERNOON, BECOMING NORTHWEST
AGAIN AFTER 22Z FRI. -03
MARINE
NO SIGNIFICANT CHANGES IN THE OVERALL PATTERN AS HIGH
PRESSURE OFFSHORE WILL CONTINUE TO SUPPORT NORTHERLY WINDS ALONG
WITH BENIGN CONDITIONS ACROSS ALL WATERS THROUGH NEXT WEEK. WINDS
FROM THE NORTH TO NORTHWEST WITH GUSTS LESS THAN 21 KTS WILL
CONTINUE THROUGH AT LEAST THE WEEKEND, WITH WIND DRIVEN SEAS
EXPECTED TO REMAIN AROUND 3-5 FT. -10/42
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
WWW.WEATHER.GOV/PORTLAND
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