256
FXUS66 KPQR 270505 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
1005 PM PDT FRI JUN 26 2026
UPDATED AVIATION DISCUSSION
SYNOPSIS
THE NEXT SEVEN DAYS ARE HIGHLIGHTED BY BELOW
AVERAGE TEMPERATURES FOR THIS TIME OF YEAR WITH PERIODIC CHANCES
FOR RAIN SHOWERS AND A GOOD DEAL OF CLOUD COVER. THE BEST
CHANCES FOR WIDESPREAD RAIN SHOWERS ARE THIS AFTERNOON THROUGH
SATURDAY EVENING WITH A 15-25% CHANCE OF THUNDERSTORMS SATURDAY
AFTERNOON. MOST OF THE SHOWERY ACTIVITY EXPECTED FROM SUNDAY
ONWARD WILL BE FOCUSED OVER THE MOUNTAINS.
DISCUSSION...FRIDAY AFTERNOON THROUGH THURSDAY NIGHT
VISIBLE
SATELLITE IMAGERY FROM EARLY FRIDAY AFTERNOON SHOW WIDESPREAD
STRATUS HAS DISSIPATED FOR MUCH OF THE AREA EAST OF THE COAST
WITH CUMULUS CLOUDS ASSOCIATED WITH DEVELOPING SHOWERS TAKING
PRECEDENCE. A STATIONARY FRONT THAT HAS BEEN SITUATED OFF OF THE
WEST COAST SINCE LATE LAST NIGHT IS FINALLY BEGINNING ITS PUSH
EASTWARD. THE FORCING FROM THIS FRONT ALONG WITH DAYTIME HEATING
WITH THE GAPS IN THE CLOUDS IS ALLOWING FOR MORE CONVECTIVE
SHOWERS TO FORM ACROSS THE REGION. MODEL SOUNDINGS INDICATE
THESE SHOWERS WILL BE PRETTY SHALLOW, THOUGH INSTABILITY COULD
IMPROVE TO AROUND 100 J/KG THIS AFTERNOON, ALLOWING SOME SHOWERS
TO BECOME STRONGER AND PRODUCE PERIODS OF HEAVIER RAIN AND
POSSIBLY A LIGHTNING STRIKE OR TWO. GIVEN THE SHOWERY NATURE OF
PRECIPITATION TODAY AND TONIGHT, ADDITIONAL RAIN AMOUNTS WILL
VARY SIGNIFICANTLY FROM LOCATION TO LOCATION, WITH SOME SPOTS
PICKING UP ONLY A FEW HUNDREDTHS OF AN INCH AND OTHERS PICKING
UP OVER 0.25 INCHES. THE LOWEST RAIN AMOUNTS ARE FAVORED IN THE
WILLAMETTE VALLEY TO THE WEST OF THE I-5 CORRIDOR WHERE RAIN
SHADOWING ON THE LEEWARD SIDE OF THE COAST RANGE IS EXPECTED;
THESE AREAS HAVE ONLY A 1-5% CHANCE FOR OVER 0.25 INCHES OF RAIN
BETWEEN 5 AM PDT FRIDAY AND 5 AM PDT SATURDAY. MEANWHILE, THE
COAST, COASTAL MOUNTAINS, CASCADES, AND CASCADE FOOTHILLS HAVE A
65-95% CHANCE. EXPECT HIGH TEMPERATURES MAINLY IN THE 60S TODAY,
EXCEPT 50S IN THE CASCADES AND ALONG THE COAST.
FORECAST RAIN AMOUNTS INCREASE FOR ALL LOCATIONS FROM THE COAST
TO THE CASCADES ON SATURDAY WITH TEMPERATURES REMAINING COOL.
THE SURFACE FRONT WILL PASS THROUGH THE REGION TONIGHT, AND A
CLOSED UPPER LEVEL LOW CURRENTLY CENTERED OFF THE B.C. COAST
WILL BEGIN MOVING DIRECTLY OVER THE PACIFIC NORTHWEST SATURDAY,
BRINGING INCREASING MOISTURE, INSTABILITY, AND LIFT. FORECAST
REFS ENSEMBLE MEAN SOUNDINGS DEPICT STEEPENING MID- LEVEL LAPSE
RATES SATURDAY AFTERNOON WITH SURFACE-BASED CAPE VALUES
INCREASING TO 200-300 J/KG AND EQUILIBRIUM LEVELS INCREASING
CLOSE TO 20,000 FEET. THIS SUGGESTS SOME HEAVIER SHOWERS AND
ISOLATED SHORT- LIVED THUNDERSTORMS WILL BE POSSIBLE, AND NBM
THUNDER PROBABILITIES OF 15-25% BACK THIS UP. GIVEN THE WEAK
ENVIRONMENTAL WIND SHEAR PROFILE IN PLACE, THE MAIN HAZARD WITH
STRONGER SHOWERS OR THUNDERSTORMS WOULD BE BRIEF HEAVY RAIN AND
PONDING OF WATER IN LOW-LYING URBAN AREAS. IT IS ALSO WORTH
MENTIONING THAT ISOLATED NON-MESOCYCLONIC COLD AIR FUNNEL CLOUDS
ARE OCCASIONALLY OBSERVED IN THIS TYPE OF WEATHER PATTERN,
HOWEVER THE ROTATION WITH THESE TYPICALLY FAILS TO LOWER TO THE
GROUND AND THUS DAMAGE DOES NOT OCCUR. IF ROTATION WITH ONE OF
THESE WERE TO LOWER TO THE GROUND, IT WOULD BE CONSIDERED A WEAK
LANDSPOUT, AND DAMAGE WITH THESE IS EXTREMELY ISOLATED IF ANY
OCCURS AT ALL. NOTE PROBABILITIES FOR 24-HOUR RAIN AMOUNTS OVER
0.25 INCHES ARE HIGHER ON SATURDAY COMPARED TO FRIDAY, PEAKING
BETWEEN 70-95% ALONG AND EAST OF THE I-5 CORRIDOR TO THE CASCADE
CREST, 30-50% WEST OF THE I-5 CORRIDOR WITHIN THE WILLAMETTE
VALLEY, AND 50-80% FOR THE COAST AND COASTAL MOUNTAINS.
LOCATIONS THAT OBSERVE REPEATED HEAVY SHOWERS COULD SEE OVER
0.5-1.0 INCHES OF RAIN, ESPECIALLY IN THE CASCADE FOOTHILLS.
RAIN AMOUNTS TREND MUCH LIGHTER ON SUNDAY AS THE UPPER LEVEL
LOW SHIFTS EASTWARD INTO IDAHO. HOWEVER, AT LEAST SOME LIGHT
SHOWERS WILL LINGER OVER THE AREA WITH MOIST ONSHORE FLOW ON
THE BACKSIDE OF THE LOW, ESPECIALLY OVER HIGHER TERRAIN. SUNDAY
WILL ALSO BE ANOTHER COOL DAY WITH A GOOD DEAL OF CLOUD COVER
AND HIGHS IN THE 60S ACROSS THE LOWLANDS. GENERAL LONGWAVE
TROUGHING OVER THE WESTERN US CONTINUES MONDAY THROUGH
WEDNESDAY, KEEPING TEMPERATURES COOLER THAN AVERAGE
TEMPERATURES WITH SHOWER CHANCES CONTINUING, MAINLY CONFINED TO
THE MOUNTAINS. -23/03
AVIATION
COOL/MOIST ONSHORE FLOW AND WIDESPREAD CLOUD COVER
WILL PERSIST ACROSS THE AIRSPACE THROUGH THE TAF PERIOD.
PRECIPITATION WILL CONTINUE TO DECREASE, BUT EXPECT A RETURN OF
LIGHT SHOWERY PRECIPITATION TO THE COAST AROUND 07Z-10Z SATURDAY
FOR THE COAST AND AROUND 10Z-12Z SATURDAY FOR INLAND LOCATIONS.
CURRENTLY, EXPECT A MIXTURE OF MVFR TO LIFR CONDITIONS ALONG THE
COAST WHICH WILL BECOME MORE MVFR/IFR WITH OCCASIONAL ROUNDS OF
VFR AS SHOWER ACTIVITY INCREASES AFTER 10Z SATURDAY. INLAND LOCATIONS
WILL MAINTAIN GENERALLY VFR CONDITIONS, BUT SHOWERS WILL RESULT
IN PERIODS OF MVFR CONDITIONS AFTER 12Z SATURDAY. GENERALLY
SOUTHWESTERLY WINDS WILL BECOME MORE WESTERLY BEHIND THE FRONTAL
PASSAGE AROUND 12Z-15Z SATURDAY. WINDS AT OR BELOW 10 KT THROUGH
THE TAF PERIOD.
INSTABILITY WILL INCREASE THROUGH THE DAY AND WILL RESULT IN A
15-30% CHANCE OF THUNDERSTORMS FOR ALL INLAND LOCATIONS STARTING
AROUND 18Z SATURDAY THROUGH 00Z SUNDAY. HAVE INCLUDED PROB30S FOR
INLAND TAF LOCATIONS. ANY THUNDERSTORMS THAT DO DEVELOP, COULD
PRODUCE LIGHTING ALONG WITH GUSTY AND ERRATIC WINDS.
KPDX AND APPROACHES...GENERALLY VFR CONDITIONS THROUGH THE TAF
PERIOD. SHOWERY PRECIPITATION WILL START AROUND 10Z-12Z SATURDAY
AND WILL PERSIST THROUGH THE TAF PERIOD. THERE IS A 15-30% CHANCE
OF THUNDERSTORMS STARTING AROUND 18Z SATURDAY THROUGH 00Z SUNDAY.
HAVE INCLUDED A PROB30 GROUP WITHIN THE TAF PACKAGE. GENERALLY
SOUTHWESTERLY WINDS WILL BECOME MORE WESTERLY BEHIND THE FRONTAL
PASSAGE AROUND 12Z-15Z SATURDAY. WINDS AT OR BELOW 10 KT THROUGH
THE TAF PERIOD. /42
MARINE
WINDS AND SEAS WILL INCREASE SATURDAY INTO SUNDAY AS
A PAIR OF FRONTS MOVE SOUTHWARD OVER THE COASTAL WATERS AND
PERSISTENT NORTHWESTERLY WINDS ALLOW FOR THE DEVELOPMENT OF A
FRESH NORTHWEST SWELL UPWARDS OF 7-9 FT AT 9-10 SECONDS, HIGHEST
OVER THE OUTER WATERS BEYOND 10 NM OFFSHORE. GIVEN SEAS WILL
BECOME STEEPER AND WINDS WILL GUSTS UP TO 20-25 KT OVER THE
OUTER WATERS, A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE
OUTER WATERS FROM SATURDAY MORNING THROUGH SUNDAY NIGHT.
ALTHOUGH HIGH PRESSURE BUILDS OVER THE WATERS ON MONDAY, NORTHWEST
WINDS WILL PERSIST AND WILL MAINTAIN A FRESH NORTHWEST SWELL WITH
SIGNIFICANT WAVE HEIGHTS PEAKING NEAR AT LEAST 8-11 FT. THERE IS
A 20-40% CHANCE SIGNIFICANT WAVE HEIGHTS WILL PEAK OVER 11 FT
BEYOND 30 NM OFFSHORE ON MONDAY, MAINLY TO THE NORTH OF CAPE
FOULWEATHER. ~12/23
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 5 AM SATURDAY TO 11 PM PDT SUNDAY
FOR PZZ271>273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page