406
FXUS66 KPQR 121139
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
439 AM PDT SUN JUL 12 2026
SYNOPSIS
NEAR NORMAL TEMPERATURES EXPECTED TODAY, THEN
INCREASING MONDAY AND TUESDAY AS A RIDGE AMPLIFIES OVER THE
NORTHERN PLAINS. THE TEMPERATURE AND PRECIPITATION FORECAST
BECOMES MORE UNCERTAIN WEDNESDAY THROUGH FRIDAY, HOWEVER ODDS
ARE LEANING TOWARDS WARMER THAN NORMAL TEMPERATURES CONTINUING
WITH MAINLY DRY CONDITIONS.
SHORT TERM...NOW THROUGH MONDAY NIGHT
NORTH TO NORTHWEST ONSHORE
FLOW EXPECTED TO CONTINUE IN THE LOW LEVELS WITH SOUTHWEST FLOW
IN THE UPPER LEVELS EXPECTED THROUGH MONDAY. HEIGHTS ALOFT
REBOUND TODAY IN THE WAKE OF A WEAK UPPER LEVEL DISTURBANCE,
EXITING TO THE NORTHEAST. THE HREF ENSEMBLE MEAN CONTINUES TO
DEPICT CLOUD COVER BACKBUILDING OFF THE CASCADES AND INTO THE
WILLAMETTE VALLEY AND PORTLAND METRO. BROKEN CLOUD COVER IS ALSO
EXPECTED ALONG THE COAST BUT HAS BEEN MORE SCATTERED. DESPITE
MORNING CLOUDS, AFTERNOON HIGHS ARE EXPECTED TO REACH A FEW
DEGREES HIGHER THAN SATURDAY WITH A TREND TOWARD CLEARING SKIES
IN THE AFTERNOON. INTERIOR LOWLANDS CAN EXPECT UPPER 70S TO LOW
80S WHILE THE COASTAL AREAS SEE THE 60S.
NOT EXPECTING NEARLY AS MUCH CLOUD COVER TO DEVELOP TONIGHT
INTO MONDAY MORNING DUE TO THE WEAKENING PRESSURE GRADIENT AND
THEREFORE, WEAKER ONSHORE FLOW. COULD STILL SEE SOME LOW LEVEL
CLOUDS ALONG THE COAST LINGERING INTO MONDAY MORNING. UPPER
LEVEL HEIGHTS WILL CONTINUE TO INCREASE ON MONDAY AS THE 500 MB
PATTERN AMPLIFIES OVER OVER THE CONUS. A LARGE RIDGE OF HIGH
PRESSURE CENTERED OVER THE NORTHERN PLAINS WILL PERSIST WHILE A
SHORT WAVE DROPS SOUTHWARD ALONG THE WESTERN PERIPHERY OF THE
RIDGE, OFF THE WESTERN CANADA COAST AND TOWARD HE PACNW. LACK OF
MORNING CLOUD COVER AND THE AMPLIFYING PATTERN WILL SUPPORT
INCREASING AFTERNOON TEMPERATURES ON MONDAY, JUMPING INTO THE
MID TO UPPER 80S ACROSS THE INTERIOR LOWLANDS AND MID 60S TO LOW
70S ALONG THE COAST.
IT IS ALSO WORTH NOTING THE POTENTIAL FOR HAZY SKIES IN THE CASCADES
OF EASTERN LANE COUNTY DURING THE AFTERNOON/EVENING HOURS ON SUNDAY
AND MONDAY DUE TO SMOKE COMING FROM A WILDFIRE BURNING IN NORTHWEST
JACKSON COUNTY BETWEEN WIMER, OR AND SHADY GROVE, OR. THE RRFS SMOKE
MODEL BACKS UP THIS EXPECTATION, WITH VERTICALLY INTEGRATED SMOKE
VALUES INCREASING TO NEAR 100 MG/M^2 NEAR THE CASCADE CREST.
FORTUNATELY, SMOKE ALOFT IS NOT EXPECTED TO MIX DOWN TO THE SURFACE
IN EASTERN LANE COUNTY. -19/23
LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
THE WARM CONDITIONS ARE
EXPECTED TO PERSIST INTO TUESDAY AS THE UPPER LEVEL RIDGE
REMAINS IN CONTROL OVER THE AREA. HIGHS IN THE UPPER 80S TO LOW
90S ARE EXPECTED ACROSS THE INTERIOR LOWLANDS AND MID 60S TO
LOW 70S ALONG THE COAST. A WEAK DISTURBANCE IS EXPECTED TO PASS
OVER CENTRAL OREGON AND COULD SUPPORT SHOWERS OR THUNDERSTORMS
ALONG THE CASCADE CREST DURING THE AFTERNOON. PROBABILITIES AT
THIS TIME ARE AROUND 15-30% ALONG THE LANE AND LINN COUNTY
CASCADES.
THE PATTERN CONTINUES TO SHOW A DECENT AMOUNT OF UNCERTAINTY HEADING
INTO WEDNESDAY AND THE REMAINDER OF THE WEEK WITH TEMPERATURE
AND PRECIPITATION DISCREPANCIES AT THE FOREFRONT. ENSEMBLES
CONTINUE TO STRUGGLE WITH A CLOSED LOW THAT IS EXPECTED TO
DEVELOP SOMEWHERE OFF THE SOUTHERN COAST OF BRITISH COLUMBIA AND
INTO THE PACNW. DEVELOPMENT FARTHER NORTH AROUND VANCOUVER
ISLAND WILL SUPPORT ANOTHER DAY OF WARM TEMPERATURES IN THE 80S
WHILE A MORE SOUTHERN DEVELOPMENT OFF THE OREGON COAST WOULD
LEAD TO TEMPERATURES LIKELY IN THE UPPER 70S TO LOW 80S, AT THIS
POINT, ENSEMBLES FAVOR THE FARTHER NORTH DEVELOPMENT WITH
70-80% OF ECMWF MEMBERS AND ~60% OF GFS MEMBERS. NBM SPREAD
BETWEEN THE 10TH-90TH PERCENTILES HAS DECREED FROM AROUND 20
DEGREES TO 15 DEGREES, RANGING FROM THE UPPER 70S TO LOW 90S
NOW. THERE ALSO REMAINS A LOW (10-20%) CHANCE FOR SHOWERS ACROSS
THE AREA WEDNESDAY AFTERNOON AND EVENING. CONFIDENCE INCREASES
FOR DRY WEATHER ON FRIDAY, HOWEVER THE TEMPERATURE FORECAST
REMAINS UNCERTAIN WITH THE NBM 10TH-90TH PERCENTILE FOR HIGHS
RANGING FROM THE LOWER 80S TO UPPER 90S FOR INLAND VALLEYS. -19
AVIATION
A WEAK TROUGH CONTINUES TO MOVE NORTHEAST AWAY FROM
THE AIRSPACE, CONTINUING SOUTHWESTERLY FLOW ALOFT. WHILE SOME
STRATUS MAY BACK BUILD ALONG THE CASCADES TONIGHT, EXPECT VFR
CONDITIONS AT ALL INLAND TERMINALS THROUGH THE TAF PERIOD (LESS
THAN 20% CHANCE OF MVFR CIGS BETWEEN 08-15Z SUN). AS FOR THE
COAST, THERE IS LOW CONFIDENCE FOR CEILING CONDITIONS BETWEEN 07Z
AND 18Z SUN, WITH A 40-50% CHANCE OF MVFR CIGS AT ALL COASTAL
TERMINALS. WHILE MOST COASTAL TERMINALS ARE CURRENTLY VFR, LOW
SCATTERED CLOUDS HAVE STARTED TO DEVELOP SO MVFR CIGS MAY DEVELOP
BY 07-08Z SUN. BY 15-18Z SUN, COASTAL TERMINALS WILL RETURN TO VFR
AND REMAIN SO THROUGH THE REMAINDER OF THE TAF PERIOD. EXPECT
WINDS TO REMAIN GENERALLY LIGHT AND VARIABLE OVERNIGHT, THEN
INCREASE TO AROUND 5-10 KT AND SHIFT NORTHWESTERLY AROUND 18Z SUN.
COASTAL TERMINALS WILL SEE A BIT STRONGER WINDS, GENERALLY 12-17
KT WITH GUSTS UP TO 25 KT BETWEEN 18Z SUN AND 04Z MON.
KPDX AND APPROACHES...VFR WITH NORTHWESTERLY WINDS, LIGHT
OVERNIGHT THEN INCREASING TO AROUND 10 KT BY 18-21Z SUN. 10-20%
CHANCE OF MVFR CIGS BETWEEN 08-14Z SUN. ~12
MARINE
A WEAK AREA OF LOW PRESSURE SITS OFFSHORE AND WILL
SLOWLY MOVE INLAND OVERNIGHT. THE LOW PRESSURE CENTER IS
ENHANCING THE ALREADY PRESENT NORTHWESTERLY SWELL, AND WINDS ARE
INCREASING AROUND BUOY 46029 WHERE GUSTS UP TO 17 KT HAVE BEEN
REPORTED. THESE CONDITIONS ARE NOT NECESSARILY GOING TO AMPLIFY
SIGNIFICANTLY TONIGHT BUT WE WILL SEE A RESPONSE ON SUNDAY.
THE LOW WILL SHIFT INLAND CAUSING SEAS TO SLOWLY BUILD TO 7-9 FT
AT 8-9 SECONDS, AND WINDS WILL BEGIN TO AMPLIFY. WILL SEE SMALL
CRAFT ADVISORY LEVEL WINDS IN THE CENTRAL AND SOUTHERN WATERS AS
EARLY AS LATE SUNDAY MORNING, AND THEN THOSE SPEEDS WILL MOVE
NORTH INCORPORATING THE NORTHERN WATERS. OVERALL, THEY ARE GOING
TO BE HOVERING RIGHT ALONG THE THRESHOLD OF 15 TO 20 KT WITH GUSTS
UP TO 25 KT SO WINDS MAY NOT BE AS WIDESPREAD. HOWEVER, GIVEN THE
INCOMING PATTERN AND THE HIGH PRESSURE DEVELOPING COMBINED WITH
THE DIURNAL COMPONENT TO OUR WIND, THERE IS ENOUGH CONFIDENCE FOR
AT LEAST THIS ADVISORY.
WINDS WILL EASE TO BELOW THRESHOLDS ON MONDAY BUT SEAS WILL REMAIN
AROUND 7-8 FT AT 8 SECONDS THUS LEAVING CHOPPIER CONDITIONS.
BECAUSE OF THIS, COULD SEE THE ADVISORY EXTENDED, BUT AT THIS TIME
CONFIDENCE IS TOO LOW TO PROJECT TOO FAR INTO THE FUTURE GIVEN
ITS MARGINAL NATURE. -27
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 2 AM PDT
MONDAY FOR PZZ251-271.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 11 AM PDT
MONDAY FOR PZZ252-253-272-273.
WWW.WEATHER.GOV/PORTLAND
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