839
FXUS66 KPQR 122059
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
158 PM 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 LATE WEDNESDAY INTO THURSDAY, HOWEVER CHANCES
FOR RAIN SHOWERS DURING THAT TIME HAVE INCREASED WITH THE LATEST
FORECAST UPDATE. TRENDING WARM AND DRY FRIDAY AND SATURDAY.
SHORT TERM...SUNDAY AFTERNOON THROUGH TUESDAY NIGHT
SATELLITE
OBSERVATIONS FROM EARLY SUNDAY AFTERNOON DEPICTED MOSTLY CLEAR SKIES
ACROSS SOUTHWEST WA AND NORTHWEST OR. SURFACE HIGH PRESSURE REMAINS
IN PLACE WITH LOW-LEVEL ONSHORE FLOW AND DRY SOUTHWEST FLOW ALOFT.
EXPECT THIS TREND TO CONTINUE THROUGH TUESDAY, ASIDE FROM A PERIOD OF
CLOUDIER SKIES ALONG THE COAST TUESDAY MORNING.
CONFIDENCE REMAINS HIGH FOR NOTICEABLY WARMER TEMPERATURES MONDAY
INTO TUESDAY AS 500 MB HEIGHTS AND 850 MB TEMPERATURES RISE AHEAD OF
A DEVELOPING CLOSED UPPER LEVEL LOW THAT WILL BE CENTERED SOMEWHERE
OVER THE FAR NORTHEAST PACIFIC EARLY IN THE WEEK. TOTAL MODEL SPREAD
FOR HIGH TEMPERATURES ON MONDAY AND TUESDAY REMAINS VERY NARROW, WITH
INLAND VALLEYS EXPECTED TO WARM INTO THE UPPER 80S TO NEAR 90
DEGREES, WARMEST ON TUESDAY. ONSHORE WINDS WILL KEEP THE COAST MUCH
COOLER WITH HIGHS RANGING BETWEEN 65-70 DEGREES. DRY CONDITIONS WILL
CONTINUE SUNDAY AFTERNOON THROUGH TUESDAY NIGHT, WITH ONE POTENTIAL
EXCEPTION IN THE HIGH CASCADES OF LANE AND LINN COUNTIES LATE TUESDAY
AFTERNOON THROUGH TUESDAY EVENING. THIS AREA HAS A 15-35% CHANCE OF
RAIN SHOWERS AND A 10% CHANCE OF THUNDERSTORMS DURING THAT TIME WITH
THE PASSAGE OF A WEAK UPPER LEVEL IMPULSE. COMPOSITE REFLECTIVITY
GUIDANCE FROM THE NAM NEST AND THE RRFS MODEL BOTH SUGGEST THE VAST
MAJORITY OF CONVECTION ON TUESDAY WILL OCCUR EAST OF THE CASCADE
CREST, WHICH MAKES SENSE GIVEN THE SOUTH-SOUTHWEST TO SOUTHWEST WINDS
ALOFT EVIDENT IN FORECAST SOUNDINGS.
IT IS ALSO WORTH NOTING THE POTENTIAL FOR HAZY SKIES IN THE CASCADES
OF EASTERN LANE COUNTY DURING THE LATE AFTERNOON/EVENING HOURS 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 25 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...WEDNESDAY THROUGH SATURDAY NIGHT
THE UPPER LEVEL LOW
RESPONSIBLE FOR WARMER TEMPERATURES MONDAY AND TUESDAY WILL BE THE
SAME LOW RESPONSIBLE FOR UNCERTAINTY IN THE FORECAST LATE WEDNESDAY
INTO THURSDAY, PARTICULARLY IN REGARDS TO THE TEMPERATURE AND
PRECIPITATION FORECAST. ALTHOUGH MODEL ENSEMBLE GUIDANCE IS IN GOOD
AGREEMENT REGARDING THE DEVELOPMENT OF A CLOSED LOW SOMEWHERE OVER
THE FAR NORTHEAST PACIFIC EARLY IN THE WEEK, GUIDANCE BEGINS TO VARY
MORE WHEN IT COMES TO THE STRENGTH AND TRACK OF THIS LOW LATE
WEDNESDAY INTO THURSDAY. AROUND 60% OF THE MULTI-MODEL ENSEMBLE
(GEFS/GEPS/ENS) SUGGESTS THE LOW WILL TRACK DIRECTLY OVER THE WA
AND/OR NORTH OR COAST, WHILE THE REMAINING 40% SUGGESTS THE LOW WILL
STAY NEARLY STATIONARY OFFSHORE WHILE WEAKENING. IF THE LOW DOES MOVE
INLAND AND TAKES A TRACK TOWARDS WESTERN WA OR NORTHWEST OR, EXPECT
TEMPERATURES TO END UP COOLER THAN THE CURRENT DETERMINISTIC FORECAST
WITH INCREASING CHANCES FOR RAIN SHOWERS. IF THE LOW STALLS OFFSHORE
AND WEAKENS, CONDITIONS WILL TREND WARMER AND MAINLY DRY, ASIDE FROM
CHANCES FOR SHOWERS AND ISOLATED THUNDERSTORMS IN THE CASCADES GIVEN
THE PERSISTENT SOUTHERLY FLOW ALOFT THIS SET-UP WOULD RESULT IN.
TOTAL MODEL SPREAD FOR HIGH TEMPERATURES ON THURSDAY REMAINS LARGE
DUE TO THIS UNCERTAINTY, WITH INLAND HIGHS RANGING ANYWHERE FROM THE
UPPER 70S TO MID 90S PER THE NBM 10TH-90TH PERCENTILE.
ONE THING WORTH NOTING IS CHANCES FOR A LOW TRACK THAT IS MORE
FAVORABLE FOR SHOWERS IN SOUTHWEST WA AND NORTHWEST OR, INCLUDING
LOCATIONS WEST OF THE CASCADES, HAVE INCREASED WHEN COMPARED TO
YESTERDAY. THE LATEST NBM GUIDANCE REFLECTS THIS WELL AND HAS
INCREASED POPS TO 20-40% WEDNESDAY NIGHT INTO THURSDAY. CHANCES FOR
AT LEAST 0.25 INCHES OF RAIN OR MORE HAVE ALSO INCREASED AND NOW
RANGE BETWEEN 10-20% ACROSS ALL OF NORTHWEST OR AND SOUTHWEST WA FROM
THE COAST TO THE CASCADE CREST, WITH THE HIGHEST PROBABILITIES OVER
SOUTHWEST WA, THE NORTH OR COAST/COAST RANGE, LOWER COLUMBIA, AND
PORTLAND METRO. THERE IS A 1-10% CHANCE FOR 0.50 INCHES OF RAIN OR
MORE, WHICH REPRESENTS THE WETTEST MODEL SOLUTIONS.
CONFIDENCE IN THE FORECAST ACTUALLY INCREASES A BIT FRIDAY INTO
SATURDAY. THIS IS WHEN MODEL ENSEMBLE GUIDANCE IS IN GOOD AGREEMENT
FOR DRY AND WARM CONDITIONS, WITH HIGH TEMPERATURES SOMEWHERE IN THE
80S OR 90S FOR INLAND VALLEYS. CHANCES FOR HIGHS OF 90 DEGREES OR
WARMER PEAK ON SATURDAY AT 50-60% ACROSS THE WILLAMETTE VALLEY,
PORTLAND METRO, COLUMBIA RIVER GORGE, AND UPPER HOOD RIVER VALLEY.
CHANCES FOR HIGHS ABOVE 100 DEGREES ARE AROUND 1-10%, SUGGESTING
EXTREME HEAT AND SIGNIFICANT HEAT-RELATED IMPACTS ARE UNLIKELY TO
OCCUR NEXT WEEKEND. -23
AVIATION
HIGH PRESSURE BUILDS OVER THE REGION WITH WIDESPREAD
VFR CONDITIONS. WINDS ARE LARGELY NORTHERLY AROUND 5-8 KT, BUT
AREAS THAT ARE NORTH-SOUTH ALIGNED LIKE THE WILLAMETTE VALLEY ARE
ALREADY SEEING GUSTS UP TO 15 KT. THIS WILL BE THE TREND THROUGH
THE DAY WITH WINDS INCREASING ALONG THE COAST THIS AFTERNOON UP TO
25 KT. UNCERTAINTY MOVES IN TONIGHT WITH WHETHER OR NOT MVFR
CONDITIONS RETURN. BASED ON THE PATTERN, THERE IS AROUND A 40-50%
CHANCE OF MVFR AND AROUND A 10% CHANCE OF IFR CIGS AFTER 08Z MON
ALONG THE COAST. HIGH RESOLUTION MODELS THOUGH ARE NOT PROJECTING
PERVASIVE CLOUDS BUT RATHER PATCHY. THEREFORE, TERMINALS LIKE KONP
AND KAST COULD SEE MORE VARIABLE CONDITIONS OVERNIGHT. KTTD WILL
SEE SIMILAR STRUGGLES WITH ANY BACKBUILDING OFF OF THE CASCADES.
LARGELY THOUGH, VFR CONDITIONS WILL PREVAIL INLAND.
KPDX AND APPROACHES...VFR WITH NORTHERLY WINDS OVER THE NEXT 24
HOURS. LESS THAN A 20% CHANCE OF MVFR CIGS TONIGHT. -27
MARINE
HIGH PRESSURE OVER THE WATERS WITH A TYPICAL SUMMER TIME
PATTERN. FLOW REMAINS NORTH TO NORTHWEST WITH A THERMAL TROUGH
FORMING ALONG THE COAST. WINDS ARE GENERALLY 8-10 KT BUT WILL
CONTINUE TO RISE THROUGH THE AFTERNOON WITH GUSTS UP TO 25 KT.
ALONG THE COASTLINE AND MOORAGES, GUSTS UP TO 25 KT HAVE BEEN
REPORTED. SMALL CRAFT ADVISORY (SCA) WINDS ARE EXPECTED WITH
SUSTAINED WINDS OF 15-20 KT AND GUSTS TO 25 KT OVER MUCH OF THE
WATERS, BUT LATEST MODELS HAVE REDUCED COVERAGE IN THE NORTHERN
WATERS. OVERALL, THE SCA IS MARGINAL AND WILL LIKELY FLUCTUATE
BELOW AND ABOVE CRITERIA. WINDS WILL EASE OVERNIGHT INTO MONDAY
MORNING AND THEREFORE HAVE SHORTENED THE LENGTH OF TIME FOR THE
HAZARD. SEAS WILL BE AROUND 5-7 FT AT 6-8 SECONDS. COULD SEE
PERIODS OF CHOPPIER SEAS, BUT NOT NECESSARILY WIDESPREAD ENOUGH
FOR HAZARDOUS SEAS. CONDITIONS THE REST OF THE WORK WEEK ARE
EXPECTED TO BE BENIGN WITH WIND WAVES RAMPING UP ON SATURDAY.
A SCA HAS BEEN ISSUED AS WELL FOR ROUGH SEAS IN THE COLUMBIA RIVER
BAR DUE TO A STRONG EBB AND SEAS OF 7 FT. -27
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 1 AM TO 7 AM PDT MONDAY FOR PZZ210.
SMALL CRAFT ADVISORY UNTIL 2 AM PDT MONDAY FOR PZZ251>253-
271>273.
WWW.WEATHER.GOV/PORTLAND
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