992
FXUS66 KPQR 112148
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
248 PM PDT MON AUG 11 2025
SYNOPSIS
HOT WEATHER CONTINUES THROUGH TUESDAY UNDER STRONG HIGH
PRESSURE, WITH VALLEY HIGHS NEAR OR ABOVE 100 DEGREES IN SOME
LOCATIONS. POOR OVERNIGHT TEMPERATURE RECOVERY IS EXPECTED
TONIGHT, WITH LOWS ONLY FALLING INTO THE MID TO UPPER 60S FOR
MOST, AND EVEN NEAR 70 DEGREES IN URBAN AREAS. COOLER AIR
ARRIVES WEDNESDAY AS ONSHORE FLOW STRENGTHENS AND WINDS SHIFT
WEST NORTHWESTERLY, BRINGING MORE SEASONAL TEMPERATURES THROUGH
LATE WEEK. BY FRIDAY AND INTO THE WEEKEND, A DEVELOPING FALL-
LIKE TROUGH WILL BRING MEASURABLE RAINFALL AND BREEZIER
CONDITIONS.
SHORT TERM...NOW THROUGH TUESDAY NIGHT
STRONG HIGH PRESSURE
REMAINS FIRMLY IN PLACE OVER THE EASTERN PACIFIC, KEEPING SKIES
CLEAR AND TEMPERATURES WELL ABOVE AVERAGE. AFTERNOON HIGHS
TODAY ARE TOPPING OUT IN THE UPPER 90S TO MAYBE 100 FOR MUCH OF
THE INTERIOR VALLEYS, PRODUCING ELEVATED HEAT RISK FOR MOST
LOWLAND AREAS. WINDS ARE GENERALLY LIGHT, THOUGH LOCALIZED
BREEZES ARE DEVELOPING NEAR THE COAST.
TUESDAY WILL REMAIN HOT, WITH HIGHS AGAIN IN THE UPPER 90S TO
LOW 100S. WHILE THE RIDGE BEGINS TO SHIFT SLIGHTLY WESTWARD
INTO THE OPEN PACIFIC, ANY COOLING WILL BE NEGLIGIBLE AS THE
UPPER LEVEL AIRMASS WILL REMAIN AROUND 22-23C. THE COLUMBIA
RIVER GORGE WILL SEE INCREASING WINDS TUESDAY NIGHT INTO
WEDNESDAY, WITH GUSTS UP TO 30 MPH POSSIBLE AS PRESSURE
GRADIENTS TIGHTEN. ELSEWHERE, STRONGER ONSHORE FLOW WILL BEGIN
TO TAKE HOLD LATE TUESDAY, BRINGING THE FIRST SIGNS OF COOLING
AND HELPING OVERNIGHT LOWS DROP FURTHER INTO THE 60S AND INTO
THE UPPER 50S IN COOLER RURAL LOCATIONS. OTHERWISE, COASTAL FOG
AND LOW CLOUDS MAY DEVELOP EARLY TUESDAY MORNING.
LONG TERM...WEDNESDAY THROUGH SUNDAY
WEDNESDAY MARKS THE
START OF A NOTABLE COOLDOWN AS HIGH PRESSURE IS REPLACED BY
UPPER-LEVEL TROUGHING OVER WESTERN CANADA. THIS WILL BRING A
SHIFT IN LOW-LEVEL WINDS FROM NORTHWESTERLY TO MORE WEST
NORTHWESTERLY, ENHANCING THE MARINE PUSH INLAND. HIGHS WILL BE
10-15 DEGREES COOLER THAN TUESDAY FOR MANY AREAS, WITH THE
GREATEST CHANGE FELT ACROSS THE NORTH. HEATRISK WILL EASE BACK
INTO THE MINOR CATEGORY, AND OVERNIGHT LOWS WILL RETURN TO MORE
COMFORTABLE VALUES.
THURSDAY THROUGH THE WEEKEND, INLAND HIGHS SHOULD HOLD NEAR OR
SLIGHTLY BELOW SEASONAL NORMS - GENERALLY IN THE UPPER 70S TO
LOW 80S, WITH COASTAL HIGHS IN THE 60S TO LOW 70S. PATCHY
MORNING COASTAL FOG AND LOW CLOUDS MAY DEVELOP THURSDAY MORNING
BEFORE BURNING OFF BY MIDDAY.
RAIN CHANCES INCREASE EARLY FRIDAY INTO SATURDAY AS A DEEPER,
FALL-LIKE TROUGH DIGS INTO THE NORTHEAST PACIFIC. THIS SYSTEM
WILL SHIFT WINDS TO A MORE SOUTHERLY TO SOUTHWESTERLY DIRECTION
FRIDAY AND INTO THE WEEKEND. WIDESPREAD MEASURABLE RAIN IS
POSSIBLE, WITH ENSEMBLE GUIDANCE SHOWING A 40-60% CHANCE OF A
WETTING RAIN FOR THE NORTH COAST AND SOUTHWEST WASHINGTON, ABOUT
45% FOR PORTLAND, AND AROUND 25% NEAR EUGENE. SATURDAY WILL
HAVE LINGERING SHOWERS, AND WHILE THE OVERALL SETUP IS NOT
FAVORABLE FOR THUNDERSTORMS, A FEW LIGHTNING STRIKES CANNOT BE
ENTIRELY RULED OUT - THOUGH CONFIDENCE IS CURRENTLY LOW. BY
SUNDAY, THE TROUGH WEAKENS AND MOVES EAST, ALLOWING TEMPERATURES
TO RETURN TO NEAR SEASONAL NORMS UNDER DRIER CONDITIONS.
~HALL
AVIATION
THIS AFTERNOON VFR CONDITIONS ARE IN PLACE ACROSS THE
REGION WITH CLEAR SKIES OVERHEAD. THE PRIMARY CHALLENGE TONIGHT
WILL BE THE REDEVELOPMENT OF FOG AND LOW STRATUS SOUTH TO NORTH
ALONG THE COAST STARTING BETWEEN 02-08Z. COME 12Z TUESDAY GUIDANCE
SUGGESTS A 40% CHANCE FOR LIFR CIGS/VIS AT KAST AND 70-80% CHANCE
FOR THE SAME CONDITIONS AT KONP. EXPECT CEILINGS TO LIFT AS
TUESDAY MORNING PROGRESSES HOWEVER CONFIDENCE IN THE TIMING FOR A
RETURN TO MVFR OR VFR IS ONLY LOW TO MODERATE AT THIS TIME.
EXPECT GENERALLY NORTHERLY TO NORTHWESTERLY WINDS UNDER 10 KT
THROUGH THE FORECAST PERIOD.
IMPORTANT NOTE: WITH THE ABNORMALLY HOT TEMPERATURES FORECAST
THROUGH TUESDAY AFTERNOON, BE AWARE OF HIGH DENSITY ALTITUDE
CONCERNS (AND REDUCED AIRCRAFT PERFORMANCE AS A RESULT).
PDX AND APPROACHES...VFR WITH CLEAR SKIES THROUGH THE TAF PERIOD.
NORTHWESTERLY WINDS UNDER 10 KT. -SCHULDT
MARINE
A RIDGE OF HIGH PRESSURE OVERHEAD CONTINUES TO MAINTAIN
NORTHERLY WINDS ACROSS THE COASTAL WATERS INTO TUESDAY AND
WEDNESDAY. THAT SAID, THESE WINDS GRADUALLY WEAKEN AS TIME GOES
ON BUT STILL WILL GUST IN THE 15-22 KNOT RANGE DURING THE
AFTERNOON HOURS, ESPECIALLY ACROSS THE OUTER WATERS. EXPECT SEAS
AROUND 7-9 FT AT 10-11 SECONDS THROUGH TUESDAY INTO TUESDAY NIGHT
AS WELL WITH NORTHWESTERLY SWELL SMALL CRAFT ADVISORIES IN PLACE
GIVEN THE SEA STATE. THE SMALL CRAFT ADVISORIES FOR THE INNER
WATERS SOUTH OF CAPE FALCON REMAIN IN EFFECT THROUGH 1700 THIS
AFTERNOON BEFORE CONDITIONS IMPROVE. LOOKING HEAD A PATTERN CHANGE
IS IN STORE ON THURSDAY AS A LOW PRESSURE IN THE NORTHEAST
PACIFIC SHIFTS WINDS MORE SOUTHWESTERLY. WE'LL NEED TO WATCH
SOUTHERLY WINDS ON FRIDAY INTO SATURDAY AS GUIDANCE NOW SUGGESTS
A 30-40% CHANCE FOR SMALL CRAFT CONDITIONS - AN INCREASE FROM
PREVIOUS FORECAST CYCLES. -SCHULDT
PQR WATCHES/WARNINGS/ADVISORIES
OR...HEAT ADVISORY UNTIL 10 PM PDT TUESDAY FOR ORZ104-105-108.
EXTREME HEAT WARNING UNTIL 10 PM PDT TUESDAY FOR ORZ109>125.
WA...HEAT ADVISORY UNTIL 10 PM PDT TUESDAY FOR WAZ202-204-208.
EXTREME HEAT WARNING UNTIL 10 PM PDT TUESDAY FOR WAZ205>207-209-
210.
PZ...SMALL CRAFT ADVISORY UNTIL 5 PM PDT THIS AFTERNOON FOR PZZ252-
253.
SMALL CRAFT ADVISORY UNTIL 11 PM PDT TUESDAY FOR PZZ271>273.
WWW.WEATHER.GOV/PORTLAND
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