112
FXUS66 KPQR 120404 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
904 PM PDT MON AUG 11 2025
UPDATED AVIATION DISCUSSION
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.
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
WIDESPREAD VFR CONDITIONS UNDER CLEAR SKIES FOR INLAND
LOCATIONS THROUGH THE TAF PERIOD. THE PRIMARY CHALLENGE THROUGH
THE OVERNIGHT HOURS WILL BE THE REDEVELOPMENT OF IFR/LIFR FOG AND
LOW STRATUS SOUTH TO NORTH ALONG THE COAST. THERE IS A 50%-80%
PROBABILITY OF THE LOWERED FLIGHT CONDITIONS BETWEEN K6S2 AND
KONP. THESE CONDITIONS ARE CURRENTLY BEING OBSERVED AT K6S2 AND
ARE SLOWLY SPREADING TOWARDS KONP WITH A LIKE START TIME AROUND
08Z-10Z TUESDAY. KAST COULD ALSO SEE LOWERED FLIGHT CONDITIONS
BUT WITH ONLY A 15-25% PROBABILITY. LOWERED FLIGHT CONDITIONS
ALONG THE COAST ARE EXPECTED TO LIFT TOWARDS VFR/MVFR AROUND
20Z-22Z TUESDAY. EXPECT GENERALLY NORTH/NORTHWEST WINDS UNDER
10 KT THROUGH THE FORECAST PERIOD.
IMPORTANT NOTE: ABNORMALLY HOT TEMPERATURES ARE FORECASTED
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. /42
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. 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 11 PM PDT TUESDAY FOR PZZ271>273.
WWW.WEATHER.GOV/PORTLAND
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