162
FXUS66 KPQR 190555
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
1055 PM PDT FRI SEP 18 2026
.UPDATED AVIATION DISCUSSION.
SYNOPSIS
TEMPERATURES WARM UP A FEW DEGREES THIS WEEKEND AS
AN UPPER LEVEL SHORTWAVE RIDGE MOVES OVER THE AREA. TRENDING A
BIT COOLER AGAIN NEXT WEEK AS AN UPPER LEVEL TROUGH SLOWLY DROPS
SOUTHWARD FROM THE GULF OF ALASKA. DRY CONDITIONS ARE HEAVILY
FAVORED THROUGH THURSDAY WITH A POSSIBLE PATTERN SHIFT TOWARD
COOLER AND WETTER CONDITIONS BY NEXT FRIDAY, SEPTEMBER 25TH.
DISCUSSION..NOW THROUGH NEXT FRIDAY
THE LATEST SATELLITE
IMAGERY SHOWS STRATUS STILL DISSIPATING ACROSS THE NORTHERN
PORTION OF THE WILLAMETTE VALLEY AND AROUND THE PORTLAND METRO.
STRATUS HAS STUCK AROUND MUCH LONGER THAN ORIGINALLY EXPECTED
AND HAS KEPT TEMPERATURES FROM INCREASING WITH OBSERVATIONS
ACROSS THE INTERIOR LOWLANDS RANGING FROM THE LOW 60S TO UPPER
60S WHERE CLOUDS HAVE CLEARED. STRATUS IS EXPECTED TO DISSIPATE
OVER THE NEXT HOUR OR SO AND WILL LEAD TO MOSTLY CLEAR SKIES
THROUGH THE EVENING AND EARLY OVERNIGHT. AREAS ALONG THE COAST
LIKELY REMAIN SOCKED IN WITH LOW CLOUDS WHICH RESURGE BACK
THROUGH THE COASTAL GAPS LATER TONIGHT.
THE WEEKEND LOOKS LIKE IT WILL BE QUITE PLEASANT WITH A SLIGHT
WARMING TREND THROUGH SUNDAY AS SHORTWAVE RIDGING PERSISTS ACROSS
THE REGION. EACH MORNING IS EXPECTED TO BEGIN WITH STRATUS DURING
THE MORNING HOURS BUT THIS STRATUS LAYER WON'T BE AS THICK MOVING
FORWARD AND SHOULD DISSIPATE BY MID TO LATE MORNING INLAND. HIGHS
ACROSS THE LOWLANDS ARE EXPECTED TO TOP OUT IN THE UPPER 70S ON
SATURDAY AND LOW 80S ON SUNDAY BUT THIS WILL DEPEND ON HOW QUICKLY
THE STRATUS DISSIPATES. THERE IS HIGH CONFIDENCE THAT CONDITIONS
REMAIN DRY THROUGH THE WEEKEND.
THE UPPER LEVEL PATTERN BEGINS TO SHIFT NEXT WEEK AS A LARGE TROUGH
OVER THE GULF OF ALASKA SLOWLY PROGRESSES SOUTHEAST THROUGH THE
WEEK. THE EASTERN PERIPHERY OF THE TROUGH WILL SHIFT UPPER LEVEL FLOW
TO THE WEST/SOUTHWEST. TEMPERATURES WILL TREND SLIGHTLY COOLER BUT
WILL GENERALLY PEAK IN THE MID TO UPPER 70S ACROSS THE INTERIOR
LOWLANDS AND 60S FOR THE COAST AND HIGHER TERRAIN. THE MAJORITY OF
ENSEMBLE MEMBERS SHOW DRY CONDITIONS THROUGH THE MIDDLE OF THE WEEK
WITH WEAK COLD FRONTS LOSING STEAM BEFORE THEY REACH THE AREA. A
MORE SUBSTANTIAL SHORTWAVE AND ASSOCIATED COLD FRONT IS POSSIBLE
DURING THE LATE THURSDAY INTO FRIDAY TIMEFRAME WHICH COULD FINALLY
BRING SOME RAIN TO THE AREA. ROUGHLY 40-50% OF ENSEMBLE MEMBERS SHOW
LIGHT RAINFALL BY AROUND THIS TIME. UNCERTAINTY REMAINS HIGH DURING
THIS TIME FRAME AS MODELS DIFFER IN STRENGTH AND TIMING THIS FAR IN
ADVANCE. -19
AVIATION...THROUGH 06Z SATURDAY
LATE THIS EVENING MARINE STRATUS
REMAINS LOCKED IN PLACE ALONG THE COAST WITH GENERALLY MVFR
CONDITIONS BEING REPORTED AT KAST AND KONP. AS THE NIGHT GOES ON,
THESE COASTAL TERMINALS WILL SEE CIGS SLOWLY LOWER WITH A
40-60% CHANCE FOR IFR CONDITIONS DEVELOPING BETWEEN 12-17Z -
MOST LIKELY AT KONP. THIS STRATUS DECK IS ONCE AGAIN EXPECTED TO
FORM INLAND STARTING AROUND 11-13Z, LIKELY BECOMING FAIRLY
WIDESPREAD ALBEIT NOT AS ROBUST AS THE DAY PRIOR (FRIDAY).
ADDITIONALLY, THERE'S ALSO A 30-50% CHANCE FOR THE MAJORITY OF
INLAND TERMINALS DEGRADE TO IFR (CIGS) BETWEEN 12-16Z. STRATUS
IS LIKELY TO HANG AROUND INTO THE LATE MORNING AND MIDDAY HOURS
BEFORE CLEARING AND BECOMING VFR AFTER 17-20Z. COMPARED TO
YESTERDAY (FRIDAY) MODELS SHOW A SHALLOWER CLOUD LAYER COME
SATURDAY MORNING WHICH SHOULD ADD MORE CONFIDENCE TO THE MIDDAY
RETURN OF VFR CONDITIONS. WINDS ONCE AGAIN STAY FAIRLY LIGHT,
GENERALLY LESS THAN 10 KNOTS.
KPDX AND APPROACHES...VFR CONDITIONS REMAIN IN PLACE THROUGH MUCH
OF THE OVERNIGHT HOURS, HOWEVER, STARTING AROUND 12-14Z SAT,
LOW-END MVFR CIGS LIKELY RETURN (70% CHANCE) WITH A 30-40% CHANCE
OF IFR CIGS ~13-16Z. CIGS ARE NOT EXPECTED TO IMPROVE TO VFR
UNTIL AFTER 18-20Z. -99/03
MARINE
HIGH PRESSURE REMAINS OVER THE WATERS THROUGH THE
WEEKEND. LIGHT WINDS WILL STRENGTHEN OUT OF THE NORTH SATURDAY
AFTERNOON AND EVENING WITH GUSTS UP TO 15-20 KT, STRONGEST OVER
THE CENTRAL AND SOUTHERN WATERS. NORTHERLY WINDS PEAK IN
STRENGTH SUNDAY AFTERNOON AND EVENING WHEN THERE IS A 50-90%
CHANCE FOR MAXIMUM WIND GUSTS OF 21 KT OR SLIGHTLY STRONGER
ACROSS THE WATERS, WITH THE HIGHEST CHANCES ACROSS THE INNER
WATERS OUT TO 10 NM OFFSHORE. GIVEN WIND GUSTS OF THIS MAGNITUDE
ARE NOT EXPECTED TO BE FREQUENT OR WIDESPREAD, SMALL CRAFT
ADVISORIES ARE NOT ANTICIPATED AT THIS TIME. SIGNIFICANT WAVE
HEIGHTS WILL REMAIN AROUND 4 TO 6 FT THROUGH THE WEEKEND, MAINLY
DRIVEN BY A PERSISTENT NORTHWESTERLY SWELL WITH A DOMINANT WAVE
PERIOD NEAR 8 TO 9 SECONDS.
NORTHERLY WINDS ARE EXPECTED TO LINGER MONDAY THROUGH WEDNESDAY,
WITH WIND GUSTS GENERALLY STAYING UNDER 20 KT. A LONG PERIOD
WEST-NORTHWESTERLY SWELL IS SET TO ARRIVE EITHER MONDAY AFTERNOON
OR EVENING, PUSHING SEAS UP BY ONE OR TWO FEET. HOWEVER, SEAS WILL
NOT BE PARTICULARLY STEEP AS THE DOMINANT WAVE PERIOD WITH THIS
SWELL WILL BE AROUND 11-13 SECONDS. -23/03
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
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