466
FXUS66 KPQR 201707 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
1006 AM PDT TUE OCT 20 2026
UPDATED AVIATION DISCUSSION.
SYNOPSIS
LARGELY DRY WEATHER EXPECTED THROUGH MIDWEEK. ABOVE
AVERAGE TEMPERATURES TODAY AND WEDNESDAY. CHANCES FOR WETTER
AND COOLER WEATHER RETURN LATE IN THE WEEK WITH POTENTIAL FOR A
MORE ROBUST SYSTEM OVER THE WEEKEND.
DISCUSSION...NOW THROUGH MONDAY
DRY CONDITIONS ARE EXPECTED
THROUGH AT LEAST THURSDAY. THE UPPER LEVEL LOW CONTINUES TO
PINCH OFF FROM THE MAIN FLOW AS IT DROPS SOUTH TOWARD CALIFORNIA
TODAY. IN ITS WAKE, SHORTWAVE RIDGING WILL BUILD INTO THE PACNW
TODAY. CLOUD COVER WILL DISSIPATE THROUGH THE DAY WITH LIGHT
OFFSHORE WINDS DEVELOPING ON THE EASTERN FLANKS OF THE CASCADES
AND COAST RANGE AND THROUGH THE WESTERN COLUMBIA RIVER GORGE.
THESE OFFSHORE WINDS ARE NOT EXPECTED TO BE IMPACTFUL THOUGH
THEY MAY BE LOCALLY GUSTY UP TO 40 MPH IN THE TYPICAL SPOTS
WITHIN THE GORGE. HIGHS JUMP TO AROUND10 DEGREES ABOVE NORMAL
TODAY AND WEDNESDAY, TRANSLATING TO AFTERNOON HIGHS IN THE 60S
ON THE COAST AND IN TERRAIN, AND IN THE LOW TO MID 70S WITHIN
INLAND VALLEYS.
THE LATTER HALF OF THE WEEK AGAIN TRENDS TOWARD COOLER
TEMPERATURES AND MODEST CHANCES FOR RAIN. CLUSTER ANALYSIS SHOWS
GOOD AGREEMENT IN TROUGHING DEVELOPING OVER THE GULF OF ALASKA
AND DROPPING SOUTHEAST TOWARD THE PACNW THURSDAY INTO FRIDAY.
THIS PATTERN WOULD FAVOR A RETURN TO NEAR NORMAL TEMPERATURES
AND CHANCES FOR LIGHT PRECIPITATION. CURRENTLY, THE BEST CHANCES
FOR PRECIPITATION ARE OVER THE CASCADE FOOTHILLS AND AREAS EAST
OF I-5 BUT REMAIN RATHER LOW AT 20-40%. RAINFALL ASSOCIATED
WITH THIS SYSTEM IS NOT EXPECTED TO BE NOTEWORTHY IF IT OCCURS
AT ALL. OVERNIGHT LOWS THURSDAY AND FRIDAY NIGHT ARE EXPECTED TO
BE MUCH COOLER THAN THE START OF THE WEEK. MORE WIDESPREAD
TEMPERATURES BELOW 37 DEGREES ARE POSSIBLE THROUGHOUT THE
CENTRAL AND SOUTHERN WILLAMETTE VALLEY, CASCADE FOOTHILL
VALLEYS, AND PARTS OF THE COAST RANGE VALLEYS. IF TRENDS
CONTINUES, WILL LIKELY NEED FROST ADVISORIES FOR SOME OR ALL OF
THESE LOCATIONS.
DETAILS HEADING INTO THE WEEKEND REMAIN MURKY AS ENSEMBLES
SOLUTIONS REMAIN UNDECIDED IN REGARDS TO THE DEVELOPING PATTERN.
THERE IS A LOW TO MODERATE CHANCE THAT A ROBUST SHORTWAVE
DEVELOPS OVER THE GULF OF ALASKA AND DROPS SOUTHWARD, SUPPORTING
A SURFACE LOW AS IT APPROACHES THE PACNW. AROUND 30-40% OF
ECMWF ENSEMBLE MEMBERS DEPICT BOTH OF THESE FEATURES HEADING
INTO SATURDAY AND SUNDAY. HOWEVER, THERE IS A NOTICEABLE TREND
IN SEVERAL OF THE MEMBERS TO KEEP THE CORE OF THE SURFACE LOW
OFFSHORE AND EVEN HAS IT RETROGRADING BACK OUT TO SEA DURING THE
LATTER HALF OF THE WEEKEND. THIS CURRENT TREND SIGNAL LOWER
POTENTIAL FOR MUCH NEEDED RAINFALL ACROSS THE AREA BUT ALSO
LOWER CHANCES FOR IMPACTFUL WINDS ACROSS THE REGION. GIVEN THIS
POTENTIAL SYSTEM IS STILL SEVERAL DAYS OUT, DETAILS REMAIN
UNCLEAR AND WILL HOPEFULLY BE FLESHED OUT IN THE COMING DAYS. -19
AVIATION...THROUGH 18Z WEDNESDAY
VFR FLIGHT CONDITIONS WILL
CONTINUE ACROSS THE AREA THROUGH 18Z WEDNESDAY WITH SCATTERED THIN
HIGH CLOUDS FROM TIME TO TIME. CEILINGS WITH THESE HIGH CLOUDS ARE
ABOVE 20 KFT. OFFSHORE WINDS WILL STRENGTHEN A BIT BETWEEN 17-21Z
TUESDAY, BRINGING WIND GUSTS UPWARDS OF 15-20 KT AT KPDX AND KTTD.
A FEW MAX WIND GUSTS AS HIGH AS 25 KT ARE POSSIBLE AT KTTD. WINDS
WILL BE MORE NORTHERLY AT KUAO, KSLE, AND KEUG, STRONGEST AT KUAO
AT AROUND 10 KT AND GENERALLY AROUND 5 KT OR LESS AT KSLE AND
KEUG. WINDS WEAKEN THIS EVENING INTO TONIGHT, EXCEPT AT KTTD WHERE
EASTERLY WINDS WILL CONTINUE.
KPDX AND APPROACHES...VFR WITH A FEW THIN HIGH CLOUDS WITH
CEILINGS ABOVE 20 KFT THROUGH 18Z WEDNESDAY. EASTERLY WINDS AROUND
10 KT WITH GUSTS AS HIGH AS 20 KT EXPECTED THIS AFTERNOON, BEFORE
WINDS WEAKEN THIS EVENING. -23
MARINE
NORTHERLY WINDS CONTINUE ACROSS THE WATERS IN THE
WAKE OF A SYSTEM THAT IS DROPPING SOUTHWARD. WIDESPREAD WIND
GUSTS UP TO 25 KT WILL BE POSSIBLE OVER THE OUTER WATERS BEYOND
10 NM OFFSHORE THROUGH THE AFTERNOON. A SMALL CRAFT ADVISORY
REMAINS IN EFFECT FOR THE OUTER WATERS THROUGH 5 PM. BEYOND 5
PM TOMORROW, WINDS AND SEAS WILL BE ON THE DECREASE AS HIGH
PRESSURE RETURNS.
WINDS AND SEAS ARE SET TO INCREASE AGAIN THURSDAY INTO FRIDAY
MORNING WITH THE PASSAGE OF A WEAK COLD FRONT, ESPECIALLY OVER
THE NORTHERN WATERS TO THE NORTH OF CAPE FALCON WHERE
CONDITIONS WILL LIKELY BE HAZARDOUS TO SMALL CRAFT. THERE IS THE
POTENTIAL FOR A STRONGER LOW PRESSURE SYSTEM OVER THE UPCOMING
WEEKEND, BRINGING A 20-40% CHANCE FOR GALE FORCE WIND GUSTS AND
SEAS OVER 10 FEET. OVERALL CONFIDENCE IN THE EXACT TRACK AND
STRENGTH OF THIS POTENTIAL LOW PRESSURE SYSTEM IS LOW AT THIS
TIME, AND THE FORECAST IS WORTH MONITORING OVER THE NEXT SEVERAL
DAYS. -19/23
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 5 PM PDT THIS AFTERNOON FOR
PZZ271>273.
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