471
FXUS66 KPQR 181105
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
405 AM PDT SAT APR 18 2026
SYNOPSIS
WARM AND DRY CONDITIONS CONTINUE THROUGH AT LEAST
MONDAY. AN UPPER LEVEL LOW IS EXPECTED TO DEVELOP OFF THE PACNW
COAST DURING THE LATTER HALF OF THE WEEKEND. UNCERTAINTY
REMAINS IN THE FORECAST HEADING INTO TUESDAY REGARDING THE
POSITION OF THE UPPER LOW. CONFIDENCE IS HIGHER THAT CONDITIONS
TURN COOL AND WET ON WEDNESDAY.
SHORT TERM...NOW THROUGH SUNDAY NIGHT
MID AND UPPER LEVEL
CLOUDS CONTINUE TO MOVE OVER THE AREA WITH THE THICKEST
CLOUDCOVER OVER SOUTHWEST WASHINGTON. MOSTLY CLEAR SKIES OVER
THE SOUTHERN WILLAMETTE VALLEY WILL ALLOW TEMPERATURES TO COOL
MORE THAN MOST OF THE AREA. A FROST ADVISORY REMAINS IN EFFECT
UNTIL 8 AM FOR THE SOUTHERN WILLAMETTE VALLEY AND THE UPPER HOOD
RIVER VALLEY, MAINLY ABOVE 1500 FEET. TEMPERATURES ARE EXPECTED
TO DROP INTO THE MID 30S, ALLOWING FOR AREAS OF FROST TO
DEVELOP. THE REST OF THE INLAND LOWLANDS ARE EXPECTED TO DROP
INTO THE UPPER 30S TO LOW 40S.
AN UPPER LEVEL TROUGH OVER THE ALEUTIAN ISLANDS WILL PROGRESS
EASTWARD TOWARD THE PACNW THROUGH THE DAY, HELPING AMPLIFY
SHORTWAVE RIDGING OVER THE REGION. THIS WILL CONTINUE SUPPORTING
THE WARMING TREND TODAY WITH INLAND HIGHS REACHING THE LOW TO
MID 70S WHILE COASTAL AREAS WILL SEE HIGHS IN THE UPPER 50S TO
MID 60S. A WEAKENING COLD FRONT APPROACHES LATE SATURDAY BUT IS
EXPECTED TO LOSE STEAM AS THE UPPER LOW BEGINS TO SHIFT MORE
SOUTHEAST INSTEAD OF EAST. LIGHT SHOWER ACTIVITY IS POSSIBLE
OVER THE WATERS BUT ONLY AND INCREASE IN UPPER LEVEL CLOUD COVER
IS EXPECTED OVER MOST OF THE AREA DURING THE EVENING AND
OVERNIGHT HOURS. OVERNIGHT LOWS MODERATE INTO THE MID TO UPPER
40S TONIGHT AS CLOUD COVER INCREASES AND DAYTIME TEMPERATURES
TREND UPWARD, ELIMINATING THE THREAT FOR FROST/FREEZE POTENTIAL
FOR THE NEXT FEW DAYS.
HIGHS ON SUNDAY ARE EXPECTED TO BE SIMILAR TO SATURDAY WITH
HIGHS A DEGREE OR TWO WARMER BUT ULTIMATELY STILL IN THE LOW TO
MID 70S INLAND AND UPPER 50S TO MID 60S ALONG THE COAST. THERE
IS A CHANCE FOR URBAN LOCATIONS AROUND THE PORTLAND/VANCOUVER
METRO TO REACH 80 DESPITE INCREASING CLOUD COVER. PROBABILITIES
ARE 30-60% AS FAR WEST AS BANKS, SOUTH TO AURORA, AND WEST TO
LATOURELL. -19
LONG TERM...MONDAY THROUGH FRIDAY
THE AFOREMENTIONED TROUGH
WILL SLOW ITS EASTWARD PROGRESSION ON SUNDAY, EVENTUALLY
PINCHING OFF FROM THE MAIN UPPER LEVEL FLOW INTO A CLOSED LOW
OFF THE PACNW COAST ON SUNDAY. THIS FEATURE BECOMES MORE
INFLUENTIAL HEADING INTO THE NEXT WORK WEEK. CLUSTER ANALYSIS
SHOWS INCREASED AGREEMENT FOR MONDAY WITH THE CENTER OF THE
CLOSED LOW REMAINING OFF NORTHERN CALIFORNIA. THAT SAID,
INCREASING CLOUD COVER IS STILL EXPECTED AS HEIGHTS ALOFT
DECREASE OVER THE AREA. MILD TEMPERATURES ARE STILL EXPECTED
WITH HIGHS IN THE UPPER 60S TO LOW 70S INLAND AND UPPER 50S TO
LOW 60S ALONG THE COAST.
COME TUESDAY, THERE REMAINS SOME UNCERTAINTY AMONG THE
ENSEMBLES. TRENDS POINT TOWARD THE UPPER LOW BEGINNING TO SHIFT
ONSHORE WHICH WOULD BRING COOLER TEMPERATURES AND INCREASING
POPS OVER THE REGION. HOWEVER, THERE IS STILL A ~70-30 SPLIT
AMONG THE ENSEMBLES FAVORING THIS PROGRESSION WHICH MEANS THERE
IS STILL CHANCE FOR MILD AND DRY CONDITIONS. LOCATIONS FARTHER
SOUTH AND WEST WILL SEE THE TRANSITION TO COOLER,
WETTER CONDITIONS EARLIER GIVEN THE LOCATION OF THE UPPER LOW.
THERE IS MUCH BETTER AGREEMENT FOR TUESDAY NIGHT INTO WEDNESDAY
BEING COOL AND WET. CLUSTER ANALYSIS SHOWS GOOD AGREEMENT IN THE
CLOSED LOW MOVING EAST AND BECOMING AN OPEN WAVE. RIDGING BEGIN
BUILDING BACK INTO THE REGION THURSDAY AND FRIDAY, SUPPORTING A
WARMING TREND ALONG WITH DRIER CONDITIONS. -19
AVIATION
VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE TAF
PERIOD. HIGH LEVEL CLOUDS CONTINUE TO MOVE OVER THE AREA WITH A
FEW BREAKS IN THE SOUTHERN HALF OF THE WILLAMETTE VALLEY. COULD
SEE SOME PATCHY FROST DEVELOP ON ELEVATED OR METAL SURFACES
WHERE TEMPS DROP INTO THE MID 30S, MAINLY AROUND KEUG. EXPECT
SKIES TO TREND CLEARER THROUGH THE DAY. VARIABLE WINDS AROUND 5
KT OR LESS FOR MOST TERMINALS, EXCEPT SLIGHT TIGHTENING OF
KTTD-KDLS PRESSURE GRADIENTS WILL RESULT IN EASTERLY WINDS
AROUND 5-10 KT IN THE FAR EAST PORTLAND METRO (KTTD). ALONG THE
COAST, LIGHT OFFSHORE WINDS TONIGHT TURN MORE SOUTHWESTERLY
AFTER 18Z SAT. THIS OFFSHORE FLOW ALONG THE COAST WILL HELP
PREVENT LOW MARINE STRATUS FROM DEVELOPING.
KPDX AND APPROACHES...VFR CONDITIONS THROUGH THE TAF PERIOD WITH
HIGH SCT/BKN CLOUDS GRADUALLY DECREASING ON SATURDAY. VARIABLE
WINDS AROUND 5 KT OR LESS. LIGHT EASTERLY WINDS DEVELOPS THROUGH
THE COLUMBIA RIVER GORGE AFTER 12Z SAT, BUT NOT EXPECTED TO
REACH KPDX. -19/10
MARINE
BENIGN CONDITIONS CONTINUE THROUGH THE WEEKEND.
SOUTHERLY WINDS TO AROUND 10 KT EXPECTED TODAY WITH SEAS
REMAINING LESS THAN 5 FT.
THERE IS HIGHER FORECAST UNCERTAINTY FOR WINDS AND SEAS EARLY NEXT
WEEK AS AN AREA OF LOW PRESSURE OFFSHORE APPROACHES THE COAST. THE
PLACEMENT OF THE LOW WILL DETERMINE THE CONDITIONS ACROSS THE
WATERS, WITH THE FORECAST AT THIS LEAD TIME FAVORING INCREASING
ONSHORE FLOW THROUGH WEDNESDAY, WHEN WNW GUSTS MAY REACH 20-25 KT
BEYOND 30 NM. HIGHER WINDS AND A FRESHLY ARRIVING NW SWELL MAY PUSH
SEAS TO 10-12 FT WEDNESDAY INTO THURSDAY.
VERY STRONG EBB CURRENTS WILL CONTINUE ACROSS THE COLUMBIA RIVER BAR
EACH MORNING THROUGH TUESDAY. WITH SEAS EXPECTED TO BUILD SLIGHTLY
BY EARLY NEXT WEEK, A STEEP EBB CHOP MAY NECESSITATE SMALL CRAFT
ADVISORIES IN THE HOURS AROUND PEAK FLOW EACH DAY. -19/36
PQR WATCHES/WARNINGS/ADVISORIES
OR...FROST ADVISORY UNTIL 8 AM PDT THIS MORNING FOR ORZ116>118-121.
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