035
FXUS66 KPQR 181737 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
1036 AM PDT SAT APR 18 2026
UPDATED AVIATION DISCUSSION.
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
HIGH PRESSURE WILL MAINTAIN WIDESPREAD VFR FLIGHT
CONDITIONS THROUGH 18Z SUNDAY WITH SCATTERED HIGH CLOUDS AROUND
20-25 KFT. WINDS WILL REMAIN LIGHT AND VARIABLE LESS THAN 5 KT,
WITH ONE EXCEPTION. EASTERLY WINDS AT KTTD WILL REMAIN BREEZY
THROUGH AT LEAST 20-21Z SATURDAY WITH GUSTS UP TO 20-25 KT BEFORE
EAST WINDS DECREASE IN STRENGTH BETWEEN 21-00Z. KPDX WILL ALSO SEE
A LIGHT EASTERLY WIND AT TIMES THROUGH 21-23Z SATURDAY BEFORE
WINDS BECOME LIGHT AND VARIABLE AGAIN THEREAFTER. EXPECT EASTERLY
WINDS TO RESTRENGTHEN A BIT BETWEEN 12-18Z SUNDAY AT BOTH KTTD AND
KPDX, BEGINNING AT KTTD FIRST.
KPDX AND APPROACHES...SCATTERED HIGH CLOUDS WITH CIGS ABOVE 20-25
KFT WILL MAINTAIN VFR FLIGHT CONDITIONS THROUGH 18Z SUNDAY. EXPECT
LIGHT EASTERLY WINDS UNDER 7 KT THROUGH 21-23Z SATURDAY BEFORE
WINDS BECOME LIGHT AND VARIABLE UNDER 5 KT. EXPECT EASTERLY WINDS
TO RESTRENGTHEN TOWARDS 17Z SUNDAY WITH SUSTAINED WIND SPEEDS
APPROACHING 10 KT. -23
MARINE
BENIGN CONDITIONS CONTINUE THROUGH THE WEEKEND. SOUTHERLY
WINDS UP 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...NONE.
WA...NONE.
PZ...NONE.
WWW.WEATHER.GOV/PORTLAND
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