550
FXUS66 KPQR 201012
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
311 AM PDT WED MAY 20 2026
SYNOPSIS
DRY AND WARM WEATHER IS EXPECTED ACROSS THE
REGION THROUGH MUCH OF THE WEEK INTO THE WEEKEND WITH HIGH PRESSURE
OVER THE NORTHEAST PACIFIC SHIFTING EAST INTO THE PACIFIC NW. WEAK
SYSTEMS ALOFT MAY BRING ENHANCED CLOUD COVER ON SOME DAYS, BUT RAIN
CHANCES ARE MINIMAL. UNCERTAINTY IN THE FORECAST INCREASES SUNDAY
INTO EARLY NEXT WEEK AS CHANCES FOR PRECIPITATION RETURN FOR
MEMORIAL DAY.
DISCUSSION...NOW THROUGH TUESDAY
WATER VAPOR SATELLITE IMAGERY
THIS MORNING SHOWS AN AMPLIFIED UPPER LEVEL TROUGH OVER THE
NORTHEAST PACIFIC WITH NORTHWESTERLY FLOW STREAMING ONSHORE. THE
GOES NIGHTTIME MICROPHYSICS IMAGERY REVEALS STRATUS ALONG THE COAST,
THROUGH THE LOWER COLUMBIA RIVER VALLEY, AND BACKBUILDING OFF THE
CASCADES INTO THE WILLAMETTE VALLEY. MORNING CLOUDS ARE EXPECTED TO
SCATTER OUT BY THE AFTERNOON ALLOWING TEMPERATURES TO WARM AGAIN
INTO THE LOWER 70S INLAND AND AROUND 60 DEGREES AT THE COAST. HIGH
PRESSURE WILL MAINTAIN DRY CONDITIONS THROUGH THE END OF THE WEEK.
AS OFFSHORE RIDGING SHIFTS EAST LATER IN THE WEEK, TEMPERATURES WILL
TREND WARMER, REACHING THE 60S TO NEAR 70 DEGREES ON THE COAST AND
UPPER 70S TO MID 80S INLAND. THIS WILL SUPPORT WIDESPREAD MINOR
HEATRISK EXCEPTING ONLY THE IMMEDIATE COAST. CHANCES FOR MODERATE
HEATRISK ON THURSDAY ARE 15-35% IN PORTLAND AND THE ADJACENT
NORTHERN WILLAMETTE VALLEY, 5-20% IN SALEM AND ALBANY/CORVALLIS, AND
5% OR LESS ELSEWHERE. CONCERNS FOR HAZARDOUS WEATHER OTHERWISE
REMAIN LOW. TEMPERATURES ON FRIDAY ARE NOW TRENDING ONLY A DEGREE OR
TWO COOLER THAN THURSDAY AS BROAD RIDGING MOVES OVER THE REGION.
SATURDAY THROUGH THE HOLIDAY WEEKEND, UNCERTAINTY IN THE EVOLUTION
AND POSSIBLE BREAK-DOWN OF THE UPPER-LEVEL RIDGE YIELDS GROWING
UNCERTAINTY IN FORECAST TEMPERATURES AND PRECIPITATION. IN GENERAL,
AS THE RIDGE DEAMPLIFIES, TEMPERATURES ARE MORE LIKELY TO TREND
COOLER THROUGH THE PERIOD, ESPECIALLY BY MONDAY. THERE CONTINUES TO
BE GREATER CONSENSUS OF AN UPPER-LEVEL TROUGH DIGGING OVER THE NE
PACIFIC ON MONDAY, SUPPORTING MUCH COOLER TEMPERATURES AND 40-70%
CHANCES FOR RAIN ACROSS THE AREA. THIS MEANS THERE ARE INCREASING
CHANCES THAT A FRONT BRINGS WIDESPREAD RAIN SOMETIME ON MEMORIAL
DAY. ENSEMBLE CLUSTERS STILL SHOW QUITE A LARGE RANGE OF POTENTIAL
RAINFALL, SO WILL CONTINUE TO SEE HOW MODELS RESOLVE THE PATTERN
INTO THIS WEEKEND. DH/36
AVIATION
AN UPPER LEVEL RIDGE OFFSHORE WILL MAINTAIN NORTHWEST
FLOW ALOFT OVER THE REGION TODAY. MARINE STRATUS ALONG THE COAST
AND PUSHING UP THE COLUMBIA RIVER WILL LIKELY SUSTAIN MVFR CIGS
AT IMPACTED TERMINALS THROUGH 18-20Z. STRATUS BACK-BUILDING OFF
THE CASCADES INTO THE WILLAMETTE VALLEY EARLY THIS MORNING COULD
REACH INLAND TERMINALS AS WELL, WITH GUIDANCE SUGGESTING THERE IS
A 20-40% CHANCE OF THIS OCCURRING, EXCEPT AROUND A 60-80% CHANCE
AT KTTD. PREDOMINATELY VFR CONDITIONS ARE EXPECTED BY THIS
AFTERNOON.
KPDX AND APPROACHES...AS OF 09Z, VFR CONDITIONS PERSIST. BUT,
SATELLITE IMAGERY SHOWS LOW STRATUS EXPANDING TOWARDS THE
TERMINAL. THERE IS AROUND A 40-50% CHANCE FOR MVFR CIGS AT THE
TERMINAL BETWEEN 12-18Z THIS MORNING. AFTERWARDS, VFR CONDITIONS
EXPECTED THROUGH THE REMAINDER OF THE TAF PERIOD. NORTHWEST WINDS
CONTINUE AT AROUND 5-10 KT, STRONGEST IN THE AFTERNOON AND
EVENING. /DH
MARINE
HIGH PRESSURE CONTINUES OFFSHORE AS NORTHERLIES ARE
EXPECTED TO PERSIST THROUGH THE END OF THE WEEK. STRONGEST WINDS
ARE EXPECTED DURING THE AFTERNOON AND EVENING PERIODS AS THE
SURFACE THERMAL TROUGH STRENGTHENS OVER THE NORTHERN CA/SOUTHERN
OR COAST. MORE WIDESPREAD WIND GUSTS TO 25 KT ARE EXPECTED LATER
TODAY AND AGAIN ON THURSDAY AS INLAND TEMPERATURES WARM. SMALL
CRAFT CONDITIONS FOR MOST COASTAL WATER ZONES WILL PERSIST EACH
AFTERNOON AND EVENING. SEAS 6 TO 9 FEET ARE EXPECTED THROUGH THE
WEEK AS WELL. A SMALL CRAFT ADVISORY IS ALSO IN PLACE FOR THE
COLUMBIA RIVER BAR FOR THIS MORNING DUE TO STRONG EBB CURRENTS.
STRONG EBB CURRENTS ARE POSSIBLE DURING THE MORNING HOURS EACH DAY
THIS WEEK. THE SUMMER-LIKE PATTERN IS LIKELY TO BREAK DOWN LATER
SUNDAY AS A FRONT APPROACHES THE WATERS BY MONDAY NEXT WEEK. /DH
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 6 AM TO 10 AM PDT THIS MORNING FOR
PZZ210.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 5 AM PDT
THURSDAY FOR PZZ252-271-272.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 5 AM PDT
THURSDAY FOR PZZ253.
SMALL CRAFT ADVISORY UNTIL 5 AM PDT THURSDAY FOR PZZ273.
WWW.WEATHER.GOV/PORTLAND
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X.COM/NWSPORTLAND
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