475
FXUS66 KPQR 191017
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
317 AM PDT TUE MAY 19 2026
SYNOPSIS
DRY AND BENIGN WEATHER IS EXPECTED ACROSS THE
REGION THROUGH MUCH OF THE NEXT WEEK AS HIGH PRESSURE BUILDS
OVER THE NORTHEAST PACIFIC, RESULTING IN A WARMING TREND. WEAK
SYSTEMS ALOFT MAY BRING ENHANCED CLOUD COVER ON SOME DAYS, BUT RAIN
CHANCES ARE MINIMAL. UNCERTAINTY IN THE FORECAST INCREASES SUNDAY
INTO MONDAY AS CHANCES FOR PRECIPITATION RETURN.
DISCUSSION...NOW THROUGH MONDAY
WATER VAPOR SATELLITE IMAGERY
THIS MORNING SHOWS A BROAD UPPER LEVEL RIDGE OVER THE NE PACIFIC
WHILE MID-TO-UPPER LEVEL MOISTURE CONTINUES TO STREAM SCATTERED HIGH
CLOUDS OVER THE AREA. MARINE STRATUS IS ALSO FILTERING IN ACROSS
PORTIONS OF FAR NORTHWEST OREGON, ESPECIALLY ALONG THE COLUMBIA
RIVER THIS MORNING. CLOUDS SHOULD SCATTER OUT BY THE AFTERNOON,
EXCEPT ALONG THE NORTH OREGON COAST WHERE A DEEPENING MARINE LAYER
WILL BRING A CHANCE FOR SOME VERY LIGHT RAIN OR DRIZZLE NEAR
ASTORIA. OTHERWISE, EXPECT RATHER COMFORTABLE WEATHER TO CONTINUE
TODAY WITH HIGHS REACHING INTO THE UPPER 60S TO LOWER 70S, DEPENDING
ON WHICH AREA SEES MORE OF THE SUNSHINE TODAY.
CONCERNS FOR HAZARDOUS WEATHER REMAIN LOW THROUGH THE WEEK AND INTO
THE WEEKEND. STILL EXPECTING A SLIGHT WARMING TREND THROUGH THE
WEEK, WITH THE WARMEST DAY MOST LIKELY BEING ON THURSDAY AS THE
UPPER RIDGE AXIS SHIFTS EAST OVER THE PACIFIC NW. TEMPERATURES ON
THURSDAY WILL LIKELY WARM INTO THE UPPER 70S TO LOW 80S ALONG THE I-
5 CORRIDOR. AT THIS TIME, THERE IS MINOR HEATRISK FORECAST ACROSS
THE REGION, MEANING THOSE WHO ARE MOST SENSITIVE TO HEAT MAY BE
AFFECTED. HOWEVER, THERE ARE 5-15% CHANCES MODERATE HEATRISK OCCURS
IN SOME URBAN AREAS ALONG I-5 IF DAYTIME HIGHS END UP SOMEWHAT
HOTTER. THERE IS GENERALLY AROUND A 10-30% CHANCE THAT MAX TEMPS
EXCEED 85 DEGREES THURSDAY AFTERNOON IN THE PORTLAND METRO AREA.
FRIDAY THROUGH NEXT WEEKEND, UNCERTAINTY IN THE EVOLUTION AND
POSSIBLE BREAK-DOWN OF THE UPPER-LEVEL RIDGE INTRODUCES MORE
UNCERTAINTY IN FORECAST TEMPERATURES AND PRECIPITATION. FORECAST
DAYTIME HIGHS CURRENTLY TREND DOWNWARD THROUGH THE HOLIDAY WEEKEND
AS CHANCES INCREASE THAT RIDGING DEAMPLIFIES OR IS REPLACED BY AN
UPPER TROUGH, BUT THERE IS AN INCREASINGLY WIDE RANGE OF POSSIBLE
OUTCOMES. THE 80%-CONFIDENCE ENVELOPES (THE DIFFERENCE BETWEEN THE
10TH AND 90TH PERCENTILES) IN TEMPERATURE WIDEN FROM 8-13 DEGREES ON
FRIDAY AND SATURDAY TO 16-19 DEGREES ON SUNDAY AND MONDAY ALONG THE
I-5 CORRIDOR. THERE IS GREATER CONSENSUS THAT THE RIDGE WILL BREAK
DOWN LATE SUNDAY INTO MONDAY, YIELDING INCREASING CHANCES OF COOLER
TEMPERATURES AS WELL AS THE HIGHEST CHANCES OF RAINFALL, 25-50%, IN
OVER A WEEK. 36/DH
AVIATION
AN UPPER LEVEL RIDGE OFFSHORE WILL MAINTAIN NORTHWEST
FLOW ALOFT WITH HIGH PRESSURE OVER THE REGION, WHILE ONSHORE FLOW
IN THE LOWER LEVELS CONTINUES TODAY. AS OF 09Z TUESDAY, SATELLITE
IMAGERY AND SURFACE OBSERVATIONS REVEAL MVFR STRATUS EXPANDING
ACROSS FAR NORTHWEST OREGON, INCLUDING KAST TO KSPB, AS WELL AS
OVER THE EAST PORTLAND METRO. EXPECT THESE LOW CLOUDS TO FILL IN
ALONG THE COLUMBIA RIVER WITH MVFR CONDITIONS LIKELY AT KPDX
(30-40% CHANCE) AND KTTD (50-60% CHANCE) BY 12Z THIS MORNING.
EXPECT CONDITIONS TO IMPROVE BACK TO PREDOMINATELY VFR BY 19-20Z
EXCEPT ALONG THE NORTH OREGON COAST. AT KAST, THERE IS A 20-30%
CHANCE FOR IFR CONDITIONS BETWEEN 12-22Z, ALONG WITH INCREASING
CHANCES OF LIGHT RAIN OR DRIZZLE THIS AFTERNOON AS THE MARINE
LAYER DEEPENS.
KPDX AND APPROACHES...VFR CONDITIONS WILL LIKELY DETERIORATE TO
MVFR AS LOW STRATUS PUSHING UP THE RIVER SPREADS INTO THE PORTLAND
METRO AREA, WHILE STRATUS BACK BUILDING OFF THE CASCADE FOOTHILLS
EXPANDS INTO KTTD. GUIDANCE SUGGESTS THERE IS AROUND A 40-50%
CHANCE MVFR CIGS PERSIST THROUGH 19-20Z. LIGHT NORTHWEST WINDS
EXPECTED TO INCREASE AGAIN TO AROUND 7-10 KT THIS AFTERNOON AND
EVENING. /DH
MARINE
NORTHERLIES ARE EXPECTED TO PERSIST THROUGH MUCH OF
THE WEEK AS THE SUMMER-LIKE PATTERN SETTLES IN. STRONGEST WINDS
ARE EXPECTED DURING THE AFTERNOON AND EVENING PERIODS AS A SURFACE
THERMAL TROUGH STRENGTHENS OVER THE SOUTHERN OREGON COAST. A
SMALL CRAFT ADVISORY IS AGAIN IN EFFECT FOR THE SOUTHERN COASTAL
WATERS SOUTH OF CAPE FOULWEATHER LATER THIS AFTERNOON INTO THIS
EVENING FOR GUSTS UP TO 25 KT. SIMILAR CONDITIONS ARE EXPECTED ON
WEDNESDAY, THOUGH GUIDANCE IS SUGGESTING SLIGHTLY STRONGER WIND
GUSTS MAY EXPAND NORTHWARD TOWARD CAPE FALCON. SEAS AROUND 6 TO 9
FEET ARE EXPECTED THROUGH THE WEEK AS WELL. CHANCES INCREASE ON
THURSDAY FOR MORE WIDESPREAD WIND GUSTS FOR ALL MARINE ZONES.
SMALL CRAFT ADVISORIES ARE IN PLACE FOR THE COLUMBIA RIVER BAR
FOR EARLY THIS MORNING AND AGAIN WEDNESDAY MORNING DUE TO STRONG
EBB CURRENTS WHICH WILL PRODUCE CONDITIONS HAZARDOUS TO SMALL
CRAFT. STRONG EBB CURRENTS ARE POSSIBLE DURING THE MORNING HOURS
EACH DAY THIS WEEK. /DH
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 5 AM TO 9 AM PDT THIS MORNING FOR
PZZ210.
SMALL CRAFT ADVISORY FROM 6 AM TO 10 AM PDT WEDNESDAY FOR PZZ210.
SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 2 AM PDT
WEDNESDAY FOR PZZ253-273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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