311
FXUS66 KPQR 031803
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
1103 AM PDT SUN MAY 3 2026
UPDATED AVIATION DISCUSSION AND HAZARDS SECTION.
SYNOPSIS
BROAD HIGH PRESSURE OVER THE REGION WILL MAINTAIN
GENERALLY DRY CONDITIONS THROUGH THE NEXT SEVERAL DAYS.
TEMPERATURES ARE EXPECTED TO PEAK TODAY WITH DAILY RECORD HIGHS
IN THE FORECAST FOR SOME INLAND AREAS. AN UPPER LEVEL LOW
OFFSHORE MAY BRING ISOLATED CASCADE SHOWERS OR THUNDERSTORMS
THIS AFTERNOON AND EVENING. TEMPERATURES WILL COOL BUT REMAIN
ABOVE NORMAL HEADING INTO THE WORKWEEK.
SHORT TERM...NOW THROUGH TONIGHT
A CLOSED UPPER LOW WILL
CONTINUE TO MEANDER OFF THE CALIFORNIA COAST BENEATH THE APEX OF
BROAD UPPER RIDGING SPANNING THE NORTHEASTERN PACIFIC AND MUCH
OF THE WESTERN CONUS. OFFSHORE FLOW ON THE NORTHERN FLANK OF
THIS LOW WILL PUSH TEMPERATURES SOME 15 TO 25 DEGREES ABOVE
NORMAL ACROSS THE REGION. ONE POINT OF UNCERTAINTY IN THE
TEMPERATURE FORECAST IS THE POTENTIAL FOR HIGH-LEVEL CLOUD COVER
IF DEBRIS FROM UPSTREAM CONVECTION LIMITS INSOLATION; THIS IS
MORE LIKELY SOUTH OF TO THE SOUTH OF US-20 AND IS REFLECTED IN
FORECAST HIGH TEMPERATURES A FEW DEGREES COOLER THAN AREAS TO
THE NORTH. CHANCES FOR TEMPERATURES TO EXCEED 90 DEGREES REMAIN
THE HIGHEST, 50-75%, IN THE PORTLAND/VANCOUVER METRO INCLUDING
THE TUALATIN VALLEY, NORTH TO KELSO/LONGVIEW, AND EAST INTO THE
COLUMBIA RIVER GORGE. CHANCES DECREASE TO THE SOUTH THROUGH THE
WILLAMETTE VALLEY, ALTHOUGH SMALLER CASCADE AND COAST RANGE
VALLEYS AROUND THE PERIPHERY OF THE SOUTHERN WILLAMETTE VALLEY
ARE ALSO MORE LIKELY TO SEE AREAS NEAR THE 90 DEGREE MARK.
THESE FORECAST HIGH TEMPERATURES REMAIN ON TRACK TO CHALLENGE
DAILY RECORDS AT CLIMATE SITES ALONG THE I-5 CORRIDOR; REFER TO
THE CLIMATE SECTION BELOW FOR DETAILS ON THE CURRENT RECORDS
AND FORECAST VALUES ACROSS THE REGION. HOT FORECAST TEMPERATURES
YIELD MODERATE HEATRISK ACROSS THE PORTLAND/VANCOUVER METRO
INCLUDING THE TUALATIN VALLEY, AND LOWER COLUMBIA & COWLITZ
VALLEYS, AND A HEAT ADVISORY THEREFORE REMAINS IN EFFECT FOR
THESE AREAS FROM 9 AM THROUGH 11 PM TODAY. THOSE SENSITIVE TO
HEAT OR PARTICIPATING IN STRENUOUS OUTDOOR ACTIVITIES MAY BE AT
HIGHER RISK OF DEVELOPING HEAT ILLNESS, AND SHOULD DRINK PLENTY
OF FLUIDS OR FIND A COOL PLACE TO AVOID THE PEAK AFTERNOON HEAT.
DESPITE HOT AIR TEMPERATURES, AREA RIVERS AND LAKES REMAIN COLD
ENOUGH TO CAUSE COLD SHOCK WHICH CAN BE FATAL. THOSE HEADING TO
THE COAST TO AVOID THE HEAT SHOULD ALSO REMAIN AWARE OF AN
ELEVATED RISK FOR SNEAKER WAVES. SNEAKER WAVES CAN SWEEP YOU OFF
OF YOUR FEET AND DISLODGE LOGS CAUSING HAZARDOUS CONDITIONS.
AVOID JETTIES, ROCKS, AND LOGS WITHIN THE SURF ZONE, AND NEVER
TURN YOUR BACK ON THE OCEAN.
ROBUST SURFACE HEATING IS LIKELY TO YIELD ABUNDANT CONDITIONAL
INSTABILITY, WITH GREATER THAN 70% CHANCES OF SURFACE-BASED CAPE
EXCEEDING 1000 J/KG ACROSS MUCH OF NORTHWESTERN OREGON, AND
EVEN 30-50% CHANCES OF 2000 J/KG OVER MUCH OF THE EASTERN
WILLAMETTE VALLEY AND CASCADE FOOTHILLS SOUTH OF SALEM. WITH THE
UPPER LOW LOCATED FARTHER TO THE SOUTH HOWEVER, THERE WILL BE
LESS SYNOPTIC SUPPORT FOR ASCENT, AND THEREFORE LOWER CHANCES
FOR REALIZATION OF THIS BUOYANCY. CHANCES FOR SHOWERS AND
THUNDERSTORMS REMAIN AROUND 15-30% IN THE CASCADES AND FOOTHILLS
FROM 2-9 PM THIS AFTERNOON AND EVENING, LARGELY TO THE SOUTH OF
OR-22, REFLECTING THE TENDENCY FOR CAMS TO KEEP STRONGER
UPDRAFTS LIMITED TO PORTIONS OF LANE, LINN, AND MARION COUNTIES
EAST OF THE WILLAMETTE VALLEY. STORMS THAT ARE ABLE TO BREAK
THE LOW-LEVEL CAP AND REALIZE THE AVAILABLE INSTABILITY MAY
BECOME STRONG, BUT DEEP-LAYER SHEAR OF ONLY 10-20 KT AT MOST
WILL FAIL TO SUPPORT CONVECTIVE ORGANIZATION AND LIMIT OVERALL
STORM INTENSITY, PRODUCING BRIEF HEAVY DOWNPOURS OR LOCALLY
GUSTY WINDS AT MOST. THE OUTLOOK FOR ANY SEVERE THUNDERSTORMS
THEREFORE REMAINS VERY LOW. -36
LONG TERM...MONDAY THROUGH SATURDAY
THE LARGE-SCALE PATTERN
WILL SLOWLY SLIDE EASTWARD THROUGH THE EARLY PORTION OF THE
WORKWEEK, WITH A SOUTHERLY WIND REVERSAL AND EXTENSIVE MARINE
STRATUS ALONG THE COAST AND RENEWED ONSHORE FLOW INLAND ACTING
TO COOL TEMPERATURES SUBSTANTIALLY ON MONDAY AND TUESDAY.
FORECAST HIGHS LARGELY IN THE 60S ALONG THE COAST AND IN HIGH
TERRAIN AND 70S WITHIN INLAND VALLEYS WILL FEEL MUCH COOLER, BUT
STILL REMAIN ABOVE NORMAL FOR EARLY MAY. ENSEMBLE GUIDANCE
CONTINUES TO FAVOR LARGELY DRY CONDITIONS BENEATH THE UPPER
RIDGE, BUT THERE WILL STILL BE LOW (10-20%) CHANCES FOR ISOLATED
SHOWERS OR THUNDERSTORMS OVER THE CASCADES OF LANE AND LINN
COUNTIES, AS WELL AS PERIODS OF DRIZZLE WITHIN COASTAL MARINE
STRATUS IN THE OVERNIGHT OR EARLY MORNING HOURS EACH DAY.
BY THE MIDDLE TO LATE PORTIONS OF THE WORKWEEK, LONG-RANGE
ENSEMBLES CONTINUE TO FAVOR A FLATTENING OF THE LONGWAVE RIDGE
WHICH WILL OTHERWISE PERSIST OVER THE WEST COAST. THIS
DEAMPLIFICATION OF THE PATTERN MAY ALLOW SHORTWAVE TROUGHS TO
TRAVERSE THE APEX OF THE RIDGE, YIELDING INCREASED CHANCES FOR
COOLER TEMPERATURES AS WELL AS LOW CHANCES FOR LIGHT RAIN,
PARTICULARLY ON FRIDAY AND SATURDAY. NONETHELESS, CURRENT
FORECAST HIGH TEMPERATURES STILL REMAIN 5-10 DEGREES ABOVE
SEASONAL NORMS IN THE 60S ALONG THE COAST AND IN HIGH TERRAIN,
AND IN THE 70S WITHIN INLAND VALLEYS. -36
AVIATION
VFR CONDITIONS PREVAIL AT ALL NW OR AND SW WA
TERMINALS ON SUNDAY UNDER HIGH PRESSURE. WINDS ALONG THE COAST
EXPECTED TO BE NORTHWEST TO WESTERLY LESS THAN 10 KTS. WESTERLY
WINDS AT KONP MAY PRODUCE MVFR/IFR VIS FROM SEA SPRAY AT TIMES.
INLAND, WINDS MAINLY NORTH TO NORTHEAST LESS THAN 10 KTS. AFTER 21Z
SUN, CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASE OVER THE WESTERN
SLOPES OF THE CENTRAL OREGON CASCADES, BUT CONFIDENCE IN TERMINAL
IMPACTS REMAINS VERY LOW. THE MORE LIKELY SCENARIO IS CONVECTIVE
OUTFLOW DEBRIS IN THE FORM OF HIGH CLOUD COVER MAY DEVELOP IN THE
LATE AFTERNOON TO EARLY EVENING.
AFTER 03-06Z MON, A WIND REVERSAL WILL SEE LOW-LEVEL FLOW TURN
SOUTHERLY ACROSS THE REGION, SPREADING FROM SOUTH TO NORTH THROUGH
12Z MON. AT COASTAL TERMINALS, A RENEWED PUSH OF MARINE STRATUS WILL
MOST LIKELY SEE A RETURN TO MVFR/IFR CIGS, RETURNING BY 03-06Z MON
AT KONP AND 09-12Z MON AT KAST. THIS MARINE PUSH LOOKS STRONG ENOUGH
REACH INLAND TO KEUG AND THE SOUTHERN WILLAMETTE VALLEY BY 09-12Z
MON WITH A 70-80% CHANCE OF MVFR CONDITIONS AND 50-60% CHANCE OF IFR
CONDITIONS. ADDITIONALLY, THERE'S A 30-40% CHANCE MVFR CIGS REACH AS
FAR NORTH AS KSLE AND A 20-30% CHANCE THEY REACH KPDX AND
SURROUNDING TERMINALS. EXPECT INLAND LOCATIONS TO IMPROVE TO VFR BY
18-21Z MON.
KPDX AND APPROACHES...VFR CONDITIONS EXPECTED THROUGHOUT THE PERIOD
BENEATH LARGELY CLEAR SKIES. NORTHEASTERLY FLOW AROUND 5-8 KT WILL
TURN NORTHERLY AROUND 00Z MON, THEN ULTIMATELY SOUTHERLY BY 10-12Z
MON. CONVECTIVE DEBRIS IN THE FORM OF HIGH CLOUD COVER MAY INCREASE
THIS AFTERNOON AND EVENING, BUT NO TERMINAL IMPACTS ARE ANTICIPATED.
THERE'S A 20-30% CHANCE OF MARINE STRATUS WITH MVFR CONDITIONS
IMPACTING KPDX AND SURROUNDING TERMINALS AFTER 10-14Z MON. -03/36
MARINE
NORTHERLY WINDS CONTINUE TODAY, PEAKING IN THE
AFTERNOON AND EASING OVERNIGHT. SEAS OF 5-6 FT THIS MORNING WILL
SLOWLY BUILD TOWARDS 6-8 FT AS A LONG-PERIOD NORTHWEST SWELL
ARRIVES. A SMALL CRAFT ADVISORY REMAINS IN EFFECT THROUGH 9 AM
THIS MORNING WITHIN THE COLUMBIA RIVER BAR AS A STRONG EBB
CURRENT YIELDS STEEP SEAS OF 7-8 FT.
A SOUTHERLY WIND REVERSAL IS ON MONDAY IS EXPECTED TO BRING
RESURGENT NEARSHORE MARINE STRATUS THROUGH TUESDAY NIGHT, AS
WELL AS OVERNIGHT OR EARLY MORNING DRIZZLE OR LIGHT RAIN.
NORTHERLY WINDS RETURN TOWARDS THE LATTER PART OF THE WEEK WITH
PERSISTENT SEAS OF 4-6 FT. -36/42
CLIMATE
DAILY RECORD HIGH TEMPERATURES FOR SUNDAY, MAY 3
LOCATION FORECAST RECORD YEAR
ASTORIA 78 81 1992, 1944
VANCOUVER 90 84 1944
PORTLAND INT'L 91 89 1992
HILLSBORO 91 82 2017
MCMINNVILLE 86 87 1992
SALEM 86 86 1992
EUGENE 83 83 1944
PQR WATCHES/WARNINGS/ADVISORIES
OR...HEAT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR ORZ108-109-111-
112.
WA...HEAT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR WAZ204>207.
PZ...NONE.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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