828
FXUS66 KPQR 231745 AAA
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
1045 AM PDT TUE JUN 23 2026
UPDATED AVIATION DISCUSSION
SYNOPSIS
HOT AND DRY CONDITIONS CONTINUE TODAY, BRINGING
WIDESPREAD MODERATE HEATRISK ACROSS ALL INTERIOR VALLEYS.
INCREASING ONSHORE FLOW TONIGHT INTO WEDNESDAY WILL BRING HIGH
TEMPERATURES DOWN A FEW DEGREES WEDNESDAY AFTERNOON. COOLER AND
WETTER CONDITIONS ARRIVE THURSDAY THROUGH SATURDAY, WITH A
SLIGHT CHANCE FOR THUNDERSTORMS SATURDAY AFTERNOON. DRIER
CONDITIONS RETURN SUNDAY-MONDAY, BUT WE'LL STILL MAINTAIN
SLIGHT CHANCES FOR RAIN ACROSS THE COAST RANGE AND CASCADES.
DISCUSSION...TODAY THROUGH MONDAY
SATELLITE IMAGERY AS OF
EARLY TUESDAY MORNING DEPICTS WIDESPREAD MARINE STRATUS ALONG
THE COAST AND MOSTLY CLEAR SKIES INLAND WITH A FEW HIGH CLOUDS.
AS DAYTIME HEATING PROGRESSES TODAY, WE'LL SEE INCREASED MIXING
AND SOME STRATUS BREAK-OUT BY LATE MORNING. HOWEVER, THERE IS A
20-30% CHANCE THAT STRATUS LINGERS THROUGHOUT THE DAY ALONG THE
COAST.
HOT AND DRY CONDITIONS CONTINUE TODAY WITH AFTERNOON HIGH
TEMPERATURES FORECAST IN THE UPPER 80S TO MID 90S, WARMEST ALONG
THE I-5 CORRIDOR FROM SALEM TO THE COWLITZ VALLEY. THIS WILL
RESULT IN WIDESPREAD MODERATE HEATRISK ACROSS ALL INTERIOR
VALLEYS. THIS LEVEL OF HEAT WILL AFFECT THOSE WHO ARE SENSITIVE
TO HEAT, ESPECIALLY THOSE WITHOUT ADEQUATE COOLING OR HYDRATION.
THE HEAT ADVISORY REMAINS IN EFFECT THROUGH 11 PM TONIGHT ALONG
THE I-5 CORRIDOR FROM SALEM TO THE COWLITZ VALLEY, THE COLUMBIA
RIVER GORGE, AND UPPER HOOD RIVER VALLEY. MAKE SURE TO STAY
HYDRATED, WEAR LIGHT-COLORED AND LOOSE-FITTED CLOTHING, WEAR
SUN PROTECTION, TAKING FREQUENT BREAKS FROM THE HEAT, AND
LIMITING STRENUOUS OUTDOOR ACTIVITIES DURING THE HOTTEST PART OF
THE DAY.
ONSHORE FLOW INCREASES TONIGHT INTO WEDNESDAY AS A WEAK TROUGH
PASSING THROUGH THE REGION. THE AIRMASS IS DRY, SO THIS TROUGH
IS NOT EXPECTED TO BRING PRECIPITATION. OVERNIGHT LOWS IN THE
LOW TO MID 50S FOR MOST AREAS WILL PROVIDE OVERNIGHT RELIEF FROM
THE HEAT. AN EXCEPTION IS THE PORTLAND/VANCOUVER METRO AREA AND
COLUMBIA RIVER GORGE, WHERE WEDNESDAY MORNING BETWEEN 60 TO 65
DEGREES WILL PROVIDE LIMITED RELIEF FROM THE HEAT. BECAUSE OF
URBAN HEAT ISLAND EFFECTS, THE PORTLAND/VANCOUVER METRO ALSO HAS
A 10-25% CHANCE FOR WEDNESDAY MORNING LOWS EXCEEDING 65
DEGREES. WEDNESDAY AFTERNOON HIGHS WILL STILL BE VERY WARM BUT A
COUPLE DEGREES COOLER THAN TODAY. WILL ALSO NOTE THAT SOME
HIGH-RESOLUTION GUIDANCE IS SHOWING SOME VERY LIGHT
PRECIPITATION OVER THE CASCADES THIS AFTERNOON AS THE
AFOREMENTIONED TROUGH MOVES THROUGH, HOWEVER, THERE IS LOW
CONFIDENCE IT WILL ACTUALLY REACH THE GROUND DUE TO HOW DRY THE
AIR IS (AKA IT WOULD FALL AS VIRGA).
A LARGE-SCALE PATTERN CHANGE TO COOLER AND WETTER CONDITIONS
REMAINS ON TRACK THURSDAY INTO THE WEEKEND AS ENSEMBLE GUIDANCE
IS IN AGREEMENT WITH AN UPPER-LEVEL TROUGH APPROACHING THE
PACIFIC NORTHWEST. MOST ENSEMBLE MEMBERS HAVE RAINFALL REACHING
THE COAST BY LATE THURSDAY AFTERNOON/EVENING AND THEN SPREADING
INTO THE I-5 CORRIDOR BY LATE THURSDAY NIGHT INTO FRIDAY
MORNING. WE'LL REMAIN IN THIS COOL AND WET PATTERN THROUGH AT
LEAST SATURDAY, BUT AT LEAST TOTAL RAIN AMOUNTS AT THIS TIME
APPEAR BENEFICIAL AND GENERALLY NON-IMPACTFUL. CHANCES FOR
48-HOUR RAIN AMOUNTS EXCEEDING 0.50 INCH FROM 5 AM FRIDAY TO 5
AM SUNDAY ARE AROUND 60-80% FOR THE COAST AND COAST RANGE,
50-70% ALONG THE I-5 CORRIDOR, AND GREATER THAN 90% ACROSS THE
CASCADES DUE TO WESTERLY FLOW BRINGING OROGRAPHIC ENHANCEMENT.
WILL NOTE THAT THE WESTERNMOST PARTS OF THE WILLAMETTE VALLEY
THAT ARE WEST OF I-5 (INCLUDING MCMINNVILLE AND CORVALLIS) ONLY
HAVE A 25-35% CHANCE FOR EXCEEDING 0.50 INCH DURING THIS
TIMEFRAME DUE TO POTENTIAL RAINSHADOWING FROM THE COAST RANGE.
ON SATURDAY, THE UPPER-LEVEL TROUGH WILL TRANSITION INTO A
CLOSED UPPER-LEVEL LOW AND MOVE DIRECTLY OVER THE PACIFIC
NORTHWEST. TEMPERATURES WILL COOL DOWN ALOFT, INCREASING
ATMOSPHERIC INSTABILITY AND BRINGING CAPE VALUES OF 100-200 J/KG
ACROSS THE REGION LATE SATURDAY MORNING INTO THE AFTERNOON. THIS
INSTABILITY PLUS SUFFICIENT LIFT FROM THE LOW WILL SUPPORT A
SLIGHT CHANCE (15-20%) FOR THUNDERSTORMS ACROSS NORTHWEST OREGON
AND SOUTHWEST WASHINGTON. LREF GUIDANCE ALSO SUGGESTS 0-500 MB
WIND SHEAR VALUES AROUND 25-35 KT WITH LIMITED DIRECTION SHEAR,
SO IT APPEARS THAT THESE THUNDERSTORMS WILL AT LEAST TREND NON-
SEVERE. ANY PASSING THUNDERSTORMS MAY PRODUCE LIGHTNING, BRIEF
HEAVY RAIN, ERRATIC WINDS, AND/OR SMALL HAIL. ALSO CAN'T RULE
OUT A FEW COLD AIR FUNNEL CLOUDS.
BY SUNDAY-MONDAY, THE MAJORITY OF ENSEMBLE MEMBERS ARE SHOWING
THE UPPER-LEVEL LOW SHIFTING EASTWARD, RETURNING RELATIVELY
DRIER CONDITIONS AND A WARM-UP OF A FEW DEGREES. WILL STILL
MAINTAIN PRECIPITATION CHANCES ACROSS THE COAST RANGE AND
CASCADES AS WESTERLY FLOW CONTINUES TO SUPPORT OROGRAPHIC
ENHANCEMENT OF PRECIPITATION, HOWEVER, ANY ADDITIONAL RAIN
AMOUNTS APPEAR LIGHT. WESTERLY WINDS THROUGHOUT THIS COOL AND
WET PATTERN WILL BE BREEZIEST ALONG THE CENTRAL COLUMBIA RIVER
GORGE AND ACROSS UPPER HOOD RIVER VALLEY, WITH CHANCES FOR
ISOLATED WIND GUSTS EXCEEDING 45 MPH AROUND 10-30% FROM FRIDAY
TO THE END OF THE WEEKEND. -10
AVIATION
SOUTHWEST FLOW ALOFT AHEAD OF A WEAK UPPER LEVEL
TROUGH THAT WILL MOVE ACROSS THE REGION THIS AFTERNOON. CONTINUED
DRY CONDITIONS WITH SCATTERED TO BROKEN HIGH CLOUDS WILL MAINTAIN
PREDOMINATELY VFR CONDITIONS ACROSS INLAND TERMINALS. THE MAIN
EXCEPTION IS THE SHALLOW MARINE STRATUS ALONG THE COAST. AS OF
17Z, SATELLITE IMAGERY SHOWS THE STRATUS PULLING OFFSHORE FROM
KAST, BUT CONTINUES TO LINGER FROM KTMK SOUTHWARD WITH
PREDOMINATELY IFR CIGS. VISIBILITIES SHOULD CONTINUE TO IMPROVE
THROUGH THE LATE MORNING AND EARLY AFTERNOON HOURS. THERE REMAINS
MODERATE CHANCES FOR IMPROVEMENT TO VFR NEAR KONP, HOWEVER THERE
IS A 30-50% CHANCE FOR MARINE STRATUS TO PERSIST THROUGH THE
AFTERNOON. CHANCES FOR IFR/LIFR STRATUS RETURNING TO THE COAST
INCREASE AGAIN AFTER 02-03Z WED. LIGHT WINDS UNDER 5 KT BECOME
WNW, INCREASING TO 7-10 KT IN THE AFTERNOON ACROSS ANY GIVEN
TERMINAL.
IN ADDITION, HIGH TEMPERATURES BETWEEN 90 TO 95 DEGREES ARE
FORECAST ACROSS THE WILLAMETTE VALLEY THIS AFTERNOON. BE AWARE OF
HIGH DENSITY ALTITUDE WHICH MAY REDUCE AIRCRAFT PERFORMANCE.
KPDX AND APPROACHES...VFR THROUGH THE TAF PERIOD WITH SCT/BKN HIGH
CLOUDS THROUGH THIS AFTERNOON. LIGHT AND VARIABLE WINDS EXPECTED
TO BECOME NORTHWESTERLY, INCREASING TO 7-10 KT IN THE
AFTERNOON/EVENING. /DH
MARINE
HIGH PRESSURE WILL MAINTAIN NORTH-NORTHWESTERLY WINDS
ACROSS THE COASTAL WATERS THROUGH WEDNESDAY. WINDS GENERALLY
EXPECTED TO REMAIN UNDER 20 KT, BUT THERE IS A 60-80% CHANCE FOR
ISOLATED WIND GUSTS UP TO 25 KT FOR THE WATERS BEYOND 30 NM
OFFSHORE. GIVEN THE LOW CONFIDENCE FOR WIDESPREAD AND FREQUENT
WIND GUSTS GREATER THAN 21 KT, DECIDED AGAINST ISSUING SMALL CRAFT
ADVISORIES FOR THE OUTER WATER ZONES BEYOND 10 NM OFFSHORE.
WEAKENING HIGH PRESSURE WILL GIVE WAY TO A FRONTAL SYSTEM
APPROACHING THE AREA ON THURSDAY. WINDS ARE EXPECTED TO BACK WEST
TO SOUTHWESTERLY BEFORE THE COLD FRONT PUSHES ACROSS THE COASTAL
WATERS LATE THURSDAY INTO FRIDAY. SOUTHWEST WINDS ARE EXPECTED TO
BE STRONGEST FOR THE WATERS NORTH OF CAPE FOULWEATHER AND UP TO 10
NM OFFSHORE, BUT THERE IS ONLY AROUND A 10-20% CHANCE OF SMALL
CRAFT WIND GUSTS EXCEEDING 21 KT AT ANY GIVEN HOUR THROUGH FRIDAY
MORNING. WEST TO NORTHWEST WINDS WILL PERSIST BEHIND THE FRONT
LATER FRIDAY AND INTO THE WEEKEND AS WEAK LOW PRESSURE LINGERS
NEAR VANCOUVER ISLAND. HIGH PRESSURE GRADUALLY BUILDS ACROSS THE
WATERS LATE WEEKEND. SEAS REMAIN AROUND 5 TO 7 FT THROUGH
WEDNESDAY, SUBSIDING TO 4 TO 5 FT ON THURSDAY. -10/DH
PQR WATCHES/WARNINGS/ADVISORIES
OR...HEAT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR ORZ108>115-
119>123.
WA...HEAT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR WAZ204>210.
PZ...NONE.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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