611
FXUS66 KPQR 290544
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
1044 PM PDT TUE JUL 28 2026
UPDATED AVIATION DISCUSSION
SYNOPSIS
WEAK FRONT WITH LIGHT SHOWERS SHIFT EASTWARD TODAY.
ONSHORE FLOW PERSISTS THROUGH THE NEXT WEEK. HIGH PRESSURE
BEGINS TO BUILD THROUGH FRIDAY WITH FRIDAY EXPECTED TO BE THE
HOTTEST DAY THIS WEEK. ANOTHER SYSTEM ARRIVES ON SATURDAY WHICH
WILL BRING INCREASING PROBABILITIES OF PRECIPITATION AND
WESTERLY WINDS.
SHORT TERM...NOW THROUGH THURSDAY
OVERALL, LITTLE CHANGE IN
THE FORECAST. THE FRONTAL SYSTEM THAT MOVED THROUGH THIS
MORNING CONTINUES TO CHUG ALONG PRODUCING VERY LIGHT TO ALMOST
NO RAIN. THEREFORE, NO IMPACT HAS BEEN DETECTED OTHER THAN
MAINTAINING STEADY STRATUS OVER THE AREA. THIS FRONT WILL
CONTINUE TO MOVE EASTWARD OVERNIGHT WITH DRIER AND CLEARER
CONDITIONS TRAILING BEHIND IT. THESE CONDITIONS WILL BE
AMPLIFIED BY A RIDGE ALOFT FORMING OVER THE ROCKIES, AND A
TROUGH OVER THE COAST STEMMING FROM A BROAD LOW IN THE NORTHEAST
PACIFIC. WHILE NOT NECESSARILY A SIGNIFICANT PATTERN SHIFT, IT
WILL MAINTAIN WESTERLY FLOW THROUGH THURSDAY AT LEAST.
TEMPERATURES WILL BE MODERATE AND SEASONABLE ON WEDNESDAY AND
THURSDAY WITH HIGHS IN THE INTERIOR LOWLANDS IN THE LOW 80S, MID
60S ALONG THE COAST, AND IN THE 70S ALONG THE CASCADES. -27
LONG TERM...THURSDAY NIGHT THROUGH TUESDAY
THE TROUGH IN THE
NORTHEAST PACIFIC WILL REMAIN THROUGH MUCH OF THE WEEKEND BUT ON
THURSDAY, A BRIEF SHORTWAVE WITH AN ASSOCIATED WEAK FRONT WILL
PASS NORTH OF THE AREA, BUT STRATUS MAY FILL. ON FRIDAY, WHILE
ONSHORE FLOW PERSISTS, A WEAK RIDGE FORMS WHICH WILL USHER IN
WARMER AIR TO THE REGION. 850 MB TEMPERATURES WILL REACH AROUND
15 DEG C IN THE AFTERNOON AND THE 850-250 MB RH DIFFERENCE
REMAINS VERY DRY. THEREFORE, FRIDAY WILL LIKELY BE THE HOTTEST
DAY OF THE WEEK THOUGH NOT ANYWHERE NEAR RECORD BREAKING. WITHIN
THE WILLAMETTE VALLEY WE WILL SEE TEMPERATURES IN THE MID TO
UPPER 80S WITH SOME AREAS, ESPECIALLY URBAN ONES, REACHING 90.
THE COAST WILL BE BEAUTIFUL IN THE MID TO UPPER 60S.
THIS WARM UP WILL BE SHORT LIVED THOUGH AS THE TROUGH PREVIOUSLY
MENTIONED TRAVERSES EASTWARD. A COOLER FRONTAL SYSTEM WILL DIP
DOWN OVER THE REGION INCREASING PRECIPITATION CHANCES, AND
BRINGING IN COOLER AIR. TEMPERATURES WILL LIKELY DROP BY AROUND
10 DEGREES OR SO ON SATURDAY WITH INCREASING CHANCES FOR
PRECIPITATION. MOST MODELS ARE KEEPING THE BULK OF THE RAIN TO
THE NORTH, BUT THERE REMAINS AROUND A 30-40% CHANCE OF
MEASURABLE RAIN OVER THE TERRAIN OF SOUTHWEST WASHINGTON AND THE
COAST NORTH OF TILLAMOOK. OVERALL THOUGH, ACCUMULATIONS WILL BE
LIGHT. AS IS COMMON WITH COLD FRONTAL PASSAGES, THE ENVIRONMENT
WILL BECOME CONVECTIVE HOWEVER THUNDERSTORMS ARE NOT EXPECTED AT
THIS TIME. WE ARE MISSING A BULK OF THE INSTABILITY THAT WE
WOULD NEED TO SEE ANOTHER THUNDERSTORM OUTBREAK. ANOTHER
COMPONENT IS WIND. IN GENERALLY, WIND WILL BE TEMPERATURE AND
PRESSURE GRADIENT DRIVEN WITH THE HIGHEST WIND SPEEDS THROUGH
THE E-W ALIGNED TERRAIN LIKE THE COLUMBIA RIVER GORGE AND THE
PASSES OF THE CASCADES.
ONSHORE ZONAL FLOW REMAINS THROUGH EARLY NEXT WEEK WITH DRY
CONDITIONS EXPECTED. -27
AVIATION
AREAS OF LOW CLOUD COVER ARE SLOWLY SPREADING ALONG
THE IMMEDIATE COASTLINE WITH A MIX OF VFR TO LIFR CONDITIONS.
UNCERTAINTY REMAINS MODERATE REGARDING THE EXACT PROGRESSION OF
CEILING HEIGHTS INTO THE MORNING ACROSS THE REGION, AS WELL AS
WHETHER OR NOT CLOUD COVER WILL BE PREDOMINATELY SCATTERED OR
BROKEN COME THE SUNRISE HOURS. THE LATEST GUIDANCE SUGGESTS A
BROKEN CLOUD DECK WILL ATTEMPT TO FILL IN OVER PORTIONS OF THE
WILLAMETTE VALLEY AND PORTLAND METRO BETWEEN 08-13Z. HOWEVER,
PROBABILITIES CURRENTLY FAVOR LOW-END VFR CEILINGS WITH THIS
POTENTIAL STRATUS DECK. PROBABILITIES FOR MVFR CEILINGS BELOW
3000 FT PEAK BETWEEN 10-16Z WEDNESDAY ARE STILL BETWEEN 15-30%
AT ALL INLAND TAF SITES. MUCH HIGHER CONFIDENCE IN WIDE-SPREAD
VFR CONDITIONS BY THE 18Z ONWARD AS THE STRATUS QUICKLY
DISSIPATES.
KPDX AND APPROACHES...VFR CONDITIONS IN PLACE LATE THIS EVENING WILL
MOST LIKELY REMAIN IN PLACE THROUGH THE TAF PERIOD. THAT SAID,
WE'LL STILL HAVE TO WATCH LOW STRATUS FORMATION NEAR SUNRISE AS
THERE IS ~20% CHANCE FOR MVFR CEILINGS BELOW 3000 FT BETWEEN
12-16Z. VFR CIGS/VIS ARE HEAVILY FAVORED AFTER THIS POINT. WINDS
GENERALLY REMAIN OUT OF THE NORTHWEST AT 5-10 KNOTS. -99/23
MARINE
BUOY OBSERVATIONS FROM EARLY TO MID TUESDAY AFTERNOON
SHOWED SEAS REMAINING WITHIN THE 4 TO 6 FOOT RANGE. THESE SEAS
ARE EXPECTED TO CONTINUE WITH A DOMINANT WEST TO NORTHWEST SWELL
AT 7-9 SECONDS AND A SECONDARY LONG-PERIOD SOUTH-SOUTHWESTERLY
SWELL PERSISTING THROUGH MUCH OF THE WEEK. NORTHWEST WINDS WILL
DEVELOP OVER THE WATERS TUESDAY EVENING IN THE WAKE OF A COLD
FRONTAL PASSAGE. NORTH WINDS ON WEDNESDAY WILL BECOME LIGHTER
AND BACK TO THE SOUTH ON THURSDAY WITH ANOTHER WEAK FRONTAL
PASSAGE.
YET ANOTHER WEAK FRONT LOOKS TO TRAVERSE THE WATERS EARLY THIS
WEEKEND, AFTER WHICH NORTHWESTERLY FLOW WILL STRENGTHEN AND VEER
OUT OF NORTH INTO EARLY NEXT WEEK AS HIGH PRESSURE BUILDS
OFFSHORE. CONFIDENCE IN WIND GUSTS OF AT LEAST 20-25 KT IS
MODERATE TO HIGH ON SUNDAY, INCREASING FROM AROUND 60% WEST OF THE
MOUTH OF THE COLUMBIA TO GREATER THAN 90% OFFSHORE OF FLORENCE.
THOSE CHANCES ARE EVEN HIGHER ON MONDAY, SOME 90-95% OR HIGHER
ACROSS THE COASTAL WATERS. THE CHANCES FOR GALE-FORCE GUSTS ON
MONDAY ARE LOW BUT NOT NEGLIGIBLE, GENERALLY 10-20% SOUTH OF CAPE
FOULWEATHER AS WELL AS WITHIN 10 NM OF THE COAST FROM CAPE FALCON
TO CAPE FOULWEATHER. -36/23
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
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