174  
FXUS66 KPQR 102245  
AFDPQR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PORTLAND OR  
345 PM PDT THU JUL 10 2025  
   
SYNOPSIS
 
PARTLY CLOUDY SKIES WITH SEASONABLE TEMPERATURES  
THIS AFTERNOON. TEMPERATURES WARM UP TOMORROW INTO THE WEEKEND  
AS HIGH PRESSURE BUILDS. EXPECT MORNING MARINE CLOUDS ALONG THE  
COAST AND OVER THE WATERS. TEMPERATURES COOL SLIGHTLY ON  
MONDAY, BUT STILL REMAIN VERY WARM AND DRY. AN EXTREME HEAT  
WATCH HAS BEEN ISSUED FOR SOME INTERIOR VALLEY LOCATIONS FROM  
TUESDAY TO WEDNESDAY NEXT WEEK AS TEMPERATURES BETWEEN 95 TO  
105 DEGREES ARE POSSIBLE WITH OVERNIGHT LOWS STRUGGLING TO FALL  
BELOW 65 TO 70 DEGREES.  
 

 
   
SHORT TERM...NOW THROUGH SATURDAY NIGHT
 
SATELLITE IMAGERY AS  
OF EARLY THURSDAY AFTERNOON DEPICTS PARTLY CLOUDY SKIES AND DRY  
CONDITIONS ACROSS MOST OF NORTHWEST OREGON AND SOUTHWEST  
WASHINGTON. AFTERNOON HIGHS TODAY ARE FORECAST TO PEAK IN THE  
UPPER 70S TO LOW 80S ACROSS INTERIOR LOCATIONS, WHICH IS NEAR OR  
SLIGHTLY BELOW SEASONAL NORMS. TOMORROW (FRIDAY), AN UPPER LEVEL  
RIDGE BEGINS TO RE-BUILD, LEADING TO WARMER TEMPERATURES AND  
SUNNY SKIES. DO EXPECT SOME MARINE FOG/STRATUS AS HIGH PRESSURE  
ALOFT KEEPS CLOUDS TO THE LOWEST PART OF THE ATMOSPHERE.  
 
FRIDAY AFTERNOON HIGHS ARE FORECAST IN THE UPPER 80S ACROSS  
INTERIOR VALLEYS WHILE THE COAST REMAINS MILD IN THE 60S TO LOW  
70S WITH ONSHORE FLOW. EXPECT BREEZY NORTHWESTERLY WINDS ALONG  
THE COAST WITH GUSTS UP TO 25 MPH, WHILE NORTHERLY WINDS GUST UP  
TO 20 MPH ACROSS THE WILLAMETTE VALLEY. THE STRONGEST WINDS WILL  
BE IN THE AFTERNOON WHEN PRESSURE GRADIENTS ARE TIGHTEST. HIGH  
PRESSURE PERSISTS ON SATURDAY, MAINTAINING SIMILAR TEMPERATURES  
TO FRIDAY WITH GENERALLY NORTHERLY FLOW. -ALVIZ  
 

 
   
LONG TERM...SUNDAY THROUGH WEDNESDAY
 
ENSEMBLE GUIDANCE  
SUGGESTS THAT HIGH PRESSURE THIS WEEKEND PEAKS ON SUNDAY,  
LEADING TO VERY WARM TEMPERATURES IN THE LOW TO MID 90S ACROSS  
THE WILLAMETTE VALLEY. THIS WILL LEAD TO WIDESPREAD MODERATE  
HEATRISK - THIS LEVEL OF HEAT AFFECTS MOST INDIVIDUALS  
SENSITIVE TO HEAT, ESPECIALLY THOSE WITHOUT EFFECTIVE COOLING  
AND/OR ADEQUATE HYDRATION. WE WILL CONTINUE TO EVALUATE IF A  
HEAT ADVISORY IS WARRANTED FOR THIS WEEKEND (PARTICULARLY  
SUNDAY). ON MONDAY, TEMPERATURES FALL ABOUT 5-10 DEGREES AS MOST  
ENSEMBLE GUIDANCE SUGGESTS AN UPPER LEVEL SHORTWAVE TROUGH  
DIPPING INTO THE CANADIAN ROCKIES AND NORTHERN INTERMOUNTAIN  
WEST. THOUGH 500 MB HEIGHTS FALL OVER OUR AREA WITH THIS  
SHORTWAVE TROUGH, THEY STILL REMAIN ABOVE-NORMAL AND WILL  
MAINTAIN WARM TEMPERATURES WITH HIGHS IN THE UPPER 80S TO LOW  
90S FOR INTERIOR VALLEYS.  
 
ALL EYES ARE ON TUESDAY TO WEDNESDAY AS THERE IS POTENTIAL FOR  
EXTREME HEAT. AN EXTREME HEAT WATCH HAS BEEN ISSUED FROM TUESDAY  
AFTERNOON (JULY 15) TO LATE WEDNESDAY EVENING (JULY 16) ACROSS  
THE GREATER PORTLAND/VANCOUVER METRO, WESTERN AND CENTRAL  
COLUMBIA RIVER GORGE, THE CORBETT AREA AND THE HOOD RIVER  
VALLEY, LOWER COLUMBIA RIVER AND COWLITZ RIVER VALLEYS, AND  
CENTRAL WILLAMETTE VALLEY. DANGEROUSLY HOT CONDITIONS WITH  
TEMPERATURES BETWEEN 95 TO 105 DEGREES ARE POSSIBLE. LOW  
TEMPERATURES BETWEEN 65 TO 70 DEGREES ARE POSSIBLE AS WELL,  
WHICH WOULD LIMIT OVERNIGHT RELIEF ESPECIALLY TUESDAY NIGHT.  
CURRENTLY, THIS WATCH ENCOMPASSES AREAS WHERE OVERNIGHT LOW  
TEMPERATURES MAY STRUGGLE TO FALL BELOW 65 TO 70 DEGREES. THE  
LATEST GUIDANCE SUGGESTS THAT THERE IS A 40-50% CHANCE THAT  
TUESDAY NIGHT LOW TEMPERATURES REMAIN ABOVE 70 DEGREES. IN  
ADDITION, THERE IS ALSO A 20-40% CHANCE THAT TUESDAY AND  
WEDNESDAY HIGH TEMPERATURES EXCEED 105 DEGREES ACROSS THE  
WILLAMETTE VALLEY. AS A REMINDER, AN EXTREME HEAT "WATCH" IS  
ISSUED WHEN DANGEROUS HEAT IS POSSIBLE. AN EXTREME HEAT  
"WARNING" IS ISSUED WHEN DANGEROUS HEAT IS HAPPENING OR ABOUT TO  
HAPPEN.  
 
MAJOR HEATRISK IS CURRENTLY FORECAST FOR AREAS WITHIN THE  
EXTREME HEAT WATCH. THIS LEVEL OF HEAT WOULD AFFECT ANYONE  
WITHOUT EFFECTIVE COOLING AND/OR ADEQUATE HYDRATION. HEAT  
RELATED ILLNESSES INCREASE SIGNIFICANTLY DURING EXTREME HEAT  
EVENTS.  
 
IN ADDITION TO THE UPPER LEVEL HIGH PRESSURE, MODELS ARE ALSO  
INDICATING A THERMAL TROUGH DEVELOPING OVER THE WILLAMETTE  
VALLEY ON TUESDAY. IF THIS OCCURS, THEN IT WOULD LEAD TO MORE  
OFFSHORE FLOW. CURRENTLY, THE EASTERLY WINDS FORECAST WITH THIS  
THERMAL TROUGH ARE NOT LOOKING VERY STRONG, AND WILL MAINLY BE  
THROUGH THE COLUMBIA RIVER GORGE AND CASCADES. CURRENT GUIDANCE  
SHOWS PRESSURE GRADIENTS OF -2 TO -4 MB THROUGH THE GORGE ON  
TUESDAY, WHICH WOULD LEAD TO WIND GUSTS UP TO 20-25 MPH IN THAT  
AREA. -ALVIZ  
 

 
   
AVIATION
 
MARINE STRATUS ACROSS THE AIR SPACE CONTINUES TO  
SCOUR OUT RESULTING IN A MIXTURE OF VFR/MVFR CONDITIONS ACROSS THE  
AIRSPACE. CURRENTLY, WINDS ARE NORTHERLY AROUND 5-10 KT, BUT  
EXPECTED TO INCREASE OVER THE NEXT FEW HOURS. THIS WILL RESULT IN  
GUSTY CONDITIONS FOR ALL TERMINALS, WITH GUSTS UP TO 20 KT  
THROUGH AROUND 02Z FRIDAY.  
 
WESTERLY FLOW CONTINUES ACROSS NW OREGON AND SW WASHINGTON  
THROUGH THE TAF PERIOD. AS A RESULT, EXPECT SIMILAR CONDITIONS AS  
TO WHAT HAS BEEN OBSERVED OVER THE PAST 24-48 HOURS. EXPECT  
COASTAL CONDITIONS TO REDEVELOP IFR/LIFR CONDITIONS AROUND  
00Z-03Z FRIDAY. FOR INLAND LOCATIONS, WHILE ONSHORE FLOW WILL BE  
PRESENT, IT WILL BE NORTHERLY AND THIS PATTERN WILL MITIGATE MARINE  
STRATUS INFILTRATING THROUGH THE GAPS AND FLOWS AS WELL AS THE  
COLUMBIA RIVER. HOWEVER, MODELS ARE SHOWING SOME BACKBUILDING  
CLOUDS OFF THE CASCADES AND THAT COULD BRING SOME MVFR FLIGHT  
CONDITIONS TO NORTHERLY (KPDX,KTTD,KVUO) AND SOUTH/CENTRAL (KSLE  
AND KEUG) TERMINALS. THESE CONDITIONS WILL LIKELY START AROUND  
10Z-12Z FRIDAY. CONDITIONS ACROSS THE AIRSPACE TO SLOWLY IMPROVE  
STARTING AROUND 12Z-15Z FRIDAY.  
 
PDX AND APPROACHES...PREDOMINATELY VFR CONDITIONS THROUGH THE  
MAJORITY OF THE TAF PERIOD. BACKBUILDING CLOUDS OFF THE CASCADES  
WILL LIKELY BRING MVFR CONDITIONS TO THE THE TERMINAL AND EASTWARD  
STARTING AROUND 12Z FRIDAY. CONDITIONS EXPECTED TO IMPROVE BACK  
TOWARDS VFR AROUND 16Z-18Z FRIDAY. NORTHERLY WINDS 5-10 KT, WITH  
GUSTS UP TO 20 KT POSSIBLE THROUGH AROUND 02Z FRIDAY. /42  
 

 
   
MARINE
 
NORTH/NORTHWEST WINDS ACROSS ALL WATERS WILL PERSIST  
THROUGH THE WEEKEND AS A BROAD AREA OF HIGH PRESSURE AND A  
THERMALLY INDUCED TROUGH SPREADS NORTHWARD. AS THE HIGH PRESSURE  
AND ASSOCIATED THERMALLY INDUCED TROUGH MATURE, EXPECT GUSTY  
NORTHERLY WINDS AND CHOPPIER WIND DRIVEN SEAS. AS A RESULT HAVE  
ISSUED A SMALL CRAFT ADVISORY FOR ZONES PZZ237,PZZ253, PZZ272 AND  
PZZ252 STARTING FRIDAY MORNING AND CONTINUING THROUGH AT LEAST  
EARLY SATURDAY MORNING. /42  
 

 
   
PQR WATCHES/WARNINGS/ADVISORIES
 
 
OR...EXTREME HEAT WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY  
EVENING FOR ORZ108>115-119>122.  
 
WA...EXTREME HEAT WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY  
EVENING FOR WAZ204>207-209-210.  
 
PZ...SMALL CRAFT ADVISORY FROM 2 PM TO 11 PM PDT FRIDAY FOR PZZ252-  
272.  
 
SMALL CRAFT ADVISORY FROM 11 AM FRIDAY TO 2 AM PDT SATURDAY FOR  
PZZ253-273.  

 
 

 
 
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