485  
FXUS66 KPQR 090945  
AFDPQR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PORTLAND OR  
245 AM PDT FRI MAY 9 2025  
   
SYNOPSIS  
BENIGN WEATHER CONDITIONS THROUGH THE END OF THE  
WEEK WITH DAYTIME HIGHS IN THE 60S-70S THROUGH THE WEEKEND AND  
INTO NEXT WEEK. TODAY IS EXPECTED TO BE THE WARMEST, BUT AS A  
BROAD AREA OF LOW PRESSURE STARTS TO PUSH EASTWARD, TEMPERATURES  
ARE EXPECT TO SLOWLY COOL TOWARDS THE 50S ALONG THE COAST AND  
60S FOR INLAND LOCATIONS. WETTER WEATHER IS ALSO EXPECTED TO  
MAKE A RETURN ON SUNDAY INTO EARLY NEXT WEEK.  
 
 
   
SHORT TERM...TODAY THROUGH SUNDAY NIGHT  
DRY CONDITIONS WITH  
MOSTLY CLEAR SKIES PERSIST TODAY AS A RIDGE OF HIGH PRESSURE  
REMAINS THE DOMINANT SYNOPTIC FEATURE. HOWEVER, THIS WILL SLOWLY  
CHANGE AS A BROAD AREA OF LOW PRESSURE WILL BRING ABOUT A  
PATTERN CHANGE FOR THE REGION TOWARDS THE START OF NEXT WEEK.  
DAYTIME HIGHS TODAY WILL BE IN THE 60S ALONG THE COAST AND 70S  
FOR INLAND LOCATIONS. GENERALLY NORTHERLY WINDS TODAY, WITH  
GUSTS PEAKING UP TO 20 MPH. WINDS DECREASE GOING INTO THE LATE  
AFTERNOON/EVENING, AND WILL BE FAIRLY LIGHT AND VARIABLE  
THROUGHOUT TONIGHT. TONIGHT THROUGH SUNDAY, CLOUD COVER BEGINS  
TO INCREASE AS THE RIDGE BEGINS TO SLOWLY ACQUIESCE TO AN  
INCOMING LOW FROM THE EASTERN PACIFIC. THIS WILL START A SLOW  
COOLING TREND ACROSS THE CWA PUSHING OUT OF THE REGION,  
RESULTING IN SLIGHTLY COOLER TEMPERATURES. DAYTIME HIGHS ON  
SATURDAY LOOK TO BE IN THE UPPER 60S TO LOW 70S INLAND AND INTO  
THE 50S TO 60S ALONG THE COAST. SUNDAY WILL BE EVEN COOLER WITH  
DAYTIME HIGHS IN THE LOW TO MID 60S INLAND AND UPPER 40S TO MID  
50S ALONG THE COAST. MODELS ARE EVEN SHOWING A FRONTAL PASSAGE  
LATE SATURDAY/EARLY SUNDAY WITH MOST OF THE RAINFALL ARRIVING  
SUNDAY; 30-60% PROBABILITY OF LIGHT RAINFALL STARTING LATE  
SATURDAY NIGHT AND THE PROBABILITY OF RAINFALL INCREASING  
THROUGH SUNDAY. CURRENT STORM TOTAL RAINFALL STARTING LATE  
SATURDAY NIGHT THROUGH SUNDAY LIGHT WILL BE AROUND 0.15 INCHES  
TO 0.50 INCHES, HIGHEST RAINFALL TOTALS LOOK TO BE ALONG THE  
CENTRAL OREGON COAST RANGE. /42  
   
LONG TERM...MONDAY THROUGH THURSDAY  
A MORE ROBUST FRONT IS  
EXPECTED WITH THE SYSTEM BY THE START OF NEXT WEEK.  
PRECIPITATION TOTALS WITH THE SECOND FRONT LOOKS TO BE AROUND  
0.10 TO 0.25 INCHES FOR MONDAY. NBM PROBABILITIES FOR 24 HOUR  
LIQUID PRECIPITATION EXCEEDING 0.25 INCHES ENDING 5 PM MONDAY  
ARE AROUND 30-60% ALONG THE COAST AND HIGH TERRAIN, AND 25-60%  
FOR INTERIOR VALLEYS. ALSO, THIS TROUGH WILL ADVECT MORE COLD  
AIR ALOFT WHICH MAY HELP CREATE A MORE UNSTABLE ATMOSPHERE. NBM  
GUIDANCE CURRENTLY POINTING TOWARDS A 5-10% PROBABILITY OF  
THUNDERSTORMS MONDAY AFTERNOON. HOWEVER, THIS WILL BE HEAVILY  
DEPENDENT ON WHETHER OR NOT SUFFICIENT CLEARING IN CLOUD COVER  
OCCURS AS WELL AS THE PATH OF THE INCOMING LOW. IF THE LOW MOVES  
MORE NORTHWARD TOWARDS OUR CWA, THE PROBABILITY OF  
THUNDERSTORMS WILL INCREASE, WHILE IF THE LOW TRACKS MORE  
TOWARDS THE OR/CA BORDER THE PROBABILITY WILL BE LOWER. SHOWERY  
CONDITIONS WITH LIGHT PRECIPITATION REMAIN IN THE FORECAST  
THROUGH FRIDAY AS WPC 500MB CLUSTER GUIDANCE SHOWS STRONG  
AGREEMENT IN TROUGHING CONTINUING THROUGH AT LEAST THURSDAY. /42  
 
 
   
AVIATION  
VFR OVER THE AREA THROUGH THE NEXT 24 HOURS. ALONG THE  
COAST, CLEAR SKIES AND LOWERING TEMPERATURES WILL PROMOTE THE  
DEVELOPMENT OF IFR CONDITIONS. AREAS THAT WILL BE THE MOST AT RISK  
WILL BE AROUND KONP AND KTMK. SOME MODELS ARE SUGGESTING A WEAK  
EASTERLY WIND WHICH WOULD KEEP ANY FOG OR LOW STRATUS AT BAY.  
AFTER SUNRISE, CONDITIONS WILL IMPROVE. WITH THE HIGH PRESSURE  
IN PLACE, WINDS WILL TRANSITION TO THE NORTH THROUGH THE AFTERNOON  
AND AMPLIFY ALONG THE COAST.  
 
TOWARDS THE END OF THE TAF PACKAGE, 40-60% CHANCE OF MVFR/IFR  
CONDITIONS REDEVELOPING.  
 
PDX AND APPROACHES...VFR CIGS/VIS THROUGH THE NEXT 24 HOURS.  
-MUESSLE  
 
   
MARINE  
HIGH PRESSURE WILL MAINTAIN STEADY CONDITIONS THROUGH AT  
LEAST SUNDAY. SEAS WILL BE 5-7 FT AT 10 SECONDS. WINDS WILL BE  
NORTHERLY 5-10 KT THROUGH SATURDAY MORNING BEFORE TRANSITIONING TO  
THE SOUTH IN THE EVENING AS A LOW PRESSURE SYSTEM MOVES TOWARDS  
THE NORTHEAST PACIFIC. ON SUNDAY, WINDS WILL BE 10-15 KT WITH  
GUSTS UP TO 20 KT. THERE IS AROUND A 50% CHANCE OF GUSTS UP TO 25  
KT IN THE SOUTHERN PORTIONS OF PZZ273 LATE SUNDAY INTO MONDAY.  
 
THE NEXT PATTERN SHIFT OCCURS ON MONDAY. A STRENGTHENING LOW  
PRESSURE SYSTEM WILL MOVE OVER THE COASTAL WATERS CAUSING WINDS  
AND SEAS TO INCREASE. THERE IS STILL A LOT OF INCONSISTENCY IN  
MODELED LOCATION OF THE LOW. HOWEVER, WITH THE COLDER AIR FILLING  
IN BEHIND THE LOW, CANNOT RULE OUT A FEW THUNDERSTORMS EMBEDDED  
WITHIN THE PRECIPITATION. -MUESSLE  
 
 
   
PQR WATCHES/WARNINGS/ADVISORIES  
 
OR...NONE.  
WA...NONE.  
PZ...NONE.  
 
 
 
 
 
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