876  
FXUS66 KPQR 221748 AAA  
AFDPQR  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE PORTLAND OR  
1048 AM PDT TUE APR 22 2025  
   
..UPDATED WWA AND PUBLIC/AVIATION DISCUSSIONS  
 
   
SYNOPSIS  
EXPECT WARMING TEMPERATURES AND MOSTLY CLEAR SKIES  
THROUGH THURSDAY. PATTERN CHANGE RETURNS LATE THURSDAY INTO FRIDAY  
AS AN APPROACHING SYSTEM RETURNS COOLER TEMPERATURES AND CHANCES  
FOR PRECIPITATION.  
 
 
   
MORNING UPDATE  
THE FROST ADVISORIES ACROSS THE AREA AND THE  
FREEZE WARNING IN THE UPPER HOOD RIVER VALLEY HAS BEEN ALLOWED TO  
EXPIRE AS TEMPERATURES HAVE RISEN ABOVE 36 DEGREES. EXPECT A  
RELATIVELY WARMER DAY WITH MOSTLY SUNNY SKIES AND HIGHS IN THE  
MID 50S ALONG THE COAST AND LOW TO MID 60S FOR INTERIOR VALLEYS.  
-ALVIZ  
 
   
SHORT TERM...NOW THROUGH WEDNESDAY NIGHT  
THIS MORNING, CLEAR  
SKIES, LIGHT WINDS, AND DRY AIR HAVE SUPPORTED EFFICIENT  
RADIATIONAL COOLING ACROSS THE REGION. TEMPERATURES HAVE DROPPED  
INTO THE 33-36 DEGREE RANGE ACROSS MUCH OF THE INTERIOR WEST OF THE  
CASCADES, WITH COLDER POCKETS IN OUTLYING VALLEYS AND SHELTERED  
RURAL AREAS. SHOULD SEE SOME FROST FORMATION PARTICULARLY OVER  
GRASSY AND EXPOSED SURFACES. A FROST ADVISORY REMAINS IN EFFECT  
UNTIL 9 AM FOR MOST LOWLAND AREAS, EXCLUDING THE IMMEDIATE COAST AND  
INNER PORTLAND METRO, WHERE URBAN HEAT ISLAND EFFECTS LIKELY HAVE  
KEPT TEMPERATURES HIGHER.  
 
IN THE UPPER HOOD RIVER VALLEY, TEMPERATURES HAVE FALLEN INTO  
THE UPPER 20S TO LOW 30S, WITH THE COLDEST SPOTS ABOVE 1000 FEET  
BETWEEN PARKDALE AND ODELL. A FREEZE WARNING REMAINS IN EFFECT  
FOR THIS AREA THROUGH 9 AM. RESIDENTS IN THIS AREA SHOULD  
ENSURE OUTDOOR PLANTS REMAIN PROTECTED UNTIL TEMPERATURES  
RECOVER LATER THIS MORNING.  
 
A PRONOUNCED WARMING TREND IS EXPECT THROUGH MIDWEEK, WITH HIGH  
PRESSURE AND UPPER-LEVEL RIDGING BUILDING OVER THE REGION.  
HIGHS TODAY WILL REACH THE LOW TO MID 60S ACROSS THE INTERIOR,  
CLIMBING TO THE HIGH 60S TO LOW 70S BY WEDNESDAY UNDER MOSTLY  
SUNNY SKIES AND DRY CONDITIONS. NO PRECIPITATION IS EXPECTED  
THROUGH AT LEAST WEDNESDAY NIGHT.  
~HALL  
 
   
LONG TERM...THURSDAY TO SUNDAY  
 
DRY AND MILD WEATHER CONTINUES THURSDAY AS UPPER-LEVEL RIDGING  
HOLDS OVER THE REGION, KEEPING CONDITIONS STABLE. THURSDAY WILL  
LIKELY BE THE WARMEST DAY OF THE WEEK, WITH INTERIOR HIGH  
TEMPERATURES FORECASTED TO REACH THE MID TO UPPER 70S. THERE IS  
A LOW-END CHANCE (15-35%) THAT PARTS OF THE PORTLAND/VANCOUVER  
METRO COULD FLIRT WITH 80 DEGREES.  
 
A TRANSITION BEGINS THURSDAY NIGHT INTO FRIDAY AS ENSEMBLE  
GUIDANCE FROM GEFS, EPS, AND GEPS ALIGNS ON AN UPPER TROUGH  
APPROACHING THE PACIFIC NORTHWEST. ALTHOUGH THERE IS STILL SOME  
SPREAD IN TIMING AND EXACT PLACEMENT OF THE LOW, CONFIDENCE IS  
GROWING THAT THIS SYSTEM WILL BRING A NOTICEABLE SHIFT BACK TO  
COOLER TEMPERATURES AND INCREASE RAIN CHANCES. IF THE TIMING  
HAPPENS TO BE EARLIER AND RAIN BEGINS THURSDAY EVENING, COULD  
SEE SOME THUNDERSTORM DEVELOPMENT NEAR THE LANE COUNTY CASCADES  
AND CASCADE FOOTHILLS.  
 
BY FRIDAY, PROBABILITIES FOR 0.25 INCHES OR MORE OF RAIN IN A  
24 HOUR WINDOW (5 AM FRIDAY TO 5 AM SATURDAY) RANGE FROM 20-30%  
ALONG THE COAST AND WILLAMETTE VALLEY, AND CLOSER TO 40-70% IN  
THE COAST RANGE AND CASCADES. PRECIPITATION CHANCES AND BELOW-  
NORMAL TEMPERATURES LOOK TO PERSIST INTO THE WEEKEND AS THE  
TROUGH DEEPENS AND EXPANDS ACROSS THE WESTERN US. ~HALL  
 
 
   
AVIATION  
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD ACROSS  
NW OREGON AND SW WASHINGTON. MOSTLY CLEAR SKIES ACROSS THE REGION  
EXPECTED, THOUGH SCATTERED CUMULUS AROUND 2-3 KFT MAY DEVELOP  
UNDER FAIR, NORTHERLY FLOW. NORTHERLY WINDS GENERALLY LESS THAN 10  
KTS THROUGH THE TAF PERIOD FOR MOST AREAS. WINDS TO INCREASE  
ALONG THE COAST AND IN THE CENTRAL/SOUTHERN WILLAMETTE VALLEY INTO  
THE EVENING, WITH GUSTS UP TO 18-25 KNOTS POSSIBLE, RELAXING  
AFTER 03Z WEDNESDAY.  
 
PDX AND APPROACHES...VFR CONDITIONS OVER THE TAF PERIOD. COULD SEE  
SOME SCATTERED CUMULUS DEVELOP AROUND 2-3 KFT WITH FAIR, NORTHERLY  
FLOW. NORTH WINDS LESS THAN 10 KTS THROUGH THE TAF PERIOD. -BATZ  
 
 
   
MARINE  
STRONG HIGH PRESSURE OFFSHORE ALONG WITH A SURFACE  
LEVEL THERMAL TROUGH DEVELOPING AND STRENGTHENING OVER THE  
SOUTHERN AND CENTRAL OREGON COAST WILL MAINTAIN NORTHERLY WINDS  
ACROSS ALL WATERS THROUGH THE MIDDLE OF THE WEEK. CENTRAL OREGON  
COASTAL WATERS WILL SEE INCREASING WINDS THIS EVENING INTO TUESDAY  
MORNING WITH GUSTS OF 20-25 KTS AT TIMES. A SMALL CRAFT ADVISORY  
REMAINS IN EFFECT FOR ZONE PZZ273. AS THE THERMAL TROUGH  
STRENGTHENS OVER THE COAST, THESE WINDS ARE EXPECTED TO SPREAD  
NORTH ALONG THE NORTHERN OREGON AND SOUTHERN WASHINGTON COASTAL  
WATERS LATE TUESDAY INTO WEDNESDAY NIGHT, WITH GUSTS 25-30 KTS  
POSSIBLE AT TIMES. A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR  
ZONES PZZ253, PZZ252, AND PZZ272 STARTING 2 PM TUESDAY. HAVE ALSO  
ADDED A SMALL CRAFT ADVISORY FOR ZONES PZZ271 AND PZZ251 FOR THE  
SAME TIME AS GUIDANCE IS INDICATING A 60-70% CHANCE OF WIND GUSTS  
OVER 21 KTS IN THE SOUTHERN HALF OF THESE ZONES AS WELL AS NEAR  
THE WESTERN BORDER OF ZONE PZZ271. STRONGEST WINDS ARE EXPECTED  
TO EBB AND FLOW DIURNALLY, STRONGEST IN THE LATE AFTERNOON TO  
OVERNIGHT HOURS, BACKING OFF IN THE MORNING HOURS. SEAS ARE  
EXPECTED TO PERSIST AROUND 6 TO 8 FT AROUND 10 SECONDS THROUGH THE  
MIDDLE OF THE WEEK. -HEC  
 
 
   
PQR WATCHES/WARNINGS/ADVISORIES  
 
OR...NONE.  
WA...NONE.  
PZ...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 2 AM PDT  
WEDNESDAY FOR PZZ251>253-271-272.  
 
SMALL CRAFT ADVISORY UNTIL 2 AM PDT WEDNESDAY FOR PZZ273.  
 
 
 
 
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