573  
FXUS66 KPQR 231628  
AFDPQR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PORTLAND OR  
928 AM PDT THU MAY 23 2019  
   
SYNOPSIS
 
A RIDGE OF HIGH PRESSURE OFF THE COAST WILL BRING  
WARMER TEMPERATURES TODAY, WHILE LOW PRESSURE TO THE EAST KEEPS A  
CHANCE FOR SHOWERS AND THUNDERSTORMS, MAINLY FOR THE CASCADES. ON  
FRIDAY AN UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE DOWN THE BRITISH  
COLUMBIA COAST AND OVER THE PACIFIC NORTHWEST, BRINGING COOLER  
TEMPERATURES AND RENEWED CHANCES FOR SHOWERS LASTING THROUGH THE  
WEEKEND.  
 

 
   
SHORT TERM...TODAY THROUGH SATURDAY
 
THE UPPER LOW OVER THE  
DESERT SOUTHWEST EARLY THIS MORNING IS EXPECTED TO LIFT NORTH  
THROUGH UTAH TODAY AND INTO WYOMING TONIGHT. CASCADES REMAIN ON THE  
NORTHWEST PERIPHERY OF THE CLOSED LOW TODAY, LEAVING THE AREA OPEN  
TO A CHANCE FOR SHOWERS AND THUNDERSTORMS. AREAS FURTHER WEST  
HOWEVER ARE LIKELY TO REMAIN DRY TODAY AND TONIGHT AS A RIDGE OF  
HIGH PRESSURE ALOFT OFFSHORE PRESSES CLOSER TO THE COAST AND RAISES  
HEIGHTS ALOFT. THIS ALSO EXPECTED TO RESULT IN WARMER TEMPERATURES  
FOR MUCH OF THE AREA TODAY AS 850 MB TEMPERATURES CLIMB SEVERAL  
DEGREES.  
 
MODELS AGREE ON A SHORTWAVE MOVING SOUTH DOWN THE BRITISH COLUMBIA  
AND WASHINGTON COAST FRIDAY, DIGGING IN FOR A CLOSED LOW SINKING  
SOUTH OVER THE REGION FRIDAY NIGHT. A SURFACE TROUGH OF LOW PRESSURE  
TRAILING THE LOW TO THE NORTH, BRINGS ENHANCED LOW LEVEL ONSHORE  
FLOW TO THE REGION FRIDAY. THIS BRINGS A CHANCE FOR SHOWERS BACK TO  
THE ENTIRE REGION, BUT POPS WILL BE A BIT ON THE CONSERVATIVE SIDE  
GENERALLY CHANCE CATEGORY EXCEPT OVER TERRAIN IN THE NORTH, AS  
MOISTURE IS LIMITED TO JUST THE VERY LOW ELEVATIONS. A SECOND LOW  
FOLLOWS THE FIRST ONE DOWN THE COASTLINE ON SATURDAY, MAINTAINING A  
SHOWERY COOL AIR MASS FOR THE AREA.  
   
LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
 
NO CHANGES.  
PREVIOUS DISCUSSION FOLLOWS. THE MODELS AGREE ON THE GENERAL TREND  
THROUGHOUT THE EXTENDED. A LOW WILL SLOWLY TRACK OVER THE FORECAST  
AREA THROUGH SUNDAY LEAVING A WAKE OF SHORTWAVES THAT WILL KEEP  
CHANCES OF PRECIPITATION WITHIN THE FORECAST THROUGH MONDAY NIGHT.  
THE EURO IS LEANING MORE TOWARDS THE WETTER SIDE AS ITS LOW HAS A  
MORE ORGANIZED CIRCULATION AND STRONGER FRONTAL FORMATION, THIS  
RESULTS IN MORE RAIN. THE FORECAST HOWEVER, IS LEANING MORE TOWARDS  
THE GFS WHICH STILL SHOWS PRECIPITATION BUT NOT AS HEAVY. BOTH  
MODELS SHOW HEAVIER PRECIPITATION IN THE CASCADES MONDAY NIGHT.  
 
A HIGH PRESSURE MOVING IN FROM OFF-SHORE TUESDAY WILL REDUCE  
PRECIPITATION FOR THE REST OF THE EXTENDED. A NOTABLE FEATURE WILL BE  
 
THE INVERSIONS THAT OCCUR SUNDAY THROUGH TUESDAY IN THE EARLY  
MORNING HOURS (AROUND 5AM); THIS WILL INCREASE TEMPERATURES ABOVE  
1500FT BY ROUGHLY 5 DEGREES. -BPHILLIPS  
 

 
   
AVIATION
 
A MARINE STRATUS SURGE HAS BROUGHT A MIX OF MVFR AND  
IFR CONDITIONS TO THE LOWLANDS OF SW WASHINGTON AND NW OREGON  
THIS MORNING. THE COAST IS PREDOMINANTLY IFR CURRENTLY, WHILE  
THE INTERIOR IS PREDOMINANTLY MVFR. RUNNING A LOCAL STRATUS  
BREAKOUT PROGRAM WITH A COUPLE OF PIREPS FROM EARLIER THIS  
MORNING SUGGESTS THAT THE INTERIOR WILL SEE CLOUDS BREAK UP  
BETWEEN 19Z- 20Z, WITH VFR THEN EXPECTED THROUGH THE REMAINDER OF  
THE DAY AND THIS EVENING. CHANCES FOR ANY SIGNIFICANT  
IMPROVEMENT AT THE COAST DO NOT LOOK NEARLY AS PROMISING. THERE  
MAY BE A COUPLE OF HOURS OF VFR LATE THIS AFTERNOON, BUT IFR OR  
LOW MVFR STRATUS SHOULD PUSH QUICKLY BACK IN BY EARLY THIS  
EVENING. THE STRATUS SHOULD RETURN TO THE INTERIOR LOWLANDS  
OVERNIGHT, LIKELY REACHING MOST SITES BETWEEN 08Z-12Z.  
 
KPDX AND APPROACHES...MVFR STRATUS TO PERSIST THROUGH THIS  
MORNING. EXPECT BREAKOUT TO VFR CONDITIONS BETWEEN 19Z-20Z, WITH  
VFR THEN CONTINUING THROUGH THIS AFTERNOON AND EVENING. MVFR  
STRATUS WILL RETURN TONIGHT, LIKELY ARRIVING BETWEEN 08Z-12Z. PYLE  
 

 
   
MARINE
 
LATEST BUOY OBS SHOW WINDS BELOW 20 KT AND THEY WERE  
MARGINAL EARLIER EVEN AT BUOY 89, SO HAVE DROPPED CURRENT SMALL  
CRAFT ADVISORY FOR WINDS. HOWEVER, IT DOES LOOK LIKE WINDS WILL  
PICK UP AGAIN OUT OF THE NORTHWEST BEHIND THE CURRENT SYSTEM OVER  
THE WATERS BEYOND ABOUT 15 NM OFFSHORE, SO ADDED A NEW SMALL  
CRAFT ADVISORY FOR WINDS STARTING 5 PM PDT THURSDAY.  
 
THIS NORTHERLY WIND PATTERN CONTINUES THROUGH AT THE WEEKEND.  
IT APPEARS WINDS WEAKEN OVER THE WEEKEND. MEANWHILE, SEAS HAVE  
DROPPED SOME TO 8 TO 9 FT AT 8 TO 10 SECONDS. HAVE KEPT THE SMALL  
CRAFT ADVISORY FOR HAZARDOUS SEAS IN PLACE AS IT, BUT WILL NOT  
EXTEND AS SEAS WILL CONTINUE TO DROP A LITTLE BIT WITH DOMINANT  
WAVE PERIOD REMAINING AROUND 9 SECONDS.  
 
MODEL GUIDANCE SHOWS SEAS EXCEEDING 10 FT AGAIN FRIDAY NIGHT AS  
THE NEXT LOW PRESSURE AREA ALONG THE BRITISH COLUMBIA COAST DROPS  
SOUTH. LATEST SPECTRAL GUIDANCE HAS SEAS PEAKING AROUND 14 FT IN  
THE NORTHERN OUTER WATERS. SEAS THEN FALL JUST BELOW 10 FT  
SATURDAY AND LOOK TO CONTINUE FALLING THROUGH SUNDAY TO AROUND 4  
TO 5 FEET. BOWEN  
 

 
   
PQR WATCHES/WARNINGS/ADVISORIES
 
 
OR...NONE.  
WA...NONE.  
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 5 PM THIS AFTERNOON TO 5 AM  
PDT FRIDAY FOR WATERS FROM CAPE SHOALWATER WA TO FLORENCE  
OR FROM 10 TO 60 NM.  
 
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 AM PDT THIS  
MORNING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO  
FLORENCE OR OUT 60 NM.  
 

 
 

 
 
INTERACT WITH US VIA SOCIAL MEDIA:  
WWW.FACEBOOK.COM/NWSPORTLAND  
WWW.TWITTER.COM/NWSPORTLAND  
 
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON  
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THIS AREA IS  
COMMONLY REFERRED TO AS THE FORECAST AREA.  
 
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