Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 030349
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
849 PM PDT THU JUL  2 2015

.SYNOPSIS...STRONG HIGH PRESSURE ALOFT IS THE MAIN FEATURE OVER
OREGON AND SOUTHWEST WASHINGTON FOR THE NEXT FEW DAYS...WITH
NORTHWEST FLOW ALOFT AND WEAK TROUGHING NORTH IN CANADA AND AN UPPER
LOW OFF THE CENTRAL CALIFORNIA COAST. THUNDERSTORM MOISTURE WILL
MOSTLY STAY SOUTH OF OUR AREA...BUT MAY BEGIN BRUSHING THE LANE
COUNTY CASCADES AS EARLY AS SUNDAY. A SLIGHT LOWERING OF 500 MB
HEIGHTS FROM THE NORTHWEST FLOW IN CANADA MAY INCREASE THE MARINE
LAYER ALONG THE COAST EARLY IN THE WEEKEND AND EASE TEMPS A COUPLE OF
DEGREES INLAND...BUT SUNDAY LOOKS ABOUT AS WARM AGAIN AS TODAY
INLAND. ONLY GRADUAL CHANGES EXPECTED NEXT WEEK...PERHAPS A FEW MORE
THUNDERSTORMS WORKING THEIR WAY NORTH ALONG THE CASCADES AND TEMPS
INLAND DROPPING A COUPLE OF DEGREES BUT CONTINUING WELL ABOVE NORMAL.
&&

.SHORT TERM...NW TO SE ORIENTED RIDGE AXIS EXPECTED TO REMAIN JUST
TO THE SOUTH OF THE FORECAST AREA THROUGH THE WEEKEND. MODELS
CONTINUE TO SHOW SOME WEAKENING OF THE RIDGE OVER THE REGION
RESULTING IN THE DEVELOPMENT OF A COL. OVERALL THIS RESULTS IN A
CONTINUED RATHER STAGNANT WEATHER PATTERN.

LOW CLOUDS THIS EVENING ARE PRETTY SPARSE OVER THE COASTAL WATERS AND
SUSPECT SIMILAR COVERAGE LATE TONIGHT AND FRIDAY MORNING NEAR THE
COAST WHEN COMPARED TO THIS MORNING. HAVE SLOWED DOWN THE ARRIVAL OF
THE LOW CLOUDS AND LOCAL FOG ALONG THE COAST IN THE FORECAST FOR
TONIGHT. ALSO BUMPED TEMPS FOR FRIDAY UP A BIT ABOVE THE PREVIOUS
FORECAST...BUT A COUPLE OF DEGREES DOWN FROM TODAY.

THE LOW LEVEL ONSHORE FLOW IS EXPECTED TO STRENGTHEN A BIT BY SAT AS
UPPER HEIGHTS COMING DOWN A LITTLE...AIDED IN PART BY A SHORTWAVE
ROTATING AROUND THE WEST CANADA UPPER LOW...AND THIS SUGGESTS
DAYTIME HIGHS TO COME DOWN A FEW DEGREES MAINLY SATURDAY. MODEL H8
TEMPS HOWEVER REMAIN IN THE 20 TO 22 DEGREE C RANGE...SO EXPECT HIGH
TEMPS LIKELY TO REMAIN ABOVE 90 THROUGH SATURDAY IN THE INLAND
VALLEYS. AS THE SOUTHWEST CANADA SHORTWAVE MOVES ON...UPPER HEIGHTS
REBOUND AND H8 TEMPS RETURN ON SUNDAY TO NEAR THE VALUES FROM TODAY.
WITH THE QUICK RETURN TO VERY HOT WEATHER SUNDAY...THE DAY SHIFT
EXTENDED THE CURRENT HEAT ADVISORY OUT THROUGH SUNDAY AND WILL
CONTINUE WITH THAT. ANY SLIGHT LOWERING OF TEMPS BY SATURDAY WILL
STILL RESULT IN TEMPS ABOVE 90 INLAND. MARINE CLOUDS THROUGH THIS
PERIOD WILL REMAIN RATHER LIMITED. WITH THE STRENGTHENED ONSHORE
FLOW EXPECT TO SEE SOME MORE CLOUDS ALONG THE COAST AND POSSIBLY
INTO THE LOWER COLUMBIA BY SATURDAY MORNING...THEN LESS CLOUDS AGAIN
SUNDAY MORNING. TOLLESON

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
SUNDAY NIGHT THROUGH THURSDAY...THE EXTENDED PERIOD BEGINS WITH HIGH
AMPLITUDE 500 MB REX BLOCK OVER THE EASTERN PACIFIC AND OR/WA IN WEAK
TROUGH OR COL SEPARATING SWRN U.S. RIDGE AND ERN PACIFIC/GULF OF AK
RIDGE. DESPITE THE WEAK TROUGHINESS...AMS REMAINS WARM WITH ABOVE
AVERAGE HEIGHTS AND NLY LOW LEVEL FLOW. LITTLE CHANGE OCCURS IN
OVERALL PATTERN INTO TUESDAY. BY WEDNESDAY...BLOCK BEGINS TO BREAK
DOWN WITH RIDGING TO THE NORTH AND PACIFIC CUTOFF MAKING SLOW EWD
PROGRESS TOWARD CNTRL CA CSTLN. DETERMINISTIC MODELS AND GEFS MEMBERS
IN GOOD AGREEMENT THROUGH TUESDAY...WITH DIFFERENCES THEREAFTER
MAINLY IN AMPLITUDE OF RIDGING OVER OR/WA/WRN CANADA AND POSITION OF
ERN PACIFIC CUTOFF. DESPITE THE INCREASING UNCERTAINTY MID
WEEK...WARM TEMPERATURES NEARLY CERTAIN /10-12 DEG ABOVE NORMAL/ BUT
INFLUENCE OF ERN PACIFIC CUTOFF PROVIDES A CHANCE OF INLAND/MOUNTAIN
THUNDERSTORMS TUESDAY-THURSDAY. BRIGHT
&&

.AVIATION...WIDESPREAD VFR NEXT 24 HRS AT INLAND TAF SITES UNDER
STABLE WESTERLY FLOW ALOFT. VFR ALONG THE COAST THIS EVENING WILL
GIVE WAY TO IFR STRATUS AGAIN TONIGHT...BUT LATER THAN LAST
NIGHT...MOST LIKELY FILLING IN FROM SOUTH TO NORTH AFTER 06Z-08Z FRI.
SHOULD STILL SEE SOME MARINE STRATUS INLAND UP THE COLUMBIA RIVER
TONIGHT AND COULD BRING PERIODS OF MVFR CIGS TO KKLS AND POSSIBLY
KSPB. THE STRATUS DOES NOT LOOK LIKE IT WILL REACH THE PORTLAND METRO
TERMINALS.

KPDX AND APPROACHES...VFR WILL PERSIST FOR THE NEXT 24 HOURS. /27
&&

.MARINE...HIGH PRES OVER THE NE PAC AND THERMAL LOW PRES INLAND WILL
CONTINUE TO PRODUCE GUSTY NORTHERLY WINDS INTO THE WEEKEND. THE
STRONGEST WINDS ARE EXPECTED TO CONTINUE OVER THE OUTER WATERS SO
DECIDED TO EXTEND THE SMALL CRAFT ADVISORY TILL SAT MORNING. ADVISORY
LEVEL WINDS OVER THE INNER WATERS WILL CONTINUE THOUGH LATE THIS
EVENING BEFORE FALLING BELOW 20 KT. THERMAL LOW PRES WILL MOVE
OFFSHORE THIS WEEKEND WITH WINDS ACROSS ALL WATERS REMAINING BELOW 20
KT INTO NEXT WEEK.

EXPECT PERIODS OF STEEP AND CHOPPY SEAS OVER THE OUTER WATERS TO
CONTINUE INTO THIS WEEKEND WITH COMBINED SEAS OF 7 TO 8 FT AND A
DOMINATE PERIOD AROUND 8 SECONDS. AS SUCH...DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY TILL SAT MORNING FOR SQUARE SEAS. STRONG WINDS
OFF OF VANCOUVER ISLAND WILL PRODUCE A BUILDING NW SWELL THIS WEEKEND
THAT COULD PUSH SEAS ABOVE 10 FT. SEAS WILL SUBSIDE EARLY NEXT WEEK
TO AROUND 4 TO 5 FT.
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...HEAT ADVISORY UNTIL 6 PM PDT SUNDAY FOR CASCADE FOOTHILLS IN
     LANE COUNTY-CENTRAL COAST RANGE OF WESTERN OREGON-CENTRAL
     COLUMBIA RIVER GORGE-CENTRAL WILLAMETTE VALLEY-GREATER
     PORTLAND METRO AREA- LOWER COLUMBIA-NORTHERN OREGON CASCADE
     FOOTHILLS-SOUTH WILLAMETTE VALLEY-UPPER HOOD RIVER VALLEY-
     WESTERN COLUMBIA RIVER GORGE.

WA...HEAT ADVISORY UNTIL 6 PM PDT SUNDAY FOR CENTRAL COLUMBIA RIVER
     GORGE-GREATER VANCOUVER AREA-I-5 CORRIDOR IN COWLITZ COUNTY-
     SOUTH WASHINGTON CASCADE FOOTHILLS-WESTERN COLUMBIA RIVER
     GORGE.

PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 7 AM PDT SATURDAY FOR
     WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR FROM 10 TO 60
     NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 7 AM PDT
     SATURDAY FOR WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR
     FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT THIS EVENING
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR
     OUT 10 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. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.


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