Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 050355
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
855 PM PDT SAT JUL  4 2015

.SYNOPSIS...LITTLE CHANGE IN THE OVERALL WEATHER PATTERN IS EXPECTED
THROUGH THE HOLIDAY WEEKEND AND INTO EARLY NEXT WEEK. A STRONG UPPER
LEVEL RIDGE WILL REMAIN OVER THE REGION TO KEEP INLAND TEMPS WELL
ABOVE NORMAL WITH CONTINUED DRY CONDITIONS. EARLY NEXT WEEK AN UPPER
LEVEL LOW THAT HAS BEEN LOCATED OFF THE CENTRAL CALIFORNIA COAST MAY
SPIN SOME MOISTURE UP TOWARD THE LANE COUNTY CASCADES FOR A CHANCE OF
THUNDERSTORMS. SOME COOLING LOOKS POSSIBLE LATE IN THE WEEK AS THE
UPPER LEVEL RIDGE GIVES WAY TO WEAK LOWER PRESSURE ALOFT AND A BIT
MORE ONSHORE FLOW.
&&

.SHORT TERM...NOT A LOT OF CHANGES OF CONSEQUENCE DURING THE NEXT FEW
DAYS. A RIDGE OF HIGH PRES THAT HAS BEEN STRETCHING FROM THE DESERT
SOUTHWEST...ACROSS SOUTHWEST OREGON...TO OFF THE PACIFIC NORTHWEST
COAST IS EXPECTED TO REMAIN OVER THE FORECAST AREA. MODEL H8 TEMPS
EXPECTED TO REMAIN IN THE 20 TO 22 DEG C RANGE THROUGH TUESDAY AND
UPPER HEIGHTS DIMINISH ONLY SLIGHTLY. A BIT OF SEEPAGE OF MARINE AIR
AND LIGHT SOUTH WINDS IN THE SOUTH WILLAMETTE VALLEY EASED TEMPS IN
THAT AREA TODAY. OTHERWISE TEMPS INLAND TODAY WERE ONLY A COUPLE OF
DEGREES LESS THAN THE SCORCHING NUMBERS THURSDAY AND FRIDAY.

OTHER THAN SOME HIGHER CLOUDS MOVING NORTH ACROSS THE FORECAST
AREA...THERE ARE REALLY NO LOW CLOUDS ALONG THE COAST OR THE COASTAL
WATERS EXCEPT NEAR FLORENCE THIS EVENING. THUS EXPECT IT WILL TAKE
SOME TIME FOR THE LOW CLOUDS TO SPREAD NORTH ALONG THE COAST
TONIGHT. BUT A LIGHT SOUTH FLOW WILL PERHAPS GIVE A BIT MORE
COVERAGE BY MORNING AS COMPARED TO THIS MORNING. THIS WILL LIKELY
KEEP SOME MARINE SEEPAGE INTO THE SOUTH VALLEY TONIGHT AS WELL.

THE MODELS SHOW A SOUTHERLY WIND REVERSAL WORKING ITS WAY NORTH ALONG
THE COAST SUNDAY...CONTINUING SUNDAY NIGHT. THIS MAY MAKE THE COAST
A BIT SLOWER TO SEE THE LOW CLOUDS BREAK OUT ON SUNDAY...THEN HAVE
THE LOW CLOUDS INCREASE EARLIER SUNDAY NIGHT. THIS WILL LIKELY CAUSE
THE SOUTHWEST WINDS IN THE SOUTHERN VALLEY TO CONTINUE AND SUNDAY
AND SUNDAY NIGHT...AND SUPPRESS TEMPS COMPARED TO FARTHER NORTH ON
SUNDAY. WITH THIS IN MIND...HAVE EASED BACK ON THE HIGH TEMP
FORECAST FOR EUGENE ON SUNDAY. AREAS FARTHER NORTH IN THE VALLEY
WILL STILL BE PRETTY HOT THOUGH ON SUNDAY.

OTHER THAN A BIT MORE LOW CLOUDS AGAIN ALONG THE COAST GOING INTO
MONDAY...DO NOT SEE A LOT OF CHANGE MONDAY. SOME OF THE THUNDERSTORM
MOISTURE TO OUR SOUTH MAY GET CLOSER...BUT IT IS NOT CERTAIN IT WILL
REACH OUR LANE COUNTY CASCADES YET. TEMPS INLAND WILL STILL BE QUITE
HOT...BUT PERHAPS DOWN A COUPLE OF DEGREES FROM THOSE SUNDAY.
TOLLESON

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
TUESDAY NIGHT THROUGH SATURDAY...REX BLOCK REMAINS IN PLACE THROUGH
MID-WEEK WITH CONTINUED HOT AND DRY WEATHER ACROSS THE AREA. MODELS
CONTINUE TO SUGGEST REX BLOCK OVER THE WEST COAST STARTS TO BREAK
DOWN LATER THIS WEEK AS AN UPPER-LEVEL TROUGH PUSHES THE RIDGE OF
HIGH PRESSURE OFF TO THE EAST. THERE IS STILL SOME DISAGREEMENT ON
WHEN THIS WILL ACTUALLY BREAK DOWN...BUT ENSEMBLES SUGGEST A GOOD
CHANCE THAT THE BLOCKING PATTERN BREAKS DOWN BY FRIDAY. THIS SHOULD
BRING TEMPERATURES DOWN SOME FOR FRIDAY AND SATURDAY WITH A CHANCE
FOR SOME CLOUD COVER AS WELL. THERE IS A SLIGHT CHANCE FOR A
THUNDERSTORM OR TWO LATER THIS WEEK IN THE LANE COUNTY CASCADES AS
THE UPPER-LEVEL TROUGH MOVES THROUGH...BUT ELSEWHERE LOOKS TO REMAIN
DRY INTO NEXT WEEKEND. -MCCOY
&&

.AVIATION...EXPECT A THIN BAND OF IFR/MVFR STRATUS TO DEVELOP ALONG
THE IMMEDIATE COAST LATE TONIGHT BETWEEN 06 AND 09Z. THIS STRATUS
SHOULD CLEAR BY 17Z SUNDAY. WIDESPREAD VFR CONDITIONS INLAND THROUGH
SUNDAY. A SOUTHERLY WIND REVERSAL WILL DEVELOP ALONG THE COAST FROM
SOUTH TO NORTH DURING THE DAY SUN...WITH WINDS GENERALLY LESS THAN 10
KT.

KPDX AND APPROACHES...VFR WILL CONTINUE THROUGH SUNDAY. TJ
&&

.MARINE...THE PRESSURE GRADIENT WILL WEAKEN OVER THE WATERS TONIGHT
AS A THERMALLY INDUCED LOW MOVES OFFSHORE THE WASHINGTON COAST...AND
THE NORTHERLY WINDS WILL GRADUALLY DECREASE. THE THERMAL LOW WILL
EXPAND OFF OF THE OREGON COAST SUNDAY RESULTING IN A SOUTHERLY WIND
REVERSAL. SOUTHERLY WINDS WILL DEVELOP FIRST FOR THE CENTRAL OREGON
COAST LATE SUNDAY AFTERNOON...THEN FOR THE WASHINGTON COAST LATE
SUNDAY NIGHT. A WEAK PRESSURE GRADIENT WILL CONTINUE THROUGH AT LEAST
WEDNESDAY KEEPING SURFACE WINDS LIGHT...LESS THAN 15 KT. THE THERMAL
LOW WILL WEAKEN BY THURSDAY WITH W-NW WINDS RETURNING.

SEAS WILL GRADUALLY SUBSIDE TONIGHT AND SUNDAY AND REMAIN BELOW 6
FEET THROUGH THURSDAY. TJ

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...HEAT ADVISORY UNTIL 6 PM PDT TUESDAY FOR CASCADE FOOTHILLS IN
     LANE COUNTY-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.

     HEAT ADVISORY UNTIL 6 PM PDT SUNDAY FOR CENTRAL COAST RANGE OF
     WESTERN OREGON.

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

PZ...NONE.
&&

$$

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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