Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 042130 CCA
AFDPQR

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

UPDATED MARINE DISCUSSION

.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 CUTTING OFF NEAR 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 A WEAK LOW PRES SYSTEM ALOFT.

&&

.SHORT TERM...NOT A LOT OF CHANGES OF CONSEQUENCE DURING THE NEXT
FEW DAYS. A RIDGE OF HIGH PRES STRETCHING FROM THE DESERT SW...
ACROSS SW OREGON...TO OFF THE PACIFIC NW COAST IS EXPECTED TO REMAIN
OVER THE REGION. MODEL H8 TEMPS EXPECTED TO REMAIN IN THE 20 TO 22
DEG C RANGE THROUGH TUE AND UPPER HEIGHTS DIMINISH ONLY SLIGHTLY.
WINDS ALONG THE COAST EXPECTED TO TURN MORE NORTHERLY THIS
EVENING...AND NE OVERNIGHT WHICH SHOULD TEND TO INHIBIT MARINE CLOUD
REDEVELOPMENT OVERNIGHT ESP ON THE N PART OF THE COAST. GFS...NAM
AND ECWMF ALL CONTINUE TO SHOW A SWITCH TO A SSW WIND MOVING UP THE
COAST SUN AND SUN EVENING...SPREADING MARINE CLOUDS BACK UP THE
COAST. THIS EXPECTED TO DEEPEN THE MARINE LAYER ON THE COAST A BIT
SUN BUT GIVEN THE HIGH HEIGHTS ALOFT THE INLAND IMPACT APPEARS
LIKELY TO BE SMALL. WILL MAKE LITTLE CHANGE TO FORECAST TEMPS
THROUGH TUE...WITH INLAND HIGHS GENERALLY EXPECTED TO REMAIN IN THE
90S. WITH THE CONTINUED HOT DAYTIME TEMPS AND MILD OVERNIGHT LOWS
EXPECTED TO CONTINUE...WILL EXTEND THE HEAT ADVISORY THROUGH TUE.

THE UPPER LEVEL RIDGE AXIS IN TODAYS 12Z RUNS TENDS TO SHIFT N A
LITTLE MON AND TUE INTO NW OREGON. AT THE SAME TIME THE UPPER LOW
OFF THE CENTRAL CA COAST IS EXPECTED TO DRIFT E A BIT WHICH ALLOWS
THE MID AND UPPER LEVEL FLOW OVER THE FAR S PART OF THE FORECAST
AREA TO OPEN UP TO THE S. FORECAST MODELS SOUNDINGS IN THE S
CASCADES MON REMAIN STABLE LOOKING...BUT BY TUE AFTERNOON AIR MASS
IN THE LANE COUNTY CASCADES BEGINS TO LOOK POTENTIALLY UNSTABLE.
WILL DROP THE MENTION OF CONVECTION ON MON...BUT KEEP A SLIGHT
CHANCE FOR THUNDERSTORMS IN THE LANE COUNTY CASCADES TUE.

.LONG TERM...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...WIDESPREAD VFR CONDITIONS IN CONTROL THIS AFTERNOON
WITH STABLE WESTERLY FLOW ALOFT. EXPECT IFR/MVFR STRATUS TO
REDEVELOP AT THE COAST BY AROUND 06Z THIS EVENING AND PERSIST INTO
MID MORNING SUN. VFR TO CONTINUE THROUGH SUN FOR INTERIOR TAF
SITES. A SOUTHERLY WIND REVERSAL WILL DEVELOP ALONG THE COAST FROM
SOUTH TO NORTH DURING THE DAY SUN.

KPDX AND APPROACHES...VFR IN CONTROL FOR THE NEXT 24 HRS. PYLE

&&

.MARINE...BREEZY NORTHWESTERLY WINDS CONTINUE OVER THE OUTER WATERS
THIS AFTERNOON. HOWEVER...A THERMALLY INDUCED SURFACE LOW WILL
MOVE WESTWARD TOWARDS THE COAST TONIGHT AND SUN. THIS WILL WEAKEN
THE PRES GRADIENT OVER THE WATERS AND LEAD TO A SLACKENING IN THE
WINDS. WINDS SHOULD REMAIN BELOW 10 KT TOMORROW. A SOUTHERLY FLOW
REVERSAL WILL ALSO OCCUR FROM SOUTH TO NORTH DURING THE DAY.
EXPECT WINDS TO REMAIN MOSTLY AT 15 KT OR LOWER THROUGH NEXT WEEK.

THE BREEZY NORTHWESTERLY WINDS OFF VANCOUVER ISLAND CONTINUE TO
PRODUCE SOMEWHAT CHOPPY CONDITIONS WITH SHORTER PERIOD WIND WAVE
AND FRESH SWELL DOMINATED SEAS. SEAS OVER THE OUTER WATERS REMAIN
7 TO 9 FT WITH A PERIOD OF AROUND 9 SEC. EXPECT SEAS TO SUBSIDE
BELOW 5 FT SUN AND EARLY NEXT WEEK IN RESPONSE TO THE SLACKENING
WINDS. PYLE

&&

.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...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 PM PDT THIS
     EVENING FOR WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD
     OR FROM 10 TO 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. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.


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