Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 281713
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
1013 AM PDT TUE JUL 28 2015

.SYNOPSIS...HIGH PRESSURE ALOFT BUILDING INTO THE REGION WILL BRING A
DRAMATIC WARM UP TODAY. EXPECT THE HOTTEST TEMPERATURES TO OCCUR
WEDNESDAY THROUGH FRIDAY...BUT TEMPERATURES IN THE WILLAMETTE VALLEY
MAY STILL BE FLIRTING WITH 90F OVER THE WEEKEND AND EVEN EARLY NEXT
WEEK.

&&

.SHORT TERM...VISIBLE SATELLITE REVEALS JUST A FEW AREAS OF LOW
CLOUDS IN THE WILLAPA HILLS AND THE FAR NORTH OREGON COAST AROUND
ASTORIA AND THE MOUTH OF THE COLUMBIA RIVER. HIGH PRESSURE ALOFT
CONTINUES TO BUILD OVER THE PACIFIC NORTHWEST AND WILL ENABLE A
SHARPLY NOTICEABLE INCREASE IN TEMPERATURES TODAY. GENERALLY EXPECT
TEMPERATURES TO WARM BETWEEN 5 AND 10 DEGREES F TODAY FROM
YESTERDAY...AND AN ADDITIONAL 5 TO 10 DEGREES FROM TODAY TO
WEDNESDAY. THURSDAY STILL ON TRACK FOR THE HOTTEST DAY OF THIS
STRETCH FOR MOST LOCATIONS...AND MAY VERY WELL BE THE HOTTEST DAY SO
FAR THIS YEAR AT MANY. EXPANDED THE HEAT ADVISORY TO INCLUDE THE
OREGON COAST RANGE FOR WEDNESDAY THROUGH FRIDAY NIGHT AS THE STRONG
SUBSIDENCE INVERSIONS WILL PROVIDE LITTLE OVERNIGHT RELIEF TO GO
ALONG WITH THE VERY WARM DAYTIME TEMPERATURES. A HEAT ADVISORY WAS
ALSO ISSUED FOR THE LOWER COLUMBIA/I-5 CORRIDOR IN SW WASHINGTON FOR
WEDNESDAY AND THURSDAY. TEMPERATURES WILL LIKELY COOL A BIT ON
FRIDAY ALONG THE IMMEDIATE COAST AND UP THE COLUMBIA TO NEAR KELSO
AS A LITTLE MARINE AIR MAY ENTER THE REGION AS THE THERMAL LOW
PRESSURE AXIS BEGINS TO SHIFT EAST OF THE CASCADES BY EARLY FRIDAY.

OVERALL...THE PRIMARY MESSAGE REMAINS THAT ANOTHER EXTENDED ROUND OF
WARMING IS UNDERWAY WITH VERY HOT CONDITIONS EXPECTED WEDNESDAY
THROUGH FRIDAY...WITH WARM CONDITIONS CONTINUING INTO THE WEEKEND.
THURSDAY WILL LIKELY BE THE WARMEST FOR MOST SPOTS...BUT THE
INTERIOR LOWLANDS LIKELY STILL REMAIN AROUND 95F ON FRIDAY. THE
WARMEST TEMPERATURES ARE EXPECTED IN THE SOUTH WILLAMETTE VALLEY AND
CENTRAL COLUMBIA RIVER GORGE WHERE OFFSHORE FLOW WILL BE A BIT
STRONGER AND TEMPERATURES NEAR EUGENE MAY REACH TRIPLE DIGITS FROM
WEDNESDAY THROUGH FRIDAY. CULLEN

&&

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...THE UPPER
LEVEL RIDGE AXIS WILL REMAIN OVER THE REGION THROUGH THE
WEEKEND...BUT LOWERING 500MB HEIGHTS SHOULD ALLOW A TEMPERATURES TO
COOL A COUPLE DEGREES EACH DAY. NONETHELESS...TEMPERATURES COULD
STILL BE FLIRTING WITH 90F ON MONDAY. SOME MID LEVEL MOISTURE AND
INSTABILITY WILL ALSO APPROACH THE REGION FROM THE SOUTH DURING THIS
PERIOD. WHILE IT APPEARS RAIN AND THUNDERSTORMS WILL GENERALLY
REMAIN SOUTH AND EAST OF THE AREA...KEPT A SLIGHT CHANCE MENTION OF
THUNDER NEAR THE OREGON CASCADE CREST DURING MOST OF THIS PERIOD TO
ACCOUNT FOR UNCERTAINTY AT THIS POINT. /NEUMAN

&&

...FIRE WEATHER...A THERMAL TROUGH HAS BUILT INTO SOUTHERN OREGON
TODAY...LEADING TO DRYING NORTHERLY TO NORTHEASTERLY WINDS
DEVELOPING OVER THE REGION. THE THERMAL TROUGH IS EXPECTED TO EXPAND
NORTHWARD INTO THE OREGON CASCADES AND OVER THE SOUTHERN WILLAMETTE
VALLEY AND ADJACENT FOOTHILLS ON WED AND THU. THIS WILL BRING
ENHANCED INSTABILITY AND MIXING...THAT COMBINED WITH THE EXPECTED
VERY HOT AND DRY CONDITIONS...MAY CREATE CRITICAL FIRE WEATHER
CONDITIONS. ALSO...ALTHOUGH MANY LOCATIONS RECEIVED RAIN OVER THE
WEEKEND...FUELS ARE FORECASTED TO DRY OUT RAPIDLY DURING THE MIDWEEK
PERIOD. A FIRE WEATHER WATCH HAS BEEN ISSUED STARTING WED AFTERNOON
AND CONTINUING THROUGH THU EVENING. THE THERMAL TROUGH IS CURRENTLY
EXPECTED TO PUSH EAST OF THE CASCADES OVER THE WEEKEND. PYLE

&&

.AVIATION...BRIEF MVFR CIGS AT KAST ALREADY DISSIPATING THIS
MORNING. WIDESPREAD VFR CONDITIONS WILL PREVAIL NEXT 24 HRS.
GUSTY NORTHERLY WINDS LIKELY THIS AFTERNOON/EVENING FOR THE
CENTRAL AND SOUTH WILLAMETTE VALLEY AND CENTRAL COAST WITH GUSTS
TO 25 KT POSSIBLE.

KPDX AND APPROACHES...VFR THE NEXT 24 HOURS. GUSTY NORTHERLY WINDS
15 TO 20 KT POSSIBLE BETWEEN 22-05Z. /64/27

&&

.MARINE...OUR TYPICAL SUMMERTIME PATTERN CONTINUES THE REST OF THE
WEEK. HIGH PRES WILL CONTINUE TO BUILD OVER THE NE PAC WITH
THERMAL LOW PRES STRENGTHENING OVER S OREGON. AS THE THERMAL LOW
STRENGTHENS AND PUSHES FURTHER NORTH WE COULD SEE A FEW BORDERLINE
GALE FORCE GUSTS TO 35 KT OVER THE CENTRAL WATERS TODAY AND
TOMORROW. HOWEVER...CHANCES OF GALES REMAIN FAIRLY LOW SO WILL
KEEP THE CURRENT SMALL CRAFT ADVISORY FOR WINDS AS IS.

GUSTY WINDS WILL LIKELY GENERATE PERIODS OF STEEP AND CHOPPY
CONDITIONS OVER THE WATERS...ESPECIALLY OVER THE CENTRAL WATERS.
EXPECT SEAS TO BUILD THIS AFTERNOON TO AROUND 7 TO 8 FT WITH A
DOMINATE PERIOD AROUND 7 TO 8 SECONDS. DECIDED TO EXTEND THE
SMALL CRAFT ADVISORY FOR SQUARE SEAS THROUGH THU MORNING...BUT WE
WILL LIKELY BE ABLE TO END THIS A FEW HOURS EARLY.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH THURSDAY
     EVENING FOR ZONE 604-ZONE 605-ZONE 606-ZONE 607-ZONE 608.

     HEAT ADVISORY FROM 11 AM WEDNESDAY TO 9 PM PDT FRIDAY FOR
     CENTRAL COAST RANGE OF WESTERN OREGON-CENTRAL COLUMBIA
     RIVER GORGE-CENTRAL WILLAMETTE VALLEY-COAST RANGE OF
     NORTHWEST OREGON-GREATER PORTLAND METRO AREA-SOUTH
     WILLAMETTE VALLEY-UPPER HOOD RIVER VALLEY-WESTERN COLUMBIA
     RIVER GORGE.

     HEAT ADVISORY FROM 11 AM WEDNESDAY TO 9 PM PDT THURSDAY FOR
     LOWER COLUMBIA.

WA...HEAT ADVISORY FROM 11 AM WEDNESDAY TO 9 PM PDT FRIDAY FOR
     CENTRAL COLUMBIA RIVER GORGE-GREATER VANCOUVER AREA-WESTERN
     COLUMBIA RIVER GORGE.

     HEAT ADVISORY FROM 11 AM WEDNESDAY TO 9 PM PDT THURSDAY FOR I-5
     CORRIDOR IN COWLITZ COUNTY.

PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 AM PDT THURSDAY FOR
     COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT
     60 NM.

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 AM PDT THURSDAY FOR
     COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 AM PDT THURSDAY
     FOR ALL COASTAL WATERS

&&
$$

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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