Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 282209
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
308 PM PDT TUE JUL 28 2015

.SYNOPSIS...STRONG UPPER LEVEL HIGH PRESSURE CONTINUES TO BUILD OVER
THE REGION TONIGHT AND TOMORROW. THIS WILL BRING CONSIDERABLY WARMER
TEMPERATURES TO THE REGION. THE HOTTEST TEMPERATURES WILL OCCUR
WEDNESDAY THROUGH FRIDAY...BUT TEMPERATURES MAY REMAIN AROUND 90
DEGREES IN THE WILLAMETTE VALLEY THROUGH THE WEEKEND AND PERHAPS INTO
EARLY NEXT WEEK.

&&

.SHORT TERM...TONIGHT THROUGH FRIDAY. A PLEASANT LATE JULY
DAY...ESPECIALLY FOR THOSE WHO ENJOY CLEAR SKIES AND A BIT OF
WARMTH...HAS DEVELOPED OVER THE REGION THIS AFTERNOON AS TEMPERATURES
HAVE WARMED INTO THE 80S AT MOST INLAND STATIONS WITH TEMPERATURES AS
OF 2 PM RUNNING 5 TO 10 DEGREES WARMER THAN THIS TIME YESTERDAY.
MEANWHILE...SOME BREEZY WINDS WITH GUSTS AROUND 25 MPH HAVE BEGUN IN
THE CENTRAL AND SOUTHERN WILLAMETTE VALLEY AS WELL AS THE CENTRAL
OREGON COAST AS THE THERMAL TROUGH OVER N CALIFORNIA AND S OREGON
COAST BUILDS NORTHWARD.

AS THE RIDGE OF HIGH PRESSURE ALOFT CONTINUES TO STRENGTHEN THROUGH
THE NEXT FEW DAYS...FORECAST MODELS SUGGEST H5 HEIGHTS BUILDING TO
590 DAM BY LATE THURSDAY AFTERNOON. MEANWHILE H8 TEMPS AROUND 14 C
TODAY WILL INCREASE TO AROUND 22 C BY THE SAME TIME. THIS GENERALLY
TRANSLATES TO SURFACE TEMPERATURES AROUND 7 F TO 10 F WARMER FOR
WEDNESDAY...BEFORE WARMING AN ADDITIONAL FEW DEGREES FOR THURSDAY.
MODELS CONTINUE TO POINT TO THURSDAY AS THE LIKELY PEAK OF THE
STRETCH OF HOT WEATHER FOR MANY LOCATIONS AS THE THERMALLY INDUCED
SURFACE LOW PRESSURE LOOKS TO PUSH EAST OF THE CASCADES INTO THE
COLUMBIA BASIN BY LATE THURSDAY. THERE IS A LITTLE MORE SPREAD IN THE
MODEL GUIDANCE FOR TEMPERATURES THIS AFTERNOON...PARTICULARLY FROM
THE GFS BUT ALSO IN THE ECMWF...LIKELY DUE TO RESOLVING A BIT
STRONGER AND MORE WELL DEFINED THERMAL LOW STRETCHING INTO SOUTHEAST
WASHINGTON. THIS WOULD TURN THE LOW LEVEL FLOW A BIT MORE NORTHWEST
RATHER THAN NORTHEAST AND ALLOW SOME MARINE AIR TO FILTER INTO THE
WILLAMETTE VALLEY. THIS MAY ALLOW TEMPERATURES TO COOL A LITTLE ALONG
THE LOWER COLUMBIA AND NORTH WILLAMETTE VALLEY ON FRIDAY...THOUGH
WINDS IN THE SOUTH AND CENTRAL VALLEY AND OVER THE
COAST RANGE LIKELY REMAIN NORTH TO NORTHEAST SO SIMILAR CONDITIONS
ARE LIKELY FRIDAY FOR THESE LOCATIONS. ALL OF THIS SAID...WHILE
CONFIDENCE IS SLIGHTLY LOWER FOR FRIDAY FOR NORTHERN LOCATIONS...THE
HEAT ADVISORIES REMAIN ON TRACK.  CULLEN

&&

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY. FEW CHANGES NEEDED TO THE
EXTENDED PERIOD TODAY. THE BROAD UPPER RIDGE WILL REMAIN OVER THE
REGION BUT WILL FLATTEN WITH LOWERING H5 HEIGHTS OVER THE AREA WITH A
FEW WEAK DISTURBANCES PASSING INTO SOUTHERN CANADA. MEANWHILE...THERE
IS A SMALL CHANCE THAT MID LEVEL MOISTURE MAY ROTATE INTO THE REGION
FROM THE SOUTH. THIS REMAINS RATHER SMALL AT THIS POINT...SO
RESTRICTED SLIGHT CHANCE OF THUNDER PRIMARILY IN THE HIGHER CASCADES
OF LANE COUNTY. IN TERMS OF TEMPERATURES THROUGH THE FIRST PART OF
NEXT WEEK...GUIDANCE STILL SUGGESTS TEMPERATURES MODERATING A BIT
FROM THE END OF THIS WEEK...BUT STILL WELL ABOVE NORMAL ACROSS THE
REGION.   CULLEN

&&

.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...AND POTENTIALLY INTO
FRI AS WELL. 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 WARNING 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...WIDESPREAD VFR CONDITIONS WILL PREVAIL NEXT 24 HRS.
COULD SEE SOME PATCHY MVFR STRATUS AT KAST BETWEEN 10Z-14Z WED.
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 THROUGH 05Z WED. AFTER A BRIEF DECLINE IN
WINDS...EXPECT WINDS TO PICK UP AGAIN BY 22Z WED. /27

&&

.MARINE...TYPICAL SUMMERTIME PATTERN CONTINUES INTO THIS WEEKEND.
HIGH PRES WILL REMAIN 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 THIS EVENING...BUT
ESPECIALLY WED AFTERNOON. HOWEVER...CHANCES OF GALES STILL 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 EVENING 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...RED FLAG WARNING FROM NOON WEDNESDAY TO 11 PM PDT THURSDAY 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 ADVISORIES FOR WINDS AND 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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