Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 020946
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
245 AM PDT THU JUL  2 2015

.SYNOPSIS...STRONG HIGH PRESSURE ALOFT WILL PERSIST OVER THE FORECAST
AREA FOR THE NEXT SEVERAL DAYS. THE WARMEST DAY OF THIS RECENT HOT
PERIOD APPEARS TO BE SUNDAY. SLIGHT COOLING LOOKS TO OCCUR EARLY NEXT
WEEK...BUT DAYTIME TEMPERATURES WILL REMAIN SEVERAL DEGREES ABOVE
NORMAL.

&&
.SHORT TERM...LIKE THE SONG SAYS...THE HEAT GOES ON. STRONG HIGH
PRESSURE ALOFT WILL MAINTAIN ITS HOLD OVER THE FORECAST AREA THROUGH
THE SHORT TERM. WATER VAPOR IMAGERY SHOWS A SHORT-WAVE MOVING ACROSS
SRN VANCOUVER ISLAND AS OF 09Z...PUTTING A SLIGHT DENT IN THE UPPER
RIDGE. NORMALLY...THE PASSAGE OF SUCH A SHORT-WAVE WOULD ENHANCE THE
ONSHORE LOW-LEVEL FLOW. THIS DOES NOT LOOK TO BE THE CASE THIS TIME.
THE JUL 2 00Z KSLE SOUNDING YIELDED AN 850 MB TEMP OF 23.2C...A
LITTLE HIGHER THAN THE 24-HR FORECAST. LATEST GFS INDICATES 22C FOR
00Z FRI. OVERALL...LITTLE CHANGE IN MAX TEMPS COMPARED TO WED. THIN
RIBBON OF MARINE STRATUS ALONG THE S OREGON COAST SLOWLY WORKING ITS
WAY NORTH...UP TO NEAR CASCADE HEAD AT 09Z. HI-RES ARW MODEL SEEMS TO
BE HANDLING THIS REASONABLY WELL. MODEL SHOWS STRATUS REACHING KAST
AND THE S WA COAST AROUND 12Z...BUT LITTLE INLAND PENETRATION.

MODELS SUGGEST A LITTLE MORE ONSHORE FLOW THU NIGHT AND FRI FOR
SLIGHT COOLING. GFS SHOWS 850 MB TEMPS AROUND 21C FOR KSLE AND
KPDX...DOWN ABOUT A DEGREE FROM THU. SW WA MAY GET THE BEST
RELIEF...ALBEIT MINOR...FRI WITH LOWER 500 MB HEIGHTS. SAT APPEARS TO
BE SIMILAR TO FRI. MAY NEED TO EXTEND THE HEAT ADVISORY THROUGH
SATURDAY...BUT WILL LET THE DAY SHIFT MAKE THE CALL. ALL IN ALL...
LOOKING AT A GOOD POSSIBILITY OF ANOTHER 3 90 DEGREE OR HIGHER DAYS
FOR MANY AREAS. THAT WOULD BE 13 90 DEGREE DAYS FOR KPDX...WELL ABOVE
THE SEASONAL NORM. WEISHAAR

.LONG TERM...THE STRONG RIDGE EXTENDING NW TO SE ACROSS THE REGION
AT THE END OF THE WEEKEND IS EXPECTED TO GRADUALLY ERODE AS THE HIGH
CONSOLIDATES OVER THE NE PACIFIC OFF THE BC COAST. HOWEVER...THE MEX
GUIDANCE SHOWS SUN BEING THE WARMEST DAY OF THE LONG-DURATION HOT
SPELL. THE GFS AND ECMWF SHOW MUCH OF THE FORECAST AREA IN A 500 MB
COL AREA SUN AND WITHIN A BROAD THERMALLY-INDUCED SURFACE TROUGH.
ECMWF SHOWS SOME MOISTURE TRYING TO WORK NWD FROM NRN CAL BUT DO NOT
THINK IT WILL REACH THE SRN PART OF THE CENTRAL CASCADES. HOWEVER...
THIS WILL BE SOMETHING THAT WILL NEED TO BE MONITORED. AFTER ANOTHER
HOT DAY OR TWO SUN AND MON...THE DEVELOPING TROUGHINESS ALOFT WILL
LOWER HEIGHTS AND ENCOURAGE A STRONGER ONSHORE FLOW. THIS IS LIKELY
TO RESULT IN COOLER TEMPS TUE AND WED AND MORE MARINE CLOUDS PUSHING
INLAND. THE REGION WILL ALSO BECOME MORE SUSCEPTIBLE A SOUTHERLY
FLOW ALOFT AT TIMES SPREADING MOISTURE AND INSTABILITY ALOFT UP FROM
THE S. WEISHAAR
&&

.AVIATION...VFR WILL PERSIST INLAND NEXT 24 HRS WITH DRY/STABLE
WESTERLY FLOW SFC AND ALOFT. COAST IS A DIFFERENT STORY WITH
WIDESPREAD IFR/LIFR LINCOLN CITY SOUTHWARD...LIKELY TO LINGER
THROUGH AT LEAST MIDDAY. PATCHY IFR IS ALSO DEVELOPING FURTHER
NORTH WITH KAST REPORTING BKN008 IN THE PAST HOUR. SUSPECT THIS
WILL BECOME A LITTLE MORE WIDESPREAD BY 12Z BUT NOT QUITE AS SOLID
AS THE STRATUS ALONG THE CENTRAL COAST.

KPDX AND APPROACHES...VFR WITH DRY ONSHORE FLOW NEXT 24 HRS. LIGHT
W-NW WINDS PICK UP TO 10-15 KT BETWEEN 21Z-04Z.  WEAGLE

&&

.MARINE...CLASSIC SUMMERTIME PATTERN WITH STRONG HIGH PRESSURE
OVER THE NE PACIFIC AND THERMAL LOW PRESSURE INLAND...RESULTING IN
GUSTY AFTERNOON AND EVENING N-NW WINDS ALONG THE COAST. DECIDED TO
SHOW MORE OF A DIURNAL TREND IN THE WINDS ALONG THE COAST...WITH
WINDS SLACKENING SOME DURING THE NIGHT AND MORNING HOURS WHILE
THEY REMAIN MORE STEADY OFFSHORE. EXPECT STEEP SHORT-PERIOD SEAS
FROM THE GUSTY AFTERNOON/EVENING WINDS...AND MORE PERSISTENT STEEP
SEAS IN THE OUTER WATERS. SQUARE SEAS OF 8 FT/8 SEC ALREADY BEING
REPORTED AT BUOY 46089...SO WE ISSUED AN SCA FOR SEAS OUTER WATERS
THROUGH FRI. STRONG NW WINDS OFF VANCOUVER ISLAND THE NEXT COUPLE
DAYS WILL ALSO GENERATE SOME SHORT PERIOD SWELL WHICH WILL AFFECT
THE S WA/N OR WATERS AS WELL. THE COMBINATION OF THE LOCALLY
GENERATED WIND WAVE AND THE FRESH SWELL COULD PUSH SEAS UP TOWARDS
10-11 FT BY SAT MORNING...SO THE SCA FOR SEAS MAY NEED TO BE
EXTENDED/EXPANDED EVENTUALLY.

THERMAL LOW PRESSURE IS EXPECTED TO DRIFT OFFSHORE LATER THIS
WEEKEND...SHOVING THE STRONGEST PRESSURE GRADIENT OFFSHORE AND
ALLOWING WINDS TO EASE FOR THE COASTAL WATERS. SEAS SHOULD COME
DOWN AS WELL...SUBSIDING TO BACKGROUND SWELL AND LIGHT WIND WAVE
EARLY-MID NEXT WEEK.  WEAGLE

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...HEAT ADVISORY UNTIL 9 PM PDT FRIDAY FOR NW OREGON INTERIOR
     LOWLANDS...CASCADE FOOTHILLS...AND CENTRAL OREGON COAST RANGE.

WA...HEAT ADVISORY UNTIL 9 PM PDT FRIDAY FOR LOWER COLUMBIA AND
     SW WASHINGTON INTERIOR LOWLANDS.

PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 11 AM THIS MORNING TO 3 AM
     PDT FRIDAY FOR WATERS FROM CAPE SHOALWATER TO FLORENCE FROM
     10 TO 60 NM OFFSHORE.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM PDT FRIDAY
     FOR WATERS FROM CAPE SHOALWATER TO FLORENCE FROM 10 TO 60 NM
     OFFSHORE.

     SMALL CRAFT ADVISORY FOR WINDS FROM 11 AM THIS MORNING TO 11 PM
     PDT THIS EVENING FOR COASTAL WATERS FROM CAPE SHOALWATER TO
     FLORENCE 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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