Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 021651
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
950 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 THE
CURRENT HOT SPELL APPEARS TO BE SUNDAY. SLIGHT COOLING LOOKS TO
OCCUR EARLY NEXT WEEK...BUT DAYTIME TEMPERATURES WILL REMAIN SEVERAL
DEGREES ABOVE NORMAL.

&&
.SHORT TERM...MARINE CLOUDS AND FOG AGAIN RESTRICTED TO AREAS ALONG
AND NEAR THE COAST THIS MORNING. MOISTURE IS SHALLOW...AND LIKELY
WILL SEE CLOUDS RECEDE QUICKLY BACK TO THE COAST TODAY. LOW LEVELS
OF 12Z SLE SOUNDING TODAY A SHADE WARMER THAN YESTERDAYS 12Z
SOUNDING...BUT MODELS SUGGEST A LITTLE STRONGER ONSHORE FLOW THIS
AFTERNOON SO ALL TOLD EXPECT HIGHS TODAY TO BE CLOSE TO WED HIGHS.

REMAINDER OF SHORT TERM DISCUSSION UNCHANGED...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...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS. 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 CONDITIONS WILL PERSIST AT INLAND TAF SITES FOR
THE NEXT 24 HOURS UNDER STABLE WESTERLY FLOW ALOFT. HOWEVER...
MARINE STRATUS LOOKS TO PUSH INLAND UP THE COLUMBIA RIVER TONIGHT
AND COULD BRING PERIODS OF MVFR CIGS TO KKLS AND POSSIBLY KSPB.

SATELLITE IMAGERY CURRENTLY SHOWS POCKETS OF STATUS ALONG THE
NORTH COAST. EXPECT THESE POCKETS TO BURN OFF BY 19Z WITH VFR
CONDITIONS EXPECTED THROUGH AROUND 05Z. STRATUS ALONG THE CENTRAL
OREGON COAST SOUTH OF KONP LOOKS TO CONTINUE A BIT LONGER...BUT
SUSPECT THIS STRATUS TO DISSIPATE BY 21Z WITH VFR CONDITIONS
EXPECTED INTO THE EVENING. WIDESPREAD IFR/LIFR CONDITIONS
EXPECTED TO RETURN TONIGHT ALONG THE COAST AFTER 06Z.

KPDX AND APPROACHES...VFR THE NEXT 24 HOURS UNDER STABLE WESTERLY
FLOW ALOFT.

&&

.MARINE...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...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 UNTIL 3 AM PDT FRIDAY FOR WATERS
     FROM CAPE SHOALWATER WA TO FLORENCE OR FROM 10 TO 60 NM.

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

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT THIS EVENING FOR
     COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR 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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