Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 201548
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
848 AM PDT SUN APR 20 2014

.SYNOPSIS...HIGH PRES WILL BRING MAINLY DRY AND A LITTLE WARMER
WEATHER TODAY. THE NEXT PACIFIC COLD FRONT WILL APPROACH THE REGION
MON AND MOVE THROUGH MON NIGHT BRINGING A COOLER SHOWERY AIR MASS. A
WARM FRONT APPROACHING THE COAST WILL KEEP A THREAT FOR SHOWERS
GOING WED...THEN ANOTHER COOL SHOWERY TROUGH IS EXPECTED LATE IN THE
WEEK.
&&

.MORNING UPDATE...QUIET CONDITIONS ON AN SPEGG-TACULAR SUNDAY ACROSS
THE NORTHWEST. COOL TEMPERATURES WITH SCATTERED CLOUDS AND PATCHY
FOG ABOUT. EXPECT FILTERED SUNSHINE TODAY WITH PASSING HIGH CLOUDS
AND READINGS INTO THE MID 60S SHOULD BE EASILY ATTAINABLE WITH A DRY
WARM FRONTAL BOUNDARY LIFTING NORTHWARD. MINIMAL COSMETIC CHANGES TO
GRIDS THIS MORNING FOR SKY COVER/TEMP TRENDS.

LARGEST IMPACT TODAY IS THE HIGH SURF STILL WORKING ITS WAY THROUGH
THE WATERS WITH LONG PERIOD SEAS OF 18-20 FT . EXPECT HAZARDOUS
CONDITIONS IN THE SURF ZONE TO CONTINUE TODAY...THEN BEGIN TO EASE
LATE IN THE DAY. EXERCISE CAUTION IF HEADED TO THE BEACHES TODAY. KMD

&&

.SHORT TERM...EARLY THIS MORNING IT LOOKED LIKE THE LAST OF THE
SHOWERS ASSOCIATED WITH THE DEPARTING TROUGH WERE COMING TO AN END
OVER THE N PART OF THE FORECAST AREA. A TRANSIENT SURFACE HIGH IS
EXPECTED TO MOVE ACROSS THE PACIFIC NW TODAY FOR DRY AND WARMER
WEATHER. THE WARM FRONT LIFTING UP TO THE WA COAST APPEARS TO
LACK MOIST ISENTROPIC LIFT THIS MORNING SO WILL DROP THE CHANCE FOR
SHOWERS ON THE S WA COAST.

NEXT PACIFIC SYSTEM EXPECTED TO APPROACH MON. MODELS CONTINUE TO
SHOW THE TROUGH DIGGING AS IT APPROACHES THE COAST...SO INITIALLY
THE FRONT IS EXPECTED TO BE SLOW TO REACH THE COAST WITH MUCH OF THE
BEST DYNAMICS HEADED S. FLOW HOWEVER BACKS TO THE SSW ALOFT MON
BRINGING MID AND UPPER LEVEL MOISTURE UP INTO THE REGION. WILL
CONTINUE TO CARRY AN INCREASING THREAT FOR SHOWERS MON AND MON
NIGHT...BUT HOLD OFF ON LIKELY OR HIGHER POPS UNTIL MON NIGHT WHEN
THE FRONT BAND FINALLY PUSHES INLAND AND THE UPPER TROUGH AXIS
FINALLY REACHES THE COAST. AS THE COOL UPPER TROUGH MOVES INLAND
SHOWERY CONDITIONS WILL PERSIST INTO TUE. THIS WILL ALSO USHER IN
BELOW NORMAL TEMPS WED AS H8 TEMPS GO BELOW ZERO C.

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...TUE NIGHT
THROUGH SATURDAY... THE EXTENDED PORTION OF THE FCST IS LOOKING
INCREASINGLY WET WITH BELOW NORMAL TEMPERATURES. WE START OUT FAIRLY
QUIET TUE NIGHT AND EARLY WED...WITH A FEW SHOWERS AROUND ON THE
BACKSIDE OF AN UPPER LEVEL TROUGH THAT IS DEPARTING TO THE EAST. THE
NEXT FRONTAL SYSTEM IS EXPECTED TO BRING STEADY RAIN BEGINNING WED OR
EARLY THU. CONFIDENCE IN THE TIMING OF THIS SYSTEM IS NOT HIGH AT
THIS POINT. THE 12Z ECMWF RUN CAME IN MUCH MORE PROGRESSIVE THAN PAST
RUNS...BRINGING RAIN ONSHORE WED AFTERNOON. THE 12Z GFS AND THE
MAJORITY OF ITS ENSEMBLES HOLD THE RAIN OFF UNTIL OVERNIGHT WED INTO
THU. AT ANY RATE...PRECIPITABLE WATER VALUES WITH THIS SYSTEM ARE
LOOKING FAIRLY HIGH SO WE WILL LIKELY GET A PRETTY GOOD DOSE OF RAIN
THROUGH THU NIGHT. A BROAD AND COLD UPPER LEVEL TROUGH WILL BUILD
INTO THE NE PAC FOR FRI INTO NEXT WEEKEND...BRING MORE RAIN CHANCES.
PYLE
&&

.AVIATION...GENERALLY VFR CONDITIONS ACROSS THE REGION TODAY. A
SCT-BKN LAYER BETWEEN 3000-4000 FT DEVELOPED NORTH OF KPDX-KTMK
LINE WILL PROBABLY PERSIST THROUGH EARLY AFTERNOON. OTHERWISE
JUST PATCHY FOG ACROSS THE AREA. KEUG THE ONLY TAF SITE WITH LIFR
CONDITIONS THAT SHOULD IMPROVE TO VFR 17Z- 18Z.

KPDX AND APPROACHES...VFR PREVAILING FOR THE NEXT 24 HOURS.

&&

.MARINE...LARGE WESTERLY SWELL TRAIN CONTINUES ACROSS THE WATERS
THIS MORNING. MODEL FORECAST IS RUNNING ABOUT 1 TO 2 FT ABOVE
OBSERVATIONS SO HAVE MADE SLIGHT ADJUSTMENTS TO FORECAST FOR
TODAY AND ADDED A FEW MORE HOURS TO THE HIGH SURF ADVISORY.
SEAS WILL SLOWLY SUBSIDE TODAY...DIMINISHING TO AROUND 15 FT
TONIGHT...AND TO 10 FT TUE MORNING. THE SMALL CRAFT FOR HAZARDOUS
SEAS CONTINUE THROUGH EARLY TUE.

A RELATIVELY QUIET PERIOD IN TERMS OF WIND OVER THE WATERS
THROUGH THE FIRST HALF OF THIS WEEK. A WEAK SYSTEM WILL APPROACH
THE WATERS THIS AFTERNOON AND COULD BRING A FEW OCCASIONAL GUSTS
TO 20-25 KT OVER THE FAR NORTHERN OUTER WATERS. OTHERWISE...THE
NEXT SIGNIFICANT SYSTEM ARRIVES LATE WED OR THU...LIKELY BRINGING
SMALL CRAFT WINDS.   CULLEN

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...HIGH SURF ADVISORY UNTIL 1 PM PDT THIS AFTERNOON FOR CENTRAL
     OREGON COAST-NORTH OREGON COAST.

WA...HIGH SURF ADVISORY UNTIL 1 PM PDT THIS AFTERNOON FOR SOUTH
     WASHINGTON COAST.

PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 AM PDT
     TUESDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA
     TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL
     3 AM PDT MONDAY.

&&


$$

MORE WEATHER INFORMATION ONLINE AT...
    HTTP://WEATHER.GOV/PORTLAND

INTERACT WITH US VIA SOCIAL MEDIA
    WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
    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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