Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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000
FXUS66 KSEW 271558
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 AM PDT THU AUG 27 2015

.SYNOPSIS...A FRONT JUST OFF THE COAST WILL BRING RAIN TO THE COAST
TONIGHT AND INTO THE INTERIOR OF WESTERN WASHINGTON BY DAYBREAK
FRIDAY. PERIODS OF RAINY BLUSTERY WEATHER ARE ON TAP INTO THE
WEEKEND. AN UPPER LEVEL TROUGH WILL SHIFT OVER THE REGION THROUGH
THE MIDDLE OF NEXT WEEK.

&&

.SHORT TERM...CLOUDS WILL START TO INCREASE TODAY AND THEN THE FRONT
JUST OFFSHORE WILL SPREAD RAIN TO THE COAST TONIGHT...AND INLAND BY
DAYBREAK FRIDAY. WET AND COOLER WEATHER IS ON TAP THROUGH
SATURDAY...THERE WILL BE SEVERAL PERIODS OF SOAKING RAIN. RAINFALL
TOTALS OVER 48HRS FRI AND SAT SHOULD GENERALLY BE 1-3 INCHES ACROSS
WRN WA...EXCEPT NOT AS WET IN THE OLYMPIC RAIN SHADOW AND PERHAPS
SOME 3-5 INCH AREAS IN THE OLYMPICS AND NORTH CASCADES. IT WILL BE
LOCALLY WINDY ON THE COAST AND PARTS OF THE NORTHWEST INTERIOR ON
SATURDAY.

.LONG TERM...THE MEDIUM RANGE SOLUTIONS REMAINED IN FAIRLY GOOD
AGREEMENT THAT THE PACIFIC NORTHWEST WILL REMAIN IN AN ACTIVE
WEATHER PATTERN. THE SNOW LEVELS SHOULD FALL TO AROUND 6000FT BY
ABOUT NEXT TUE OR WED AND LOWLAND TEMPS WILL ALSO BE BELOW NORMAL.

&&

.AVIATION...FAIRLY DRY AND STABLE SOUTHWEST FLOW ALOFT WILL PREVAIL
OVER W WA TODAY BETWEEN A LARGE UPPER LEVEL LOW OVER THE NE PACIFIC
AND A BROAD UPPER LEVEL RIDGE OVER THE ROCKIES. PATCHY STRATUS ALONG
THE COAST SHOULD DISSIPATE BY 18Z. THE SW FLOW ALOFT WILL BRING HIGH
CLOUDS ACROSS THE AREA TODAY.

AN UPPER LEVEL SHORTWAVE TROUGH EMBEDDED IN THE SW FLOW ALOFT WILL
SPREAD CLOUDS AND LIGHT RAIN OVER W WA AFTER 06Z...CONTINUING
THROUGH SATURDAY. CONDITIONS SHOULD DETERIORATE TO MVFR LATE TONIGHT
WITH POSSIBLE IFR CONDITIONS ALONG THE COAST.

KSEA...GOOD VFR CONDITIONS THROUGH 06Z WITH SCT-BKN CIRRUS OVER THE
AREA. SURFACE WINDS WILL BE S-SW 4-7 KT. CIGS BKN-OVC060-100 WILL
INCREASE AFTER 06Z. KAM

&&

.MARINE...A WEAK SURFACE RIDGE WILL REMAIN OVER THE WA COAST THROUGH
FRIDAY WHILE LOWER PRESSURE CONTINUES OVER E WA. THIS WILL KEEP
ONSHORE PRESSURE GRADIENTS WEAK...ALTHOUGH THERE IS STILL A FAIR
LIKELIHOOD OF BORDERLINE SMALL CRAFT ADVISORY WEST WINDS IN THE
CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA THIS EVENING.

A SERIES OF FRONTAL SYSTEMS WILL MOVE ACROSS THE REGION FRIDAY INTO
EARLY NEXT WEEK. THESE SYSTEMS WILL INCREASE THE SOUTHERLY FLOW OVER
WA WATERS WITH SCA WINDS LIKELY AT TIMES. LATEST MODELS ARE
INDICATING THE FRONT THAT MOVES N ACROSS THE AREA ON SATURDAY COULD
BE RATHER STRONG...WITH THE STRONGEST MODELS SUGGESTING GALE FORCE
WINDS. WEAKER SOLUTIONS INDICATE SCA WINDS. KAM

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 3
AM PDT FRIDAY FOR CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-EAST
ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.

&&

$$

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