Small Craft Advisory 1025, NWS Seattle, WA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
830 PM PDT FRI JUL 6 2012

.SYNOPSIS...HIGH PRESSURE ALOFT OVER THE WESTERN U.S. IS EXPECTED TO
CONTINUE BUILDING OVER WASHINGTON THROUGH THE WEEKEND FOR MORE
SUNSHINE AND WARMER TEMPERATURES. HIGH TEMPERATURES FROM ABOUT
SEATTLE SOUTH WILL RISE INTO THE 80S. DEVELOPING SOUTHERLY FLOW
ALOFT WITH SOME EMBEDDED MOISTURE EARLY NEXT WEEK SHOULD GIVE RISE
TO A THREAT OF LATE DAY THUNDERSTORMS OVER THE CASCADES. OTHERWISE
THE WEEK AHEAD LOOKS DRY AND WARM AS WELL.

&&

.SHORT TERM...NEGATIVELY TILTED STRONG UPPER LEVEL RIDGE FROM THE
GREAT BASIN TO BRITISH COLUMBIA THIS EVENING. UPSTREAM...A LARGE
UPPER LEVEL LOW CENTERED NEAR 53N/153W. SATELLITE IMAGERY AND
DOPPLER WEATHER RADAR SHOWS SOME OF THE EMBEDDED MONSOONAL MOISTURE
TO THE WEST OF THE UPPER RIDGE AXIS HAS HELPED FIRE OFF SOME
CONVECTION FROM THE NE OREGON BLUES INTO THE IDAHO PANHANDLE THIS
EVENING...A HINT.

THE 00Z NAM JUST IN CONTINUES THE PREVIOUS GUIDANCE TREND OF THE
FLOW ALOFT BACKING AND BECOMING MORE SOUTHERLY AS THE UPPER RIDGE
CONTINUES TO BUILD INTO THE PACIFIC NW AND THE UPPER LEVEL LOW DIGS
FURTHER SOUTH WELL OFFSHORE. HENCE THE AVAILABLE MOISTURE SHOULD
REACH THE CASCADES BY LATE IN THE WEEKEND WITH A THREAT OF
THUNDERSTORMS PER THE CURRENT FORECAST.

LOW LEVEL ONSHORE FLOW IS STRONGER THIS EVENING THAN LAST. YET THE
LAST VISIBLE SATELLITE IMAGES SHOW MARINE STRATUS WELL OFF THE
COAST. SO ADVECTION OF STRATUS ONSHORE IS NOT A LIKELY SOURCE FOR
AREAS OF MORNING CLOUDS SAT MORNING. BETTER LIKELIHOOD IS FOR
FORMING IN PLACE...FIRST ALONG THE COAST AND THEN INTO THE STRAIT AS
WELL AS THE SOUTH SOUND REGIONS. YET THE MARINE CLOUDS SHOULD BE
QUITE SHALLOW AND BURN OFF QUICKLY FOR A WARMER SAT WITH A LIKELY
REPEAT ON SUN. FORECASTS LOOK ON TRACK INTO EARLY NEXT WEEK. BUEHNER

.LONG TERM...FROM THE PREVIOUS EDITION...MODELS HAVE STRONG ONSHORE
GRADIENTS EACH EVENING NEXT WEEK. ONE OF THOSE NIGHTS IS LIKELY TO
FEATURE A MARINE PUSH. THE KICKER COULD BE AN UPPER TROUGH THAT IS
SCHEDULED TO PASS BY NORTH INTO BRITISH COLUMBIA WEDNESDAY NIGHT IN
THE GFS OR THURSDAY NIGHT IN THE EURO. UNCERTAINTY IS GREAT
ESPECIALLY AS THE EURO HAS BEEN TAKING THE UPPER TROUGH IN A MORE
NORTHERLY DIRECTION LATELY. FOR NOW WILL KEEP THE FORECAST MOSTLY
SUNNY EXCEPT FOR AREAS OF LATE NIGHT AND MORNING CLOUDS...WITH HIGHS
NEAR SEASONAL NORMS. BURKE

&&

.AVIATION...SOUTHWEST FLOW ALOFT WILL CONTINUE THROUGH SATURDAY. AT
THE SURFACE...HIGH PRESSURE WILL REMAIN OFFSHORE WITH LOWER PRESSURE
INLAND. AIR MASS DRY AND STABLE...EXCEPT AREAS OF LOW LEVEL MOISTURE
LATE NIGHT AND MORNING HOURS.

STRATUS BURNED OFF THIS AFTERNOON AND EVENING...EVEN OVER THE
COASTAL WATERS. HOWEVER...ONSHORE GRADIENTS ARE A BIT STRONGER
COMPARED TO YESTERDAY AT THIS TIME. SOME STRATUS SHOULD REFORM LATE
TONIGHT ALTHOUGH IT PROBABLY WILL NOT BE TOO EXTENSIVE OR DEEP AND
SHOULD BURN OFF PRETTY QUICKLY LATER SATURDAY MORNING.

KSEA...NORTHERLY WIND 4-8 KNOTS. STRATUS COULD FORM AT THE TERMINAL
FOR A FEW HOURS SATURDAY MORNING BUT THIS WILL BE HIT OR MISS.
SCHNEIDER

&&

.MARINE...HIGH PRESSURE OFFSHORE AND LOWER PRESSURE EAST OF THE
CASCADES WILL MAINTAIN ONSHORE FLOW OF VARYING STRENGTH THROUGH
EARLY NEXT WEEK. SMALL CRAFT ADVISORY WEST WINDS ARE LIKELY LATE
AFTERNOON THROUGH EARLY MORNING HOURS IN THE CENTRAL STRAIT OF JUAN
DE FUCA AND EAST ENTRANCE...AND POSSIBLY INTO ADMIRALTY INLET...FOR
THE NEXT SEVERAL DAYS. SCHNEIDER

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EAST STRAIT AND ADMIRALTY
     INLET.

&&

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