Small Craft Advisory 956, NWS Seattle, WA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
930 AM PDT SAT APR 7 2012

.SYNOPSIS...HIGH PRESSURE CENTERED OVER EASTERN WASHINGTON WILL
GIVE WESTERN WASHINGTON DRY LOW LEVEL OFFSHORE FLOW TODAY. AN UPPER
LEVEL LOW OFF THE SOUTHERN OREGON COAST WILL SEND MOSTLY MID AND
HIGH LEVEL MOISTURE OVER THE AREA TONIGHT AND SUNDAY WITH A CHANCE
OF SHOWERS ALONG THE COAST IN THE AFTERNOON. THE LOW WILL CONTINUE
TO SPIN OFF THE OREGON COAST THROUGH MOST OF THE WEEK GIVING WESTERN
WASHINGTON MOSTLY CLOUDY SKIES WITH A CHANCE OF SHOWERS.

&&

.SHORT TERM...IT IS A CHILLY START FOR WESTERN WA THIS MORNING.
TEMPS WERE DOWN TO THE 20S IN THE SW INTERIOR AND HOOD CANAL WITH
LOWER TO MID 30S ELSEWHERE. BUT WE ARE ALREADY STARTING TO WARM UP
WITH SUNNY SKIES AND OFFSHORE FLOW. TEMPS WILL REBOUND NICELY THIS
AFTERNOON WITH WIDESPREAD UPPER 50S TO LOWER 60S EXPECTED. NO
PLANNED UPDATES THIS MORNING.

A SPINNING STACKED LOW NEAR 40N/140W WILL SLOWLY WOBBLE CLOSER TO
SHORE ON SUNDAY. THIS SYSTEM WILL SPREAD MID/HIGH LEVEL CLOUDS INTO
WESTERN WA...MAYBE A FEW SPRINKLES ALONG THE COAST. BUT THE CLOUDS
WILL HELP KEEP THE MORNING LOWS ABOVE FREEZING. AFTERNOON HIGHS ARE
STILL LOOKING ABOVE NORMAL WITH ANOTHER ROUND OF UPPER 50S TO LOWER
60S IN THE FORECAST.

THE UPPER LEVEL RIDGE AXIS WILL SHIFT INTO MONTANA MON AND TUE AS
THE BROAD UPPER LEVEL LOW CONTINUES TO SPIN OVER THE OFFSHORE
WATERS. THERE IS VERY LITTLE CHANGE IN THE PATTERN. THIS SYSTEM WILL
CONTINUE TO PULL SOME MOISTURE INTO WESTERN WA OVER THE PERIOD.
HOWEVER...IT JUST LOOKS LIKE ISOLATED TO SCATTERED SHOWERS ACROSS
THE AREA. 33

.LONG TERM...PREVIOUS DISCUSSION...EXTENDED MODELS IN FAIRLY GOOD
AGREEMENT FOR THE FIRST PART OF THE EXTENDED WITH THE UPPER LEVEL
LOW WOBBLING AROUND OFF THE SOUTHERN OREGON/NORTHERN CALIFORNIA
COAST TUESDAY. THE LOW DISSIPATES ON WEDNESDAY LEAVING JUST AN UPPER
LEVEL TROUGH OFFSHORE WITH CONTINUED SOUTHERLY FLOW ALOFT. THE
TROUGH REMAINS OFFSHORE ON THURSDAY. THROUGH THE WHOLE TIME FRAME NO
REAL ORGANIZED SYSTEM MOVING INTO THE AREA BUT WITH THE SOUTHERLY
FLOW ALOFT WILL HAVE TO KEEP A CHANCE OF SHOWERS IN THE FORECAST.
MODEL SOLUTIONS START TO DIVERGE THURSDAY NIGHT INTO FRIDAY WITH THE
GFS MOVING THE TROUGH INLAND TO THE SOUTH OF THE AREA WHILE THE
ECMWF KEEPS THE TROUGH OFFSHORE. WITH THE LACK OF MODEL CONSENSUS
FOR DAY 7 WILL GO WITH A CLIMATOLOGY FORECAST WHICH WILL KEEP THE
CHANCE OF SHOWERS FORECAST GOING INTO FRIDAY. FELTON

&&

.HYDROLOGY...THERE IS NO THREAT OF RIVER FLOODING IN THE FORECAST
AREA DURING THE NEXT 7 DAYS.

&&

.AVIATION...A WEAK UPPER RIDGE WILL PREVAIL OVER THE REGION TODAY
FOR WLY FLOW ALOFT. EXPECT INCREASING LOW LEVEL OFFSHORE FLOW.

THERE WERE AREAS OF LOW CLOUDS AND FOG /VSBYS 1-3SM AND CIGS AOB 500
FT/ ROUGHLY ALONG THE I-5 CORRIDOR FROM KOLM TO S OF KTDO. ANOTHER
PATCH WAS OVER THE KITSAP PENINSULA. STRATUS /CIGS 1-2K FT/ WAS ALSO
LOCATED ALONG THE STRAIT OF JUAN DE FUCA AND WAS BEING CAUSED BY
NLY UPSLOPE FLOW. THE LOW CLOUDS AND FOG SHOULD DISSIPATE LATER THIS
MORNING. THUS EXPECT VFR CONDITIONS TO PREVAIL OVER THE AREA THIS
AFTERNOON.

KSEA...VFR CONDITIONS WILL PREVAIL OVER THE TERMINAL TODAY. EXPECT
NLY WINDS TO INCREASE TO 10-15 KNOTS THIS AFTERNOON.

&&

.MARINE...
FALLING PRESSURES OFFSHORE WILL RESULT IN STRENGTHENING EASTERLY
FLOW THIS WEEKEND FOR THE POSSIBILITY OF GALE FORCE EASTERLIES NEAR
THE WEST ENTRANCE TO THE STRAIT OF JUAN DE FUCA. EXPECT THE OFFSHORE
FLOW TO WEAKEN SUNDAY AFTERNOON.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORIES FOR WINDS IN EFFECT FOR THE WEST
     ENTRANCE TO THE STRAIT OF JUAN DE FUCA AND FOR THE COASTAL
     WATERS EXCEPT FROM JAMES ISLAND TO POINT GRENVILLE OUT TO
     10 NM.

     GALE WATCH IN EFFECT FROM THIS EVENING THROUGH SUNDAY MORNING
     FOR THE NEAR SHORE WATERS FROM CAPE FLATTERY TO JAMES ISLAND
     OUT TO 10 NM AND THE WEST ENTRANCE TO THE STRAIT OF JUAN DE
     FUCA.

&&

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