Small Craft Advisory 1144, NWS Seattle, WA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
830 AM PST SAT DEC 22 2012

.SYNOPSIS...LOW PRESSURE ALOFT OFF THE COAST IS EXPECTED TO CONTINUE
TO SPIN SHOWERS ONSHORE BEFORE IT MOVES INLAND BY LATE SUNDAY.
HIGHER PRESSURE ALOFT SHOULD BRING A BRIEF DRY SPELL MONDAY. THEN
ANOTHER PACIFIC FRONTAL SYSTEM IS FORECAST TO MORE PRECIPITATION
ONSHORE WITH THE POSSIBILITY OF SNOW ON SOME LOWLANDS.

&&

.SHORT TERM...A COOL UPPER LEVEL TROUGH REMAINS OFF THE COAST THIS
MORNING. IR SATELLITE IMAGERY SHOWS LOTS OF COLD TOPPED SHOWERS
ROTATING THROUGH THE TROUGH AND MOVING INTO THE PACIFIC NW. SO THE
FORECAST ONSHORE OF SHOWERS TODAY AND PERHAPS SOME BREAKS IN THE
CLOUDS LOOKS GOOD INTO SUNDAY WITH SHOWERS EASING. THE CHANCE OF
TSTMS IN THE COASTAL OFFSHORE WATERS LOOKS ON TRACK AS WELL GIVEN
THE COLD TOPPED CLOUDS.

12Z PROGS IN THUS FAR CONTINUE THE TREND OF MOVING THE TROUGH
ONSHORE LATER ON SUNDAY. THEN SOME RIDGING ALOFT FOR A DRYING TREND
INTO MONDAY. ACTUALLY SOME QUIETER WEATHER HEADING INTO THE
CHRISTMAS HOLIDAY. BUEHNER

.LONG TERM...FROM THE PREVIOUS DISCUSSION...A STRONG FRONTAL SYSTEM
WILL IMPACT THE REGION ON CHRISTMAS FOR MORE RAIN AND MOUNTAIN SNOW
AS WELL AS GUSTY WINDS. THIS SYSTEM BEARS WATCHING AS IT HAS THE
POTENTIAL TO PRODUCE SIGNIFICANT SNOWFALL ON PARTS OF THE HOOD CANAL
AREA AND KITSAP PENINSULA. THE SNOW LEVELS WILL BE FAIRLY LOW...SO
THERE IS A CHANCE THAT THE PRECIP COULD START OUT AS SNOW OR A
RAIN/SNOW MIX ELSEWHERE ACROSS THE LOWLANDS. WOULD NOT RULE OUT SOME
ACCUMULATIONS ELSEWHERE ACROSS THE LOWLAND INTERIOR BUT IT APPEARS
THAT THE HOOD CANAL AREA WILL PROBABLY RECEIVE THE MOST.

UNSETTLED CONDITIONS WILL PERSIST ON WED AS AN UPPER TROF MOVES OVER
THE REGION. IT LOOKS LIKE THERE MAY BE A PERIOD OF DRIER WEATHER
NEXT THU AND FRI DUE TO HIGHER PRESSURE ALOFT. CUSHMEER

&&

.HYDROLOGY...
FLOODING ON AREA RIVERS IS NOT EXPECTED THROUGH THE END OF NEXT
WEEK. CUSHMEER

&&

.AVIATION...AN UPPER TROUGH AND SURFACE LOW OVER THE EASTERN PACIFIC
WILL MOVE SLOWLY EAST TODAY AND TONIGHT WITH SOUTHERLY FLOW ALOFT
OVER WESTERN WASHINGTON. AIR MASS MOIST AND SLIGHTLY UNSTABLE.

KSEA...EAST WIND 4-8 KNOTS WILL BECOME SOUTH 9-13 KNOTS THIS
AFTERNOON. SHOWERS SHOULD DECREASE LATER TODAY AS AN UPPER SHORT
WAVE MOVES NORTH. SCHNEIDER

&&

.MARINE...A SURFACE LOW OVER THE WASHINGTON OFFSHORE WATERS WILL
PERSIST THROUGH THE WEEKEND GIVING LIGHT TO MODERATE OFFSHORE FLOW.
IMPULSES ROTATING AROUND THIS LOW WILL MOVE THROUGH THE WATERS...
GIVING PERIODS OF SMALL CRAFT ADVISORY WINDS TO MOST WATERS.

LIGHTER WINDS WILL PREVAIL SUNDAY NIGHT AND MONDAY AS WEAK HIGH
PRESSURE BUILDS OVER THE AREA.

A FRONTAL SYSTEM WILL MOVE OVER THE COASTAL WATERS TUESDAY GIVING
GALE FORCE WINDS THERE. THE FRONT WILL WEAKEN AS IT MOVES INLAND...
BUT SMALL CRAFT ADVISORY CONDITIONS CAN BE EXPECTED AS THE FRONT
MOVES INTO THE INTERIOR TUESDAY NIGHT. SCHNEIDER

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY ALL WATERS EXCEPT PUGET SOUND AND HOOD
     CANAL.
    .SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

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