Small Craft Advisory 5, NWS Seattle, WA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
305 PM PST TUE JAN 12 2016

.SYNOPSIS...A SERIES OF WEATHER SYSTEMS WILL KEEP THE WEATHER
GENERALLY WET FOR THE NEXT WEEK.

&&

.SHORT TERM...A VIGOROUS FRONTAL SYSTEM WILL MOVE ONSHORE TONIGHT
WITH RAIN CHANGING TO SHOWERS LATE. SHOWERS WILL GRADUALLY TAPER
ON WEDNESDAY WITH A WEAK UPPER TROUGH MOVING OVERHEAD. THE
MOUNTAINS WILL GET A DECENT SHOT OF SNOW TONIGHT. SNOW LEVELS
WILL BE SOMEWHAT HIGH...MAYBE 4000-4500 FEET...BUT EAST WINDS
WILL KEEP COLD AIR IN THE PASSES. ADVISORIES ARE UP FOR THE TWO
NORTHERNMOST CASCADE ZONES. A WINTER STORM WARNING IS IN EFFECT
FOR THE SOUTHERN THIRD OF THE CASCADES...MAINLY FOR PARADISE ON
MOUNT RAINIER WHERE HEAVY SNOW IS POSSIBLE BY WEDNESDAY MORNING.

A WEAK UPPER RIDGE WILL BRING A RELATIVE LULL IN THE WET WEATHER
WEDNESDAY NIGHT AND THURSDAY MORNING...FOLLOWED BY THE NEXT RAIN
PRODUCING FRONTAL SYSTEM THURSDAY AFTERNOON AND NIGHT. THE
HEAVIEST PRECIPITATION WITH THIS SYSTEM IS GOING INLAND TO THE
SOUTH BUT ALL OF WESTERN WASHINGTON SHOULD GET ANOTHER ROUND OF
RAIN. AN UPPER RIDGE WILL BUILD OVER THE AREA ON FRIDAY BUT IT
LOOKS PRETTY DIRTY AND THERE WILL BE A LEAST SOME LINGERING
SHOWERS. SCHNEIDER

.LONG TERM...MODELS ARE IN PRETTY GOOD AGREEMENT SHOWING ANOTHER
WET FRONTAL SYSTEM REACHING THE AREA ON SATURDAY. THIS WILL BE
FOLLOWED RAPIDLY BY ADDITIONAL FRONTS AND UPPER LEVEL
DISTURBANCES SUNDAY...MONDAY...AND TUESDAY...AT LEAST ON THE GFS.
THE EC AND GEM GENERALLY AGREE THIS WILL BE A WET PERIOD BUT THE
DETAILS ARE A LITTLE DIFFERENT WHICH IS NOT SURPRISING GIVEN THE
HIGHLY PROGRESSIVE NATURE OF THE PATTERN. SCHNEIDER

&&

.AVIATION...A SLOW MOVING FRONTAL SYSTEM JUST OFFSHORE WILL CONTINUE
TO SPREAD RAIN ACROSS W WA THROUGH TONIGHT. MOIST SW FLOW ALOFT WILL
CONTINUE. THE SURFACE FRONT WILL STALL OVER THE WA COAST LATER THIS
EVENING AND SLOWLY DISSIPATE. THIS WILL LEAVE A MOIST AIR MASS OVER
W WA THROUGH WEDNESDAY.

CONDITIONS AT 22Z WERE MAINLY VFR OVC040-060 IN LIGHT RAIN. CIGS ARE
STILL EXPECTED TO LOWER TO MVFR LEVELS AFTER 06Z THIS EVENING AS THE
LIGHT RAIN CONTINUES. MVFR CONDITIONS WITH CIGS BKN-OVC010-025 ARE
LIKELY WEDNESDAY MORNING...WITH EVEN SOME SPOTTY IFR CIGS.

KSEA...VFR CIGS OVC060 WILL EVENTUALLY LOWER TO MVFR AROUND ROUGHLY
06Z. IT WILL BE A GRADUAL PROCESS SO TIMING IS IFFY. VISIBILITY
SHOULD DROP TO 4-6SM AS WELL. MVFR CIGS ARE EXPECTED ALL DAY ON
WEDNESDAY. SURFACE WINDS WILL BE SE 8-12 KT THROUGH 08Z THEN BECOME
MORE SOUTHERLY 5-10 KT. KAM

&&

.MARINE...A WEAKENING COLD FRONT JUST OFFSHORE WILL MOVE OVER THE
COAST THIS EVENING THEN DISSIPATE. COASTAL OBS SHOW WINDS A GOOD BIT
BELOW GALE LEVELS SO THE GALE WARNING HAS BEEN ENDED. RESIDUAL SCA S-
SE WINDS WILL SHIFT TO WEAKER WESTERLY WINDS OVER THE COASTAL WATERS
THIS EVENING. A SHORT DURATION PUSH OF SCA WEST WINDS IN THE
CENTRAL/EAST STRAIT IS STILL EXPECTED LATER THIS EVENING. SEAS
REMAIN HIGH ON THE COAST AND W ENTRANCE SO A SCA FOR HAZARDOUS SEAS
WILL TAKE OVER BY LATER THIS EVENING.

ONSHORE FLOW WILL PREVAIL TONIGHT THROUGH WEDNESDAY NIGHT WHILE A
WEAK SURFACE RIDGE MOVES ACROSS THE REGION. THE ONLY ISSUE WILL BE
THE CONTINUING SEAS ABOVE 10 FT OVER THE COASTAL WATERS...SO A SCA
FOR HAZARDOUS SEAS WILL REMAIN IN EFFECT.

A COUPLE MORE VIGOROUS FRONTS ARE STILL EXPECTED THURSDAY AND AGAIN
ON SATURDAY. LATEST MODELS STILL INDICATE BORDERLINE GALES OVER
PRIMARILY THE OUTER COASTAL WATERS WITH EACH FRONT. SMALL CRAFT
ADVISORIES ARE LIKELY OVER THE NORTHERN INTERIOR WATERS PRONE TO SE
FLOW. KAM

&&

.HYDROLOGY...HEAVY RAINS ON THE SOUTH SLOPES OF THE OLYMPICS
COULD DRIVE THE SKOKOMISH RIVER IN MASON COUNTY ABOVE FLOOD STAGE
TONIGHT. A FLOOD WATCH IS CURRENTLY IN EFFECT.

IF THE SKOKOMISH DOES FLOOD TONIGHT...IT SHOULD BE RELATIVELY
MINOR AND SHORT-LIVED WITH RIVER LEVELS FALLING WEDNESDAY IN
BETWEEN WEATHER SYSTEM. ADDITIONAL WET WEATHER SYSTEM LATER THIS
WEEK THROUGH EARLY NEXT WEEK COULD BRING MORE FLOODING CONCERNS
TO THE EXCEPTIONALLY FLOOD- PRONE SKOKOMISH. OTHERWISE...RIVER
FLOODING IS NOT EXPECTED FOR THE NEXT 7 DAYS. SCHNEIDER

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WINTER STORM WARNING UNTIL 10 AM PST WEDNESDAY FOR CASCADES OF
     PIERCE AND LEWIS COUNTIES.

     WINTER WEATHER ADVISORY UNTIL 10 AM PST WEDNESDAY FOR CASCADES
     OF SNOHOMISH AND KING COUNTIES-CASCADES OF WHATCOM AND
     SKAGIT COUNTIES.

     FLOOD WATCH FROM 10 M PST THIS EVENING THROUGH WEDNESDAY
     MORNING FOR MASON COUNTY.

PZ...SMALL CRAFT ADVISORY FOR ROUGH BAR UNTIL 6 AM PST THURSDAY FOR
     GRAYS HARBOR BAR.

     SMALL CRAFT ADVISORY UNTIL MIDNIGHT PST TONIGHT COASTAL
     WATERS.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM MIDNIGHT
     TONIGHT TO 4 AM PST THURSDAY COASTAL WATERS.

     SMALL CRAFT ADVISORY UNTIL 10 PM PST THIS EVENING FOR NORTHERN
     INLAND WATERS INCLUDING THE SAN JUAN ISLANDS.

     SMALL CRAFT ADVISORY UNTIL 4 AM PST WEDNESDAY FOR CENTRAL U.S.
     WATERS STRAIT OF JUAN DE FUCA-EAST ENTRANCE U.S. WATERS
     STRAIT OF JUAN DE FUCA.

     SMALL CRAFT ADVISORY UNTIL 6 PM PST THIS EVENING FOR WEST
     ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 6 PM THIS EVENING
     TO 4 PM PST WEDNESDAY FOR WEST ENTRANCE U.S. WATERS STRAIT
     OF JUAN DE FUCA.

&&

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