Small Craft Advisory 29, NWS Seattle, WA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PST MON FEB 10 2014

.SYNOPSIS...A FRONTAL SYSTEM WILL PRODUCE RAIN AT TIMES TONIGHT WITH
MORE SNOW IN THE MOUNTAINS. THERE WILL BE A LULL IN RAINFALL TUESDAY
MORNING...THEN INCREASING RAIN IN THE AFTERNOON. ANOTHER STRONGER
LOW PRESSURE SYSTEM WILL BRING RAIN...MOUNTAIN SNOW...AND WINDY
CONDITIONS TO WESTERN WASHINGTON LATE TUESDAY AFTERNOON INTO
WEDNESDAY. THE WET WEATHER PATTERN WILL CONTINUE THE REST OF THE
WEEK AND INTO THE WEEKEND. THE MOUNTAINS WILL RECEIVE SIGNIFICANT
SNOWFALL.

&&

.SHORT TERM...MOIST WESTERLY FLOW WILL CONTINUE ACROSS WESTERN WA
TONIGHT FOR RAIN AT TIMES...WITH SNOW IN THE MOUNTAINS. THERE WERE
EVEN A FEW LIGHTNING STRIKES AT NEAH BAY. PRECIP AMOUNTS WILL BE
HEAVIEST ACROSS THE WEST SLOPES OF THE CASCADES AND A WINTER WEATHER
ADVISORY REMAINS IN EFFECT TONIGHT.

IT LOOKS LIKE WE WILL SEE A BRIEF BREAK IN THE WEATHER TUE
MORNING...THEN MORE RAIN TUE NIGHT AS ANOTHER WARM FRONT MOVES
INLAND. THIS SYSTEM IS WETTER WITH 1-2 INCHES OF RAIN FORECAST ALONG
THE COAST...AND 0.50-1 INCH IN THE INTERIOR. THE MOUNTAINS WILL SEE
2-4 INCHES OF PRECIP THROUGH WED MORNING. SNOW LEVELS WILL START
AROUND 3000 FT THEN RISE TO 4000 FT WED MORNING. A WINTER STORM
WATCH IS IN EFFECT...MAINLY FOR THE HIGHER PEAKS. WE MAY ALSO SEE
STRONG WINDS TUE NIGHT THROUGH EARLY WED MORNING AS THE SURFACE LOW
MOVES INLAND. BOTH THE GFS AND EURO BRING A 986-993 MB LOW INTO
SOUTHERN B.C. BETWEEN 06-12Z WED. THE HIGHEST WINDS WILL BE ALONG
THE COAST AND OVER THE NW INTERIOR - WIND ADVISORIES POSSIBLE.

SHOWERS WILL CONTINUE WED AFTERNOON THROUGH THURSDAY WITH ZONAL FLOW
ALOFT. THE MOUNTAINS WILL SEE A FEW MORE INCHES OF SNOW. 33

.LONG TERM...PREVIOUS DISCUSSION...THE PROGRESSIVE WESTERLY FLOW
PATTERN WILL USHER IN A PARADE OF WET WEATHER SYSTEMS FRIDAY THROUGH
MONDAY OF NEXT WEEK. MODELS INDICATE THE MAIN STORM TRACK WILL
REMAIN DIRECTED INTO WESTERN WASHINGTON WITH PERIODS OF RAIN...HEAVY
AT TIMES. THERE MAY BE SHORT BREAKS BETWEEN SYSTEMS BUT NOT ENOUGH
IN THIS FAST MOVING PATTERN TO PUT ANY DRY PERIODS IN THE EXTENDED
FORECAST. THE MOUNTAINS WILL PICK UP A LOT OF NOW. SNOW LEVELS WILL
FLUCTUATE THROUGH EARLY NEXT WEEK BUT WILL GENERALLY REMAIN AT PASS
LEVELS SO THE SKI RESORTS COULD PICK UP SEVERAL MORE FEET OF SNOW.
MERCER

&&

.HYDROLOGY...A STRONG LOW PRESSURE SYSTEM WILL BRING HEAVY RAIN TO
THE OLYMPICS LATE TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING.  2 TO
4 INCHES OF RAIN MAY FALL DURING THIS PERIOD. THIS IS NORMALLY
SUFFICIENT TO BRING THE SKOKOMISH RIVER TO FLOOD STAGE.
HOWEVER..CONDITIONS HAVE BEEN UNUSUALLY DRY RECENTLY SO MORE RAIN
COULD BE NEEDED TO MAKE THE SKOKOMISH FLOOD. THE SITUATION BEARS
WATCHING. IT IS CERTAINLY POSSIBLE THAT ADDITIONAL WEATHER SYSTEMS
LATER THIS WEEK COULD MAKE THE SKOKOMISH RIVER FLOOD.

RIVER FLOODING IS NOT EXPECTED ELSEWHERE OVER THE NEXT 7 DAYS.
HOWEVER THE WET AND MILDER WEATHER PATTERN WILL PRODUCE SHARP RISES
ON RIVERS THROUGHOUT THE AREA THIS WEEK. MERCER

&&

.AVIATION...STRONG WESTERLY FLOW ALOFT WILL CONTINUE TONIGHT AND
TUESDAY. MOIST ONSHORE SURFACE FLOW WILL KEEP SHOWERS GOING ACROSS
WESTERN WASHINGTON TONIGHT. THERE IS SOME RAIN SHADOWING IN THE
SEATTLE METRO AREA. AIR MASS IS SLIGHTLY UNSTABLE. ONSHORE FLOW WILL
KEEP GUSTY SOUTHWEST SURFACE WINDS IN THE 12-25KT RANGE FOR A FEW
MORE HOURS THIS EVENING.

CEILINGS ARE M VFR 1-2K FT IN SHOWERS BUT VFR 3-5K FT AWAY FROM
SHOWERS. THIS PATTERN WILL CONTINUE THROUGH THE NIGHT. CEILINGS WILL
LIKELY RISE A BIT TUESDAY AFTERNOON BUT THE NEXT FRONT WILL BRING
MOSTLY MVFR ALONG WITH PLENTY OF RAIN TUESDAY NIGHT.

KSEA...DISCUSSION ABOVE APPLIES. MAINLY MVFR CEILINGS AND NOT
LOOKING FOR ANY IFR TONIGHT. VISIBILITY COULD FALL TO 3SM IN
SHOWERS. SOUTH TO SOUTHWEST WIND 10-14 KT TONIGHT. CHB

&&

.MARINE...GRADIENTS WILL SLOWLY RELAX TONIGHT. WINDS WILL EASE BELOW
SMALL CRAFT ADVISORY CRITERIA LATE TONIGHT. WINDS SHOULD GENERALLY
REMAIN BELOW 20 KT TUESDAY MORNING AS A WEAK SURFACE RIDGE MOVES
ACROSS THE AREA.

A STRONGER SYSTEM WILL ARRIVE TUESDAY NIGHT.  MODELS ARE IN GOOD
AGREEMENT IN BRINGING A FILLING SURFACE LOW ASHORE SOMEWHERE BETWEEN
CAPE FLATTERY AND TOFINO EARLY WEDNESDAY MORNING. SOUTHERLY WINDS
WILL INCREASE BEGINNING TUESDAY AFTERNOON AND GALES ARE LIKELY ON
THE COAST AND OVER THE ENTRANCES AND NORTHERN INLAND WATERS TUESDAY
NIGHT. A GALE WATCH COVERS THIS.

POST-FRONTAL ONSHORE FLOW WILL CONTINUE WEDNESDAY AND THURSDAY. BOTH
GFS AND ECMWF HAVE ANOTHER FRONT ARRIVING THURSDAY NIGHT. CHB

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WINTER WEATHER ADVISORY IN EFFECT UNTIL MIDNIGHT TONIGHT FOR
     THE CASCADES.

     WINTER STORM WATCH IN EFFECT FOR TUESDAY AFTERNOON THROUGH
     WEDNESDAY MORNING FOR THE CASCADES.

PZ...SMALL CRAFT ADVISORY ALL WATERS.
     GALE WATCH COAST...ENTRANCES...NORTHERN INLAND WATERS TUESDAY
     NIGHT.

&&

YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML