Gale Watch 9, NWS Seattle, WA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
330 AM PST THU FEB 4 2016

.SYNOPSIS...SHOWERS AND MOUNTAIN SNOW WILL CONTINUE THIS MORNING. A
WARM FRONT LIFTS OVER THE AREA THIS AFTERNOON AND EVENING WITH LIGHT
RAIN AT TIMES. THE NEXT STRONGER FRONTAL SYSTEM WILL MOVE THROUGH
FRIDAY AFTERNOON AND FRIDAY NIGHT FOR RAINY AND WINDY WEATHER.
SHOWERS WILL LINGER SATURDAY...AND A STRONG UPPER RIDGE SHOULD BRING
DRY MILD WEATHER SUNDAY THROUGH WEDNESDAY.

&&

.SHORT TERM...RADAR INDICATES SHOWERS CONTINUING TO STREAM INTO WRN
WA IN POST-FRONTAL ONSHORE FLOW. THE TRAILING UPPER LEVEL SHORT WAVE
TROUGH IS CURRENTLY MOVING OVER THE AREA WITH MODERATELY STRONG
WESTERLY FLOW AT 850 MB HELPING TO ENHANCE SNOWFALL RATES IN THE
MOUNTAINS. SNOW AMOUNTS SNOW FAR THIS MORNING RANGE FROM AROUND 6-8
INCHES IN THE PASSES AND NEAR A FOOT AT SOME HIGHER SKI RESORT
LOCATIONS. A FEW MORE INCHES OF SNOW COULD FALL EARLY THIS MORNING
BEFORE GRADUALLY TAPERING OFF. THE SNOW ADVISORY WILL REMAIN IN
EFFECT UNTIL NOON TODAY.

MODELS INDICATE A WARM FRONT OFFSHORE WILL SLOWLY LIFT NE OVER THE
AREA THIS AFTERNOON AND EVENING. THIS WILL PRODUCE PERIODS OF LIGHT
RAIN BUT QPF AMOUNTS WILL BE LIGHT AND LITTLE ADDITIONAL SNOW IS
EXPECTED IN THE MOUNTAINS. THIS FEATURE LIFTS N OF THE AREA LATE
TONIGHT AND FRIDAY PUTTING WRN WA IN THE WARM SECTOR AHEAD OF THE
NEXT VIGOROUS COLD FRONT. SNOW LEVELS SHOULD RISE CONSIDERABLY
OVERNIGHT INTO EARLY FRIDAY. FREEZING LEVELS ON THE MODELS ARE SLOW
TO MODERATE THE AIR MASS OVER THE CASCADES BUT GIVEN THE STRONG FLOW
DEVELOPING AND WEDGE OF WARMER AIR AT 850 MB AROUND +4 C...SNOW
LEVELS SHOULD RISE TO AT LEAST 6000 FEET. THE ONLY AREA IN QUESTION
IS THE N CASCADES WHERE SNOW LEVELS COULD REMAIN LOWER AT SPOTS LIKE
MOUNT BAKER.

RAIN ARRIVES AT THE COAST FRIDAY MORNING AND SPREADS INLAND DURING
THE AFTERNOON. PRECIPITATION MAY START OFF AS SNOW IN SOME MOUNTAIN
AREAS BUT SHOULD MIX AND THEN CHANGE OVER TO RAIN IN THE PASSES
RATHER QUICKLY. SNOW LEVELS WILL CRASH WITH THE FRONT FRIDAY EVENING
WITH SNOW LEVELS FALLING TO PASS LEVELS AGAIN. SEVERAL INCHES OF
SNOW IS POSSIBLE BUT THE HIGH SNOW LEVELS TO START SHOULD CUT BACK
POTENTIAL AMOUNTS CONSIDERABLY. THE WRF-GFS PICKS UP ON THIS IDEA
WITH ONLY HIGHER MOUNTAIN LOCATIONS GETTING ACCUMULATIONS FRIDAY
AFTERNOON...THEN UP TO 6 INCHES POSSIBLE AT PASS LEVEL FRIDAY NIGHT.
AN ADVISORY MAY BE NEEDED BUT PROBABLY NOT WARNING AMOUNTS. MOUNT
BAKER COULD BE THE ONE SPOT THAT PICKS UP LOCALLY MORE SNOW.

SHOWERS AND MOUNTAIN SNOW GRADUALLY TAPER OFF SATURDAY IN POST
FRONTAL ONSHORE FLOW. MODELS STILL HOLD ONTO SOME SPOTTY LIGHT QPF
INTO THE AFTERNOON/EVENING AND WILL KEEP THE CHANCE POPS IN THE
FORECAST...THOUGH MOST SPOTS WILL PROBABLY NOT MEASURE AFTER MIDDAY.

.LONG TERM...A HIGH AMPLITUDE UPPER RIDGE IS STILL ADVERTISED BY
MODELS TO BUILD OVER THE WRN U.S. SUNDAY AND PERSIST THROUGH MID
WEEK. THERE IS A SLIGHT CHANCE THAT A WARM FRONT OFFSHORE BRUSHES
THE AREA WITH SOME LIGHT RAIN SUNDAY MORNING BUT THIS WOULD BE
LIMITED TO THE OLYMPIC PENINSULA AND NOT LIKELY TO REACH INLAND
AREAS. CLOUDS WILL DECREASE WITH MOSTLY SUNNY SKIES BY MONDAY AS THE
LOW LEVEL FLOW TURNS OFFSHORE. MODELS SHOW 500 MB HEIGHTS RISING TO
OVER 5800M MONDAY WITH 850 MB TEMPS WARMING TO AROUND +14C. HIGHS
WERE NUDGED UPWARD A BIT WITH UPPER 50S TO AROUND 60 FORECAST BUT I
WOULD NOT BE SURPRISED IF LOW 60S WERE MORE WIDESPREAD THAN FORECAST
OR WHAT MOS INDICATES. HEIGHTS COME DOWN SLIGHTLY TUESDAY AND
WEDNESDAY SO HIGH TEMPERATURES MAY STRUGGLE TO REACH 60 BUT IT WILL
STILL BE A PLEASANT STRETCH OF SUNNY DRY WEATHER. MERCER

&&

.AVIATION...COLD FRONT FROM LAST NIGHT IS CURRENTLY ON THE EAST SIDE
OF THE CASCADES. WITH THAT...UPPER LEVEL FLOW WILL TURN FROM WEST-
SOUTHWEST TO A MORE NORTHWESTERLY DIRECTION AS UPPER LEVEL RIDGING
MAKES ITS WAY INTO THE AREA THROUGH THE DAY TODAY. THIS WILL TURN
WESTERLY THIS AFTERNOON AND EARLY EVENING. AIR MASS WILL REMAIN
MOIST AND MOSTLY STABLE.

CURRENT RADAR SHOWS SHOWER ACTIVITY ON EITHER SIDE OF THE
SOUND...WITH BANDS OF PRECIP ENTERING THE CASCADE FOOTHILLS AND THE
CENTRAL OLYMPIC PENINSULA. THIS GAP SHOULD ALLOW MOST TAF SITES TO
REMAIN DRY FOR THE NEXT 1 TO 3 HOURS...DEPENDING ON LOCATION.
ANOTHER ROUND OF SHOWERS IS EXPECTED BY LATE THIS MORNING INTO EARLY
AFTERNOON BEFORE THE TRAVERSING RIDGE BRINGS PRECIP TO AN END BY
THIS EVENING.

CIGS OVER WESTERN WASHINGTON GENERALLY LOW END VFR TO MVFR. MAY SEE
THEM LOWER DOWN INTO LOW END MVFR WITH AFTERNOON PRECIP...BUT ARE
EXPECTED TO REBOUND WITH UPPER LEVEL RIDGE THIS EVENING. SMR

KSEA...GENERALLY DRY THROUGH ABOUT 12Z THIS MORNING. SCATTERED
SHOWERS POSSIBLE AFTERWARD...WITH CHANCES INCREASING IN THE
AFTERNOON THEN ENDING BETWEEN 00-03Z. CIGS FALLING TO MVFR FROM MID
MORNING THROUGH AFTERNOON...REBOUNDING WITH PRECIP END. SOUTHERLY
WINDS WILL CONTINUE TO SLOWLY DIMINISH WITH SPEEDS TYPICALLY 7-12
KTS. SMR

&&

.MARINE...THE PASSAGE OF COLD FRONT LAST NIGHT WILL ALLOW FOR WINDS
TO GRADUALLY DIMINISH. CURRENT BATCH OF SMALL CRAFT ADVISORIES OVER
MOST WATERS WILL BE ALLOWED TO EXPIRE...AS NO SITES AT THIS TIME
OBSERVING WINDS THAT MEET CRITERIA. EXCEPTION TO THIS WILL BE
COASTAL WATERS. THEY REMAIN CLOSE...ONLY A FEW KNOTS UNDER
CRITERIA...AND WITH WINDS OVER THESE WATERS EXPECTED TO RISE AGAIN
LATE THIS MORNING AND THIS AFTERNOON...NO REASON TO YO-YO THE
ADVISORY.

NEXT FRONT ON FRIDAY WILL BRING WINDS UP...ONCE AGAIN PRECEDED BY
STRONG EAST TO SOUTHEAST GRADIENTS...THEN GRADUALLY RELAXING AND
SHIFTING SOUTH TO SOUTHWEST FRIDAY NIGHT. WITH MODELS REMAINING
CONSISTENT ON GALES...OPTED TO GET THE BALL ROLLING BY ISSUING A
GALE WATCH FOR THE COASTAL WATERS. EAST ENTRANCE AND NORTHERN INLAND
WATERS MAY REQUIRE INCLUSION...ALBEIT A LITTLE BIT LATER THAN THE
COASTAL WATERS...BUT WILL LEAVE THAT DECISION TO DAY SHIFT
FORECASTER.

ENERGETIC SWELL EXPECTED FOR THE COASTAL WATERS...PEAKING ON EARLY
THIS MORNING AROUND 16-18 FEET WITH A LONG PERIOD OF 19-20 SECONDS.
DESPITE BEING UNDER 20 FEET...THE LONG PERIOD ENERGY HAS PROMPTED A
HIGH SURF ADVISORY FOR BOTH THE CENTRAL AND NORTH COAST. SWELL THIS
LARGE HAVE THE POTENTIAL TO CAUSE MORE BEACH EROSION PROBLEMS ALONG
THE WASHINGTON COAST ESPECIALLY IN WESTPORT AND OCEAN SHORES. ON
FRIDAY...ANOTHER SWELL TRAIN WILL ARRIVE...BUT THE PERIOD WILL BE
UNDER 15 SECONDS...AND THE HIGHEST WAVES WILL ARRIVE DURING A LOW
TIDE ON FRI PM...SO DO NOT ANTICIPATE AS MUCH ISSUE WITH BEACH
EROSION ON FRI. 	 SMR/HANER

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WINTER WEATHER ADVISORY UNTIL NOON PST TODAY FOR THE CASCADES OF
     PIERCE AND LEWIS COUNTIES-CASCADES OF SNOHOMISH AND KING
     COUNTIES-CASCADES OF WHATCOM AND SKAGIT COUNTIES.

     HIGH SURF ADVISORY UNTIL 1 PM PST TODAY FOR CENTRAL COAST-
     NORTH COAST.

PZ...SMALL CRAFT ADVISORY FOR ROUGH BAR UNTIL 6 PM PST TODAY FOR
     GRAYS HARBOR BAR.

     SMALL CRAFT ADVISORY UNTIL 3 PM PST TODAY FOR COASTAL WATERS
     FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60 NM-COASTAL
     WATERS FROM CAPE FLATTERY TO JAMES ISLAND OUT 10 NM-COASTAL
     WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10 TO 60 NM-
     COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE OUT 10
     NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE SHOALWATER
     10 TO 60 NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE
     SHOALWATER OUT 10 NM-WEST ENTRANCE U.S. WATERS STRAIT OF
     JUAN DE FUCA.

     GALE WATCH COASTAL WATERS LATE TONIGHT THROUGH FRIDAY.

     SMALL CRAFT ADVISORY UNTIL 4 AM PST TODAY FOR CENTRAL U.S.
     WATERS STRAIT OF JUAN DE FUCA-EAST ENTRANCE U.S. WATERS
     STRAIT OF JUAN DE FUCA-NORTHERN INLAND WATERS INCLUDING THE
     SAN JUAN ISLANDS.

     SMALL CRAFT ADVISORY UNTIL 6 AM PST TODAY FOR PUGET SOUND AND
     HOOD CANAL.

&&

WWW.WEATHER.GOV/SEATTLE

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