High Wind in Washington, November 19 to 20, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
330 PM PST THU NOV 19 2009

.SYNOPSIS...WINDY AND RAINY CONDITIONS WILL CONTINUE ACROSS WESTER
WASHINGTON. THE HEAVIEST PRECIPITATION WILL BE ALONG THE COAST AND
OLYMPICS. WINDS WILL EASE LATE THIS EVENING. FRIDAY WILL STAY COOL
AND SHOWERY AS A DEEP UPPER LEVEL TROUGH MOVES INLAND. ANOTHER
SYSTEM WILL CLIP THE AREA ON SATURDAY...FOLLOWED BY ANOTHER ONE ON
MONDAY.

&&

.SHORT TERM...ANOTHER STRONG PACIFIC FRONTAL SYSTEM PASSING THROUGH
THE OFFSHORE WATERS THIS AFTERNOON...HEADING N/NE TOWARD VANCOUVER
ISLAND. ESTIMATED SURFACE PRESSURE IS 980-985 MB. CURRENT SATELLITE
LOOPS SHOW THE LOW NEAR 45N 130W AND WILL MOVE INLAND OVER NORTHERN
VANCOUVER ISLAND AROUND 06Z TONIGHT. IN THE MEANTIME...WILL STRUGGLE
WITH ANOTHER ROUND OF STRONG WINDS...ONCE AGAIN PRIMARILY ALONG THE
COAST AND NORTH INTERIOR. ALREADY RECORDED HIGH WIND IN THE CENTRAL
COAST. WINDS IN THE CENTRAL SOUND WILL BE MARGINAL BUT CANNOT RULE
OUT A POSSIBLE GUST TO 50 MPH WITH MORE KNOCKED DOWN TREES AND POWER
OUTAGES. LOOKS LIKE THE WINDS WILL EASE LATE THIS EVENING.

SEE HYDRO DISCUSSION BELOW FOR ONGOING FLOOD CONCERNS.

HEAVY SNOW HAS BEEN FALLING IN THE MOUNTAINS ALL DAY. FREEZING
LEVELS WILL RISE TO AROUND 5000 FT IN THE OLYMPICS AND WILL SEE
MAINLY RAIN OR A MIX AT HURRICANE RIDGE. THE CASCADES GOT HAMMERED
BUT PRECIP WILL BEGIN TO TAPER A BIT AS THE BAROCLINIC BAND PIVOTS
MORE NORTH-SOUTH ORIENTATED AND ALIGNED ALONG THE COAST. UNTIL THEN
COULD SEE A FEW MORE INCHES WITH TEMPS IN THE PASSES STILL NEAR OR
BELOW FREEZING...BUT HEAVY AMOUNTS ARE NOT FORECAST TONIGHT. WILL
ALLOW THE WINTER STORM WARNING TO EXPIRE.

AS MENTIONED ABOVE...THE PRECIP WILL BE MAINLY FOCUSED ALONG THE
COAST AND OLYMPICS TONIGHT/FRI MORNING AS THE UPPER LEVEL TROUGH
DIGS OFFSHORE. MODELS SHOW THE TROUGH AXIS SHIFTING INLAND FRI
MORNING WITH AXIS PASSING EAST OF THE CASCADES LATE FRI NIGHT. THE
AIR MASS WILL BE COOL AND SHOWERY ACROSS THE REGION AND MAY SEE
ANOTHER QUICK ROUND OF HEAVY SNOW IN THE CASCADES. SNOW LEVELS WILL
LOWER TO AROUND 2000 FT. WILL KEEP THE WINTER STORM WATCH UP BUT 12
HR AMOUNTS MAY UNDERCUT WARNING CRITERIA. WILL WAIT FOR THE NEW RUNS
AND DEFER BACK TO THE MIDNIGHT SHIFT.

ANOTHER SYSTEM WILL TRACK THROUGH THE REGION ON SAT BUT SO FAR LOOKS
RATHER PROGRESSIVE AND COOL WITH NO ADDITIONAL FLOOD CONCERNS. 33

.LONG TERM...MODELS SHOW A WARM FRONT CLIPPING WESTERN
WASHINGTON...POSSIBLY ON MONDAY. HOWEVER THE ECMWF SHOWS THE BULK OF
THE MOISTURE AIMED AT SOUTHERN B.C. A SHORT WAVE TROUGH WILL THEN
TRAVERSE THE REGION MON NIGHT OR TUE MORNING. FORECAST CONFIDENCE
MID WEEK AND BEYOND REMAINS LOW AT THIS POINT AS MODELS ARE OUT OF
PHASE. THE UPPER LEVEL RIDGE MAY RE-AMPLIFY OVER THE PAC NW...BUT
THERE IS ANOTHER SYSTEM DEVELOPING IN THE GULF OF AK WITH THE
BAROCLINIC BAND SLIDING SE ACROSS SOUTHERN B.C. AND PERHAPS INTO
WESTERN WA. 33

&&

.HYDROLOGY...A BAND OF HEAVY RAIN PASSED SOUTH TO NORTH
THROUGH THE SOUTHWEST AND THE SEATTLE METRO AREA THIS MORNING AND IT
IS CURRENTLY OVER THE NORTHERN PART OF THE STATE. SOUTHERN AREAS
INCLUDING THE SEATTLE AREA ARE IN A LULL OF PRECIPITATION. THE
OLYMPICS...INCLUDING THE NORTHERN OLYMPIC PENINSULA...ARE RECEIVING
HEAVY RAIN. THERE HAS BEEN WARMING IN THE CENTRAL CASCADES BUT
LITTLE RAIN IS FALLING THERE. IN THE NORTH CASCADES IT IS STILL COLD
AND THROUGH HEAVY PRECIPITATION IS FALLING...IT IS SNOW. THIS WILL
CHANGE TO RAIN EARLY THIS EVENING.

SATELLITE SHOWS THE THICKEST CLOUDS HAVE MOVED NORTH. THE FORECAST
IS FOR THE CONVEYOR BELT OF MOISTURE TO SWING BACK SOUTH OVERNIGHT
AS A DEEP LOW MOVES INTO NORTHERN VANCOUVER ISLAND AND A COLD FRONT
MOVES ASHORE. AFTER 12Z FRIDAY CONSIDERABLY COOLER AIR MOVES IN AND
HYDROLOGICALLY SIGNIFICANT PRECIPITATION WILL END. BEFORE IT DOES
THE OLYMPICS COULD SEE ANOTHER 2-4 INCHES OF RAIN...AND THE WILLAPA
HILLS AND NORTH CASCADES COULD GET ANOTHER 1-2 INCHES. THESE AMOUNTS
ARE DRIVING THE RIVER MODELS WHICH GIVE THE FOLLOWING RESULTS.

THE SKOKOMISH AND SATSOP RIVERS STAY ABOVE FLOOD STAGE. THE RIVERS
ON THE NORTHERN OLYMPIC PENINSULA TURN UP THIS EVENING AND APPROACH
FLOOD STAGE. THE WARNING ISSUED EARLIER FOR THE BOGACHIEL WILL STAY
IN EFFECT...WITH A WATCH IN EFFECT FOR THE OTHER OLYMPICS RIVERS.
THE UPPER CHEHALIS AND ITS TRIBUTARIES ARE FORECAST TO STAY BELOW
FLOOD STAGE...BUT THE LOWER CHEHALIS COULD STILL FLOOD. A WATCH
REMAINS IN EFFECT FOR THE WHOLE CHEHALIS SYSTEM.

RAINFALL AMOUNTS IN THE CASCADES DO NOT APPEAR TO BE ENOUGH TO CAUSE
FLOODING. RIVERS WILL RISE BUT WILL NOT REACH FLOOD STAGE. A FEW
MORE FLASHY RIVERS SUCH AS THE TOLT OR PUYALLUP NEAR ORTING COULD
SURPRISE BUT FOR NOW CONCERNS DO NOT RISE TO THE LEVEL OF A WATCH.

ANOTHER SYSTEM IS FORECAST TO ARRIVE FROM THE NORTHWEST ON SATURDAY
NIGHT...BUT THIS SYSTEM IS COLDER AND LESS LIKELY TO PRODUCE HEAVY
RAIN. 500 MB HEIGHTS DIP INTO THE 520S AS THE UPPER LEVEL TROUGH
MOVES INLAND SO MOST OF THIS PRECIPITATION WILL BE MOUNTAIN SNOW.

ANOTHER SYSTEM ON MONDAY SHOULD BE PROGRESSIVE ENOUGH TO NOT CAUSE
ANY FLOODING. A SYSTEM NEXT THURSDAY COULD BE WETTER AND WARMER BUT
MODELS DIFFER IN SIGNIFICANT DETAILS. THE FOLLOWING WEEKEND COULD
SEE SPLIT FLOW WITH MOST OF THE NEXT SYSTEM HEADING SOUTH OF
WASHINGTON.

AT NO TIME IS ANY FLOODING FORECAST ON THE GREEN RIVER. BURKE

&&

.AVIATION...A COLD FRONT LIES OFFSHORE...EXTENDING SW FROM NEAR THE
N WA COAST. A WARM FRONT IS MOVING NORTHEAST OVER WESTERN
WASHINGTON. A STRONG SURFACE LOW MOVING NE UP THE COLD FRONT WILL
CURVE N...CROSSING N VANCOUVER ISLAND 06Z. THE COLD FRONT WILL MOVE
INLAND LATE TONIGHT. THE LOW IS CAUSING WINDS TO INCREASE AGAIN THIS
AFTERNOON. EXPECT ANOTHER ROUND OF LOW LEVEL WIND SHEAR DUE TO 925
MB /2500 FT/ WINDS INCREASING BACK TO 40-55 KT. SAND POINT PROFILER
SHOWS S WINDS 35 KT AT 2500 FEET...WHICH IS ABOUT 10 KT SLOWER THAN
FORECAST. WILL STICK WITH THE CURRENT FORECAST THOUGH SINCE THERE IS
AMPLE TIME FOR WINDS TO INCREASE. CIGS REMAIN UP...GENERALLY
BKN-OVC030-050...AS EXPECTED IN THIS WINDIER REGIME. EXPECT CIGS TO
DECREASE BACK DOWN TO MVFR LATE TONIGHT AFTER THE WINDS WEAKEN.

KSEA...SURFACE WINDS ARE TAKING THEIR TIME TO INCREASE...MAY MODIFY
THEM DOWN SLIGHTLY...BUT MAIN PROBLEM REMAINS LOW LEVEL WINDS
AFFECTING APPROACHES. EXPECT THOSE TO BE NEAR OR JUST SLIGHTLY LESS
THAN FORECAST. NO CHANGE TO CIGS FORECAST....VFR THROUGH THE
EVENING...THEN LOWERING OVERNIGHT. KAM

&&

.MARINE...SATELLITE IMAGERY SHOW MODELS REMAIN ON TRACK AS A 984 MB
LOW NEAR 48N/130W HEADS TOWARD LANDFALL ON N VANCOUVER ISLAND AROUND
06Z. WILL KEEP THE COASTAL STORM WARNINGS AND INLAND GALE WARNINGS
GOING...THOUGH INLAND WINDS ARE TAKING THEIR TIME IN INCREASING.
EXPECT THE WINDS TO DECREASE A LITTLE SOONER AFTER MIDNIGHT...THEN
THE LULL WILL LAST THROUGH MOST OF FRIDAY MORNING. MODELS SHOW
STRONG W FLOW BEHIND THE MAIN SURFACE TROUGH REACHING THE OUTER
COASTAL WATERS BY 18Z FRIDAY THEN SPREADING QUICKLY EAST AND INLAND
AFTER 21Z. THIS BURST OF W FLOW SHOULD PRODUCE GALES ALONG THE COAST
AND THROUGH THE STRAIT. RATHER THAN LOAD THE FORECAST WITH A WHOLE
BUNCH OF HEADLINES...WILL STICK WITH THE MOST IMPORTANT ONE...THE
CURRENT STORM/GALES AND HAVE THE MIDSHIFT PUT UP THE WARNINGS FOR
THE WESTERLY GALES TONIGHT. MODELS SHOW MORE FAIRLY STRONG FRONTAL
SYSTEMS SET TO ARRIVE SATURDAY AND AGAIN MONDAY...PROBABLY ANOTHER
MID NEXT WEEK.

WILL KEEP THE HIGH SURF ADVISORY GOING. BUOYS SHOW THE COMBINED SEAS
GETTING UP ABOVE 20 FEET AGAIN ON THE COAST...BUT PER THE WAVEWATCH
INDIVIDUAL SWELL TRAINS...I SUSPECT THE TRUE LONGER PERIOD SWELL
WILL PROBABLY BE LESS THAN 20 FEET. KAM

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...FLOOD WARNINGS AND/OR FLOOD WATCHES ARE IN EFFECT FOR A
     PORTION OF THE CWA.

     A HIGH WIND WARNING REMAINS IN EFFECT FOR THE COAST AND NORTH
     INTERIOR TIL MIDNIGHT TONIGHT.

     A WIND ADVISORY IS IN EFFECT FOR SEATTLE TACOMA EVERETT
     BREMERTON AREAS...EAST PUGET SOUND LOWLANDS...HOOD CANAL UNTIL
     MIDNIGHT TONIGHT.

     A HIGH SURF ADVISORY REMAINS IN EFFECT FOR THE COAST TIL 4 AM
     FRI.

     A WINTER STORM WATCH IS IN EFFECT FOR THE CASCADES FROM FRI
     AFTERNOON THROUGH LATE FRI NIGHT.

PZ...STORM WARNINGS REMAIN IN EFFECT FOR THE COASTAL WATERS AND
     WEST ENTRANCE TO THE STRAIT OF JUAN DE FUCA.

     GALE WARNINGS ARE IN EFFECT FOR THE REMAINING WATERS.

     A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR SEVERE GRAYS
     HARBOR BAR CONDITIONS.

WWW.WEATHER.GOV/SEATTLE

FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION...PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATESTWEBAFD.HTML.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SEATTLE WA
1143 AM PST THU NOV 19 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0445 PM     NON-TSTM WND GST 2 WNW ANACORTES         48.50N 122.66W
11/18/2009  M52.00 MPH       SKAGIT             WA   TRAINED SPOTTER

            SUSTAINED 30 MPH, GUST 52 MPH.

0615 PM     NON-TSTM WND GST 4 ENE VAIL              46.86N 122.58W
11/18/2009  M66.00 MPH       THURSTON           WA   TRAINED SPOTTER

            GUST TO 66 MPH LAST NIGHT IN LAKE LAWERENCE.

&&

DDAMICO