High Wind in Washington, November 9 to 11, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 AM PST FRI NOV 9 2007

.SYNOPSIS...A COLD FRONT OVER WESTERN WASHINGTON WILL MOVE EAST OF
THE CASCADES THIS MORNING...WITH RAIN GIVING WAY TO A CHANCE OF
SHOWERS. A STRONGER FRONT WILL BRING MORE RAIN TONIGHT AND SATURDAY
MORNING...WITH SUN BREAKS BEHIND THE FRONT SATURDAY AFTERNOON. A WET
PATTERN WILL CONTINUE SATURDAY NIGHT THROUGH EARLY NEXT WEEK...AND
IT WILL BE COLD ENOUGH FOR SNOW AT TIMES ON THE HIGHWAY PASSES.

&&

.SHORT TERM...A FRONTAL SYSTEM IS MOVING THROUGH THE AREA THIS
MORNING. THE SURFACE COLD FRONT WAS MAKING LANDFALL ON THE
WASHINGTON COAST AROUND 2 AM...WHILE THE BACK EDGE OF THE UPPER
CLOUD BAND WAS ALREADY INTO THE INTERIOR OF WRN WA. THE SURFACE LOW
PASSED JUST SOUTH OF THE QUEEN CHARLOTTES...HEADING NORTHEAST INTO
BRITISH COLUMBIA.

PCPN HAS BEEN MOSTLY UNIMPRESSIVE SO FAR. PARTS OF THE OLYMPICS AND
NORTH COAST HAVE HAD MORE THAN A HALF INCH...BUT MOST SPOTS IN THE
INTERIOR HAVE RECEIVED ONLY A FEW HUNDREDTHS. THE SURFACE FRONT
SHOULD BRING A LITTLE MORE PCPN THIS MORNING AS IT CROSSES THE AREA.
THE SNOW LEVEL -- WHICH WAS AROUND 8000 FT AHEAD OF THE FRONT --
WILL FALL TO 4500 FT OR SO THIS AFTERNOON...BUT BY THAT TIME PCPN
WONT AMOUNT TO MUCH.

AS WE HAVE BEEN ADVERTISING FOR DAYS NOW...THE FRONT CURRENTLY
MOVING THROUGH WILL MARK THE TRANSITION TO A MUCH WETTER ZONAL
PATTERN. A SERIES OF FRONTAL SYSTEMS WILL MAKE THEIR WAY QUICKLY
ACROSS THE AREA THROUGH AT LEAST THE EARLY PART OF NEXT WEAK.

A MORE VIGOROUS FRONT WILL BRING A MORE SIGNIFICANT ROUND OF PCPN
AND BREEZY CONDITIONS TO WRN WA TONIGHT AND SAT MORNING. THE WRN WA
INTERIOR LOWLANDS WILL GENERALLY RECEIVE 12 HOUR RAIN TOTALS OF 0.25
TO 0.50 INCH WITH SOMEWHAT HEAVIER AMOUNTS ON THE COAST...AND THE
MOUNTAINS WILL GET UP TO 1.5 INCHES OF WATER. THE SNOW LEVEL WILL BE
AROUND 5500 FT AS THIS PCPN FALLS...SO I THINK HEAVY SNOW IS
UNLIKELY EVEN ON THE HIGHEST HIGHWAYS AND PASSES. HOWEVER THE
ISSUANCE OF A SNOW ADVISORY MIGHT BE WORTH CONSIDERING LATER TODAY.

THE SNOW LEVEL WILL FALL TO 3000 FT BEHIND THE FRONT SAT AFTERNOON.
BY THAT TIME THE AIR MASS WILL BE DRYING OUT THOUGH...AND WE SHOULD
EVEN HAVE SUN BREAKS IN THE INTERIOR. A FAIRLY WEAK UPPER SHORTWAVE
WILL BRING ANOTHER ROUND OF SHOWERS SAT NIGHT. BY THEN THE SNOW
LEVEL WILL BE AROUND 2500 FT. PCPN AMOUNTS WONT BE GREAT...BUT ALL
THE HIGHWAY PASSES SHOULD GET AN INCH OR TWO OF SNOW.

ANOTHER FRONTAL SYSTEM WILL MOVE THROUGH THE FORECAST AREA SUN AND
SUN NIGHT...AND THIS ONE MIGHT PRESENT THE BEST CHANCE FOR HEAVY
SNOW IN THE MOUNTAINS. MODELS INDICATE THE SNOW LEVEL WILL REMAIN
AROUND 3000 FT AS THIS FEATURE MOVES THROUGH...AND PCPN AMOUNTS LOOK
SUBSTANTIAL -- WITH STORM TOTAL PCPN IN THE MOUNTAINS EXCEEDING TWO
INCHES OF WATER IN THE WETTEST LOCATIONS. MCDONNAL

.LONG TERM...AS MENTIONED ABOVE...THE WET PATTERN NOW DEVELOPING
WILL CONTINUE INTO AT LEAST THE EARLY PART OF THE EXTENDED FORECAST.
ANOTHER VIGOROUS SYSTEM WILL MOVE THROUGH MON AND MON NIGHT. FOR NOW
ANYWAY...IT LOOKS LIKE THERE WILL BE SOMETHING OF A BREAK BEHIND
THAT SYSTEM...BUT THERE IS STILL A FAIR AMOUNT OF INCONSISTENCY IN
THE MODELS AND UNCERTAINTY IN THE FORECAST FOR TUE NIGHT AND BEYOND.
MCDONNAL

&&

.AVIATION...COLD FRONT MOVING ACROSS WESTERN WASHINGTON EARLY THIS
MORNING. LOOKS LIKE IT REACHED THE CENTRAL COAST AROUND 2 AM PST.
CEILINGS HAVE FINALLY DROPPED TO BKN-OVC030-040 OVER THE INTERIOR.
WILL LEAVE TEMPO MVFR CEILINGS OF BKN020-030 OVER MOST TERMINALS
THROUGH MORNING HOURS WITH PRECIP. PRECIP SHOULD TAPER OFF AFTER
FRONTAL PASSAGE AND WE MAY SEE A RETURN TO VFR FOR AWHILE AFTER 21Z.
CEILINGS LIKELY DROP BACK DOWN TO MVFR AFTER 08Z TONIGHT AS PRECIP
SPREADS IN AGAIN WITH NEXT SYSTEM.

KSEA...CEILINGS BKN030-040 TEMPORARILY DROPPING TO BKN-OVC020 AS
PRECIP MOVES THROUGH WITH FRONT. COULD SEE A RETURN TO VFR FOR
AWHILE AFTER 21Z INTO THIS EVENING. WIND SOUTH TO SOUTHWEST 8 TO 12
KNOTS THROUGH THE DAY. 27

&&

.MARINE...SURFACE FRONT MOVING THROUGH WESTERN WASHINGTON INLAND
WATERS AT THE MOMENT. LOOKS LIKE FRONT PASSED CAPE ELIZABETH BUOY
AROUND 10Z. WINDS SHOULD EASE A LITTLE WITH FRONTAL PASSAGE...EXCEPT
IN PUGET SOUND WHERE THEY MAY PICK UP A BIT. SOLID SMALL CRAFT
ADVISORIES IN EFFECT FOR NEARLY ALL WATERS THROUGH THIS AFTERNOON.
THE NEXT SYSTEM FOR LATE TONIGHT AND TOMORROW HAS ANOTHER ROUND OF
SMALL CRAFT ADVISORY WINDS FOR THE WATERS. NOT GOING GALE ON THE
COAST WITH THIS ONE...YET. STILL LOOKING AT POTENTIAL FOR SEAS
APPROACHING 20 FEET OR MORE EARLY NEXT WEEK AS MODELS MAINTAIN
FAIRLY STRONG SURFACE LOW TRACKING TOWARD VANCOUVER ISLAND LATER
MONDAY. 27

&&

.SEW WATCHES/WARNINGS/ADVISORIES...SMALL CRAFT ADVISORY ALL WATERS
EXCEPT CENTRAL STRAIT. SMALL CRAFT ADVISORY FOR ROUGH BAR GRAYS
HARBOR BAR.

WEATHER.GOV/SEATTLE