Funnel Cloud in Washington, November 6, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
930 AM PST FRI NOV 6 2009

.SYNOPSIS...A BROAD UPPER LEVEL TROUGH CONTAINING COLD SHOWERY
UNSTABLE AIR WILL PERSIST OVER WESTERN WASHINGTON TODAY THROUGH
SATURDAY. THE TROUGH WILL SHIFT INLAND SATURDAY NIGHT WITH A WEAK
RIDGE OF HIGH PRESSURE TRYING TO BUILD ON SUNDAY. ANOTHER STRONG
FRONT WILL REACH THE AREA ON MONDAY. UNSETTLED WEATHER WILL CONTINUE
INTO THE MIDDLE OF NEXT WEEK.

&&

.SHORT TERM...SATELLITE IMAGERY THIS MORNING SHOWS AN IMPRESSIVE
AMOUNT OF COLD-TOPPED CU AND CB CLOUDS UPSTREAM OVER THE ERN PAC.
NOT SURPRISINGLY...THE 12Z KUIL SOUNDING LOOKED VERY UNSTABLE
THROUGH A DEEP LAYER OF THE ATMOSPHERE WITH OBSERVED 500 MB TEMP OF
-32C. MODIFIED TO A SURFACE TEMP OF 53F...THE KUIL SOUNDING YIELDED
CAPE OF 500 J/KG AND LIFTED INDEX OF -2.6. CONSIDERING THE
THERMODYNAMIC PROFILE AND ALL THE WAYS THAT STRONG WINDS ALOFT COULD
HELP ORGANIZE CONVECTION INTO FAST-MOVING CLUSTERS...THUNDER HAS
ALREADY OCCURRED OFF-AND-ON OVER WRN WA SINCE LAST EVENING...AND
THAT SHOULD CONTINUE THROUGH SATURDAY.

SINCE THE COLD FRONT PASSED LAST EVENING...SNOW LEVELS HAVE FALLEN
SIGNIFICANTLY. THE 12 KUIL SOUNDING HAD A FREEZING LEVEL OF 3900 FT
MSL. WEB CAMS CURRENTLY SHOW SNOW AT STEVENS PASS BUT RAIN AT
SNOQUALMIE PASS...SO SNOW LEVELS ARE LIKELY NEAR 3500 FT CURRENTLY.
WITH ONSHORE FLOW PUSHING STRONG CONVECTIVE ELEMENTS INTO THE
MTNS...SNOW AMTS IN THE 6-12 INCH RANGE ARE EXPECTED TODAY AND
TONIGHT. HOWEVER...CONVECTIVE NATURE OF THE PRECIP WILL MAKE SNOW
AMNTS QUITE VARIABLE WITH ISOLATED LOCATIONS GETTING IN EXCESS OF 12
INCHES.

BOTH THE NAM AND THE GFS BRING AN ORGANIZED WAVE ACROSS SW WA ON SAT
AFTN WITHIN THE COLD AND UNSTABLE AIR MASS. THIS WILL ENHANCE THE
PRECIP AND BRING HEAVY SNOW AMTS TO THE CASCADES. OFTEN TIMES...SNOW
AMTS WITH SUCH COLD AND UNSTABLE AIR ALOFT CAN BE UNDER-FORECASAT.
UPGRADING THE WINTER STORM WATCH TO A WARNING THIS AFTERNOON SEEMS
LIKE A PRETTY SURE THING. HEAVIEST SNOW ON SAT AFTN WILL AFFECT THE
CENTRAL CASCADES MORE THAN THE NORTH CASCADES.

ONCE THE WAVE PASSES ON SAT NIGHT...WEAK UPPER LEVEL RIDGING WILL
TRY TO BUILD ON SUNDAY. STILL CAN NOT RULE OUT A SHOWER ON
SUNDAY...BUT THE COVERAGE AND VIGOR OF ANY REMAINING SHOWERS WILL BE
MUCH LESS THAN TODAY AND SAT. THE 6 HOURS PRECEDING THE ARRIVAL OF
THE NEXT STRONG WEATHER SYSTEM LATE SUNDAY NIGHT STILL LOOKS LIKE
THE MOST LIKELY TIME FOR DRY WEATHER IN THE NEXT 4-5 DAYS.  HANER

.LONG TERM...FROM PREVIOUS DISCUSSION...EXTENDED MODELS ONCE AGAIN
IN GOOD AGREEMENT THIS MORNING WITH ANOTHER STRONG FRONT MOVING
THROUGH WESTERN WASHINGTON ON MONDAY. UPPER LEVEL PATTERN IS
SOMEWHAT PROGRESSIVE AND THE AIR MASS OVER WESTERN WASHINGTON DOES
NOT MODERATE MUCH OUT AHEAD OF THE FRONT WHICH WILL HELP KEEP
HYDROLOGICAL CONCERNS LOW. ANOTHER COOL UPPER LEVEL TROUGH WILL TAKE
UP RESIDENCE OFF THE COAST MONDAY NIGHT INTO TUESDAY KEEPING SHOWERS
IN THE FORECAST. UPPER LEVEL TROUGH MOVING THROUGH TUESDAY NIGHT
WITH THE FLOW ALOFT OVER WESTERN WASHINGTON BECOMING NORTHWESTERLY.
SYSTEM EMBEDDED IN THE NORTHWESTERLY FLOW MOVING DOWN OVER THE AREA
ON WEDNESDAY PREVENTING A DRY FORECAST. SOME RIDGING ON DEVELOPING
ON THURSDAY FOLLOWED BY A WET SYSTEM TOWARDS THE WEEKEND AFTER NEXT.
FELTON

&&

.HYDROLOGY...THERE ARE NO HYDROLOGY CONCERNS OR CONCERNS OF RIVER
FLOODING THROUGH THE WEEKEND. SNOW LEVELS WILL BE NEAR 3000 FEET
THROUGH SATURDAY...LIMITING RUNOFF CONCERNS FOR RIVERS WITH THEIR
HEADWATERS OVER THE MOUNTAINS. EVEN FOR LOWER ELEVATIONS...THE
CONVECTIVE NATURE OF PRECIPITATION WILL MEAN SIGNIFICANT DRY BREAKS
BETWEEN HEAVY SHOWERS AND THUNDERSTORMS.

STRONG FRONTAL SYSTEM LATE SUNDAY NIGHT AND MONDAY WILL GIVE A QUICK
SHOT OF RAIN AND RAISE FREEZING LEVELS...BUT WILL NOT STICK AROUND
LONG ENOUGH TO RAISE FLOODING CONCERNS. COOL SHOWERY WEATHER WILL BE
IN PLAY THROUGH WEDNESDAY. BOTH THE GFS AND ECMWF HAVE SOME BRIEF
RIDGING LATE NEXT WEEK BEFORE A WET SYSTEM ARRIVES ON SATURDAY.
MODELS SOLUTIONS SO FAR WITH THE SATURDAY (11/14) SYSTEM HAVE RANGED
FROM THE RIDGE KEEPING THE SYSTEM TO THE NORTH TO THE CURRENT
SOLUTION WHICH DROPS THE FRONT INTO WESTERN WASHINGTON. THIS SYSTEM
LOOKS TO BE THE ONLY ONE WITH THE POTENTIAL TO CAUSE ANY HYDRO
CONCERNS NEXT WEEK.     FELTON/HANER

&&

.AVIATION...A LARGE UPPER LEVEL TROUGH WILL REMAIN OVER THE PACIFIC
NORTHWEST TODAY...WITH THE DEEP LOW CENTERED OVER THE GULF OF
ALASKA. THE AIR MASS ACROSS WESTERN WASHINGTON IS COOL AND UNSTABLE.
IR SATELLITE SHOWS AN EXTENSIVE CUMULUS FIELD OFFSHORE DRIFTING
INLAND. SHOWERS AND POSSIBLE THUNDERSTORMS WILL CONTINUE TODAY. THE
FORECAST REMAINS UNSETTLED TONIGHT AS A SURFACE TROUGH OFFSHORE
SHIFTS INLAND...WITH CYCLONIC FLOW ALOFT. STRONG SOUTHERLY PRESSURE
GRADIENTS WILL MAINTAIN GUSTY SOUTH WINDS TODAY AND TONIGHT.

KSEA...OFF AND ON SHOWERS EXPECTED TODAY...AND WILL CONTINUE TO SEE
A THREAT FOR THUNDERSTORMS...ISOLATED IN THE MORNING...SCATTERED IN
THE AFTERNOON. WINDS WILL REMAIN GUSTY AND OUT OF THE SOUTHWEST.
HEAVIER SHOWERS MAY REDUCE VISIBILITY AND CEILINGS INTO MVFR RANGE.
SMALL HAIL IS ALSO POSSIBLE. SHOWERS WILL CONTINUE TONIGHT AS A
SURFACE TROUGH SHIFTS INLAND. CHB

&&

.MARINE...MODERATE SOUTHWEST TO WEST FLOW WILL CONTINUE ACROSS
WESTERN WASHINGTON TODAY AND TONIGHT AS A DEEP 955 MB LOW FILLS OVER
THE GULF OF ALASKA. WINDS WILL REMAIN IN THE SMALL CRAFT ADVISORY
RANGE FOR ALL WATERS. HOWEVER POSTED A GALE WARNING FOR THE WEST
ENTRANCE THIS MORNING AS TATOOSH ISLAND KEEPS GOING ABOVE GALE
FORCE. MODELS SHOW A SURFACE TROUGH PASSING THROUGH THE COASTAL
WATERS LATE TONIGHT INTO SATURDAY MORNING. ANOTHER SURFACE TROUGH
WILL PASS THROUGH WESTERN WASHINGTON SATURDAY AFTERNOON. THE NEXT
COLD FRONT WILL IMPACT THE REGION ON MONDAY...WITH SOUTHERLY GALES
POSSIBLE JUST AHEAD OF THE FRONT.

MEANWHILE...THIS SYSTEM OVER THE GULF OF AK IS SENDING LARGE SWELLS
TO THE WA COAST WITH SEAS FORECAST TO BUILD TO OVER 25 FT TODAY AT A
PERIOD AROUND 16 SEC. THE LARGE WAVES WILL CONTINUE TO IMPACT THE
COASTAL WATERS THROUGH SATURDAY AFTERNOON...THEN SUBSIDE SATURDAY
NIGHT INTO SUNDAY. CURRENTLY THERE IS A HIGH SURF WARNING FOR BIG
SWELLS IN THE SURF ZONE...RIGHT ALONG THE COAST. HIGH TIDE IS THIS
AFTERNOON. BIGGEST SWELLS ARRIVE TONIGHT WHEN THERE IS A MINUS TIDE.
ALSO THE SEA LEVEL PRESSURE IS NOT PARTICULARLY LOW...AND IT SHOULD
REMAIN IN THE 1005-1010 MB REGION. FOR THESE REASONS A COASTAL FLOOD
WARNING SEEMS UNNECESSARY AT THIS TIME. CHB

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WINTER WEATHER ADVISORY MOUNTAINS THROUGH FRIDAY NIGHT.
     WINTER STORM WATCH MOUNTAINS SATURDAY MORNING THROUGH EVENING.
     HIGH SURF WARNING FOR THE COAST 10 AM TODAY THROUGH 4 PM
     SATURDAY.
PZ...GALE WARNING THIS MORNING WEST ENTRANCE.
     SMALL CRAFT ADVISORY ALL OTHER WATERS.
     SMALL CRAFT ADVISORY FOR ROUGH BAR CONDITIONS GRAYS HARBOR BAR.

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
1222 PM PST FRI NOV 06 2009

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

1221 PM     HAIL             1 E BALLARD             47.67N 122.36W
11/06/2009  E0.25 INCH       KING               WA   TRAINED SPOTTER

            HEAVY HAIL SHOWER. HAIL COVERING THE GROUND.

&&

GRUB

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SEATTLE WA
1229 PM PST FRI NOV 06 2009

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

1229 PM     HAIL             5 ENE BALLARD           47.71N 122.30W
11/06/2009  E0.25 INCH       KING               WA   TRAINED SPOTTER

            HEAVY HAIL SHOWER. LESS THAN A QUARTER INCH. HAIL
            COVERING THE GROUND.

&&

GRUB

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SEATTLE WA
1232 PM PST FRI NOV 06 2009

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

1231 PM     HAIL             5 ESE MONTESANO         46.98N 123.50W
11/06/2009  E0.25 INCH       GRAYS HARBOR       WA   TRAINED SPOTTER

            HEAVY HAIL SHOWER PASSED THROUGH.

&&

GRUB

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SEATTLE WA
1247 PM PST FRI NOV 06 2009

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

1246 PM     HAIL             1 SSE CLEARVIEW         47.82N 122.11W
11/06/2009  M0.50 INCH       SNOHOMISH          WA   TRAINED SPOTTER

            HEAVY HAIL SHOWERS STARTING TO COVER THE GROUND. HAIL
            SIZE BETWEEN A QUARTER TO HALF INCH.

&&

GRUB