Special Weather Statement, NWS Seattle, WA

Area Forecast Discussion
National Weather Service Seattle WA
341 AM PDT Fri Oct 14 2016

.SYNOPSIS...Wet windy weather will continue today as a strong low
pressure system tracks northeast across Vancouver Island. The
remains of a Pacific typhoon will arrive late Saturday and move
through Saturday night with the potential for more widespread
damaging winds. It will also bring significant precipitation with
a threat of flooding. Showery weather will continue next week.

&&

.SHORT TERM...A vigorous Pacific frontal system is moving through
Washington early this morning. The main frontal band was moving
into the Cascades at 3 am, and precipitation has decreased over
most of Western Washington in its wake. Southerly pressure
gradients peaked around midnight, and strongest wind gusts
overnight were 45 to 55 mph at the coast and in the north
interior and 35 to 45 mph in the Puget Sound region. Rainfall
amounts for the past 24 hours have been impressive across Western
Washington with 2 to 3 inches at the coast, 3 to 5+ inches in the
Olympics, generally 1 to 3 inches in the interior lowlands and 2
to 5+ inches in the Cascades.

The low pressure center of this storm is vertically stacked with
the surface and upper low near 48N/130W at 3 am, or about 250
miles west of the north Washington coast. This part of the storm
will bring more wind and rain today as it moves into Western
Washington. Its surface low will fill from around 970 mb to 980 mb
as it tracks east-northeast, moving across central Vancouver
Island this afternoon. This should produce another round of low-
end high wind for the coast and north interior, with wind advisory
southerlies for the Puget Sound region and southwest interior.
Winds should peak mid to late afternoon and ease tonight as the
low tracks northeast across British Columbia.

There will be more rain today and tonight, but less than the last
24 hours. We can expect another 0.5 to 1.5 inches in the lowlands
and 1 to 3 inches in the mountains. The snow level will be 5500 to
6000 ft. There could also be some thunderstorms at the coast.

As we have been advertising for several days, the remains of
Pacific Typhoon Songda will approach Western Washington from the
southwest on Saturday, with its surface low possibly bringing a
major windstorm to Western Washington late Saturday and Saturday
night. The low center -- probably around 970 mb -- will travel
northeast and likely pass right over the northwest corner of the
Olympic Peninsula Saturday evening and continue into British
Columbia Saturday night. The 00Z FRI GFS solution has the low just
to the east of that, tracking across the Olympic Peninsula and
then Vancouver BC. If that GFS solution is about right, then
Western Washington -- including the greater Seattle metropolitan
area -- would likely have its most significant windstorm since the
Hanukkah Eve storm of December 2006, which left many people
without power for several days. This system will bring another
period of significant precipitation, similar to or slightly less
than the last 24 hours, with the snow level around 6000 ft.

A large upper trough will move toward the region from the west
Sunday and Sunday night, for a relatively quiet period of merely
showery weather. McDonnal

.LONG TERM...More typical October weather will prevail during the
extended period. An upper trough should keep the area fairly wet
Monday afternoon through Tuesday. Wednesday should be the driest
day, as a dirty upper ridge moves through. The south end of a
system moving into British Columbia could bring more rain on
Thursday. McDonnal

&&

.HYDROLOGY..A flood warning is in effect for the Skokomish River in
Mason county, and it reached flood stage just after midnight.
Some of the more flood-prone rivers running off the west slopes
of the Cascades are also at risk, especially the Nooksack River in
Whatcom County and the Stillaguamish River in Snohomish County. A
flood watch is in effect for those two counties.

Rainfall today and tonight will be less, but the system for
Saturday and Saturday night could bring rainfall similar to what
occurred during the past 24 hours. At this point, the Northwest
River Forecast Center guidance keeps all rivers other than the
Skokomish below flood stage through the weekend, but that can
change quickly. Small landslides could also become a concern over
the weekend. With dry antecedent conditions, we are still below
the threshold for concern, but heavy rain in the lowlands Saturday
and Saturday night could push some areas above. McDonnal

&&

.AVIATION...Moist Pacific frontal systems will bring rain to W WA
through Saturday and likely into Sunday as well. The rain may seem
nearly continuous at times but there will be waves moving across W
WA from this complex system, which will produce lulls where the rain
may briefly taper off or end. Current radar imagery shows a good
example of this...with the front generally east of most terminals in
W WA. However...showers do persist west of the front...though not
nearly as organized. Moisture associated with low pressure over
Vancouver Island will continue to push into the area through the
day...allowing for the threat of rain to persist today.

Surface and low level winds have either peaked or are peaking at the
time of this writing...depending on location. However...current
forecast fully expects winds to remain somewhat increased during
this relative lull as the main low crosses Vancouver island. Ceiling
and visibility conditions will be predominantly IFR and MVFR the
next few days.

KSEA...Southerly winds will slowly diminish after 12Z this
morning...although gusts look to remain. Speeds expected to pick up
again to 20-25 KT by late this morning and persist through the
afternoon before diminishing tonight. SMR

&&

.MARINE...Impacts from initial low pressure system will linger over
the coastal waters for much of today. Storm Warning looks good to
expire and will be replaced with a Gale Warning as winds diminish
somewhat. Winds over remaining area waters are also expected to
follow this trend...but remaining Gales will only drop down into
Small Craft winds...so still plenty of headlines to go around for
much of the day today.

Next big storm coming late Saturday or Saturday night in the form of
a low that will peak in strength as a very deep low off the coast.
Models look like they are finally starting to gel on a
solution...with the low passing NE over the Olympic Peninsula. This
storm continues to look dangerous with another round of storm-force
winds possible over the coast and plenty of gales or small craft
winds for inland waters. SMR

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...High wind warning for the coast and north interior zones until
      3 pm today.
     Wind advisory for the Puget Sound region and southwest interior
      zones until 6 pm today.
     High wind watch for all zones Saturday afternoon through
      Saturday night.

PZ...Small Craft Advisory for rough bar until 5 PM PDT for Grays
      Harbor Bar.
     Gale Warning until 2 PM PDT for Coastal Waters.
     Gale Warning until 3 PM PDT for Admiralty Inlet...East Strait
      and Northern Inland Waters.
     Gale Warning until 11 AM PDT for West Strait.
     Small Craft Advisory until 5 PM PDT for Central Strait.
     Small Craft Advisory from 11 AM PDT through this evening for
      Western Strait.
     Small Craft Advisory from 3 PM PDT through tonight for Admiralty
      Inlet...Puget Sound and Hood Canal and Northern Inland Waters.
     Small Craft Advisory from 2 PM PDT through tonight for Coastal
      Waters.

&&

www.weather.gov/seattle

You can see an illustrated version of this discussion at
www.weather.gov/seattle/gafd/latest_webafd.html

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SEATTLE WA
730 AM PDT FRI OCT 14 2016

WAZ513-516-517-141515-
OLYMPICS-NORTH COAST-CENTRAL COAST-
730 AM PDT FRI OCT 14 2016

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN GRAYS HARBOR AND
SOUTH CENTRAL JEFFERSON COUNTIES UNTIL 815 AM PDT...

AT 730 AM PDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR
AMANDA PARK...MOVING NORTHEAST AT 55 MPH.

HALF INCH HAIL AND WIND GUSTS OF 50 TO 55 MPH WILL BE POSSIBLE WITH
THIS STORM.

LOCATIONS IMPACTED INCLUDE...
AMANDA PARK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORRENTIAL RAINFALL WAS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO LOCALIZED FLOODING. DO NOT DRIVE THROUGH FLOODED ROADWAYS.

FREQUENT CLOUD TO GROUND LIGHTNING WAS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 10 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

&&

LAT...LON 4761 12405 4774 12352 4735 12401 4729 12424
      4730 12428 4734 12430
TIME...MOT...LOC 1430Z 214DEG 49KT 4744 12401

JOHNSON

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SEATTLE WA
734 AM PDT FRI OCT 14 2016

WAZ555-556-558-568-141515-
BELLEVUE AND VICINITY-SEATTLE AND VICINITY-WEST SLOPES NORTH CENTRAL
CASCADES AND PASSES-EAST PUGET SOUND LOWLANDS-
734 AM PDT FRI OCT 14 2016

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL KING COUNTY UNTIL 815 AM
PDT...

AT 733 AM PDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR
MAPLE VALLEY...OR NEAR KENT...MOVING NORTHEAST AT 60 MPH.

HALF INCH HAIL AND WIND GUSTS OF 50 TO 55 MPH WILL BE POSSIBLE WITH
THIS STORM.

LOCATIONS IMPACTED INCLUDE...
BELLEVUE...KENT...CARNATION...RENTON...SAMMAMISH...ISSAQUAH...MAPLE
VALLEY...COVINGTON...SNOQUALMIE...NEWCASTLE...SEATAC...TUKWILA...
BLACK DIAMOND...FALL CITY...MIRRORMONT...LAKE MORTON-BERRYDALE...PINE
LAKE...HOBART...MAPLE HEIGHTS-LAKE DESIRE AND LAKE MARCEL-STILLWATER.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORRENTIAL RAINFALL WAS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO LOCALIZED FLOODING. DO NOT DRIVE THROUGH FLOODED ROADWAYS.

THIS STORM MAY INTENSIFY...SO MONITOR YOUR LOCAL NEWS SOURCE FOR MORE
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

&&

LAT...LON 4730 12210 4737 12219 4742 12229 4776 12181
      4759 12170
TIME...MOT...LOC 1433Z 224DEG 53KT 4742 12212

JOHNSON

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SEATTLE WA
744 AM PDT FRI OCT 14 2016

WAZ513-516-517-141530-
OLYMPICS-NORTH COAST-CENTRAL COAST-
744 AM PDT FRI OCT 14 2016

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN GRAYS HARBOR AND SOUTH
CENTRAL JEFFERSON COUNTIES UNTIL 830 AM PDT...

AT 744 AM PDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 10
MILES WEST OF AMANDA PARK...MOVING NORTHEAST AT 40 MPH.

NICKEL SIZE HAIL AND WIND GUSTS OF 50 TO 55 MPH WILL BE POSSIBLE WITH
THIS STORM.

THIS STORM WILL REMAIN OVER MAINLY RURAL AREAS OF NORTHERN GRAYS
HARBOR AND SOUTH CENTRAL JEFFERSON COUNTIES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORRENTIAL RAINFALL WAS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO LOCALIZED FLOODING. DO NOT DRIVE THROUGH FLOODED ROADWAYS.

&&

LAT...LON 4745 12410 4746 12415 4786 12402 4775 12366
TIME...MOT...LOC 1444Z 208DEG 33KT 4750 12411

JOHNSON

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SEATTLE WA
804 AM PDT FRI OCT 14 2016

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

0803 AM     HEAVY RAIN       12 SW BREMERTON         47.43N 122.89W
10/14/2016  M3.15 INCH       MASON              WA   TRAINED SPOTTER

            3.15 INCHES OF RAIN AT HOODSPORT IN PAST 24 HOURS.

&&

HANER

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SEATTLE WA
834 AM PDT FRI OCT 14 2016

WAZ512-517-141615-
LOWER CHEHALIS VALLEY AREA-CENTRAL COAST-
834 AM PDT FRI OCT 14 2016

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN GRAYS HARBOR COUNTY
UNTIL 915 AM PDT...

AT 834 AM PDT...DOPPLER RADAR WAS TRACKING STRONG THUNDERSTORMS ALONG
A LINE EXTENDING FROM NEAR MOCLIPS TO 16 MILES WEST OF WESTPORT.
MOVEMENT WAS EAST AT 45 MPH.

WIND GUSTS OF 50 TO 55 MPH WILL BE POSSIBLE WITH THESE STORMS.

LOCATIONS IMPACTED INCLUDE...
ABERDEEN...HOQUIAM...WESTPORT...MOCLIPS...OCEAN SHORES...COPALIS
BEACH...OCEAN CITY BEACH...OYEHUT-HOGANS CORNER...MARKHAM...COHASSETT
BEACH...PACIFIC BEACH...GRAYLAND...HUMPTULIPS AND CARLISLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORRENTIAL RAINFALL WAS ALSO OCCURRING WITH THESE STORMS...AND MAY
LEAD TO LOCALIZED FLOODING. DO NOT DRIVE THROUGH FLOODED ROADWAYS.

FREQUENT CLOUD TO GROUND LIGHTNING WAS OCCURRING WITH THESE STORMS.
LIGHTNING CAN STRIKE 10 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

&&

LAT...LON 4732 12389 4681 12376 4679 12410 4680 12410
      4690 12413 4690 12409 4687 12409 4685 12406
      4690 12405 4696 12383 4698 12399 4703 12403
      4704 12413 4703 12415 4697 12414 4695 12410
      4693 12417 4693 12418 4710 12417 4729 12424
TIME...MOT...LOC 1534Z 252DEG 39KT 4723 12430 4682 12444

JOHNSON

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SEATTLE WA
840 AM PDT FRI OCT 14 2016

WAZ507-510-511-555-141630-
ADMIRALTY INLET AREA-HOOD CANAL AREA-EAST PUGET SOUND
LOWLANDS-EVERETT AND VICINITY-
840 AM PDT FRI OCT 14 2016

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN KITSAP...
SOUTHEASTERN ISLAND...WEST CENTRAL SNOHOMISH AND EASTERN JEFFERSON
COUNTIES UNTIL 930 AM PDT...

AT 839 AM PDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR
PORT LUDLOW...OR 13 MILES WEST OF EDMONDS...MOVING NORTHEAST AT 50
MPH.

PEA SIZE HAIL AND WIND GUSTS TO 50 MPH WILL BE POSSIBLE WITH THIS
STORM.

LOCATIONS IMPACTED INCLUDE...
MARYSVILLE...CAMANO...LANGLEY...SMOKEY POINT...WEALLUP LAKE...
CATHAN...WARM BEACH...JOHN SAM LAKE...FREELAND...
AND STIMSON CROSSING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORRENTIAL RAINFALL WAS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO LOCALIZED FLOODING. DO NOT DRIVE THROUGH FLOODED ROADWAYS.

&&

LAT...LON 4815 12211 4808 12233 4804 12237 4805 12229
      4792 12243 4800 12248 4797 12254 4787 12251
      4778 12269 4787 12259 4793 12262 4781 12273
      4814 12246 4806 12238 4807 12240 4807 12247
      4805 12244 4804 12240 4809 12232 4817 12237
TIME...MOT...LOC 1539Z 215DEG 44KT 4786 12267

JOHNSON