River Flood Warning 26, NWS Seattle, WA

Area Forecast Discussion
National Weather Service Seattle WA
330 PM PDT Sat Nov 3 2018

.SYNOPSIS...Rain will continue tonight with heavy amounts in the
mountains. Expect gusty winds on the coast and interior with a
cold front tonight. Onshore flow will continue into Sunday for
additional showers. Moist northwesterly flow aloft will persist
into Tuesday with the best chance for showers in the mountains. An
upper level ridge will build offshore in the middle of next week
for a brief dry spell. Another weather system will reach the area
late next week.

&&

.SHORT TERM...Expect more rain (heavy in the mountains) and
blustery winds tonight as the next Pacific frontal system moves
in.

Rain is over much of Western Washington this afternoon with a warm
front. The cold front will shift S/SE and inland tonight for
additional showers and blustery conditions. The mountains will see
another 1-3 inches of rain, keeping the rivers running high - a
Flood Watch remains in effect. In addition, expect south winds of
20-35 mph with gusts to 40-50 mph in the central coast and
interior - Wind Advisories are in effect. Showers and gusty winds
will taper off early Sunday mornings as this system exits.
However, we'll likely see a Puget Sound Convergence Zone over the
central sound. Showers with the PSCZ will likely affect King
county through much of the day, then diminish during the evening.

The flow will remain onshore through Monday with isolated to
scattered showers, mainly over the coast and mountains. We may see
showers in the central sound with another convergence zone.
Temperatures will be close to normal.

Showers will linger into Tuesday as moist onshore flow continues
an a weak upper level disturbance drops down from B.C. Snow
levels will be lower, around 3000-4000 feet, with a few inches of
snow in the mountains, including the higher passes. 33

.LONG TERM...An upper level ridge will bring drier weather
Wednesday and Thursday across the Pac NW. We'll likely see morning
fog in the lowlands but should see some sun breaks in the
afternoon. Thursday morning will be cooler with lows in the 30s.
The ridge may keep the region dry into Friday although the GFS
does show some moisture clipping the area from a weak system over
B.C. It looks like the flow will turn more zonal over the weekend
as the ridge flattens and a trough moves inland. This will bring
more moisture to the region as our next Pacific frontal system
arrives. 33

&&

.AVIATION...Strong wly flow aloft will prevail over the region
thru tonight. Expect an upper level trof and associated cdfnt to
move across the area late tonight or early Sunday. Low level
southerly flow will strengthen tonight ahead of the cdfnt. Expect
wdsprd MVFR CIGs and areas of MVFR VSBYs. The mtns will be obscd.

KSEA...Ceilings should generally remain in the 1-3K ft range thru
midmorning Sunday. The visibility will occasionally lower in the
3-5SM range through tonight. VFR conditions are anticipated from
midmorning Sunday onward. Southerly winds will increase to 10-20
knots, with occasional gusts near 35 knots, overnight before
gradually diminishing during the day Sunday.

&&

.MARINE...Strong southerly flow will develop ahead of a cold front that
will move southeast across the area late tonight or early Sunday.
Expect strong onshore or westerly flow behind the front. Gale
force winds are expected over all waters ahead of or behind the
front. Onshore flow will weaken Sunday afternoon. Light onshore
flow will prevail Sunday night and Monday.

&&

.HYDROLOGY...A front will bring another shot of heavy rain to the
mountains with 1.5 to 3.0 inches tonight. Snow levels, while not as
high as yesterday, will still be in the 6000 foot range. The heavy
recent heavy rains have moistened the soils adding to the potential
for more run-off. Hydrographs show the usual suspects (the Nooksack,
Stillaguamish, Snoqualmie and Tolt rivers) all cresting near flood
stage Sunday into early Monday. A flood watch is in effect for
Whatcom, Snohomish and King counties.

No additional river flooding is expected next week. Schneider

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory from 8 PM PDT this evening to 4 AM PST Sunday for
     Admiralty Inlet Area-Bellevue and Vicinity-Bremerton and
     Vicinity-Central Coast-Everett and Vicinity-San Juan County-
     Seattle and Vicinity-Tacoma Area-Western Skagit County-
     Western Whatcom County.

     Flood Watch from Sunday morning through late Sunday night for
     Bellevue and Vicinity-Cascades of Snohomish and King
     Counties-Cascades of Whatcom and Skagit Counties-East Puget
     Sound Lowlands-Everett and Vicinity-Seattle and Vicinity-
     Western Whatcom County.

PZ...Small Craft Advisory until 4 AM PST Sunday 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.

     Gale Watch from 6 PM PDT this evening through late tonight for
     Admiralty Inlet-East Entrance U.S. Waters Strait Of Juan De
     Fuca-Northern Inland Waters Including The San Juan Islands.

     Small Craft Advisory until 6 PM PDT this evening for East
     Entrance U.S. Waters Strait Of Juan De Fuca-Northern Inland
     Waters Including The San Juan Islands.

     Small Craft Advisory until 2 AM PST Sunday for West Entrance
     U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory from 6 PM PDT this evening to 5 AM PST
     Sunday for Puget Sound and Hood Canal.

&&

www.weather.gov/seattle