Gale Warning 5, NWS Seattle, WA

Area Forecast Discussion
National Weather Service Seattle WA
919 AM PST Tue Jan 8 2019

.SYNOPSIS...Wind and rain return today and Wednesday as a frontal
system moves through Western Washington. A warm front will lift
north of the area on Thursday. An upper ridge will build over the
area later Thursday into Saturday and possibly into early next
week for a dry spell.

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.SHORT TERM.../TODAY THROUGH THURSDAY/ Gusty east winds will
continue today with highest winds in the East Puget Sound Lowlands
below the gaps (Enumclaw, North Bend, Gold Bar). The Wind
Advisory was expanded to cover the northern tip of the WA coast
and the western Strait of Juan de Fuca - east winds of 25 to 35
mph with gusts to 50 mph possible. Otherwise, rain in the lowlands
will continue with a few inches of snow in the passes. Heavier
accumulations are expected at Mount Rainier and a Winter Weather
Advisory remains in effect. 33

Previous discussion...Snow levels will rise today and tonight but
east winds will keep temperatures below freezing in the passes
through Wednesday morning. This means there could be some freezing
rain in the passes tonight and Wednesday morning. Snow amounts in
the mountains are expected to be sub-advisory. The exception is
Paradise on Mount Rainier where 5-10 inches is possible through
early this evening.

The offshore surface low will weaken and move north into British
Columbia north of Vancouver Island later Wednesday. This will turn
low level easterly flow more southeasterly and bring windy
conditions to the coast and north interior. A trailing frontal
wave will also push onshore during this period for an increase in
rain across the area again.

Rain will decrease across the area Wednesday night and Thursday as
an inland upper ridge builds and precipitation gets pushed north
and west of the area. It should be mainly dry by afternoon,
especially for the south interior. Schneider

.LONG TERM.../FRIDAY THROUGH MONDAY/ Previous discussion...A
blocking upper ridge over the interior will keep the weather dry
for Western Washington on Friday and Saturday. Models show the
upper ridge cutting off into an area of high pressure over
northern Idaho/Western Montana Sunday and Monday which keeps
precipitation at bay for Western Washington. This a bit of a new
wrinkle. For now, have kept a chance of rain in the forecast for
Sunday and Monday but this period might turn out to be dry.
Schneider

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.AVIATION...Light rain has spread over much of the area this morning
as a weather system arrives. Flow aloft will become increasingly
southerly today and tonight. At the surface, strong easterly flow
today will ease somewhat tonight. The air mass is moist and stable.
Some precipitation this morning will be mixed in the cold air mass.
Ceilings today and tonight will be mostly VFR, even in rain, as the
east winds dry out the lower air mass.

KSEA...VFR ceilings 4-6k ft today and tonight. Winds easterly 10-15
kts with occasional higher gusts. CHB

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.MARINE...A 972 mb low well west of the offshore waters will move
northeast and weaken slightly today and tonight. Low level offshore
flow will increase today as the low moves closer to the waters and a
warm front moves through the area. Gale force winds are occurring or
expected over the coast, west entrance, and northern inland waters.

Winds will ease slightly tonight then increase again on Wednesday
for another round of gales over the same areas as the trailing cold
front moves through the area. Another frontal system will reach the
area on Thursday. An offshore flow pattern will develop by the
weekend with higher pressure over the inland waters and lower
pressure offshore with winds easing into Saturday. Felton/CHB

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.HYDROLOGY...Rain over the south slopes of the Olympics through
Wednesday could push the flood-prone Skokomish River in Mason
County above flood stage Wednesday night. A flood potential
outlook has been issued to cover this possibility and a flood
watch may be need to be issued later this morning or this
afternoon if new rainfall forecasts show the river near or above
flood stage.

Otherwise, rainfall is not expected to be heavy enough to cause
flooding on other rivers across Western Washington for the next 7
days.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory until 6 AM PST Wednesday for East Puget Sound
     Lowlands.

     Winter Weather Advisory until 6 PM PST this evening for Cascades
     of Pierce and Lewis Counties.

     Wind Advisory until 6 PM PST this evening for North Coast-
     Western Strait of Juan De Fuca.

PZ...Gale Warning until 4 PM PST Wednesday 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.

     Small Craft Advisory until 6 PM PST Wednesday for Central U.S.
     Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
     Strait Of Juan De Fuca.

     Small Craft Advisory from 4 PM this afternoon to 6 PM PST
     Wednesday for Northern Inland Waters Including The San Juan
     Islands.

     Gale Warning until 4 PM PST this afternoon for Northern Inland
     Waters Including The San Juan Islands.

     Small Craft Advisory from 6 PM this evening to 6 PM PST
     Wednesday for West Entrance U.S. Waters Strait Of Juan De
     Fuca.

     Gale Warning until 6 PM PST this evening for West Entrance U.S.
     Waters Strait Of Juan De Fuca.

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