Small Craft Advisory 72, NWS Seattle, WA

Area Forecast Discussion
National Weather Service Seattle WA
945 AM PDT Tue Apr 10 2018

.SYNOPSIS...A vigorous cold front will bring windy rainy weather
to Western Washington this morning, with sun breaks and showers in
the afternoon. Another front will bring more rain on Wednesday.
Wet weather will continue later this week and into the weekend as
additional systems move through the area.

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.SHORT TERM...A front will move inland this morning with rain
changing to showers. Wind advisory strength southerly winds look
on track for the coast and north interior today. There will be a
relative lull tonight then another front will move through the
area Wednesday. Wind advisory headlines might be needed in the
same areas again with this system although the winds look slightly
weaker. Snow levels will be lower on Wednesday...3500 to 4000
feet...and the Volcanoes will probably get advisory amounts of
snow during the day. The higher passes should receive below
advisory amounts and it will be mostly rain at Snoqualmie Pass. A
couple of upper troughs will transit the area Wednesday night and
Thursday for showers. Snow levels will be 2000-2500 feet which is
pretty low for this late in the season. Schneider

.LONG TERM...Previous discussion...An upper ridge will move
across the region around late Thursday night or Friday morning,
but the ridge will bring only a relative break in the weather.
Models agree that a fairly wet warm front will follow the ridge
later Friday or Friday night, with a trailing cold front dragging
slowly across the area Saturday and Saturday night. Then the upper
trough following the front is likely to bring cool showery
weather Sunday and Monday. McDonnal

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.AVIATION...A cold front was moving northeast across Western
Washington this morning. A few hours of gusty S-SW wind will
follow the front through early afternoon, then ease a bit late
afternoon and early evening. Another cold front will move east
across the area on Wednesday, bringing more rain. Wednesday's
front will be preceded by local areas of low-level wind shear.
Strong southwest flow aloft today will ease to moderate on Wed.
The air mass will be moist and modestly unstable.

KSEA...Cold frontal passage expected any minute now at the
terminal. It will be followed late morning and early this
afternoon by gusty S-SW wind gusts in the 25-30 knot range. Winds
will already by easing by mid-afternoon. Otherwise, a few
convective showers this afternoon. Prevailing cigs will remain
above 030. On Wednesday, another front will bring rain, reduced
vsbys, and cigs below 030 in the mid-day period, with the lowest
conditions coming from roughly 17z-22z Wed. Haner

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.MARINE...A negatively tilted cold front is currently moving
northeast across the waters. It will be followed late this morning
and early this afternoon by a surge of S-SW wind which could bring
gales to some waters. Overall, this S-SW surge is not looking as
strong as was forecast yesterday.

A more north-south oriented cold front will move across the waters
during the day on Wednesday. Strongest gradients will precede the
front, with E-SE gradients in the pre-frontal environment. SW
gradients behind the front late Wed will not be strong.

An occluded front will sail eastward across the waters on
Thursday. Strong southeast gradients will develop on Friday on the
equatorward side of a strong SW-NE oriented front that will drape
itself across Vancouver Island.  haner

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.HYDROLOGY...The accumulation of rainfall during the next several
days could eventually drive the exceptionally flood-prone
Skokomish River above flood stage by Friday or, more likely,
Saturday. Otherwise river flooding is not expected during the next
7 days. McDonnal

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.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory until 3 PM PDT this afternoon for Admiralty Inlet
     Area-Central Coast-Everett and Vicinity-North Coast-San
     Juan County-Western Skagit County-Western Whatcom County.

PZ...Small Craft Advisory for rough bar until 11 AM PDT Wednesday for
     Grays Harbor Bar.

     Gale Warning until 5 PM PDT this afternoon 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-West Entrance U.S. Waters Strait Of
     Juan De Fuca.

     Gale Warning until 3 PM PDT this afternoon for Admiralty Inlet-
     Central U.S. Waters Strait Of Juan De Fuca-East Entrance
     U.S. Waters Strait Of Juan De Fuca-Northern Inland Waters
     Including The San Juan Islands.

     Small Craft Advisory until 9 PM PDT this evening for Puget Sound
     and Hood Canal.

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