Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 121725

Area Forecast Discussion
National Weather Service Seattle WA
925 AM PST Fri Jan 12 2018

.SYNOPSIS...Showers will linger over Western Washington today in
the wake of yesterday`s front. A weak warm front will lift
northeast across the area tonight into Saturday morning for a bit
more rain. Sunday will be dry and mild as an upper ridge moves
across the area. Several fronts will move through the region next
week for a return to wet weather.


.SHORT TERM...Some showers will linger today in moist westerly
flow aloft but it should be more dry than wet overall, at least
for the lowlands. The mountains will be drippy most of the day. A
warm front will clip the area tonight and Saturday morning. Most
areas will get a little light rain but the heavier QPF will be
towards the coast and over the northwest interior and north
Cascades. Precipitation should end Saturday afternoon or evening
as an upper ridge builds into the area. Sunday should be dry and
mild with the upper ridge overhead. Schneider

.LONG TERM...Previous discussion...The upper ridge will move
further east of the forecast area on Monday, and a front should
bring wet weather back to Western Washington. Models agree that a
wet pattern will continue for the long term forecast period Monday
through Thursday. They disagree considerably on details, but we
can expect a trough to follow the Monday front, then another front
on Wednesday, followed by another trough on Thursday. The snow
level will be mainly 4000 to 5000 feet during this period of
active weather. I have increased POPs somewhat through the long
term period. McDonnal


.AVIATION...Weak low pressure will dissipate over WA today. Another
warm front will brush the area tonight into early Saturday. Light
to Moderate Southwest flow aloft. The low level air mass is moist
with a mix of IFR/MVFR/VFR cigs. KCLM/KPWT may only improve prove
to MVFR briefly this afternoon. KOLM north to KPAE should see
improvement to low VFR at times. Light rain will increase near the
coast and parts of the interior, especially north of KOLM by this
evening. Expected areas of MVFR and some IFR at KPWT/KCLM.

KSEA...A few residual showers possible today but cigs should improve
from MVFR to VFR this afternoon. Light rain should pick up this this
evening as a warm front brushes the area. Cigs may fall back to MVFR
tonight. S wind 15 to 25 kt, easing to 8-12 kt by this evening.


.MARINE...A weak low around Admiralty Inlet will produce small
craft winds over Puget Sound, especially from Seattle northward.
Meanwhile, west swells of 10 to 14 feet are over the Coastal
Waters will subside to around 10 feet tonight. Southerly flow will
increase tonight as a warm front clips the area. A weak cold
front will approach from the west on Sunday then dissipate
offshore. Stronger frontal systems are slated for Monday and
Tuesday. dtm


.HYDROLOGY...River flooding is not expected for the next 7 days.


PZ...Small Craft Advisory until 10 AM PST Saturday 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 for rough bar until 4 AM PST Saturday for
     Grays Harbor Bar.

     Small Craft Advisory until 4 PM PST this afternoon for West
     Entrance U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory until 6 PM PST this evening for Puget Sound
     and Hood Canal.


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