Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 120407

Area Forecast Discussion
National Weather Service Seattle WA
915 PM PDT Sun Mar 11 2018

.SYNOPSIS...An upper level ridge over the area will shift east
tonight through Monday night. Offshore flow will increase through
Monday night as a frontal system approaches from the southwest. High
temperatures on Monday will be well above normal. Rain will return
Tuesday as a front moves through the area. A cool upper level low
will keep a chance of showers in the forecast later in the week.


.SHORT TERM...Skies will be clear tonight and Monday. Overnight lows
will be in the 30s and low 40s. Highs Monday will be in the 60s and
low 70s. These will be record high temperatures in many places.
While most of the guidance remains in the 60s Monday, the offshore
flow will likely be strong enough that areas near the Cascades and
Olympics and any areas exposed to easterly winds will see
temperatures around 70 and possibly a bit higher.

Monday night will remain mild as easterly flow continues. In fact,
Seatac airport may remain in the 50s Monday night.

Rain with the incoming front will move onto the coast late Monday
night and will likely wait until Tuesday late morning in the
interior. With the clouds and increased moisture, Tuesday will be
much cooler with highs in the 50s. Albrecht/Burke

.LONG TERM...Previous discussion...Models continue to show the
offshore upper low dropping west of the area late Tuesday into
Wednesday then well south of the area mid to late week. The GFS
continues to keep moisture mainly just to the south of the forecast
area while the ECMWF brings short wave energy wrapping around the
upper low into our area. Next weekend, models show energy dropping
into the west coast trough from the northwest (each model and
solution slightly different). Forecasts will continue to show partly
to mostly cloudy conditions with slightly below normal to near
normal temperatures for mid to late March through the period.


.AVIATION...Southerly flow aloft will continue through Monday. An
approaching front will slowly increase the speed of the wind aloft.
At the surface, offshore flow will continue, and increase on Monday.
The air mass is dry and stable with no virtually no clouds over
Western Washington.

KSEA...Northeast wind 5-10 kt. CHB


.MARINE...Offshore flow will continue through Monday. Small craft
advisory winds are likely at times near the west entrance. An
approaching front will also bring winds up to small craft advisory
levels over the outer coast.

A front will turn winds southerly on Tuesday. Small craft advisories
are likely on the coast and possible over some inland waters.
Low end gale force winds are possible on the coast. CHB


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


PZ...Small Craft Advisory until 5 PM PDT Monday 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 Point Grenville To Cape Shoalwater 10
     To 60 Nm-West Entrance U.S. Waters Strait Of Juan De Fuca.


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