Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA
FXUS66 KSEW 242133
Area Forecast Discussion
National Weather Service Seattle WA
230 PM PDT Mon Oct 24 2016
.SYNOPSIS...A front over Western Washington will weaken and move
inland overnight. A wetter system will move into the area midweek.
Weak weather systems will bring a chance of rain at times for the
latter part of the week.
.SHORT TERM...One front will move through Western Washington this
evening. There is a strong low pressure system associated with the
front offshore, but the low is moving north, drifting away from the
area. There are a few thunderstorms offshore behind the front and so
there is a chance of showers and isolated thunderstorms for the
coast and coastal waters through Tuesday. The chance of showers
Tuesday will end Tuesday night as the deep low continues to drift
away from the area. The next front will be wetter and is due in on
Wednesday and wet weather will persist into Wednesday night with
heavy rain possible in the Olympics.
.LONG TERM...Weaker weather systems will bring a chance of showers
or a little rain at times. It is pretty hard to get away from the
forecast for a chance of rain in what has been a pretty wet overall
weather pattern for October, but if the 12z GFS is right, Friday
might be the best day of the week.
.HYDROLOGY...The front Wednesday and Wednesday night looks pretty
wet so we will be looking at the QPF and thinking about the
Skokomish river in Mason county as the models come in tonight and
Tuesday. The earliest the river could flood if there is enough rain
in the Olympics would be around daybreak Thursday.
.AVIATION...A front will move inland this evening with southerly
flow aloft. Moist southerly flow aloft will continue tonight and
Tuesday. A deep surface low - around 970 mb - will track north
near 130W tonight and Tuesday. This will maintain drier easterly low
level flow with moisture at mid and upper levels.
KSEA...Mid and high clouds tonight and Tuesday. South wind 5-10
knots, increasing to 10 to 15 knots Tuesday. Schneider
.MARINE...A 975 mb low will move slowly northward about 300 miles
west of the Washington coast tonight, bringing gales to the
Coastal Waters, Entrances to the Strait, and Northern Inland
Waters. The low will weaken and move toward Haida Gwaii Tuesday with
winds across the waters slowly easing.
A second low - 990-995 mb - will track northward inside 130W
Wednesday afternoon or Wednesday evening. The models are not in
good agreement with the timing of the low passage. There will
probably be another round of gales with this low at some point
but it is hard to pin down specifics for now. The wind forecasts for
Wednesday and Wednesday night are currently a bit tempered as a
Low level flow will turn offshore on Thursday and remain
offshore on Friday. Schneider
PZ...Gale Warning until noon PDT Tuesday for Coastal Waters From Cape
Flattery To James Island 10 To 60 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.
Small Craft Advisory for rough bar from 11 PM this evening to 5
PM PDT Tuesday for Grays Harbor Bar.
Gale Warning until noon PDT Tuesday for Coastal Waters From Cape
Flattery To James Island Out 10 Nm-Coastal Waters From
James Island To Point Grenville Out 10 Nm-Coastal Waters
From Point Grenville To Cape Shoalwater Out 10 Nm.
Gale Warning from 11 PM this evening to 3 PM PDT Tuesday for
East Entrance U.S. Waters Strait Of Juan De Fuca-Northern
Inland Waters Including The San Juan Islands.
Gale Warning from 6 PM this evening to noon PDT Tuesday for West
Entrance U.S. Waters Strait Of Juan De Fuca.
Small Craft Advisory from 6 PM this evening to 11 PM PDT Tuesday
for Central U.S. Waters Strait Of Juan De Fuca.
Small Craft Advisory from 11 PM this evening to 6 PM PDT Tuesday
for Admiralty Inlet-Puget Sound and Hood Canal.
You can see an illustrated version of this discussion at