FXUS66 KSEW 182152

Area Forecast Discussion
National Weather Service Seattle WA
300 PM PDT Mon Mar 18 2019

.SYNOPSIS...A strong upper level ridge along with low level offshore
flow will give another day of record breaking high temperatures on
Tuesday. A weak front arriving from the south could bring showers to
western sections on Thursday. Another weakening front will bring
some rain later Friday and Friday night. An upper trough will bring
some showers and near normal temperatures over the weekend.


.SHORT TERM /TONIGHT THROUGH THURSDAY/...Satellite imagery shows
zero clouds over the region. High temperatures have broken records
today at KSEA and KUIL, so far, with some other places flirting with
records. Tuesday should bring more of the same--sun and record high
temperatures, with highs mostly in the 70s. The upper ridge will
have drifted to the northeast a bit, but surface flow will still be

A slow cooling trend will commence Wednesday, with the upper level
ridge far enough away that heights over Western Washington will be
distinctly lower. Offshore surface flow will still keep temperatures
up over the interior, with highs near 70. Flow will probably turn
onshore at the coast, giving lower temperatures there, with highs
in the low to mid 60s.

Upper flow will become more southerly on Thursday. Models have a
weak upper trough which allows a little moisture into the area. Have
followed ensemble means which have low chance pops on the coast and
over the Olympics on Thursday. There will be more clouds, and the
offshore surface flow will be gone, so highs will be in the mid 50s
to low 60s. Burke

.LONG TERM /FRIDAY THROUGH MONDAY/...Models have a negatively tilted
trough reaching the coast Friday afternoon and moving inland Friday
night. Though the front may be falling apart as it moves inland, it
is probably good for at least one period of categorical pops Friday
night or Saturday. Precipitation will turn more shower Saturday
afternoon and showers will taper Sunday. Monday looks pretty dry as
an upper ridge briefly builds over the area. Temperatures will be
normal to a little above normal through the period. Burke


.AVIATION...Upper level ridge over western Washington will keep the
air mass stable and dry. Easterly flow aloft will turn more
southeasterly later this afternoon. Surface high pressure area over
southern British Columbia and east of the Cascades will lead to
continued offshore flow at the surface. Expect VFR conditions to
continue. Winds generally northeasterly from 5-15 knots, a few
easterly gusts up to 28 knots around the Puget Sound into this

KSEA...VFR conditions. Easterly winds will continue through this
evening becoming more northerly into tonight. Winds generally up to
15 knots with gusts near 28 knots through this evening. JD


.MARINE...Offshore flow will continue with surface high pressure
east of the Cascades. Breezy winds near the gaps in coastal terrain.
Strongest east wind is expected to be at the West Entrance of the
Strait of Juan de Fuca. Offshore flow will continue into tomorrow
before easing middle of the week with the return of fronts later
this week.


.HYDROLOGY...River flooding is unlikely over the next seven days.


PZ...Small Craft Advisory until 5 AM PDT Tuesday for 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 11 AM PDT Tuesday for Coastal Waters
     From Cape Flattery To James Island Out 10 Nm-West Entrance
     U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory from 11 PM this evening to 5 AM PDT Tuesday
     for Coastal Waters From James Island To Point Grenville 10
     To 60 Nm.

     Small Craft Advisory from 2 AM to 11 AM PDT Tuesday for Coastal
     Waters From Cape Flattery To James Island 10 To 60 Nm.

     Small Craft Advisory until 11 PM PDT this evening for Puget
     Sound and Hood Canal.




NWS SEW Office Area Forecast Discussion

Discussion Script by Ken True at Saratoga Weather - WFO Script by SE Lincoln Weather