FXUS66 KSEW 190403
Area Forecast Discussion
National Weather Service Seattle WA
902 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 followed by showers and near
normal temperatures through the weekend.
.SHORT TERM /TONIGHT THROUGH THURSDAY/...A very mild
evening following record high temperatures this afternoon. Records
were set at KSEA, KOLM, KHQM and KUIL. The upper level ridge will
shift eastward tonight and into Tuesday. Even so, very fine weather
will continue Tuesday with sunny skies and another run at record
high temperatures- with highs mostly in the 70s.
The upper level ridge axis will be over the northern Intermountain
area by Wednesday morning with weakening offshore flow. Flow may in
fact be weakly onshore along the coast. This will be the beginning of
a cooling trend highs over the interior near 70 and in the low to
mid 60s along the coast.
Southerly flow aloft on Thursday with a weak upper trough that will
bring some moisture into the area - mainly the coast and over the
Olympics. In a broader sense there will be more clouds, with onshore
flow - and near normal temperatures with highs in the mid 50s to low
.LONG TERM /FRIDAY THROUGH MONDAY/...from previous
discussion...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 with
southeasterly flow aloft. The air mass will remain stable and dry.
Low level offshore flow with VFR conditions. Northeasterly winds 5-
15 knots, with a few gusts up to 28 knots possible this evening.
KSEA...VFR conditions. Easterly winds 8-10 knots with gusts to near
28 knots possible this evening. Winds will become northeasterly 5-8
knots around 05Z.
.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
.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 Central U.S.
Waters Strait Of Juan De Fuca-Coastal Waters From Cape
Flattery To James Island Out 10 Nm-West Entrance U.S.
Waters Strait Of Juan De Fuca.
Small Craft Advisory until 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.
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