Scientific Forecaster Discussion
fxus66 ksew 132218
Area forecast discussion
National Weather Service Seattle Washington
315 PM PDT sun Oct 13 2019
Synopsis...an upper level ridge will build offshore tonight before
moving into western Washington later Monday. This ridge shifts east
Monday night. Rain out ahead of the first in a series of fronts to
move through the area reaching the coast Tuesday afternoon. The wet
weather will continue into the weekend.
Short term /today through Tuesday/...satellite trend shows clouds
thinning a bit over West Washington this afternoon with some peeks of clear sky
a bit inland from the coast. The remainder of the area still has
some cloudiness in place...but with the aforementioned thinning
trend likely still a chance or two for some sunshine to sneak
Models remain pretty consistent showing an upper level ridge over
the Pacific already starting to exert its influence over the area
now and allow for dry conditions to persist Monday and even into
Tuesday morning as it makes its way across the area during that
time. The slow approach for the next system looks to be still in the
cards as models agree that the front will make it to the coast as
early as late Tuesday morning...but does not really make a push
inland until Tuesday night.
High temperatures will be on a slight rise...gaining about a degree
a day...over the short term thanks in part to the aforementioned
ridge...with most low elevation locations getting into the upper 50s
to around 60 while overnight lows will remain static ranging from
the upper 30s to mid 40s.
Given both consistency and agreement in the models...minimal changes
made to inherited forecast. Smr
Long term /Wednesday through Saturday/...with the arrival of the
aforementioned front...looking at a change for the wetter with
regards to weather over West Washington as a series of systems will keep precip
in the forecast throughout the long term. The strongest of these
still looks to be Wednesday bringing breezy to windy
conditions...particularly to the coast and northwest interior. As one would
expect with the sun going on an extended sabbatical...temps will
cool throughout the long term with afternoon highs for lowland
locations starting at a High Point in the mid 50s Wednesday before
falling into the lower 50s. With the lingering clouds though...this
will be good news for overnight lows as they will remain steadily in
the mid to upper 40s. Smr
Aviation...partly to mostly cloudy skies this afternoon should
clear out finally this evening. That should set the stage for areas
of low clouds and fog patches to develop overnight later tonight
into Monday morning followed by a mostly sunny day on Monday. The
air mass will dry and become stable tonight with clearing before
areas of low level clouds and fog patches develop.
Ksea...the clouds this afternoon should clear out this evening and
then late night and morning low clouds and perhaps some fog is a
good bet for Monday morning.
Marine...weak high pressure will shift over the area through
Monday. The first in a series of vigorous fronts will arrive late in
the day Tuesday through the end of the week. Periods of Small Craft
Advisory strength winds are likely with gales possible.
Hydrology...a series of wet systems moving through the area
Tuesday night into the weekend will cause rivers to rise, but
flooding is unlikely over the next seven days.