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National Weather Service Area Forecast Discussion for Seaside, OR USA

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fxus66 kpqr 292214
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Area Forecast Discussion
National Weather Service Portland, OR or
314 pm pdt sat apr 29 2017

.synopsis...low pressure moving into british columbia will bring a
frontal system through the region tonight. light rain will spread
into the north coastal areas later this afternoon, then across
the area tonight. there will be post-cold frontal showers early
sunday, with showers decreasing through the day. another weak system
will likely bring light rain monday into monday night. higher
pressure will bring dry and much warmer weather to the area during
the mid week period, though a warm front might get close to brushing
the far north coast tuesday. an upper level trough is modeled to
approach the pac nw late thursday into fri and may linger into the
weekend. this will bring increasing precip chances and cooler
weather.

&&

.short term...tonight through tuesday...conditions are dry across
most of the region this afternoon as an upper level ridge resides
over the pac nw. however, the ridge axis is now east of the cascades
and high clouds are increasing ahead of the next approaching frontal
system. this frontal system is associated with occluding low pres
moving toward haida gwai today. the leading warm front will spread
light rain onto the south wa and far north or coast later through the
late afternoon, with rain spreading inland this evening. the cold
front will move through the region overnight.  overall rainfall
amounts through the overnight period will not be all that impressive,
with less than 0.25 inch over the interior lowlands.
the coast and higher terrain of the coast range and cascades should
generally be in the 0.25-0.5 inch range with locally higher amounts
possible.

there will be some post-frontal showers around sunday. there is not
much cold air aloft moving in behind this front, so instability will
be limited and showers should be pretty weak. the best showers should
be in the morning, with decreasing activity in the afternoon. the
airmass will be cooler, with 850 temps modeled to drop back below 0c.
this should limit high temps in the upper 50s for the lowlands.

there will be a break later sun into early mon. then the fcst models
in decent agreement that another weak low will form offshore along
the stalled baroclinic zone from tonight`s system, bringing the front
back north as a warm front during the day mon. expect rain chances to
increase mon afternoon and mon night. the system is weak enough that
confidence is not all that high that all locations will see
measurable rainfall.

the ne pac upper level ridge will strengthen significantly over the
pac nw on tue. this should mean mainly dry conditions tue, with much
warmer temps. highs over the interior lowlands will likely reach into
the mid to upper 60s. there is a slight chance that a weak warm front
will brush the far northern coastal zones with some light rain later
tue. pyle

.long term...tuesday night through saturday...the fairly strong upper
level ridge is expected to remain over the region through wed. the
model 850mb temps warm considerably wed, suggesting high temps well
into the 70s are likely for the interior lowlands. the ridge axis
shifts further east into the interior nw thu, which allows a fairly
deep trough to approach the coast later thu and fri. the fcst models
bring increasing precip chances thu afternoon, will the potential for
some thunderstorm activity. highs on thu expected to remain several
degrees above normal. precip chances continue fri and sat as the
trough shifts directly over the region, with temps cooling off
considerably. pyle

&&

.aviation...high pressure over the pacific northwest will bring
vfr conditions through early this evening. however, an incoming
front will bring a period of rain and lowering cigs overnight. a
mix of mvfr and ifr conditions appear likely to develop along
the coast between 00-06z sunday and mvfr restrictions should
become fairly widespread inland between 06-12z sunday.

kpdx and approaches...high pressure over the pacific northwest
will bring vfr conditions through this evening. however, an
incoming front will bring a period of rain and lowering cigs
overnight with mvfr restrictions likely to develop between 06-12z
sunday. /neuman

&&

.marine...a front dropping southeastward will bring small craft
advisory level wind gusts of 25 to 30 kt to the waters late this
afternoon and evening. the central oregon waters may have a hard
time reaching these thresholds, but will keep the advisory going
for now given they could still see a couple hours of 21 to 25 kt
gusts, but it admittedly looks marginal at best. high pressure
will then shift back over the waters sunday and monday and bring
more quiet weather. after a weak front skirts the waters late
monday or early tuesday, a summer-like northerly wind pattern
should develop for a couple days towards the middle of next week.
a westerly swell approaching 10 ft may impact the waters late in
the week, but confidence in this scenario is low. /neuman


&&

.pqr watches/warnings/advisories...
or...none.
wa...none.
pz...small craft advisory for winds until 1 am pdt sunday for
     coastal waters from cape shoalwater wa to cascade head or
     out 60 nm.

     small craft advisory for winds until 1 am pdt sunday for
     coastal waters from cascade head or to florence or out 60
     nm.

&&


$$

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this discussion is for northwest oregon and southwest washington
from the cascade crest to 60 nautical miles offshore. the area is
commonly referred to as the forecast area.

Information courtesy of the National Weather Service - NWS Portland...
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