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National Weather Service Area Forecast Discussion for Seaside, OR USA

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fxus66 kpqr 201726 cca
afdpqr

Area Forecast Discussion...correction
National Weather Service Portland, OR or
955 am pdt wed sep 20 2017

.synopsis...showers across northwest oregon and southwest washington
as an upper low moves over the area today. cold air aloft will
continue to keep snow levels low and allow a few thunderstorms to
develop over the area today. brief heavy showers are possible today
but will become lighter after sunset. the primary upper
trough/low will linger over washington and oregon thursday then
slowly move east by the weekend, with showers slowly decreasing. high
pressure builds in over the weekend and continues into early next
week for some great late september weather in store for the region,
with cool nights with patchy fog but mild sunny days.
&&

.short term...today through friday...deformation band precipitation
associated with upper low and surface trough is near, and north of
the columbia river this morning with some moderate showers to the
south over the remainder of northwest oregon. snow levels will be
near their lowest levels today, between 5000 and 5500 feet in the
north with some snow down to as low as 4500 feet as the cold air
associated with the upper tough moves over. don`t expect much
accumulation below 5000 feet but i have extended the winter weather
advisory through early evening for the higher elevations. snow will
taper off this evening. model soundings agree that there should
still be enough instability this afternoon for a continued threat of
thunderstorms. there is not as much shear today as yesterday as the
upper jet shifts south but surface heating from sunbreaks should
allow for some isolated stronger storms.

a threat of flash flooding will still exist this afternoon in
possible heavy showers but that threat will decrease after sunset as
heavier shower decrease. will extend the flash flood watch through
early evening and then the threat will end for the next week as
ridging and dry fall weather returns. schneider


.long term...friday night through tuesday...no updates, previous
discussion follows. an upper ridge builds over the ne pacific this
weekend and slowly expands into the pacific northwest early next
week as the inland upper low finally but slowly moves eastward. this
will bring drying and warming to the area, though the warming will
be more of the fall variety than of the summer variety as the ground
is wetter and we will probably see areas of radiational morning low
clouds and fog as nights are lengthening and cooling. the models
show some energy riding over the upper ridge to our north that may
keep some low clouds along the south washington and far north oregon
coasts at times, especially in the nights and mornings. tolleson &&

.aviation...mainly vfr conditions today with showers. brief mvfr
vis and/or cig possible with heavier showers. small chance of a
thunderstorm through the evening hours.

kpdx and approaches...vfr with showers and small chance of ts.
possible brief mvfr with any heavier showers. bowen

&&

.marine...dropped small craft advisory for the waters within 10
nm of the coast this morning as buoys have been reporting
winds below 20 kt. seas dropping as well, but still 10 ft at buoy
89, so kept sca in place for offshore waters. seas may still come
up a little bit to as high as 11 ft before finally dropping below
10 ft tonight or early thursday morning.

quieter marine weather is expected by late this week and into
the weekend as typical summertime northerlies return to the area.
bowen

&&

.pqr watches/warnings/advisories...
or...winter weather advisory until 8 pm pdt this evening for
     northern oregon cascades.

     flash flood watch until 8 pm this evening for cascades in lane
     county-central columbia river gorge-northern oregon
     cascades-western columbia river gorge.

wa...winter weather advisory until 8 pm pdt this afternoon for south
     washington cascades.

pz...small craft advisory for winds until 2 pm pdt this afternoon
     for waters from cape shoalwater wa to cascade head or from
     10 to 60 nm-waters from cascade head to florence or from
     10 to 60 nm.

     small craft advisory for hazardous seas until 5 am pdt thursday
     for waters from cape shoalwater wa to cascade head or from
     10 to 60 nm-waters from cascade head to florence or from
     10 to 60 nm.

     small craft advisory for rough columbia river bar until 1 pm
     pdt this afternoon.

&&

$$

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

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