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National Weather Service Area Forecast Discussion for Long Beach, WA USA

fxus66 kpqr 241724 rra

Area Forecast Discussion
National Weather Service Portland, OR oregon
1024 am pdt sat sep 24 2016

.synopsis...higher pressure builds in today over the pacific nw,
shunting a warm front north towards british columbia sunday. the
center of the high will shift east of the cascades sunday, bringing
offshore flow to the region for dry and warmer weather through
monday. a weak cold front will sag into nw oregon on tuesday.

.short term...(today through monday) weak high pressure will continue
to build in over the pacific northwest today as an upper level ridge
builds offshore. there is still a solid deck of low clouds and
patchy fog in the interior valleys along interstate 5, and this will
take until sometime in the afternoon before it will clear, and have
slowed down that clearing in the grids and the forecast. the coast
was already clearing. overall, this will bring a dry day today with
moderating temps.

models indicate the upper ridge shifting east over the pacific nw
sunday, pushing the surface high east of the cascades. 500 mb heights
are quite high with this ridge topping 590 dm, while projected 850 mb
temps over the interior top out between 18 and 20 deg c sunday. the
moist ground is likely to allow for development of fog and perhaps
some low clouds again sunday morning, but models do not appear to
suggest the fog/clouds would be as long lived as today, which would
allow for substantial warming in the afternoon. model soundings
indicate it is not likely to see mixing all the way up to 850 mb, but
still enough warming that most of the interior low elevations ought
to top out with a high temp somewhere over 80. the ridge is expected
to continue to progress east monday with a little more east flow
through the gorge monday morning than on sunday, so expect whatever
fog and low clouds that do develop will be rather short lived. monday
should be pleasant much like sunday.

onshore flow returns late in the day monday ahead of the next system
expected to increase clouds monday night and tuesday. tolleson

.long term...(monday night through friday) changes. previous
discussion follows. a weak upper-level shortwave moves north of us on
tuesday bringing a weak surface front across the area. this front
will bring clouds and turn winds back onshore and cool down
temperatures midweek. the south washington and far north oregon coast
may see a trace of drizzle or light rain, but everywhere else should
remain dry. zonal flow with continued low-level onshore winds will
keep temperatures cool and weather fairly nice wednesday and
thursday. will see increasing clouds thursday night ahead of our next
system. there is some uncertainty on the timing with this system, as
the gem wants to bring it in thursday night, but leaned toward the
gfs and ecmwf which are in fairly good agreement that rain will move
in friday morning. this looks to be another stingy system in the way
of precipitation.  will have a widespread chance for rain, but
amounts do not look very impressive. weather going into next weekend
right now looks to continue to be cool and showery as an upper-level
trough remains over the area.  -mccoy

.aviation...fog and low stratus will continue to bring reduced flight
conditions to interior taf sites this morning. most inland sites have
improved above airport minimums this morning, but expect lifr cigs to
persist through around 18z. low stratus in the interior will be slow
to scatter today, with ifr/mvfr cigs likely through around 21z. vfr
conditions expected this afternoon and tonight. patchy fog or low
stratus possible sun morning at khio, ksle and keug.

meanwhile, a slight offshore drift along the coast has allowed
conditions to improve to vfr. however, there could be brief periods
of ifr cigs through around 18z as stratus deep in the coastal gaps
move across the terminal. offshore flow strengthens later today and
should keep conditions vfr through sun.

kpdx and approaches...low stratus will continue to bring ifr/lifr
cigs trough around 19z. status looks to scatter out shortly after
that, with vfr conditions expected by 20z. vfr conditions continue
into sun. east winds near the columbia river gorge should prevent low
stratus sun morning. /64

.marine...seas finally fell below 10 ft earlier this morning and are
currently around 8 ft. expect seas near 5 to 7 ft to continue through
monday. winds will not be much of an issue today due to high pressure
and weak pressure gradients. however, n winds will ramp up sunday to
near sca criteria with gusts to 25 kt possible. similar conditions
expected monday, then brief easing mon night/early tue as a dry cold
front moves through. behind that front, expect another surge of n
winds later tue into wed as strong high pressure builds offshore.

.pqr watches/warnings/advisories...
pz...small craft advisory for rough columbia river bar until 2 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. the area is commonly
referred to as the forecast area.

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