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

fxus66 kpqr 211018
afdpqr

Area Forecast Discussion
National Weather Service Portland, OR
230 am pst fri nov 21 2008

.synopsis...high pressure building over area early this morning
shifts into idaho this afternoon. warm front brushes far northern
coast this morning then cold front approaches late in the day. front
moves across area tonight moving east of area early saturday. high
pressure builds to south oregon coast saturday morning then into
central coast by late ion the day. high pressure shifts inland
saturday night turning flow offshore. high pressure remains over
idaho sunday giving area moderate offshore flow. weakening front
brushes coast and north monday. a little strong front moves into area
for tuesday. high pressure builds into area for wednesday. next front
moves into area on thursday.

&&

.short term...showers have decreased to a few isolated showers
northern coastal area and cascades this morning. high pressure
building into s central ore this morning shifts into ida this
afternoon. weak flow with moist low level ams will give low clouds
and fog patches to area especially inland this morning. warm front
approaching coast will brush far northern coast this morning. cold
front still well offshore favors slower gfs solution. this will bring
chance of rain to northern coast later afternoon. front moves ashore
this eve then moves through the inland areas after 06z. solid
precipitation threat for area with heaviest northern coast and second
max cascades. nw flow aloft over area behind front sat morning. high
pres off s ore coast sat morning gives area onshore flow with some
orographic flow. this will give good threat of showers to ore
cascades with shower threat over remainder of n and most inland
areas. high builds n to central coast by late in the day.
precipitation threat ends in the afternoon over the s part of area
with drier nw flow while n part of area continues with shower threat.
high pres shifts inland sat night. onshore flow turns offshore after
06z. a few lingering showers early far n end before midnight. fog
areas develop over inland valleys as upper ridge brings warming aloft
and flow in valleys still light. high remains over ida sun giving
moderate offshore flow to area. fog clears most areas through central
and s valleys slow to clear in the afternoon. with e low level flow
basin stratus likely for e gorge. warmest temps sun coast and parts
of coast range and foothills. kosovitz

.long term...an upper level ridge will transition across the area
sun night with a weakening trough approaching the coast mon. as most
of the energy with this system dives to the south along with the cut
off low...stayed with only chances of rain over the area late mon
through tue. model consensus and run to run consistency not high for
the extended forecast...therefore made no wholesale changes. it does
seem as though we may dry out for at least part of wed into
thu...but even this is not agreed upon by the models. will need to
see future runs before committing fully to a particular solution.
brown
&&

.aviation...showers have pretty much ended as surface high pres
continues to build early this morning. a lot of clear areas leading
to fog formation. inland taf sites most vulnerable to ifr or lifr
conditions...especially khio and keug. coastal sites may have enough
offshore drift to limit or prevent fog. valley sites that get fog
likely to remain in ifr or lower conditions through the morning
hours due to very weak surface gradients. kttd should start to see
offshore gradient pick up around 18z. expect thicker mid clouds
arriving at the coast around 18z...with rain developing by 00z
sat.

kpdx and approaches...currently vfr with a southeast drift and
should stay that way. however...there is about a 30 percent chance
that some patchy fog could develop by 12z. anything that forms should
be mifg and not affect ops. expecting to see east to southeast wind
pick up a little by early afternoon as offshore gradients increase.
vfr conditions expected throughout the day. mid-level clouds will
thicken late in the day through fri evening. rain expected to
develop around 04z...with conditions likely dropping to mvfr after
06z sat. weishaar
&&

.marine...winds generally 15 to 20 kt early this morning and should
stay around 15 kt through 18z. next frontal system will bring gales
to the waters early this afternoon through about 04z sat. this will
be a quick-hitter...with about 6 hrs of gale-force wind. 850 mb and
boundary layer wind progs suggest this will be a pretty decent
front. indicated gusts around 40 kt over the waters and to 45 kt on
the headlands. wind switches to nwly behind the front and will drop
to small craft levels. wind speeds to remain 20 kt or less sat
through at least the middle of next week.

seas running at 12 ft or so and should drop a little during the next
several hours. however...as the next front approaches and gale wind
develops...expect substantial wind wave component after 20z.
combined seas likely to hit 15 ft or so just ahead and with the
front...and then remain there through sat morning. rough bar
conditions through at least 12z sat. weishaar
&&

.pqr watches/warnings/advisories...
or/wa...small craft advisory for hazardous seas cape shoalwater to
          florence through midday fri.
        small craft advisory for rough columbia river bar through
          fri night.
         gale warning cape shoalwater to florence fri afternoon and
           evening.
&&

$$

more weather information online at...
http://weather.gov/portland

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.