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

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Area Forecast Discussion
weather service portland or
240 pm pdt mon jun 17 2019

.synopsis...a rather typical weather pattern for june continues
through the week. mostly dry weather is expected early in the week,
with temperatures near normal. a trough of low pressure aloft late
in the week will bring a chance of showers to the north part of the
forecast area thursday, with temperatures temporarily cooling
to a little below normal.

&&

.short term...tonight through thursday...a continuation of onshore
flow along with lowering heights aloft will be the trend through the
middle part of the week. models show a weak shortwave cutting across
washington early thursday, with the remnants of a weak cold front
pushing into the north part of the forecast area. this should wind
up being a little more efficient in pushing late night and morning
marine clouds inland across the north tuesday and again wednesday as
more weak shortwave activity moves through. with shallow marine
moisture, there will also be a small chance for sprinkles or drizzle
to the north coast. temperatures will progressively lower several
degrees per day tuesday and wednesday as upper heights begin to
lower.

wednesday night and thursday a more impressive looking shortwave
carves out a deeper trough over the pacific northwest, although
models have minor timing issues. moisture remains mainly in the low
levels, but does deepen some to as deep as about 8000 feet. thursday
morning. models also show some low level instability with the moist
layer which coupled with the dynamics brings a chance for showers to
much of the region. thursday looks to be the coolest day of the week
as 850 mb temperatures cool to about 1c. while maybe not quite as
low as the cascade passes, it will bring snow levels down close to
pass levels.

.long term...thursday night through monday...guidance continues to
show a deep upper level trough building into the western us later
this week. this will maintain our onshore flow pattern and bring
near seasonal temps. clouds will continue to rinse and repeat with
periods of morning clouds and afternoon sun inland and stratus along
the coast. aside from an isolated shower over the cascades north of
mt. jefferson thursday night due to a departing shortwave the chance
of rain over the region generally remain low through saturday. will
see a better chance of showers sunday and monday as another upper
level low drops south into the pac nw so decided to add some slight
chance pops to the forecast. /64
&&

.aviation...at 20z the marine layer had dissipated to cover
portions of sw washington and the north oregon coast near kast.
the coast south of kast cleared out more than expected. expect
ifr to mvfr to return to the coast between 00z and 03z tue. mvfr
returns to the sw washington i-5 corridor, including kkls, by 06z
and then to the north willamette valley late tonight.

coastal areas south of ktmk should improve to vfr around 20z tue.
inland taf sites improve to vfr a little earlier. there is a
chance the west side of the willamette valley, including khio,
may not drop into mvfr.

kpdx and approaches...vfr developed at the terminal just before
19z. expect vfr through at least 10z, but cigs 035-045 likely to
develop between 03z and 06z. mvfr expected to develop 10z-12z
tue and continue through tue morning. weishaar

&&

.marine...high pressure will reside over the waters for the next
few days. the north surface pressure gradient between high pressure
over the ne pacific and a thermal trough over nw ca and sw or
will tighten tue afternoon over pzz255 and pzz275. this will
result in stronger north wind south of cascade head, with gusts
to 25 kt expected. thus, will issue a small craft advisory valid
18z tue through 07z wed. latest guidance shows possible marginal
small craft advisory level wind gusts generally south of heceta
head wed afternoon. wind speeds weaken on thursday as a weak
front moves across the waters and the gradient turns more
westerly.

seas mostly 4 to 6 ft for the next few days, although areas of
pzz255 and pzz275 likely to see brief periods of 7-8 ft tue and
wed due to the higher fresh swell contribution.  weishaar

&&

.pqr watches/warnings/advisories...
or...none.
wa...none.
pz...small craft advisory for winds from 11 am tuesday to midnight
     pdt tuesday night 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. this area is
commonly referred to as the forecast area.