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

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Area Forecast Discussion
National Weather Service Portland, OR or
330 pm pdt fri mar 13 2026

.synopsis...the region is slated to get one last burst of
moderate to locally heavy precipitation tonight into early
saturday morning as the atmospheric river which has sat over
the pacific northwest the past few days makes a final push
southward. while the probability for mainstem river flooding is
low, we continue to monitor our more flood prone/flashier rivers
and an areal flood watch remains in effect through saturday.
after a bit of a lull the later half of friday into saturday the
region remains on the northern periphery of a strong upper-
level ridge for much of next week allowing for above normal
temperatures although rainfall chances likely persist at times.

&&

.short term...now through sunday night...so far this afternoon
the bulk of the rainfall has been hung up over far nw oregon and
sw washington just north of the portland/vancouver metro as the
an atmospheric river coupled with a cold-frontal boundary
begins its slow and final journey southward. helping to drive
this progression is a the arrival of a shortwave trough from
over the eastern pacific which is expected to arrive overnight.
high confidence among model guidance this`ll further accelerate
the front and rainfall through and then our of the region.
exploring high resolution guidance like the href shows moderate
probabilities (40-50%) for a period of elevated rainfall rates
greater than 0.25in/hr this evening into the overnight hours
across the coast range and western slopes of the cascades as the
atmospheric river and strong cold front swing through the area.
while it`s within the realm of possibility to see these higher
rates over the valleys and i-5 corridor along the immediate
frontal boundary, there are much better chances (50-80%) for
rates closer to 0.10in/hr, especially around and east of i-5.
from 5pm this afternoon to 5am saturday moderate to high
confidence the portland metro will see between 0.70-1.25 inches
of rain, 0.60-1.10 inches in salem, and 0.40-0.75 inches in
eugene. obviously higher amounts are expected over the coast
range (generally 1-2 inches) and cascades (1-3 inches). this`ll
come into play when looking at the flooding treat, especially
for urban, low-lying or other poor drainage areas and flashier
small creeks/rivers as they remain highly sensitive to
additional rainfall - see the hydrology section for additional
details regarding flooding concerns.

headed through saturday morning conditions rapidly improve as
almost all deterministic and ensemble guidance show the last
remnants of the atmospheric river exiting lane county by
0700-1000. the remainder of the day appears mostly dry outside
of some lingering shower activity primarily confined to terrain
features like the coast range, cascades, and adjacent
foothills. our attention turns to a ridge of high pressure
attempting to establish itself over western conus saturday night
through sunday into early next week. while this feature and a
switch to broad southwesterly flow aloft is likely robust enough
to raise our temperatures well above normal for early next
week, it won`t be strong enough to prevent the southern
periphery of another atmospheric river headed into british
columbia from facilitating chances for light rain across far
north oregon and southwestern washington starting sunday
afternoon into sunday night. the overall pattern sees little
progression from this point through the end of the long term
period. -99



.long term...monday through thursday...looking into the start
of next week, ensemble models show yet another atmospheric
river aimed at the pacific northwest and british columbia
however most ensembles maintain a northerly trajectory with a
focus towards the vancouver island and northwest washington.
that said, the latest guidance has shifted precipitation just a
touch further south than what has been shown prior forecast
cycles but it won`t be enough to be impactful at this point. what
dictates the placement of the axis of moisture next week will
be the ridge amplitude to our south that is expected to slowly
push eastward with time. if the ridge weakens, then that would
result in our area getting more precipitation than forecast. the
ridge and southwesterly flow also push 850 mb temperatures to
around 10 to 12 degrees c, which would lead to daytime highs
into the 60s to near 70 for inland locations, 50-60s along the
coast, coast range and cascades through the middle of next week.
with temperatures this high snowmelt in the cascades is
probable. looking at the latter part of wednesday and towards
the end of next week, another round of precipitation appears to
be on deck. so, spring 2026 looks to be in full swing for the
pacific nw. -99/42


&&

.aviation...conditions continue to vary over the airspace as an
atmospheric river continues to impact the region. the atmospheric
river begins to shift south again, bringing a return of heavier
rain to the airspace north of ktmk and kuao as of 22z fri. the
atmospheric river will continue to push south through most of the
taf period, with the system expected to fully exit the airspace to
the south by 12-18z sat.

for the coastal terminals, expect ifr/lifr conditions to prevail
until around 11-13z sat, then potentially improve to vfr. for
inland terminals, expect conditions to vary between vfr and mvfr
until 12-14z sat, then potentially improve to vfr. as for the winds,
south/southwesterly winds around 10-15 kt with gusts up to 25 kt
at inland terminals and 15-20 kt with gusts up to 30 kt at coastal
terminals will persist until 09-15z sat, then weaken and shift
more westerly.

kpdx and approaches...an atmospheric river begins to shift south
through the airspace, maintaining mvfr and occasional vfr
conditions until 12-14z sat. thereafter, rain will come to an end
and conditions will improve to vfr for the rest of the taf
period. current southwesterly winds of 10-15 kt with gusts up to
25 kt will weaken and become more westerly around 09z sat.
~12

&&

.marine...seas and southerly winds will remain elevated through
late saturday, therefore the small craft advisory for all waters
will be maintained until 11 pm saturday. winds will become
northerly late tonight and through saturday. seas around 9 to 10
ft today will slowly ease below 9 feet by early saturday. beyond
saturday, conditions will remain rather benign until the start of
next week. a quick moving system could result in seas briefly
returning to 10 to 11 ft on tuesday for all waters. at the
moment, there is a 50-60% chance for seas to exceed 10 ft on
tuesday for the outer waters (beyond 10 nm) north of cape falcon
or and a 30-50% for the outer waters between cape falcon and cape
foulweather or.
~12

&&

.hydrology...moderate rainfall associated with an atmospheric river
across southwest washington and far northwest oregon is beginning to
shift back south this afternoon and will continue to slowly move
south tonight. rain is expected to end for most locations by
saturday morning, except for some lingering precipitation across the
central oregon cascades. with increasing rainfall rates, rivers are
expected to rapidly rise, especially the flashier rivers that are
already swollen near or at action stage. these include johnson creek
near sycamore, the grays river near rosburg, the cowlitz river near
kelso, and the wilson river near tillamook, which are all currently
in or forecast to go into minor flood stage. another 6-8 rivers are
forecasted to go into action stage.

as the next round of moderate rainfall moves through, minor flooding
of urban, low-lying or other poor drainage areas remain possible
small creeks and streams remain highly sensitive to this additional
rainfall. the flood watch remains in effect through saturday
afternoon, but may be able to be dropped as soon as the front pushes
through early saturday morning. continue to monitor the latest river
forecasts at water.noaa.gov as updates to forecast rainfall may
dramatically affect forecast river levels. the majority of flood
deaths occur in cars, and drivers should never attempt to cross a
flooded roadway. please heed any road closures posted by local
authorities.

&&

.pqr watches/warnings/advisories...
or...none.
wa...none.
pz...small craft advisory from 2 am to 11 pm pdt saturday for pzz210.

     small craft advisory until 11 pm pdt saturday for pzz251>253-
     271>273.
&&

$$

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