334
FXUS66 KPQR 141819
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
1019 AM PST Fri Nov 14 2025

.UPDATED AVIATION DISCUSSION...

&&

.SYNOPSIS...Persistent shower chances continue into the first
half of the weekend beneath largely zonal flow aloft, before a
more robust trough approaches the coast on Sunday, bringing
cooler temperatures, widespread rain, and mountain snow
potentially down to pass-level.

&&

.SHORT TERM...Now through Saturday Night...Latest water vapor
satellite imagery highlights a narrow and deep upper-level
trough which will split off from the main flow and linger over
California as a cutoff low through much of this weekend.
Meanwhile in the Pacific Northwest, the pinching off of the
closed low to the south will leave the region beneath a saddle
or col in the upper-level flow while weak remnant troughing
moves inland over Washington State by this afternoon. This weak
spot in the large-scale flow will see continued rain shower
chances, especially north of US-26. Snow levels at 5-6 kft will
see rain fall at Cascade passes, limiting any travel hazards to
drivers. On Saturday, weak upper-level ridging will begin to
develop east of the Cascades, lowering the chances for
additional rain inland to 25% or less while coastal areas
maintain a 35-55% chance of showers.

Chances for 24-hour rainfall totals of 0.1" of more for the
periods through 4 AM Saturday and through 4 AM Sunday are very
similar across the region, generally increasing to the north:
10-15% at Eugene, 30-35% at Salem, 50-55% at Portland, and
65-70% and Kelso/Longview for inland locales, and from 40-45% at
Florence, 60-65% at Newport, 80-85% at Tillamook, and 90-95% at
Astoria along the coast. Slightly above normal temperatures
continue across the region, with highs in the 50s to low 60s and
overnight lows largely in the 40s. -36


.LONG TERM...Sunday through Thursday...As ridging builds inland
over the Rockies, yet another elongated trough will approach
the coast this weekend. The evolution of this next trough could
look very similar to the current pattern, namely a developing
cutoff low heading into California leaving a weak trough over
the Pacific Northwest, however some global ensemble members
instead favor a more coherent trough impacting the coast. Even
modest troughing could usher in colder air aloft and allow snow
levels to fall through midweek, however at this lead time, the
majority of precipitation looks to fall while snow levels remain
above Cascade passes through Monday night. Higher passes, namely
Santiam and Willamette Passes, will most likely see 1-3 inches
of accumulating snow through Tuesday, limiting travel impacts.
Chances for more impactful amounts of 6 inches or more through
Monday night are only 5-10% at pass-level given the lack of
overlap of precipitation and sufficiently cold temperatures.

As repeated troughs bring cooler air overhead, many will see
some of the coldest nights so far this season by the second half
of the workweek, with most valley locations falling into the
30s overnight. With this cooler air mass in place, passing
shortwaves may also see further accumulating mountain snow,
yielding a 15-30% chance of 6 inches or more at Cascade passes
from Wednesday through Thursday night. -36

&&

.AVIATION...Expect a mix of flying conditions through the TAF
period as a frontal system currently hung up along the North
Oregon and Southwest Washington coast slowly progresses
it the rest of the region. Low stratus lingers in portion of
the Willamette valley late this morning with a mix of LIFR/IFR
CIGs showing slow improvement at KUAO through KSLE. Over the
next several hours (by ~20z) these degraded conditions should
improve back to MVFR/VFR but confidence is only moderate in this
early afternoon timing.

Along the coast, light rain associated with the frontal band has
already spread to KAST with a mix of MVFR/IFR conditions lasting
through much of the TAF period due to reduced CIGs/VIS.
Conversely VFR conditions at KONP well south of the frontal
boundary likely persist through a good chunk of the day (until
22z Fri to 02z Sat). It`s worth noting southerly winds remain
breezy/gusty along the coast with gusts in the 15-30 knot range
through the TAF period.

Rain will spread from northwest to southeast across the inland
terminals mainly later in the TAF period. Most likely onset times
of rain 05-08z Sat at Portland metro area and northern Willamette
Valley. Rain showers may fail to reach as far south as KEUG
however.

KPDX AND APPROACHES...Mid-level cloud cover (4-7kft) continues to
increase ahead of an approaching frontal boundary but VFR CIGs
likely (70-80%) hold in place into the evening hours. Light rain
is the expected to slowly increase, most likely after 06-07z with
MVFR cigs falling to 2-3 kft into Saturday morning. -99/36

&&

.MARINE...Westerly swell is continuing to ease early this
morning, however buoy observations maintain seas above 10 ft at
12 to 13 seconds. The Small Craft Advisory has therefore been
extended through 1 PM PST Friday afternoon across the waters
until seas fall below 10 ft. Meanwhile, southerly winds at 10-15
ft may see intermittent gusts above 20 kt this afternoon as a
weak frontal boundary traverses the region and moves onshore.
Chances for gusts up to 25 kt is the highest over the inner
waters (within 10 NM) from Cape Shoalwater to Cape Foulweather
including the mouth of the Columbia River and the Columbia River
Bar through tonight. Small Craft Advisories in these areas may
need to be further extended if the coverage of frequent gusts
increases. Otherwise, seas will continue to subside to 6-8 ft
through the weekend.

Another frontal system will traverse the waters on Sunday,
bringing increased southwester winds before turning out of the
northwest on Monday. Westerly swell rising to 10-13 ft behind
the frontal passage will see seas of 12-14 ft by Monday morning,
then falling below 10 ft again by early Tuesday. The active
pattern continues as yet another weather system may bring
hazardous winds and seas by mid to late next week. -36

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory until 1 PM PST this afternoon for PZZ210-
     251>253-271>273.
&&

$$

www.weather.gov/portland

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