596
FXUS66 KPQR 162244
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
244 PM PST Sun Nov 16 2025

.SYNOPSIS...Light rain continues through Monday morning. A
passing ridge will support mostly dry conditions on Tuesday and
Wednesday. The next impactful system takes aim at the region
during the latter half of the week. There is uncertainty in the
progression of this system but rain and mountain snow are
possible.

&&

.SHORT TERM...Now through Tuesday Night...Dreary fall conditions
expected today as thick, low clouds cover the region. A cold
front continues to move toward the coast supporting light rain
and misty conditions which has kept visibility generally less
than 5 miles. The narrow trough supporting the front is expected
to split, with the base of the pinching off and forming a cut-
off low that drops southeast along the West Coast. The northern
portion of the trough moves eastward. Rainfall totals with this
system will be on the lower side given the splitting of the
upper level trough leaving the area under weaker forcing. Inland
totals through Monday morning expected to be 0.25-0.50 inches
while along the coast and higher terrain, totals closer to 0.75
inches will be possible. Snow levels for the Cascades are
expected to remain above 6000 feet until the trough axis passes
overhead early Monday morning and much colder air filters in
overhead. Snow levels drop to 2500-3500 feet Monday night into
Tuesday morning but QPF will be much lower by this time. Not
expecting any substantial snowfall at pass level with this
system. Cooler surface temperatures are also expected on Monday
and Tuesday with the passage of this system. Expect inland and
coastal highs in the low to mid 50s and highs in the 40s for the
higher terrain./19

.LONG TERM...Tuesday Night through Sunday...A brief period of
dry conditions under shortwave ridging will keep the latter half
of Tuesday through Wednesday benign. The next potentially
impactful system is expected to impact the region late Wednesday
night into Thursday, though there is substantial differences
among the models and their ensembles. Cluster analysis remains
split between solutions with around 35% showing a weak trough,
34% showing a much deeper trough with an amplified pattern, 16%
close to zonal, and the last 15% with a deeper trough but well
offshore. Deterministic models show plenty of disagreement in
the overall progression of the trough. The GFS leans towards a
similar pattern with the trough base pinching off and dropping
southeast, leaving northwest OR and southwest WA in a region of
weaker forcing. THe EURO on the other hand, keeps the trough
intact through its eastward progression, leading to better
forcing, higher precipitation totals and a better chance for
mountain snow. Depending on what happens with this late week
system, could see impactful snow around the mountain passes
though, NBM spread is quite large with some showing no snow and
others showing 6 inches or more. Chances for 6 inches of snow
Thursday through Friday at the Cascade passes is a mere 5%. Will
need to keep an eye on this system as it approaches late next
week. /19

&&

.AVIATION...A frontal system continues to progress through the
region this afternoon with CIGs/VIS largely holding as a mix of
IFR (Portland Metro through the central Willamette Valley) to MVFR
(portions of the Oregon and the south Willamette Valley). Once the
more stratiform rainfall breaks to showers around 00-03z Mon
guidance gives CIGs/VIS better chances jump to MVFR with pockets
of VFR possible (mainly KAST) as well through the evening hours.
However it`s worth noting due to poor model performance today and
the tendency for the lower cloud decks to linger this time of
year, forecast confidence going forward is low in regards to the
timing of any VIS/CIG improvement. Winds this evening into the
early overnight hours likely shift from their current southerly
direction to west-northwesterly as well. Going through Monday,
the NBM projects a 70-80% chance for persistent MVFR conditions at
inland sites with closer to 60-70% chance at the coast excluding
KAST where these probabilities are notably lower - higher chances
for VFR conditions north Oregon Coast. Light shower activity
decreases through the day with prevail dry conditions returning
for the afternoon as well.

KPDX AND APPROACHES...IFR conditions have been persistent today
but the back edge of the stratiform rainfall will be moving
overhead shortly. After this point we`ll see better chances for
MVFR conditions to finally return. However, we`ll still need to
watch for IFR conditions through Monday morning as the
probabilities to flop back to IFR increase starting around 07-09z
Mon. Passing showers may degrade conditions as well. South winds
around 5-10 kt finally turn northwest between 06-09z.
-99

&&

.MARINE...A frontal boundary is progressing through the waters
this afternoon with southerly winds quickly shifting northwesterly
with gust up to 18-25 knots by the evening hours. This frontal feature
will also support seas building to 10-14 ft at 13-14 seconds,
likely lasting through most of Monday - a Small Craft Advisory
remains in effect into Monday evening. After this point seas are
expect to fall back into the 6-8 ft range at 11-12 seconds for
Tuesday. Lighter west-northwest winds return Monday night into
Tuesday as well. Looking ahead, after the continuation of fairly
benign winds/wave heights by late fall standards through most of
Wednesday, yet another frontal system pushes into the waters late
Wednesday into Thursday. As a result, wind gusts likely increase
into the 20-30 knot range with a mature swell building seas into
at least mid teens. The GEFs projects a 50-70% chance for wave
heights to exceed 15 ft but there is also a 10-25% chance of 20 ft
seas or higher. An active weather pattern likely continues into
the weekend. -99

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory until 7 PM PST Monday for PZZ210.
     Small Craft Advisory until 10 PM PST Monday for PZZ251>253-
     271>273.
&&

$$

www.weather.gov/portland

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