Weather alerts for the NWS Portland OR forecast area

000
FXUS66 KPQR 281102
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
402 AM PDT Wed Oct 28 2026

.SYNOPSIS...Seasonably cool and showery conditions continue 
through the workweek as repeated weather systems support 
persistent chances for rain. A drying trend beginning Friday may
bring better trick-or-treating conditions by late Saturday. 
Could see benign conditions into early next week before the 
pattern becomes more unclear by the middle of next week.

&&

.SHORT TERM...Today through Friday Night...A wet and cool 
pattern is expected to continue through the work week as several
weather systems impact the region. An upper level low over 
western Canada continues to drop south toward the PacNW, which 
will continue to send a series of embedded shortwaves into the 
region as the parent low slowly treks southward through the end
of the workweek. This will keep the probability of precipitation
elevated through the remainder of the work week with new 
rainfall totals from 5 AM Wednesday to 5 AM Thursday for the 
coast and coast range look to pick up around 0.15-0.35 inches, 
inland valleys around 0.05-0.20 inches and the Cascades picking
up around 0.15-0.60 inches. Higher amounts are expected in the 
northern OR Coast Range, southern WA coast range with the 
highest accumulations expected in the northern OR Cascades and 
southern WA Cascades. There is a 15-35% chance that areas in the
SW WA and N OR Cascades could receive and inch or more of rain 
during this time frame. 

850 mb temperatures are expected to drop through Wednesday as 
the upper level low brings cooler air with it. This will drop 
snow levels towards 4000-4500 feet by this evening and towards
3000-4000 ft by Thursday morning. This could bring snow to some
of the mountain passes which could create dangerous travel 
conditions through the Cascades. For travel around Mount Hood,
including Government Camp, chances for 1 inch or more of snow 
from early today through Thursday morning are 35-45%. During the
same period, chances are highest for Santiam Pass 75-85%. 
However, the bulk of the precipitation is not expected to 
coincide with the colder temperatures/lowest snow level. 

Friday into Saturday is looking to be a transitional period as
models have the aforementioned Canadian low being contested by 
a broad, upper level ridge developing over the Great Basin. 
Ensemble guidance is showing that the Great Basing ridge will 
keep the majority of the Canadian low just offshore. Thus 
bringing a bit of a reprieve to the precipitation for Friday. 
The NBM for example, is maintaining a high PoP, low QPF forecast
which means we are likely to see rain but it will be light. 
However, there remains some uncertainty as to the exact 
placement of both the Canadian low and Great Basin high. For 
example if the Canadian low is able to push further inland, 
then precipitation will return to the forecast for the latter 
part of the week and likely continue into the weekend. On the 
other hand, if the Great Basin ridge is able to build, then a 
drier forecast would be expected. /42

.LONG TERM...Saturday through Tuesday...Ensembles and cluster 
analysis continue to point towards a drier pattern for the 
weekend, but models are suggesting that the aforementioned 
Canadian low, will come onshore Saturday afternoon. Again 
ensemble guidance is continuing to maintain a low/moderate PoP 
(10-25%) with little to no QPF as the low moves onshore. Looking
beyond Saturday night and into early next week a shortwave 
ridge looks to develop late Sunday/early Monday, which will 
bring a return of relatively warmer daytime highs and dry 
conditions for the start of November. Exact timing and details 
of this progression still vary among the models. /42-19

&&

.AVIATION...Through 12Z Thursday...Westerly flow through the TAF 
period will result in scattered showers to continue across the 
area. Expect a mixture of VFR and MVFR conditions with VFR likely
to be the predominate flight category. Through 21Z Wednesday,
showers are expected to slowly decrease with most precipitation 
stopping around 00Z Thursday. Afterwards, conditions are expected 
to settle towards VFR with some clearing overhead. This clearing, 
along with very moist ground conditions could result in IFR/LIFR 
conditions developing across the airspace towards the end of the 
TAF period. 

Inland locations should expect south/southwest winds 10-15 kt 
with gusts up to 25 kt before winds become more westerly and 
moderate towards 5-10 kt around 16Z-21Z Wednesday. For coastal 
locations expect west/southwest winds 5-10 kt, with gusts up to 20
kt the coast, with KAST having the highest probability of these 
gusts. Winds along the coast are also expected to moderate around
00Z Thursday subsiding towards 5-10 kt.

KPDX AND APPROACHES...Expect showers which will result in a 
mixture of VFR and MVFR conditions with VFR likely to be the 
predominate flight category. Most precipitation stopping around 
00Z Thursday with some clearing afterwards. Said clearing will 
result in the potential for IFR/LIFR conditions to develop 
towards the end of the TAF period. Expect south/southwest winds 
10-15 kt with gusts up to 25 kt before winds become more westerly 
and moderate towards 5-10 kt around 16Z-21Z Wednesday. /42

&&

.MARINE...A low pressure system will keep conditions active 
across the waters through the middle of the week. This system 
is currently producing winds with gusts up to 25 kt and seas of 
7-10 ft at 10-12 seconds. As a result, the current suite of Small 
Craft Advisories will be maintained through at least this 
morning. The aforementioned low will continue to move inland 
which will result in both winds and seas slowly subsiding through 
the morning and into the late afternoon. Therefore, the Small
Craft Advisories are set to drop from south to north as the day
progresses. Overall conditions will continue to subside Thursday
into Friday with gusts below 15 kt and seas subsiding towards 4-6
ft at 10-12 seconds through the weekend. Looking towards the 
start of next week, another low pressure system from the Gulf of 
Alaska looks to bring building seas and winds back into the 
forecast, which could result in Small Craft conditions for the 
start of next week yet again. /42

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory until 11 AM PDT this morning for PZZ210-251-
     252.

     Small Craft Advisory until 8 AM PDT this morning for PZZ253-273.

     Small Craft Advisory until 5 PM PDT this afternoon for PZZ271-
     272.

&&

$$

www.weather.gov/portland

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