Western Washington

637 
FXUS66 KSEW 010334
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
834 PM PDT Sat Oct 31 2026

.SYNOPSIS...Drier conditions will settle into the region into 
Monday as an upper low moves south and a ridge builds into the 
region. The first half of next week will remain mostly dry, with
chances of precipitation increasing mid to late week as a 
series of systems approaches the Pacific Northwest.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...An upper level low
will continue to weaken as it moves onshore to the south, with 
split flow briefly developing aloft over western Washington. 
Cool overnight lows in the 30s will bring areas of additional 
frost development to the area on Sunday morning while moisture 
in the low levels promotes another round of morning fog. A Dense
Fog Advisory has been issued for portions of Puget Sound and the
Southwest Interior due to the expected fog development. Fog is
already beginning to develop in isolated river valleys, and is
expected to further expand tonight into Sunday morning. 

High pressure building into the Pacific Northwest will maintain
dry conditions and seasonable temperatures through Monday, with
periods of morning fog and afternoon sun breaks. As the upper 
level ridge axis shifts eastward on Monday, ensembles continue 
to show low chances of rain generally along the coast and over 
the Olympic Peninsula.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...Chances for light rain 
continue into Tuesday as a splitting frontal system passes over 
the region. Wetter and more unsettled conditions are expected to
return on Wednesday and beyond as a series of systems are set 
to move over the region. While ensembles continue to show a fair
amount of variability heading into next weekend, the system 
Friday looks to be the strongest and will likely bring breezy 
winds alongside widespread lowland rain and mountain snow.

JD/15

&&

.AVIATION...Most locations across western Washington are VFR 
this evening. Areas of localized fog have begun to form around 
Olympia and the in the middle Chehalis river valley and will 
continue to expand and encompass much of the western WA 
lowlands. The highest confidence remains across the metro area 
south of Everett, through will also expand, at least briefly, 
towards HQM and BLI. This will bring widespread LIFR conditions 
through Sunday morning. Improvement to VFR expected after 
18-20Z. Northerly surface winds 4-6 kt becoming light and 
variable tonight into Sunday morning. 

KSEA...VFR conditions today. Conditions will deteriorate Sunday 
morning with LIFR fog expected to form at the terminal after 10Z-
12Z, through latest satellite trends indicate the potential for an 
earlier start. Conditions will improve to VFR after 18-20Z. NW winds 
will ease this evening becoming 5 kt or less into Sunday morning.

29/62

&&

.MARINE...Shower activity was decreased this afternoon across 
the coastal waters and the threat for brief waterspouts has 
ended. 

A surface low pressure will continue to dig south today. High 
pressure will build over the waters tomorrow through Monday. A 
system will approach the coastal waters to the north, leading to an 
increase in winds over the outer coastal waters on Monday. Latest 
guidance suggests there is a 55-70% chance for wind gusts briefly 
exceeding 21 kt Monday morning over zones PZZ170 and PZZ173. High 
pressure will move inland on Tuesday. The next system arrives 
Wednesday. Winds will increase across the coastal waters; however, 
latest probabilities indicate a 40-50% chance for wind gusts meeting 
small craft thresholds. A stronger system will impact the waters 
Thursday into Friday, bringing stronger winds across the coastal 
waters and interior waters, with latest probabilities at 65-75% for 
winds above 21 kt. 

Seas 4-6 feet this afternoon, decreasing below 5 feet tonight. Seas 
will build on Monday 7-10 feet and will hover around this range 
through late in the week. With the stronger system arriving Friday, 
latest guidance suggests seas will build  up to 13-16 feet. 

29

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Dense Fog Advisory from 1 AM to 10 AM PDT Sunday for City of 
     Seattle-Downtown Everett / Marysville Area-Eastern Kitsap 
     County-Eastside-Lowlands of Lewis and Southern Thurston 
     Counties-Lowlands of Pierce and Southern King Counties-
     Olympia and Southern Puget Sound-Shoreline / Lynnwood / 
     South Everett Area.

     Dense Fog Advisory until 10 AM PDT Sunday for Lower Chehalis 
     River Valley-Middle Chehalis River Valley.

PZ...None.

&&

$$

Southwestern Washington and Western Oregon

955 
FXUS66 KPQR 312043
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
143 PM PDT Sat Oct 31 2026

.SYNOPSIS...Mostly clear skies and calm winds may bring frost 
and/or fog development across much of NW OR and SW WA in the 
mornings through Monday. Mostly dry conditions through Monday. 
Low chances for scattered showers Monday night, then 
precipitation chances increase later next week with limited 
weather impacts expected.

&&

.DISCUSSION...Through Friday...Visible satellite imagery early 
Saturday afternoon shows areas of fog/stratus across some 
inland valleys with mostly clear skies elsewhere. Afternoon 
temperatures are expected to warm into the mid- 50s, before 
quickly falling into the 40s after sunset this evening. The 
upper trough that has been spinning just offshore all week 
became elongated offshore overnight and is slowly pushing inland
today through tonight. This will bring a 20-40% chance of 
showers to mainly the Lane and Linn County Cascades and 
foothills this afternoon and evening, decreasing around 
midnight. Valley locations should remain dry with just some high
clouds overhead. 

Dry conditions continue Sunday into Monday as an upper level 
ridge of high pressure builds over the PacNW behind the trough 
passage. Skies are expected to clear after midnight tonight, 
which combined with calm winds is expected to lead to another 
round of widespread fog or low stratus across inland valleys 
Sunday morning. Radiational cooling is also expected under these
conditions, which will allow minimum temperatures outside of 
urban areas to cool into the mid to upper 30s. Fog/low stratus 
should dissipate by midday with sunny skies and high 
temperatures in the 50s. Expect a rinse and repeat of this 
forecast on Monday.

Today's 12z ensemble guidance has come into much better 
agreement on the overall weather pattern through midweek next 
week, though some uncertainty on specifics still exist. Guidance
indicates a low pressure system will develop in the eastern 
Pacific early next week as the high pressure moves inland over 
the PacNW. The majority of ensemble members indicate this low 
will move inland somewhere in northern CA or along the CA/OR 
border late Monday through Tuesday. Currently the forecast has a
10-25% chance of scattered showers Monday night into early 
Tuesday with very limited rain amounts, though depending on the 
strength and north to south extent of this low, these chances 
could decrease in subsequent forecasts. Tuesday through most of 
Wednesday look to dry out with temperatures warming to near 60 
degrees for the interior lowlands. Then precipitation chances 
increase again late Wednesday into Friday as ensemble members 
indicate another front or two could bring a couple more rounds 
of moisture to the area. At this point, no significant 
precipitation impacts are expected with any of these weather 
systems, though there's a 25-50% chance of wind gusts increasing
over 30 mph along the coast (5-20% chance inland) with each 
frontal passage late in the week. -03

&&

.AVIATION...Through 00Z Sunday...Satellite imagery and terminal
observations as of early Saturday afternoon depicts predominately
VFR conditions for most terminals except for the central and
southern Willamette Valley, where there is a mix of MVFR/IFR/LIFR
CIGs. The further south in the Valley you go, the lower the CIGs.
Satellite imagery shows stratus slowly dissipating across the
valley, so expect remaining stratus to persist through about
21-23z Sat. 

Tonight, will see another around of LIFR conditions due to fog 
and low stratus across Valley terminals as high pressure builds
aloft and brings increasing cloud breaks. Guidance suggests a 
30-60% chance for VIS < 1/2SM across the Valley at any given hour 
between 12-17z Sun. However, typical foggy spots such as KHIO and 
KEUG could see fog as early as 06-07z Sun based on what we saw 
last night. Fog/stratus development is favored across the rest of 
the Valley by 11-13z Sun. Light north/northwest winds around 5 kt 
or less across the Valley this afternoon, becoming calm 
overnight. Light easterly winds continue at the coast which will 
support VFR conditions at KAST/KONP through the TAF period.

KPDX AND APPROACHES...IFR CIGs through 19-20z Sat, improving to
VFR afterwards with high clouds. Tomorrow morning, there is a
20-40% chance for LIFR VIS due to fog at any given hour between 
12-17z Sun. Northwesterly winds around 5 kt or less today, 
becoming variable overnight.      -10 

&&

.MARINE...Weak low pressure offshore gradually dissipates today as
winds decrease below 10 kt. Seas around 4 to 5 ft continue to 
subside to 3 to 4 ft into Sunday morning. Offshore winds develop 
late Sunday night and persist into early next week. A long period
west-northwest swell also arrives Sunday evening, building seas 
to around 7 to 9 ft at 16-19 seconds on Monday. Chances for seas 
over 10 ft on Monday remain at around 30-50% across the outer 
waters. This long period swell will result in a moderate threat 
for sneaker waves at the coast Sunday evening through Tuesday. 
Caution should be used at beaches when in or near the water. 

A weak low pressure system approaches the waters mid next week, 
returning light southerly winds. By the end of the week, model 
guidance hints at a stronger system entering the waters, resulting
in a 60-80% chance for maximum wind gusts exceeding 21 kt on 
Friday with a 30-50% chance for seas exceeding 15 ft.     -10/DH

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...None.

&&

$$

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Southeastern Washington and Northeastern Oregon

550 
FXUS66 KPDT 312352
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
452 PM PDT Sat Oct 31 2026

.KEY MESSAGES...
- Near- to below-normal temperatures into next week.

- Precipitation this evening into Sunday morning, mainly for 
  eastern Oregon and far southeast Washington.

- Low chance (30% or less, except for freeze-prone areas) of a 
  season-ending freeze for the eastern Columbia River Gorge 
  Monday.

&&

.DISCUSSION...
Composite reflectivity showed a few showers popping off the NW 
Blue Mountains of Washington, near Walla Walla as well as 
elevated echoes over Franklin county early This Afternoon. Radar
returns were still sparse over the Oregon Cascades where 
initial probabilities associated with the incoming synoptic 
system for Tonight were found. Elsewhere, dense fog resulted in 
limited visibility to a quarter mile or less during the morning 
to early afternoon hours across the upper end of the Kittitas 
valley, the Walla Walla Valley as well as the Foothills of the 
Northern Blue Mountains. Based on mesonet observations and 
roadcam networks, these areas have improved visibility to at 
least 2 miles or better. REFS trends for precipitation Tonight 
suggest around a tenth and up to a quarter of an inch of liquid 
equivalent precipitation across the central Oregon 
mountains/Oregon Cascades through about the middle of the 
overnight hours. And meanwhile these trends have tended to 
reduce QPF amounts in the last few days for the northern Blue 
Mountains, where the mean QPF across the Blue Mountains and 
Wallowas on average is up to a tenth of an inch (30 to 50% 
confidence) with REFS QPF max amount over the Eagle Caps upwards
between a quarter and one half inch of liquid equivalent. Rain 
snow mix is possible higher than 6500 ft, however the REFS only 
offers about a half inch over the Oregon Cascade crest and one 
to two inches on the Eagle Caps. Sunday ultimately winds up 
being slightly warmer for parts of the forecast area like the 
Yakima Valley, and Lower Columbia Basin with abundant insolation
and light westerly surface winds  and highs in the upper 50s 
to low 60s in the Yakima and Columbia River Gorge. 

The upper ridge develops Monday behind the exiting mid level 
trough, redistributing the light westerly wind field to light 
northeast across the Basin and potentially turning winds 
southerly and breezy in the Grande Ronde Valley by Overnight 
into Tuesday morning. Overnight low Temperatures through the 
eastern Columbia River Gorge still appear mild and above 
freezing over the next 7 day as to think at least at this time, 
low confidence exists in any anticipated freeze headlines for 
these last remaining last warning eligible zones, at least for 
the first week of November.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...Mix of conditions
expected through the period. An upper low moving over the region
will bring prob30 chances of light rain at sites RDM/BDN through
06Z, and site ALW between 06Z to 12Z. Sites PDT/ALW will 
continue to see MVFR or lower CIGs through this evening, with 
recent guidance indicating improvement this evening. Sites 
RDM/BDN will see CIGs lower to around 2kft AGL after precip 
precipitation chances diminish after 06Z. Winds will be light.
12kts or less, through the period.

&&

.Preliminary Point Temps/PoPs...
PDT  34  53  31  57 /  20  20   0   0 
ALW  38  52  34  56 /  30  30   0   0 
PSC  33  59  31  56 /  10  10   0   0 
YKM  32  60  30  55 /   0   0   0   0 
HRI  32  57  31  56 /  10  10   0   0 
ELN  27  56  26  52 /   0   0   0   0 
RDM  25  51  22  56 /  20   0   0   0 
LGD  36  52  29  56 /  30  40   0   0 
GCD  35  49  30  58 /  20  20   0   0 
DLS  36  61  34  58 /  10   0   0   0 

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
WA...None.
OR...None.

&&

$$

DISCUSSION...71
AVIATION...71/82

Northeastern Washington and Northern Idaho

955 
FXUS66 KOTX 312349
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
449 PM PDT Sat Oct 31 2026

.KEY MESSAGES...

- Early morning Patchy Fog.

- Cool temperatures, light winds, and 20-60% chance of light rain 
Saturday evening into Sunday. Light rain accumulations up to a tenth 
of an inch  expected over Southeast WA and the southern Idaho 
Panhandle.

- Dry conditions Sunday evening through Wednesday.

&&

.SYNOPSIS...
Mid and high clouds Saturday bring a small chance of sprinkles and 
showers to southeastern Washington and north Idaho in the evening. 
Drier air arrives Sunday and conditions remain seasonal and dry 
through Wednesday. Mountain snow showers late week.

&&

.DISCUSSION...
Today and Sunday: The upper level pattern across the Pacific 
Northwest remains under a cool and unsettled flow out of the 
southwest. Partly to mostly cloudy skies for some areas, while other 
areas in north-central Washington and northern Idaho have improved 
to mostly clear skies on this last day of October. The upper level 
Low pressure system that is digging into northern California is 
leaving the Inland Northwest in a cool and Fall-like weather pattern 
for this weekend, keeping temperatures near or just above seasonal 
normal for end of October/start of November (normal max/min temps 
for Spokane are 49/34 and Lewiston 55/38, respectively). Pockets of 
fog and dense fog arrived early this morning for the West Plains, 
the Palouse, and some areas of the Spokane metro. Clouds have since 
cleared for most areas and winds have shifted to more easterly. 
Chances are low for a repeat of dense fog on Sunday given the 
incoming rain and moisture, but not a zero chance.

Most of the energy associated with the Low pressure system has 
shifted farther south, so earlier predictions (days before) of rain 
showers for Tonight continue to wane and become less. The latest 
high-res guidance (REFS and HRRR) keeps the precipitation chances 
for the Inland Northwest confined to the Lewiston-Pullman/Palouse 
area beginning after 8 PM and closer to 10 PM. The near-surface 
environment is dry so seeing much in the way of measureable precip 
more than a few hundredths is unlikely (10% chance of 0.01" through 
11 PM). The better chances for and more prominent band of 
precipitation will arrive between 11 PM and 11 AM. A 40-60% chance 
of 0.05 - 0.08 rain is expected from Lewiston north to Cusick, WA 
and east along the I-95 corridor from Lewiston to Hayden, Idaho. 

An influence of cooler and drier air from the west (precipitable 
water climo values at 100-120% of normal will transition to 70-80% 
of normal) should keep the chances for precipitation to a narrow 
period of time this weekend. The energy from the Low will shift 
eastward through the day Sunday leaving the start of the week with 
mild and dry weather. 

Monday through Friday: High pressure behind the departing system 
will build into the Northwest resulting in seasonal temperatures 
(near normal for early November) and dry conditions through  mid 
week. One notable change I've seen while looking at the forecast is 
the introduction of a few hours Monday morning (5 - 8 AM) of the 
potential for freezing rain across the upper Columbia Basin (Hwy 2 
corridor) and late Monday night overnight into early Tuesday morning 
the chances of snow showers in the Cascade mountains. The freezing 
rain potential noted by the National Blend of Models is a small 
period of time and about 20% chance right now. The environment 
doesn't seem as favorable with dry air and cool but not overly cold 
temperatures aloft or near the surface. Needless to say, my 
confidence is not great but I'd be doing a dis-service if I didn't 
mention the potential. Snow amounts in the Cascades above 3500/4000 
feet look favorable for several inches of accumulation for Wednesday 
through Friday (35-60% chance by end of Friday for amounts above 
4000 feet). /Dewey 

&&

.AVIATION...
00Z TAFS: Clouds are starting to overspread the Inland Northwest
and chances for light rain increase overnight for eastern WA and
north ID. Overall, conditions are expected to remain VFR except
for KPUW. Uplsope westerly flow into KPUW will lead to ceilings
dropping to IFR around 10-12Z Sunday. There is a 60% chance 
this persists until 20z. Chances drop off into the afternoon but
continued westerly flow supports MVFR ceilings to persist. 

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Moderate
confidence in IFR ceilings for KPUW. High confidence in VFR
conditions elsewhere. 

-----------------------

Confidence descriptors:
Low - Less than a 30 percent chance
Moderate - 30 to 70 percent chance
High - Greater than a 70 percent chance

For additional probabilistic information for NWS Spokane
airports, please refer to the Aviation Dashboard on our 
webpage: https:/www.weather.gov/otx/avndashboard

&&

.Preliminary Point Temps/PoPs...
Spokane        38  51  33  52  35  53 /  30  10   0   0   0   0 
Coeur d'Alene  38  52  33  51  35  53 /  20  10   0   0   0   0 
Pullman        36  48  32  51  35  52 /  30  30   0   0   0   0 
Lewiston       42  53  38  55  39  56 /  30  40   0   0   0   0 
Colville       32  51  27  51  26  53 /  30  10   0   0   0   0 
Sandpoint      35  50  32  49  32  51 /   0  10   0   0   0   0 
Kellogg        37  51  34  51  35  54 /  10  20   0   0   0   0 
Moses Lake     35  54  29  55  34  57 /  10   0   0   0   0   0 
Wenatchee      36  52  34  52  40  56 /   0   0   0   0   0   0 
Omak           35  51  31  52  36  55 /  10   0   0   0   0   0 

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...None.
ID...None.

&&

$$