or discuss
Office: MFR
FXUS66 KMFR 051101
AFDMFR
Area Forecast Discussion
National Weather Service Medford OR
301 AM PST Fri Dec 5 2025
.DISCUSSION...A strong upper ridge remains southwest of the forecast
area with a northwest flow over the area. At the same time a frontal
boundary will slip far enough south to bring light to occasionally
moderate rain to the area late this morning into this afternoon.
With the flow from the west, the bulls eye of precipitation will be
along the coast, coastal mountains and Cascades with lesser rainfall
amounts in the Umpqua Basin, Rogue Valley and east of the Cascades.
The main concern east of the Cascades will be moderate to
occasionally strong winds over the higher ridges this afternoon with
700mb winds between 40-50 kts.
There's good agreement the front will weaken as it remains nearly
stationary late this evening through Saturday. The net result will
be decreasing precipitation late this evening with most hours and
locations dry late tonight through Saturday.
A warm front will move into the area Sunday with a net increase in
precipitation with most centered west of the Cascades. Rainfall
amounts Sunday will be light with higher amounts over northern
Douglas and Coos County.
The general consensus for most of next week keeps the bulk of the
rainfall north of the forecast area. However intermittent light is
expected in northern Douglas and Coos County on the southern
fringes of the heavier core of rainfall which is likely to be
mainly from about Eugene up to western Washington next Monday
through Wednesday.
It should be noted that during this time, snow levels will be above
all the passes, therefore the concern for snow is next to zero.
-Petrucelli
&&
.AVIATION...05/12z TAFs...Ceilings have lowered over the last
several hours as a frontal boundary moves south. LIFR ceilings are
likely to be the predominate condition along the coast and just
offshore with a reduction of visibility through the TAF period,
Inland, west of the Cascades, MVFR ceilings will lower to IFR later
this afternoon through tonight.
East of the Cascades, VFR conditions will be the predominate
condition, however the higher terrain could end up partly obscured
after 18z. Stronger winds aloft could result in some turbulence
along and east of the Cascades.
Snow levels will remain higher between 8000-10000 feet. -Petrucelli
&&
.MARINE...Updated 230 AM PST Friday, December 5, 2025...Winds will
transition to south and southwest ahead of another front. Advisory
strength winds today will be strongest near shore north of Cape
Blanco. The combination of west-northwest swell, residual northerly
fresh swell, and southerly wind seas will result in steep, chaotic
seas into the weekend. Conditions remain unsettled through the first
part of next week, with several fronts bringing periods of gusty
south winds and a likelihood of high and steep seas.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...None.
CA...None.
PACIFIC COASTAL WATERS...Small Craft Advisory until 4 PM PST Saturday
for PZZ350-356-370-376.
&&
$$
Office: PQR
FXUS66 KPQR 051157
AFDPQR
Area Forecast Discussion
National Weather Service Portland OR
357 AM PST Fri Dec 5 2025
.SYNOPSIS...A steady succession of frontal systems will keep
conditions wet through the weekend and much of next week. The
most notable period continues to focus on Monday through
midweek, when a prolonged atmospheric river may bring
significant rainfall and rising rivers across southwest
Washington and northwest Oregon.
.DISCUSSION...Now through Thursday...A more robust frontal
system is moving inland early this morning, bringing widespread
rain to the region. This feature carries a stronger plume of
moisture than yesterday’s system, with integrated vapor
transport values generally running in the 500-700 kg/ms range.
This is enough to support persistent rainfall through the day,
including areas farther south that were largely missed during
the previous event. Rainfall from now through 5 AM Saturday is
expected to total about 0.25 to 0.50 inches across interior
lowlands. Totals will be notably higher along the coast,
generally in the 1.0 to 1.5 inch range, with 2 to 3 inches
common across the Coast Range and Cascades. Winds today will
turn breezy from the southwest, with gusts most frequently
reaching 25 to 35 mph through most of the day. Expect the
frontal passage to arrive around 7-10 AM today.
Showers linger into Saturday as a westerly flow pattern
persists. Another frontal wave will arrive Sunday and bring yet
another round of steady rainfall to the region. Ensemble
guidance suggests IVT values with Sundays system in the 300-500
kg/ms range, producing a widespread soaking. Rainfall totals
from Saturday through sunday are currently projected to fall in
the 0.5 to 1.0 inch range across the interior lowlands, with
0.75 to 1.0 inches along the coast and 1 to 2 inches in the
Coast Range. The Cascades are expected to receive roughly 1.5 to
3.0 inches, except for the Lane County Cascades where amounts
are closer to 0.5 to 1.5 inches. Forecast confidence in the
exact high and low ends of these ranges remains moderate.
Widespread impacts are not anticipated through Sunday; however,
if rainfall rates sustain around 0.2 to 0.3 inches per hour for
several hours, a few faster-reponding basins, such as the Grays
at Rosburg and the Willapa River, could rise quickly.
Attention then turns to the Monday-Wednesday period, where
models continue to suggest a multi-day atmospheric river. Over
the past several cycles, ensembles have become increasingly
consistent in highlighting two distinct surges of moisture: one
centered roughly on Monday, and a second sometime Tuesday or
Wednesday. Between these peaks, the moisture feed is unlikely to
shut down completely, leading to a long-duration event rather
than two isolated episodes.
Ensemble IVT guidance continues to show a broad range but
retains a strong signal for an impactful event. For the first
plume on Monday, GEFS and ECMWF are similar, with members
clustering around 600-650 kg/ms and higher-end solutions near
750-800 kg/ms. The second surge maintains mean values in the
500-600 kg/ms range with high-end members closer to 750-850
kg/ms. The precise timing and latitude of these plumes remain
uncertain, but confidence continues to increase that the region
will experience a prolonged period of moderate to heavy
rainfall. Winds early next week may also trend breezy, but
ensemble spread remains wide. Even moderate gusts in a 30-40 mph
range could be sufficient to bring down isolated trees due to
increasingly saturated soils. This remains a detail to refine as
the event draws closer.
Overall, the Monday-Wednesday period remains the primary focus
for potential high-impact hydrologic (see hydrology section
below for more details) and wind concerns. Confidence in a
multi-day atmospheric river is rising, but exact rainfall totals
and timing details still require several more forecast cycles
to resolve. While rain is looking to continue through at least
Thursday, rain amounts look much less Thursday and onward.
~12
&&
.HYDROLOGY...A series of frontal systems will keep conditions
wet through the weekend and much of next week. The most notable
period will be late Monday through late Wednesday, where a
prolonged atmospheric river may bring significant rainfall and
rising rivers across southwest Washington and northwest Oregon.
Rivers draining the Coast Range and Willapa Hills have a 10-25%
chance of reaching moderate flood stage and a 8-15% chance of
reaching major flood stage. There is also the potential for
flooding along small creeks and streams, as well as urban
flooding. Flooding of the Willamette mainstem rivers is unlikely
to occur (less than 10%). Probabilities for specific river
points can be found at the National Water Prediction Service
website. Periods of heavy rain will also increase the risk for
landslides in areas of steep terrain, and debris flows over
recently burned areas.
&&
.AVIATION...At 11z Friday, a mixed bag of flight conditions were
being observed across southwest WA and northwest OR with a warm
front draped over far northwest Oregon. South of this front,
breezy southerly winds, mild temperatures, spotty light showers
and MVFR to VFR ceilings and visibilities were being observed
from KSLE to KEUG. Along and north of the warm front, conditions
were a bit cooler with lighter winds, persistent light rain, and
LIFR to IFR ceilings and visibilities, including KHIO, KPDX, and
KTTD. LIFR ceilings persist at the coast.
A band of heavier stratiform rain is expected to move north to
south across the area between 15-21z Friday, resulting in
visibility reductions down to 2 to 4 SM much of the time, mainly
during the morning hours. LIFR to IFR cigs this morning will trend
towards low-end MVFR towards 00z Saturday, which is also when
precipitation will become more showery. The coast is expected to
remain in LIFR to IFR thresholds through the TAF period. South to
southwest winds are expected to increase Friday afternoon, with
gusts up to 20-25 kt inland and up to 30 kt at the coast.
KPDX AND APPROACHES...LIFR cigs are expected to persist this
morning, potentially rising to low-end IFR towards 16z Friday.
Low-end MVFR cigs become likely by 00z Saturday. Steady stratiform
rain is expected over the KPDX terminal between 15-19z Friday,
lowering surface visibilities down to 2 to 4 SM much of the time.
South winds increase Friday afternoon with gusts up to 25 kt. -23
&&
.MARINE...A frontal system will move over the waters today, with
westerly winds increase to 15 to 25 kt with gusts up to 30 kt,
strongest over the northern waters. Small Craft Advisories remain
in effect across all waters including the Columbia River Bar
beginning 4 AM Friday, lasting through Saturday evening. Seas of
4-5 ft early this morning will build to around 7-9 ft at 10-11
seconds by Friday evening as a northwesterly swell moves in with
the next system. Will note that a very strong ebb may lead to
higher seas of 10-11 ft in the Main Channel of the Columbia River
Bar around 4-5 PM Friday. For the rest of the waters, seas likely
(80% chance) build above 10 ft by late Saturday morning. There is
also a 25% chance that seas build above 13 ft, with the highest
chances north of Cape Lookout and beyond 10 NM. There is a 1-5%
chance seas peak as high as 15 ft.
The parade of fronts continue through the weekend and into early
next week. Chances for widespread and frequent Gale force wind
gusts of 34 kt or greater remain under 15% through early next
week; however, chances for brief and isolated Gale force wind
gusts are around 40-50% on Sunday and 50-70% on Monday. Seas are
forecast to hover close to 15 ft from late Monday through late
Wednesday, with a 10% chance seas peak around 17-18 ft. -10/23
&&
.BEACH HAZARDS...Coastal Flood Advisories remain in effect from
for minor tidal overflow during high tide from 9 AM to 3 PM Friday
and Saturday for the south Washington coast and Clatsop County
coast in Oregon. Minor flooding up to 1 foot above ground level
is possible during high tide in low lying areas near bays,
sloughs, and the low reaches of the coastal rivers. Coastal
residents in the warned area should remain alert for rising water
and take appropriate action to protect life and property. -10
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Coastal Flood Advisory from 9 AM this morning to 3 PM PST this
afternoon for ORZ101.
Coastal Flood Advisory from 9 AM to 3 PM PST Saturday for ORZ101.
WA...Coastal Flood Advisory from 9 AM this morning to 3 PM PST this
afternoon for WAZ201.
Coastal Flood Advisory from 9 AM to 3 PM PST Saturday for WAZ201.
PZ...Small Craft Advisory until 10 PM PST Saturday for PZZ210-251>253-
271>273.
&&
$$
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Office: PDT
FXUS66 KPDT 051208
AFDPDT
Area Forecast Discussion
National Weather Service Pendleton OR
408 AM PST Fri Dec 5 2025
.DISCUSSION...
Key Messages:
1. Breezy to windy conditions this afternoon through Saturday
afternoon. Wind advisories expanded both temporally and spatially.
2. Persistent rain chances through the next week combined with
high snow levels will lead to rises on area rivers.
Overview: The forecast for the next week can be succinctly
described as warm, wet, and windy as a subtropical high in the
Pacific combines with a remarkably persistent quasi-zonal to zonal
jet stream and multiple frontal systems to direct several rounds
of subtropical to tropical moisture into the Pacific Northwest.
Headline updates: The main update to headlines was the expansion
of existing wind advisories to include the Yakima Valley, Lower
Columbia Basin of Washington, and the Wallowa Valley.
Rain is beginning to overspread the forecast area again as low- to
mid-level warm air advection (WAA) associated with a warm frontal
passage this morning interacts with ample moisture. The result
will be the best precipitation chances for the lower elevations
through the remainder of the week. For mountain areas, especially
the Cascade crest and northern Blues, precipitation chances will
be more persistent into the weekend.
The main talking point today is the anticipated breezy to windy
westerly (southwesterly to northwesterly depending on the exact
location) winds that are poised to ramp later this afternoon
through tonight as a strong jet moves overhead. This afternoon
through Saturday morning, the 00Z HREF places a persistent 8-12
hPa pressure difference between PDX and GEG -- often the
threshold where advisory-level winds begin -- and an 850-hPa jet
of 40-60 kts over the Columbia Basin. While the largely nocturnal
nature of the event does reduce overall forecast confidence in
persistent, widespread advisory-level winds through the entire
advisory period, confidence is still high (70-95%) that peak gusts
will exceed 45 mph in wind-prone locations. Moreover, per NBM
calibrated probabilities, there is still a low-medium chance
(20-50%) of reaching or exceeding warning-level gusts in the most
wind-prone locations of the Columbia Plateau.
Snow levels today will remain high enough (generally 5-8 kft) to
preclude any concerns for winter weather headlines, though a
cooler air mass tonight through Saturday night will present lower
snow levels (4-5 kft) and at a medium chance (50%) of advisory-
level snowfall for White Pass. Through the bulk of the next week,
snow levels are then forecast to remain high at mostly 5-8 kft
with periodic dips to 4.5 kft along the Washington Cascades.
Lastly, will note a significant amount of precipitation is
forecast for the mountain areas Monday through Thursday of next
week. While confidence in precise amounts is still low, and will
depend on the exact location of the jet stream and incoming
frontal systems, the NBM places a 20-30% chance of reaching or
exceeding 5 inches of liquid equivalent across the Oregon Cascade
crest through the 72-hr period ending 4 AM Thursday, and an even
higher 40-50% chance for the Washington Cascades. Since much of
this precipitation is forecast to fall as rain, rises on area
rivers are anticipated. Current forecasts from the NWRFC in
Portland do place multiple rivers near or above action stage by
the latter half of next week.
&&
.AVIATION...12Z TAFS...Conditions were mainly ranged from VFR to
LIFR this morning, with BDN and RDM having VFR conditions and
ALW being socked in with low clouds and fog once again. ALl other
sites were generally either IFR or MVFR, mainly due to CIGS.
Latest radar showed an area of RA between DLS, PSC and HRI and once
this area moves through, additional RA is expected throughout the
day. Reduced CIGS/VSBYs are expected through the day everywhere
(and can't be ruled out at BDN/RDM) until late afternoon, when
conditions should begin to improve.
Winds will increase during the mid to late afternoon hours from the
southwest to west and become gusty in the 25 to 35 kt range. These
winds will help clear out any fog and bring VFR conditions to all
TAF sites by evening/overnight. The only exception is ALW, where
some lingering low clouds may keep MVFR conditions longer, but
even that location should improve to VFR by late Friday
night/early Saturday.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 54 41 52 39 / 100 40 40 30
ALW 51 42 52 41 / 100 60 50 50
PSC 51 41 56 39 / 90 10 10 10
YKM 50 38 55 34 / 80 30 20 20
HRI 54 42 55 39 / 90 20 20 20
ELN 45 36 48 32 / 90 60 40 30
RDM 55 32 50 32 / 90 40 10 10
LGD 48 38 46 34 / 100 80 80 60
GCD 48 35 46 33 / 100 60 40 40
DLS 55 47 55 44 / 100 70 70 80
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory from 1 PM this afternoon to 10 AM PST Saturday for
ORZ041-044-507-508-510.
Wind Advisory from 1 PM this afternoon to 1 PM PST Saturday for
ORZ050.
WA...Wind Advisory from 1 PM this afternoon to 10 AM PST Saturday for
WAZ024-521.
Wind Advisory from 7 PM this evening to 7 AM PST Saturday for
WAZ026>029.
&&
$$
DISCUSSION...86
AVIATION...77
