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Office: MFR
FXUS66 KMFR 091035
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
235 AM PST Tue Dec 9 2025

.DISCUSSION...Satellite and observations show that low clouds are
developing across some west side valleys, including the Rogue
Valley. Heavier cloud cover is preventing fog development in more
east side spots, including Klamath Falls for now. Radar has a few
showers passing in far northern Coos and Douglas counties as they
move east tonight. Through the morning, these showers are forecast
to reach ~0.25"- 0.50" near the Douglas/Lane County border. Snow
levels in the affected areas are above 8,000 feet tonight.

The upper level high to our southwest off of central California is
still looking to be enough to keep most of the activity north near
Portland and Seattle this week. The main areas to see rainfall for
the next few days will be the same locations to see it now. Between
this morning and Wednesday morning, very northern Coos and Douglas
counties, including parts of the Cascades, can expect 0.30"-0.75",
with near 1.25"-1.75" near the northernmost part of Douglas
County. Most of the rain will fall between this morning and into
the evening. Although most of this will be occurring in a 12 hour
period, there is a lower concern for flooding with this compared
to areas north of us. East side and Northern California have the
lowest chances for rain with less than .15" from Chemult to Fort
Rock being the most to expect.

Although the area will be dry, east side will have to deal with
stronger winds between now and this afternoon. A mid-level jet of 50-
60 kt with similar speeds at 300 mb show that strong winds are
forecast to reach the surface during this time with gusts near 50
mph. A Wind Advisory is in effect through this evening, and this
includes areas near Silver Lake, Summer Lake, and Paisley. Wind
gusts near 45 mph have already been reported at Summer Lake
early this morning. Please see the NPWMFR for more information.

Getting into the middle of the week, the high pressure to our
southwest takes control and brings drier conditions through at least
the start of next weekend. Earlier models were showing a continued
chance of showers at the coast through the work week, but this has
started to back off. The EC has also backed off on weekend rain
chances, but it is still coming in earlier than the GFS with a
Monday morning vs Monday afternoon timeframe. Either way, there is
some more agreement that early next week could have active weather
in both Southern Oregon and Northern California. In the meantime, we
will be watching for how the system the next few days moves through
and watch for how the models handle the next week after. -9

&&

.AVIATION...09/06Z TAFs...A front remains aimed at the Oregon Coast
just north of North Bend. This is bringing gusty winds to the coast
and a variety of ceiling conditions across the region. Along the
coast and just offshore, IFR and LIFR ceilings are expected to
prevail through the TAF period, with visibility also lowering
Tuesday morning as the front slowly sags south. VFR conditions
generally prevail across the region, but LIFR conditions are
developing in the Rogue/Illinois/Applegate Valleys, and these lower
conditions will prevail into Tuesday morning. In the Umpqua Basin,
the proximity of the front could limit fog development there, but
MVFR conditions are still expected tonight into Tuesday morning.

Meanwhile, strong winds aloft will persist near the Cascades and
over the east side in Oregon (north of Highway 140) tonight into
Tuesday where higher terrain could experience gusts in excess of 50
mph. This could lead to some low-level wind shear over there (NE of
Klamath Falls) since a low-level inversion probably doesn't allow
these winds to mix all the way to the surface in some valleys. Even
so, vertical mixing may improve Tuesday to allow surface wind gusts
to 50 mph from around Summer Lake eastward.

&&

.MARINE...Updated 200 AM PST Tuesday, December 9, 2025...Gusty south
winds and steep wind waves combined with westerly swell will
maintain conditions hazardous to small craft through at least today.
Winds subside tonight, but west swell persists into Wednesday,
especially north of Cape Blanco. Conditions improve for the latter
half of the week as swell dominated seas gradually lower. Expecting
showers over the waters through mid-week as well which could further
reduce visibilities (fog/low clouds expected as well) over the next
couple days.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory until 10 PM PST this evening for ORZ030-031.

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 1 AM PST
     Wednesday for PZZ356-376.

     Small Craft Advisory until 10 AM PST Wednesday for PZZ350-370.

&&

$$



Office: PQR FXUS66 KPQR 090604 PAA AFDPQR AAA Area Forecast Discussion...UPDATED National Weather Service Portland OR 1004 PM PST Mon Dec 8 2025 Updated aviation discussion. .SYNOPSIS...A strong atmospheric river is underway across the Pacific Northwest, bringing heavy rainfall, breezy winds, and widespread hydrologic concerns. Widespread river flooding is likely across the region, along with urban and small stream flooding due to persistent heavy rain. Wind may lead to downed trees and power outages due to saturated soils. && .SHORT TERM...Now through Wednesday...The strong atmospheric river (AR) event has begun across the Pacific Northwest, with radar imagery showing moderate to locally heavy rain across northwest Oregon and southwest Washington as of early Monday afternoon. Satellite imagery clearly shows a long, narrow band of moisture extending from the Pacific Northwest out 3000+ miles offshore, and about 1200 miles northwest of Hawaii. This atmospheric river is being driven by a sub-tropical ridge centered just offshore of Southern California and Baja California (~32.05N/130.94W), and a trough centered south of the Aleutian Islands of Alaska (~45.79N/164.89W). Moisture is being advected along the northwestern periphery of the ridge and the southeastern periphery of the trough, leading to the extended band of moisture progressing toward the Pacific Northwest. Ensemble guidance suggests minimal change in the synoptic pattern over the next 48 hours; therefore, this atmospheric river event and associated impacts are expected to last through at least Wednesday. There are one of two surges of moisture coming into the Pacific Northwest with this AR. The first is coming in right now, which is associated with integrated vapor transport (IVT) values of 750-900 kg/ms based off GFS and Euro ensemble guidance. This will maintain steady rainfall and lead to substantial rainfall amounts across western Washington and far northwest Oregon (especially Salem northward). Lower rainfall amounts are forecast for the southern Willamette Valley (Eugene) as most of the moisture is being directed further north. Urban and small stream flooding is possible throughout this AR event, especially in areas that are low-lying and have poor-drainage. If you will be commuting during periods of heavy rain, make sure to slow down, use your headlights, and leave plenty of distance ahead of you. Since 12 AM Monday, weather stations have already reported 1.5-2.25 inches of rain across the north Oregon and south Washington coasts, Willapa Hills, north Oregon Coast Range, and south Washington Cascades and foothills. These amounts were achieved by heavier rainfall rates of 0.25-0.50" per hour. Based off the latest REFS guidance, most ensemble members suggest that these rainfall rates will continue through late Monday evening into early Tuesday morning over the aforementioned areas. Rainfall rates this high will result in rivers and creeks that drain off the Willapa Hills and Clatsop/Tillamook Counties to start rising sharply through the evening (see hydrology section for more details on river flooding). Elsewhere, rainfall amounts since midnight generally range from 0.25-1", with the highest amounts further north you go. South of Albany, OR and across the Lane County Cascades, amounts have been around 0.10" or less, which is expected given the more northward track of the AR. This plume of AR moisture will briefly track southward tonight into early Tuesday morning, bringing increased rainfall toward Lane County. Will see a very brief break in rainfall rates across far northwest Oregon and southwest Washington Tuesday morning, but that doesn't mean we'll be clear of any impacts. Local rivers tend to lag a few hours following heavy rainfall, so will most likely see rivers continuing to rise and potentially hit flood stage even when rain has decreased. Again, more details in the hydrology section on this. The second surge of AR moisture will hit western Washington and far northwest Oregon Tuesday afternoon into Wednesday, bringing another round of moderate to locally heavy rainfall to these areas. It will be a similar set-up as today, but this time ensemble guidance suggests IVT values will be around 600-700 kg/ms. Given the amount of rain that will have fallen before this second round, local rivers will continue to rise and concerns for urban and small stream flooding will continue. For snow and winter sport lovers, unfortunately this AR will be very warm and snow levels will remain above 8000 feet through Wednesday. Wind will also potentially bring impacts during this AR event. Wind Advisories remain in effect through 4 AM Tuesday across the central/north Oregon Coast Range, Willapa Hills, Willamette Valley from Salem northward, and southwest Washington lowlands. Southerly winds are forecast to gust up to 30-40 mph tonight. Saturated soils will increase the likelihood that even moderate gusts could cause uprooting of trees and lead to damage. While there is moderate to high confidence in potential impacts due to wind, there is low confidence on exactly where impacts may occur. If you see a downed power line, move away from it. Do not drive over downed power lines. If you come into contact with a downed power line, stay inside the car and call for help. -10 .LONG TERM...Wednesday Night through Sunday...The atmospheric river event weakens Wednesday afternoon into Thursday as moisture transport gradually decreases. Light residual showers continue, with some localized areas of moderate rain showers over higher terrain across southwest Washington and the north Oregon Coast Range. By Thursday, the pattern transitions toward a more typical post- frontal regime with shower activity gradually decreasing and winds weakening. Friday becomes drier as high pressure builds over the region. Snow levels will also gradually lower heading into the weekend, but still remain above pass-level at around 5500-6500 feet. Despite the weather becoming more tame late in the week, rivers and soils will continue responding to the cumulative rainfall load from the current atmospheric river event. Any slow-responding rivers within flood stage will need extra time to subside. -10/12 && .AVIATION...The strongest portion of the first stage of the atmospheric river continues to shift southward today with the frontal edge hitting the south Washington coast. This system has been exhibiting wind speeds around 30 kt at the surface with some exposed areas within the Columbia River Gorge above 3000 ft MSL seeing gusts up to 65 kt. The winds are beginning to ease inland though are continuing to blow along the coast. Widespread gusts up to 30 kt expected along coastal terminals. Winds inland remain gusty with speeds around 20-25 kt. We are beginning to see the shift in flight conditions as the system shifts southward. Northern runways are beginning to see CIGs lift to VFR while coastal and central runways are remaining IFR or MVFR. Through the night the front will bring the southern portions of the forecast area the MVFR conditions. Through the day on Tuesday after 18Z, the atmospheric river will move north once again. Think of this system doing the "wave". As it does so, the areas that saw a brief reprieve will once again deteriorate. Overall, while a dynamic system with many different moving parts, the impacts will be similar through the next 24-hours. Will add, that while it does not impact most of our terminals or runways, wind speeds at around 5000 ft MSL are gusting as high as 80 kt then decrease to around 70 kt after 21Z Tue. This is a very active jet stream. KPDX AND APPROACHES...A mixture of VFR and MVFR conditions over the next 24 hours. Timing has been incredibly difficult due to the movement of the atmospheric river. Portland has been sitting in the bullseye of the system and therefore winds and rain have been strong. These conditions will continue to improve over the next few hours, but will deteriorate once again after 18Z Tue as the frontal system moves right back over. While winds will decrease through the day, winds aloft remain quite strong. -27 && .MARINE...Gales continue across all zones as a strong system passes over the region. Wind gusts 35-45 kt will continue through late tonight - strongest over the inner waters. The gale warning remains in effect until 1 AM Tuesday. A lull is expected early Tuesday morning as the frontal boundary drops southward, decreasing winds from north to south. Wind gusts are expected to drop below 20 kt everywhere except zones PZZ273 and PZZ253. Seas will also remain steep during this time so a Small Craft Advisory will follow the gale warning from 1 AM to 7 PM Tuesday to cover these elevated conditions. Another front is expected to pass through the waters late Tuesday into Wednesday and will push wind gusts closer to 30-35 kt. There is increasing potential for gales Tuesday evening into the overnight and may require an upgrade to another Gale Warning. Seas will increase into the low to mid teens with this second system, reaming above 10 feet through Wednesday night. -19 && .BEACH HAZARDS...Tidal overflow flooding around high tide is possible on Tuesday, December 9. Despite total tide forecasts decreasing over the coming days, river levels will be rapidly rising due to a prolonged period of heavy rain through Wednesday. Confidence has increased that several rivers along the Oregon Coast north of Lincoln City and the SW Washington Coast will reach at least 80% of flood flow by high tide Monday afternoon, when total tide forecasts are expected to peak near or slightly above 9.5 ft. Therefore, a Coastal Flood Advisory for tidal overflow remains in effect until 6 PM PST today for these coastal zones. It appears the threat for tidal overflow flooding is low on Tuesday, as total tide forecasts decrease considerably and are well below the 9.5 foot threshold. That said, minor tidal overflow flooding cannot be completely ruled out for a brief period of time around high tide on Tuesday given river levels will be running quite high at that time. Will continue to monitor the tidal and river forecasts for Tuesday. Additionally, there is an elevated threat for sneaker waves late Wednesday through Thursday along the SW Washington coast south through the central Oregon coast. The swell period increases to around 14-15 seconds with swell heights around 9-11 ft, with swell heights and swell periods decreasing late Thursday night. This will create energetic waves that will present a moderate to high risk for sneaker waves, waves which can run significantly farther up a beach than normal, including over rocks and jetties. Sneaker waves can suddenly knock beachgoers off if their feet and quickly pull them into the frigid ocean which may lead to serious injury or drowning. Caution should be used when in or near the water. Always keep an eye on the waves, and be especially watchful of children. -23/03 && .HYDROLOGY...A series of frontal systems will maintain very wet conditions through much of this week. The most notable period will extend through late Wednesday, when a long-duration atmospheric river will bring significant rainfall and the potential for widespread river flooding across southwestern Washington and northwestern Oregon. There is a 10% chance for 72-hour rainfall of up to 6-8.5 inches in the Cowlitz Valley, lower Columbia, Portland/Vancouver metro and northern Willamette Valley, 4-6 inches in the central Willamette Valley, 3-4 inches in the southern Willamette Valley, 7-11 inches in the Cascades, Cascade foothills, Coast Range, and the coast, except 3.5-7 inches from Florence to Newport and in areas of higher terrain in Lane County. While rain amounts this high are unlikely to occur, they represent a reasonable worst case scenario. This outcome would result in widespread major flooding. Chances for high total rainfall amounts as well as brief periods of locally heavy rainfall in Lane County have continued to trend downward today. This suggests future river model suites will see similar downward trends in the likelihood of river flooding. Although rain will likely become lighter on Thursday, the threat of flooding will linger along slow-responding rivers. Rivers draining the Coast Range and Willapa Hills have a 40-70% chance of reaching moderate flood stage and a 20-50% chance of reaching major flood stage, with a handful of rivers already observing flooding, namely the Grays River draining the Willapa Hills in Major flood and the Wilson River in Tillamook in Minor flood. Additionally, many Willamette River tributaries that drain from the Coast Range and Cascades have anywhere from a 40-60% chance of reaching minor flood stage and a 20-40% chance of reaching moderate flood stage. Flooding of the Willamette mainstem rivers have a very low chance to occur (5-15%). Probabilities for specific river points can be found at the National Water Prediction Service website. Flood Warnings have been issued for the Naselle River near Naselle and the Grays River near Rosburg draining the Willapa Hills in southwestern Washington, the Wilson and Trask Rivers near Tillamook, and Johnson Creek at Sycamore near Milwaukie and along the southern edge of the City of Portland. There is also increasing confidence in the potential for flooding along small creeks and streams as well as urban flooding, including roadway flooding. Latest high-resolution guidance favors a band of heavier precipitation lingering over southwestern Washington and far northwestern Oregon late this evening, before sagging southward through the early morning hours. These potential heavy rainfall rates could make for a hazardous morning commute along the I-5 corridor from Salem north through Portland/Vancouver to Kelso/Longview with abundant water atop area roadways. Periods of heavy rain will also increase the risk for landslides in areas of steep terrain and debris flows over recently burned areas. People, structures, and roads located below steep slopes, in canyons, and near the mouths of canyons may be at serious risk from rapidly moving FXUS66 KPQR 090604 PZB AFDPQR landslides. Therefore, a Flood Watch remains in effect across all of southwest Washington and northwest Oregon from now until 4 AM Friday. && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Coastal Flood Advisory from noon to 5 PM PST Tuesday for ORZ102. Wind Advisory until 4 AM PST Tuesday for ORZ104>115-123. WA...Wind Advisory until 4 AM PST Tuesday for WAZ202>208. PZ...Gale Warning until 1 AM PST Tuesday for PZZ210-251-271. Small Craft Advisory from 1 AM to 7 PM PST Tuesday for PZZ210- 251-271. Gale Warning until 7 AM PST Tuesday for PZZ252-253-272-273. Small Craft Advisory from 7 AM to 7 PM PST Tuesday for PZZ252- 253-272-273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland
Office: PDT FXUS66 KPDT 090659 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 1059 PM PST Mon Dec 8 2025 .AVIATION...06Z TAFs...Predominantly VFR conditions are forecast into the overnight hours for all sites as a strong rain shadow is keeping rain pinned to the mountains. Early Tuesday morning through Tuesday evening, rain is forecast for most sites as a band of rain sets up over the region. Some MVFR conditions are forecast within the band. Breezy to windy southwest to west winds are expected to be strongest this evening. && .PREV DISCUSSION... /issued 328 PM PST Mon Dec 8 2025/ DISCUSSION... Key Messages: 1. Windy conditions tonight, returning late Tuesday night. *Wind Advisories Active* 2. Significant rainfall leading to flood concerns through week. *Flood Watch Issued* Current radar and visible satellite imagery showing moderate to heavy rainfall west of the Cascades, with isolated showers passing through the Columbia Basin under mostly cloudy to cloudy skies. This is in response to an upper level shortwave and associated cold front that is passing through the area this evening. The passing cold front will also tighten the pressure gradient across the Columbia Basin, providing breezy winds tonight through the morning hours on Tuesday. The RAP, GFS, and NAM advertise a gradient of 9.5-11.5 mb between Portland (PDX) and Spokane (GEG), which relates to sustained southwest winds of 25-35 mph with gusts of up to 60 mph, peaking between 8PM tonight and 3AM Tuesday morning. Confidence in these wind speeds is high (75-90%) as the NBM advertises a 70-95% chance of 50 mph gusts or greater across the Simcoe Highlands and southern Blue Mountain foothills and a 50-80% chance of 45 mph gusts or greater through the northern Blue Mountain foothills, Yakima Valley, and the Lower Columbia Basin. Thus, a Wind Advisory has been issued through 7 AM Tuesday for the aforementioned areas. Winds will slowly taper off through Tuesday morning and afternoon before a second cold front passage occurs late Tuesday night through Wednesday morning, promoting a return to breezy conditions. This second frontal system is not as strong as tonight's, as the GFS and NAM indicates a pressure gradient of 8-10 mb. These values relate to sustained southwest winds of 15-25 mph and gusts up to 40 mph, which is below the wind advisory threshold (45 mph or greater). The early week system will not only bring windy conditions across the region, but substantial and widespread rainfall is anticipated through Wednesday associated with a strong atmospheric river (AR) event. The ECMWF and GFS ensembles show Precipitable Water (PW) amounts of around 1 inch, which is 225-250% above normal. The fetch associated with this AR extends to the date line (~170W), effectively tapping into subtropical moisture and temperatures. As a result, snow levels have soared into the 7000-9000 foot range as high temperatures are breaking into the upper 50s to mid-60s through the week, which is about 15-25 degrees above normal for this time of year. These warm temperatures and rain-on-snow potential due to elevated snow levels will allow rivers and streams to reach flood levels, especially for the Naches and Yakima Rivers as the current forecast reaches action stage over the next 24 hours and peaks in moderate flood stage for the Naches River near Naches and the Yakima River near Parker and Kiona Thursday and Friday. Reaches further upstream are expected to reach minor flood stage over the next 24 hours. As a result, a Flood Watch has been issued and is in effect through Friday morning. The Yakima River at Easton has already reached into action stage, with low-lying and flood prone areas already experiencing localized flooding. This has warranted the issuance of a Flood Advisory for the Elk Meadows area near Cle Elum as flooding is ongoing via contact with the public. In addition to the Yakima and Naches Rivers, the Klickitat River near Pitt and the Umatilla River near Gibbon both reach action (bankfull) stage Wednesday morning. River levels are expected to subside slowly over the weekend with all reaches currently forecast to fall below minor flood stage by early Monday morning. 75 && .PRELIMINARY POINT TEMPS/POPS... PDT 48 56 45 65 / 70 100 90 40 ALW 50 54 46 64 / 80 90 90 60 PSC 49 56 44 66 / 40 80 90 20 YKM 41 50 39 60 / 80 80 100 60 HRI 50 57 46 66 / 50 90 90 20 ELN 37 46 35 56 / 90 70 100 70 RDM 43 57 44 63 / 50 70 50 10 LGD 45 51 41 58 / 90 100 100 50 GCD 45 51 45 58 / 50 90 70 10 DLS 51 56 48 63 / 90 100 100 70 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Wind Advisory until 7 AM PST Tuesday for ORZ041-044-507-508-510. WA...Wind Advisory until 7 AM PST Tuesday for WAZ024-027>029-521. Flood Watch through Friday morning for WAZ026-027-521>523. && $$ DISCUSSION...75 AVIATION...86