788 FXUS66 KSEW 052253 CCA AFDSEW Area Forecast Discussion...CORRECTED National Weather Service Seattle WA 253 PM PST Fri Dec 5 2025 .SYNOPSIS... The weather pattern has transitioned into an active phase as a series of system bring rain, high elevation snow and wind into the region through the end of the weekend. A strong atmospheric river is still on track to region the area by Monday and last into at least the midweek time frame. This system will bring very significant rainfall and likely hydrologic impacts. Coastal flooding due to higher astronomical tides will remain minor into early next week. && .DISCUSSION... KEY MESSAGES... * RAIN: a few relatively minor systems will sweep across the area tonight, and on Sunday, before a strong atmospheric river system will bring heavy precipitation the area Monday through at least Wednesday. Models ensembles are beginning to show another round of heavy precipitation Thursday into Friday as well, now. The hydrologic implications will be detailed in the HYDROLOGY section. * SNOW: lowering snow levels tonight to just below 4000 ft will allow for significant accumulating snow for Stevens Pass and White Pass. Heavy precipitation through tonight into early Saturday, as well as the potential for a convergence zone late tonight will allow for 1-1.5"/hr+ snowfall rates, which will make travel very difficult. Wind gusts up to 30-35 mph will limit visibility at times as well. Check WSDOT for the latest pass conditions and for closures. * WIND: winds will generally be elevated through the next 7 days, but the time periods for the strongest winds will be tonight, as well as on Monday, where gusts up to 45 mph will be possible along the Pacific coast, the Strait/Northwest Interior, as well as through the Cascade Mountains. * COASTAL FLOODING: tides have now peaked for the Pacific Coast, through with larger waves coming in tomorrow, the potential for minor coastal flooding impacts will be possible again on Saturday, mainly for the beaches of Grays Harbor County. For the northern interior waters, tide levels this weekend will rise, allowing for mostly minor coastal flooding impacts. Going into next week, active weather looks to keep tide levels high and may create additional impacts for Puget Sound coastlines as well. As of this afternoon, radar imagery is showing the strong influx of moisture, creating showers across the Pacific coast and through the Cascade mountains. As the supporting shortwave trough aloft begins to move across the area, that will begin to push in even more moisture, as well as increase westerly winds across the area. Most locations will see winds gusts between 25-35 mph, but Island County may see gusts up to 45 mph, which warrants the wind advisory through tonight. This will also bring some cooler air, which will allow for snow levels to drop below 4000 ft, where impacts will start to be felt at Stevens and White Passes. With the increased westerly winds, we will likely see the development of a convergence zone across central/southern Snohomish County, which will be flirting closely with Stevens Pass. Regardless, moisture will continue to filter in across the area through tonight into Saturday, primarily focused on the Cascades. Latest hi-res guidance is showing the potential for 1-1.5"/hr+ snowfall rates over the passes tonight, and as such, total accumulations through tomorrow afternoon will likely surpass a foot at Stevens Pass, perhaps as much as 16-18 inches. Locally higher amounts are expected at the higher peaks, and at locations such as Paradise and Mt. Baker Ski Area. As such, a winter storm warning is in effect for Stevens Pass, while slightly lower amounts are forecast for White Pass, lending to a winter weather advisory. These products are in effect through Saturday evening. There will likely be a brief lull in the precipitation overnight on Saturday, but it won`t be long until the next system arrives Sunday morning. Precipitation amounts with this systems will be relatively light--a quarter to a half inch across the lowlands, with up to an inch or two for the coast and mountains. Rising snow levels back up to around 4500-5000 ft will allow for rain at the passes. No major hydrologic impacts are expected with this system, but it will prime the soil and the rivers for what will come next week. A strong 100-125 kt jet (at 500 mb) will become aimed at western Washington starting on Monday and continuing through Wednesday. Accompanying that will be a plume of significant moisture; precipitable water values will reach up to 1-1.5", which is 250-300%+ above normal for this time of year. Models are showing integrated vapor transport values reaching or exceeding 750-1000 J/kg during this time period. Needless to say, a lot of water will accompany this atmospheric river headed this way. Heavy rain will begin to arrive early on Monday and continue through early Tuesday. The main moisture plume looks to briefly sink southward on Tuesday, allowing for a brief lull in the heavy rain before another punch of moisture brings back the heavy rain on Wednesday. In this period, the latest rainfall totals put around 3 to 5 inches across the interior lowlands, 4 to 6 inches along the coast, and 8 to locally 12+ inches across the mountains. Flooding is likely; not just the rivers, but also urban/small stream flooding as well. More details on the hydrologic impacts are below in HYDROLOGY. While the forecast trend in QPF continues to inch upward, things can change, so it is pertinent to stay tuned to the latest updates. Lastly, models are starting to show indications of another weather system bringing significant precipitation late Thursday into Friday. While it may not be as much as we`ll see from Monday-Wedensday, with saturated soils and rivers already running very high, this rain may prolong or exacerbate the hydrologic impacts expected by mid-week. As typical in a rainy/atmospheric river setup, temperatures through the week will remain slightly above normal, with highs generally in the low to mid 50s and lows in the 40s. 62 && .AVIATION... Northwest flow aloft will continue tonight as a frontal system pushes inland across western Washington. Conditions are primarily a mix of IFR to MVFR across the majority of the area terminals this afternoon with latest radar showing much of the precipitation moving off into the mountains. A convergence zone is expected to develop around Snohomish County late this afternoon into this evening, which will bring additional post- frontal showers across the region tonight (mainly impacting KPAE). Localized improvements to VFR will still be possible this evening in the post-frontal airmass, however expect more widespread MVFR conditions for most terminals into Saturday morning. Shower activity will increase again overnight into Saturday morning. S/SW surface winds will peak tonight, but remain breezy into Saturday, with gusts generally ranging between 20 to 30 kts for most areas, though localized gusts to 35 kts will be possible in some spots as well. KSEA... Slow improvement to MVFR cigs this afternoon. MVFR conditions will likely persist into Saturday outside of any drizzle/shower activity. A convergence zone will develop later this afternoon, but will remain well north of the terminal. S/SW winds persisting at 10-20 kts will peak tonight, with gusts between 25-35 kts possible at times. Winds will ease somewhat into Saturday, but will remain breezy with gusts to 25 kts at times through the day. && .MARINE... A weather system moving inland tonight will continue to bring gusty winds to the area waters into Saturday morning. Westerly gale force wind gusts will remain possible into early Saturday for the Coastal Waters and western Strait of Juan de Fuca in its wake. A strong push of westerly winds is also likely along the Strait of Juan de Fuca tonight, where localized gusts to 45 kts will be possible at times. Stronger southwesterly winds are also expected along the southern portions of the northern inland waters and near Bellingham Bay tonight, where gusts to 35 kts remain possible. Gusts may also peak briefly around 35 kts for Puget Sound as well tonight, though expect predominantly SCA winds to prevail for the majority of the area. Winds will slowly subside area-wide on Saturday. Additional weather systems are expected over the next week - the next being on Sunday morning, with a stronger system following on Monday and Tuesday. Further headlines will likely be required, with potential gales again with the Monday/ Tuesday weather system. Seas will build to 13 to 18 feet tonight into Saturday morning, before subsiding back towards 8 to 10 feet by late Saturday night. Seas will build again starting late Monday as the next round of weather systems move into the region. && .HYDROLOGY... A series of wet weather systems moving across the region will increase the threat of river flooding early next week. While there`s still some uncertainty in the possible precipitation amounts with an atmospheric river moving into the region the first part of next week, confidence continues to increase in heavy rainfall occuring across western WA, especially over the Olympics and Cascades. Confidence also continues to increase that a widespread river flooding event will commence late Monday, throughout Tuesday and into Wednesday, with multiple rivers flowing off the Cascades and the Olympics reaching Minor, Moderate, and Major flood stage. Additional precipitation is also possible Thursday into Friday, which will keep rivers elevated through the second half of the week. Uncertainty does remain in regards to the exact flood levels and stages through next week, and as such, it will be critical to monitor the forecasts through the next seven days. The series of wet systems will also start to elevate the landslide risk across the region throughout the weekend, with conditions expected increase rapidly early next week with the arrival of an atmospheric river. Urban and small stream flooding, as well as areas with poor drainage, should be alert to the potential for localized nuisance flooding. Low water crossings may become impacted or impassable. 14/62 && .SEW WATCHES/WARNINGS/ADVISORIES... WA...Coastal Flood Advisory from 4 AM to 10 AM PST Saturday for Lowlands of Western Skagit and Northwestern Snohomish Counties-Lowlands of Western Whatcom County-San Juan County. Coastal Flood Advisory from 5 AM to 11 AM PST Sunday for Lowlands of Western Skagit and Northwestern Snohomish Counties-Lowlands of Western Whatcom County-San Juan County. Winter Storm Warning from 7 PM this evening to 10 PM PST Saturday for Cascades of Snohomish and Northern King Counties. Winter Weather Advisory from 7 PM this evening to 7 PM PST Saturday for Cascades of Pierce and Lewis Counties. Coastal Flood Advisory until 3 PM PST this afternoon for Eastern Strait of Juan de Fuca-Grays Harbor County Coast- Northern Washington Coast-Western Strait of Juan de Fuca. Coastal Flood Advisory from 9 AM to 3 PM PST Saturday for Grays Harbor County Coast. Wind Advisory until 7 AM PST Saturday for Island County. PZ...Small Craft Advisory from 10 PM this evening to 10 PM PST Saturday for Grays Harbor Bar. Gale Warning until 4 AM PST Saturday for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From Cape Flattery To James Island Out 10 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm- Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm-West Entrance U.S. Waters Strait Of Juan De Fuca. Small Craft Advisory from 4 AM to 10 PM PST Saturday for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From Cape Flattery To James Island Out 10 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm-West Entrance U.S. Waters Strait Of Juan De Fuca. Gale Warning until 10 AM PST Saturday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca-Northern Inland Waters Including The San Juan Islands. Small Craft Advisory until 4 AM PST Saturday for Admiralty Inlet. Small Craft Advisory until 4 AM PST Saturday for Puget Sound and Hood Canal. && $$

394 FXUS66 KPQR 052311 AFDPQR Area Forecast Discussion National Weather Service Portland OR 311 PM 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...Friday afternoon through Thursday...Radar imagery at 2 PM PST Friday indicates rain has tapered off across most of the area, though showers linger over the coast, Coast Range, and Cascades into tomorrow. The front that moved through the area this morning has stalled over the Cascades, and is expected to move very slowly into eastern Oregon overnight as it decreases in strength. This has caused tighter pressure gradients over the region, producing breezy south to westerly winds this afternoon into tonight. Expect gusts up to 25-30 mph across the Willamette Valley and up to 35-40 mph in the Cascades and Coast Range. 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 Sunday`s 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 1 to 2.5 inches for the coast and Coast Range. The Cascades are expected to receive roughly 1.25 to 3.0 inches, except for the Lane County Cascades where amounts are closer to 0.5 to 1.5 inches. 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 ensemble confidence continues to increase in a multi-day atmospheric river event. 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, leading to a long-duration event rather than two isolated episodes. The IVT spread in ensemble guidance has shrunk significantly on Monday with the first surge of moisture, with GEFS and Euro ensemble means and their high and low end solutions peaking within the 600-850 kg/ms range. The ensemble spread is still wider for the second moisture surge, partially because ensembles are still struggling to determine the location of where it will focus along the WA into OR coast along with the timing. Ensemble means are centered around the 700-800 kg/ms range. with the high ends peaking around 900-100 kg/ms and the low end around 500-650 kg/ms. In between the peaks, the ensemble means indicate the IVT values could remain between 500-700 kg/ms with the low end forecasts between 300-500 kg/ms, which is still quite a bit of moisture. 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 from over 5 days of moderate rain. This remains a detail to refine as the event draws closer. One thing to note is these are warm weather systems, meaning snow levels are very likely to remain above 6000 feet with little to no snow expected over the Cascades. Overall, the Monday through Wednesday time 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. -12/03 && .AVIATION...Radar imagery as of early Friday afternoon depicts decreasing rainfall as the current frontal system exits the region. Terminal observations show a mix of LIFR/IFR CIGs and VIS along the coast, and IFR/MVFR CIGs and VIS across the Willamette Valley. Expect some gradual improvement to high-end MVFR and low-end VFR CIGs this afternoon and evening. High confidence (60-80% chance) that CIGs will be anywhere between 2-4 kft tonight as the low-level atmosphere remains very moist. Guidance suggests 20-30% chance that CIGs fall below 2 kft at any given terminal through early Saturday morning. Southerly to southwesterly winds of 10-15 kt with gusts up to 20-25 kt along the coast and Valley continue through the evening, weakening overnight after 06-09z Sat. Scattered light showers and a mix of high-end MVFR and low-end VFR CIGs continue Saturday as active weather continues. KPDX AND APPROACHES...CIGs trend toward high-end MVFR and low-end VFR (2-4 kft) through the TAF period. Breezy southwesterly winds 10- 15 kt with gusts up to 20 kt, weakening after 08-09z Sat. Strong crosswinds expected as southwest winds remain around 40 kt through this evening. -10 && .MARINE...Breezy west-southwesterly winds with gusts up to 25 kt continue across the waters as a frontal system progresses through the area. Small Craft Advisories remain in effect across all waters including the Columbia River Bar through late Saturday evening. Seas of 7-9 ft at 10-11 seconds build to 11-14 ft at 13 sec Saturday morning as a northwesterly swell moves in. Will note that a very strong ebb may lead to seas of 12-13 ft in the Main Channel of the Columbia River Bar around 530 PM Saturday. There is also a 60-80% chance that seas build above 13 ft, with the highest chances north of Cape Lookout and beyond 10 NM. There is also 30-50% 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 this weekend; however, chances increase to 30-40% on Monday for the inner water zones out 10 NM and Columbia River Bar due to a potential coastal jet with the next system. 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 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 && .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. However, river flooding for some locations could continue into Thursday and beyond as some rivers take longer to respond to heavier rainfall. Rivers draining the Coast Range and Willapa Hills have a 30-60% chance of reaching moderate flood stage and a 10-30% chance of reaching major flood stage. Additionally, many Willamette River tributaries that drain from the Coast Range and Cascades have anywhere from a 10-55% chance of reaching minor flood stage and a 10-25% chance of reaching moderate flood stage. 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. There is also increasing confidence in the potential for flooding along small creeks and streams as well as urban flooding, including roadway flooding, for locations in the central Willamette Valley north into the southwest Washington lowlands, including the Portland metro area. Periods of heavy rain will also increase the risk for landslides in areas of steep terrain and debris flows over recently burned areas. && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Coastal Flood Advisory from 9 AM to 3 PM PST Saturday for ORZ101. WA...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. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland

157 FXUS66 KMFR 052345 AFDMFR Area Forecast Discussion National Weather Service Medford OR 345 PM PST Fri Dec 5 2025 ...Updated AVIATION discussion for 00Z TAFs... .DISCUSSION...While NW portions of our forecast area (Reedsport) will have a couple of significantly wetter periods during the next 7 days, the cut off between where it`s wet and where it isn`t will be stark and bisect the CWA from NW to SE. This is because a strong upper ridge resides well off the coast of California and is directing a subtropical feed of Pacific moisture largely to our north and west through the end of next week. If you`re traveling northward from northern California or SW Oregon up to Portland or Seattle, you`ll encounter much, much wetter conditions, where flooding is a distinct possibility, especially heading into the middle of next week. Now, that`s not to say we won`t have some wet weather down here too occasionally as disturbances move over top of the ridge, but just not to the magnitude of areas farther north. If you`re headed south, it will largely remain dry and mild for early December and SE portions of our area (Alturas) will be left wondering what all the talk of rain is about. The first disturbance is passing through our area currently and will continue into tonight with periods of moderate rainfall focused on the higher terrain of the Cascades and Cascades Foothills of Douglas County. Lighter rain will occur for points south and east. We managed to squeeze out 0.09" here at the airport since 10 am. We`re in a bit of a break now, but do expect a little more light rain into this evening. Breezes picking up from the Cascades eastward in Oregon will continue this evening with some gusts of 40-45 mph. Rainfall will taper off to drizzle for the most part overnight with a large portion of the area dry on Saturday (though some drizzle/light rain could linger from the coast to Umpqua). Models do show the snow level falling to around 5000 feet in the Cascades by Saturday morning, so, if there`s precip still around, it`s conceivable there could be a light dusting to an inch, but that`s about it. The next disturbance, a warm front, will move over the top and into WA/OR late Saturday night into Sunday. This will bring a renewed risk of steadier precipitation across N&W sections of the CWA, once again with most, if not all, precipitation staying to the north of the OR/CA border. We don`t currently predict any measurable rainfall here in Medford, but there could be a 0.10-0.50 of an inch from the coast to the Umpqua Divide/Cascades. Snow levels rise to around 7000 feet. Little or no precip is expected southeast of Highway 97. The Pacific fire hose will continue to wag back and forth Monday into mid next week with models showing another warm front shifting north of the area and snow levels rising above 8000 feet again! The steadiest/heaviest precip will be along the Douglas/Lane County border and the "force field" still appears to be the OR/CA border, where precipitation will really struggle to reach into NorCal during the stretch. There can be some minor rises on area creeks, streams and rivers across N&W sections of the CWA (up around Roseburg and north/west), but since they`re running low for this time of year, we don`t expect flooding. Again, most significant impacts from the rain will be to our north. Beyond that, model clusters/ensembles are coming into agreement for late next week and confidence has increased that the upper ridge will be the main player in West Coast weather Thu-Sat as well. Not great news since we are heading into climatologically the wettest time of the year. Most guidance moves the ridge into California/SW U.S. with some scenarios even amplifying the ridge (displacing the Pacific jet even farther north) to bring a dry, mild period that lasts through next weekend. While the colder scenario mentioned yesterday isn`t completely gone, less than 15% of the ensemble membership shows this as a viable solution. CPC 8-14 day shows strong signal for above normal temps and still shows odds leaning toward above normal precip, but this may be from an offshore frontal system finally pushing eastward toward the end of week 2 (after next weekend). All this got me to thinking about snow pack, which is woefully below normal (almost non-existent) for this time of year, and will remain that way for the next 10 days at a minimum. In fact, looking at Mt. McLoughlin from the valley (almost snowless) made me wonder what the latest date in the season that the mountain hasn`t had snow on it. We don`t have a climate record for the mountain, but at Crater Lake (where images from the visitor`s center are also snowless), the LATEST date in the season for a snow depth of ZERO occurred December 26, 1976. Hopefully, this will change heading into the end of the month and that record won`t be challenged or broken. -Spilde && .AVIATION...06/00z TAFs...Levels at west side terminals vary from MVFR to LIFR as ceilings move up and down and passing showers affect visibilities. With activity generally staying west of the Cascades, areas to the east are generally under VFR or MVFR flight levels. While showers look to ease overnight, lingering low ceilings and areas of fog will continue to affect flight conditions. Additionally, stronger winds aloft looks to cause low level wind shear along the Cascades and over terrain to the east through the night. Showers west of the Cascades continue through the TAF period but will be lighter on Saturday morning. Ceilings look to lift and winds aloft decrease on Saturday morning as well. -TAD && .MARINE...Updated 200 PM PST Friday, December 5, 2025...West winds behind the front today will transition to the south Saturday as the next system approaches the area. Steep seas will continue due to residual wind-driven waves, then steep seas will build further Saturday due to increasing northwest swell. After a brief period of improved conditions Saturday night, gusty south winds and steep seas return Sunday, especially north of Cape Blanco. 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. -BPN && .MFR WATCHES/WARNINGS/ADVISORIES... OR...None. CA...None. PACIFIC COASTAL WATERS...Small Craft Advisory until 4 PM PST Saturday for PZZ350-356-370-376. && $$ MAS/BPN

149 FXUS66 KEKA 052244 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 244 PM PST Fri Dec 5 2025 .SYNOPSIS...Light rain possible for Humboldt and Del Norte late this afternoon and evening. King tides combined with tidal anomaly will continue to bring the threat of coastal flooding in low- lying areas around Humboldt Bay Saturday. A series of frontal systems moving north of the area will bring a chance of light rain across the northern portion of the area through the weekend. && .DISCUSSION...IR satellite imagery depicts a cold front just north of the area, while downstream flow from the high pressure over Northeastern Pacific is bringing increasing moisture. A deep marine layer and stratus continues to blanket much of Del Norte and Humboldt counties. Elsewhere, generally sunny to partly cloudy sky conditions are observed. The Mckinleyville profiler indicates the marine layer depth is up to 3,000 feet MSL. Otherwise, stratus is expected to lift during the evening as the cold front approaches from the north and destabilize the marine layer. Light rain or sprinkles are expected for the northern portion of the forecast area this evening, especially for Del Norte and Humboldt counties after 4 PM this afternoon. In addition, breezy northwest winds will continue over the coastal headlands and exposed ridges this evening and into Saturday. High pressure continues to slowly weakening and "flattening", while a series of shortwaves trough and frontal systems embedded to the Aleutian Low continues to move toward the Pacific Northwest this weekend. Northwest flow aloft will bring additional light showers across Del Norte and Humboldt counties on Saturday. On Sunday, another shortwave and frontal system is expected to move north of our area. The flow aloft will become more zonal, bringing additional chances of light rain across the northern portion, especially for Del Norte and northern Humboldt counties. Elsewhere, partly to mostly cloud skies is expected to continue. The 500 mb ridge appears to slowly build back early next through mid next week. WPC ensemble clusters do show about an even split (50%) of clusters that are "drier" (at least for the North Coast) than the grand ensemble mean. The ensemble mean is by no stretch very wet with 0.10-0.25 inches of rain in 24 hours everyday from Monday through Wednesday, mostly for Del Norte. It could be wet or it could be dry or both. Stay tuned. -ZVS && .AVIATION...(18Z TAFs)...Drizzle moved through this morning for Humboldt and Del Norte Counties, bringing LIFR to IFR conditions to the coastal terminals. After a brief lull, LIFR conditions have returned to the coastal terminals. A frontal passage accompanied with drizzle or light rain late this afternoon will continue IFR to LIFR ceilings and bring lowered visibility. Lingering light showers or drizzle will ease overnight. Southeast flow ahead of another frontal passage to the north may aide in lifting ceilings and visibilities around sunrise. For areas to the south and east, including UKI, only a few high clouds are expected with generally light winds. There is around a 30% chance for IFR to MVFR stratus impacts before and around sunrise at UKI Saturday. Any low clouds and fog will lift and scatter shortly after sunrise. JB && .MARINE...Winds and seas continue to ease north of Cape Mendocino as a weak front moves through the area. South of Cape Mendocino, breezy northerly winds continue through the evening. Peak gusts of 20-30 kts are possible south of the Cape this afternoon and evening. Steep wind waves of 5-8 ft are combining with a decaying mid-period swell of 3-4 ft. Winds and steep seas ease overnight. Generally light winds are forecast this weekend, with south winds forecast north of Cape Mendocino and west-northwest winds forecast south of the Cape. Despite light winds, seas will elevate as a mid-period northwest swell fills in Saturday. This will peak at around 7-9 ft at 12 seconds. Wave heights peak Saturday night and early Sunday morning, and combined seas could briefly reach or exceed 10 ft. Seas subside Sunday and Monday as this swell decays. Light winds continue into early next week, but seas will remain elevated as a series of mid- period northwest swells fill in from systems to the north. JB && .COASTAL FLOODING...King tides are predicted to continue this weekend. High tides are forecast to be at 8.63 feet at the North Spit tide gauge at around 11:44 AM local time. High tides combined with surge and tidal anomaly will result in water levels between 8.9 to 9.2 feet MLLW (Mean Lower Low Water). Minor coastal flooding around Humboldt Bay, including King Salmon and Jackson Ranch Road in the Arcata Bottoms, will be likely between 10 AM and 1 PM. A Coastal Flooding Advisory will be in effect from 10 AM to 1 PM on Saturday. High tides are predicted to be at 8.24 feet at 12:35 PM on Sunday. At this point, coastal flooding looks marginal for Sunday with high tides diminishing. -ZVS -ZVS && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Coastal Flood Advisory from 10 AM to 1 PM PST Saturday for CAZ103. NORTHWEST CALIFORNIA COASTAL WATERS... Coastal Flood Advisory from 10 AM to 1 PM PST Saturday for PZZ415. Small Craft Advisory until 11 PM PST this evening for PZZ455-475. && $$ NOTE: The full forecast discussion is now regularly issued between 10 am/pm and 1 pm/am. Additional updates will be issued as needed. Visit us at https://www.weather.gov/eureka Follow us on Facebook and Twitter at: https://www.facebook.com/NWSEureka https://www.twitter.com/NWSEureka For forecast zone information see the forecast zone map online: https://www.weather.gov/images/eka/zonemap.png

583 FXUS66 KMTR 060006 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 406 PM PST Fri Dec 5 2025 ...New AVIATION, MARINE... .KEY MESSAGES... Updated at 1215 PM PST Fri Dec 5 2025 - Persistent forecast through the next seven days with benign conditions and no precipitation expected - Impacts from Tule Fog in the North Bay and interior East Bay valleys - Next chance for rain towards the middle of the month && .SHORT TERM... Issued at 1259 PM PST Fri Dec 5 2025 (This evening through Saturday) Owing to the slower than expected stratus mix out and warming in the valleys of the North Bay and interior East Bay, have opted to decrease today`s highs and tonight`s lows in both areas, with the high temperatures now expected to rest in the middle to upper 50s and lows in the upper 30s to lower 40s in the area, with areas in the eastern tier of Contra Costa County going up to the lower 50s today. For all other regions, the previous discussion is still valid: Satellite imagery reveals lingering impacts from the Tule Fog spillover across the valleys of the North Bay and the interior East Bay. The mix out process continues to be rather slow with marginal shrinkage of the stratus deck in the late morning, with the bulk of the mixing out expected to occur this afternoon into the evening. There is also a potential for drizzle to develop in the coastal waters tonight, fringe effects of a storm system that is bringing rain to the Pacific Northwest but is not expected to bring any precipitation on the land side of the Bay Area and Central Coast. This, in turn, could support the return of coastal stratus to the region. Otherwise, the weather remains generally clear through the day, as upper level ridging dominates the western United States. High temperatures today and Saturday range from the lower to middle 60s across the inland valleys, with the southern Salinas Valley reaching the upper 60s to near 70, and the upper 50s and the lower 60s near the coast. Lows will generally range from the lower to middle 40s inland and the middle to upper 40s along the coast. Some locations in southern Monterey County will drop into the middle 30s. Will need to monitor the need for a Cold Weather Advisory if the temperatures drop due to enhanced radiational cooling, or if temperatures in the North and East Bays stay cool due to lingering stratus impacts reducing the daytime heating effects. && .LONG TERM... Issued at 1215 PM PST Fri Dec 5 2025 (Saturday night through next Thursday) Ridging will dominate the weather patterns through the rest of the 7- day outlook, enabling a gradual warming trend across the region. Rather than a day when the temperatures shoot upwards, we will experience a extended crescendo where the highs shoot up by a degree or two each day until you notice that by the middle of next week, temperatures are running 5 to 10 degrees above seasonal averages and highs in the inland valleys have reached the upper 60s to middle 70s. By the end of the 7-day forecast period, there are hints that a burst of offshore flow could come to the region, although exactly how strong that flow will be is open to lots of refinement. Longer range model guidance suggests a possible change in the weather pattern towards the middle of the month. Ensemble model cluster analysis depicts the majority of model runs showing a continuing ridge, but substantial minorities (somewhere around 30- 40% of the ensemble members) depict a breakdown of the ridge. CPC guidance continues to show a slight lean, emphasize, a slight lean, towards precipitation totals above seasonal averages for December 13- 19 across the Bay Area. For context, within the long-term climatic averages, downtown San Francisco receives a little over an inch of rain during this period. && .AVIATION... (00Z TAFS) Issued at 406 PM PST Fri Dec 5 2025 VFR for most sites but localized fog is expected to impact STS, APC, and LVK tonight. Guidance shows some potential for low clouds/fog to impact coastal airports and SJC but confidence is too low to include in the TAF at this time. Bumped up arrival time of low clouds to LVK due to fog coverage not dissipating as much as models forecasted this afternoon. This may need to be further refined with arrival time of low clouds/fog brought even earlier. Winds generally stay onshore this afternoon and evening before weakening overnight. Moderate onshore winds return again during the day tomorrow. Vicinity of SFO...VFR through the TAF period. Not currently anticipating fog/stratus to reach SFO tonight but visibilities may drop temporarily to around 6SM overnight. Continued the development of a moderate sea breeze this evening at SFO but confidence is low to moderate given winds have not switched NW yet. Winds weaken overnight before switching lightly north to northeasterly. Another moderate sea breeze returns tomorrow afternoon/evening. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR. Winds remain lightly onshore this afternoon/evening before weakening and becoming variable at times overnight before shifting onshore again during the daytime. There is some potential for low clouds to reach MRY tonight but confidence is slightly higher that low clouds will stay just offshore over the marine environment.&& .MARINE... (Tonight through next Thursday) Issued at 406 PM PST Fri Dec 5 2025 Northerly continue to increase across the waters with fresh to strong gusts expected. Localized near gale force gusts are possible across the outer waters and in the favored coastal jet regions through the weekend. These winds persist into the upcoming work week. Moderate seas continue with seas building to between 6 to 8 feet Friday through Sunday. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Coastal Flood Advisory until 3 PM PST Sunday for CAZ006-506-508- 529-530. PZ...Small Craft Advisory until 3 AM PST Saturday for Pt Arena to Pt Reyes 0-10 nm. Small Craft Advisory from 9 AM Saturday to 3 AM PST Sunday for Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory until 9 AM PST Saturday for Pt Arena to Pt Reyes 10-60 NM. Small Craft Advisory until 3 AM PST Sunday for Pigeon Pt to Pt Pinos 10-60 NM. && $$ SHORT TERM...DialH LONG TERM....DialH AVIATION...Kennedy MARINE...RGass Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, X, and YouTube at: www.facebook.com/nwsbayarea x.com/nwsbayarea www.youtube.com/nwsbayarea

369 FXUS66 KOTX 060005 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 405 PM PST Fri Dec 5 2025 .KEY MESSAGES... - Moderate to heavy mountain snow through Saturday at the Cascade crest and the Idaho Panhandle mountains. 50% chance for 12+ inches at Stevens and Lookout Passes. - Strong, potentially damaging winds in portions of Central Washington Friday night. Gusty winds in southeast Washington. - Increased potential for rock slides next week with a mild and wet weather pattern. && .SYNOPSIS... A unsettled and complex weather pattern through the weekend and into next week. Gusty winds developing Friday night. Temperatures will modify and warm above normal with mid and wet weather continuing through the weekend and into next week. && .DISCUSSION... Today and tomorrow: A shortwave trough and associated low pressure system are driving wintry weather and windy conditions across the Inland Northwest today and into tonight. Details for each hazard below: Snow: A warm front has generated a band of snow over northeast Washington and the northern Panhandle. Low level wet bulb temperatures have remained at or below 0C through early afternoon, particularly near the Canadian border leading to all snow. Total accumulations will be around 1-3. This will persist for the next couple hours until a cold front sweeps through around sunset. By this evening, precipitation will be limited to the Cascades, extreme eastern Washington, and the Panhandle. However, snow intensities will greatly increase for Stevens Pass around 8 to 10 PM this evening as lapse rates steepen behind the front with strong lift in the saturated dendritic layer on the west slopes of the Cascades. The morning hi-res models showed a massive uptrend in the snow amounts at Stevens Pass. They indicate a 90% chance for 1/hr snowfall rates and a 40% chance for 2" per hour snowfall rates from 10 PM this evening through 5 AM Saturday. Strong winds will also contribute to a minor risk for blowing snow and reduced visibility from the surrounding peaks. Overall, expecting around 10-18 inches of heavy wet snow at the pass level when all is set and done Saturday evening. Expecting a similar story but less intense snowfall rates for Lookout pass with similar accumulations by Saturday evening. There is a 50% chance of 1/hr snowfall rates from now through 11 PM this evening. Winds: Winds get very interesting this evening in the east slopes of the Cascades as strong flow perpendicular to the Cascades behind the cold front leads to mountain wave formation. Of particular concern is 60-70 kt flow about 3000-6000 feet above sea level late tonight into Saturday. Confidence still is not very high whether these winds will make it to the valley floors, but there is moderate-high confidence of strong winds in the mountains. The 3 PM observation at Mission Ridge Summit already shows a peak gust to 78 mph. White Pass Summit has already gusted up to 83 mph as well. Higher end model solutions are already panning out in the mountains. The best chances (40-60%) for 60 mph gusts tonight are on the higher benches of the Wenatchee area and the southern Waterville Plateau so high wind warnings remain in place. Southeast Washington in the Clarkston Valley and the Palouse will be breezy too this evening and tonight with southwest winds around 20-30 mph with gusts up to 55 mph. Bumped up the timing of the wind advisory to start now as Alpowa summit is gusting to 55 mph. Winds will decrease after sunrise but stay breezy through much of the day tomorrow gusting around 25-40 mph. Sunday through Thursday: Several atmospheric rivers take aim at the region resulting in a very wet period for the Inland Northwest. The first one is the weakest arriving Sunday with precipitable water increasing to 150-175% of normal. Snow levels are around 2500-4500 feet so most of the precipitation in the valleys will be rain. One area of uncertainty is the northern valleys near the Canadian border where models still have some cooler pockets of air. More significant atmospheric rivers arrive Monday and Tuesday bringing a lot of precipitation to the region. The ECMWF ensemble mean QPF from 4 AM Sunday to 4 AM Thursday shows around 5-7.5 of precipitation at the Cascade crest, 2-4 for the east slopes of the Cascades, 0.75-1.75 in central WA valleys and eastern WA, and 1.5-3 for the ID Panhandle. These rain amounts combined with snowmelt will lead to significant rises on rivers and streams. Currently no rivers are forecast to reach flood stage, but this will be monitored closely in the coming days. This will also bring an increased risk for mud and rock slides in areas of steep, snow-free terrain and recently burned areas. DB && .AVIATION... 00Z TAFs: Fluctuating conditions are anticipated through tonight. Precip chances decreasing overnight, but winds will increase. Low level wind shear is shown in model soundings for KEAT/KMWH/KLWS/KPUW thru 06Z as winds around 2k feet AGL increase to around 40-50 kts, locally stronger at KEAT. Stronger gusts may occasional mix down to the surface in areas of Central WA around Chelan, Wenatchee, Ephrata, and Vantage. The increased winds likely to bring bring improvement to the persistent stratus except far NE WA and N ID. .FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence for increase winds and low-level wind shear. Confidence is low where and when the strongest winds gusts will surface, especially in Central WA. Strong turbulence expected as the jet crosses the mountain barriers. ----------------------- 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 35 44 35 43 38 49 / 50 30 20 80 60 80 Coeur d`Alene 35 43 35 43 38 47 / 80 70 50 90 80 90 Pullman 38 44 37 43 40 48 / 70 60 60 80 80 80 Lewiston 41 51 40 47 43 52 / 70 50 40 70 70 70 Colville 33 41 28 39 33 44 / 40 40 20 90 50 80 Sandpoint 33 39 34 39 37 43 / 80 90 80 100 90 100 Kellogg 35 39 37 41 40 46 / 100 100 90 100 100 100 Moses Lake 36 50 35 45 38 50 / 10 10 0 60 10 50 Wenatchee 38 49 37 45 39 47 / 60 30 20 70 30 70 Omak 34 43 32 40 34 42 / 40 20 10 60 20 60 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...Wind Advisory until 7 AM PST Saturday for Lower Garfield and Asotin Counties-Washington Palouse. High Wind Warning from 7 PM this evening to 7 AM PST Saturday for Moses Lake Area-Waterville Plateau-Wenatchee Area. Winter Storm Warning from 7 PM this evening to 10 PM PST Saturday for Western Chelan County. ID...Wind Advisory until 7 AM PST Saturday for Idaho Palouse. Winter Storm Warning until 4 PM PST Saturday for Central Panhandle Mountains. && $$

996 FXUS66 KPDT 052240 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 240 PM PST Fri Dec 5 2025 .DISCUSSION...Rest of Today through Sunday: Wet conditions will continue through this weekend as an upper ridge offshore continues to guide a weak to moderate atmospheric river into the PacNW. By this evening, a cold front boundary will be in the process of crossing the forecast area while accompanied by a shortwave trough aloft. Cooler air with the cold front will mainly bring temperatures near to below freezing across mountain areas mainly above 4kft to 5kft. That will result in moderate to locally heavy snowfall across the WA Cascade crest, with high confidence that White Pass will see 8 to 12 inches of snowfall through tomorrow evening. The interior of the northern Blues will also see some moderate snow accumulations, though confidence is only moderate (50-60%) in snow amounts exceeding 6 inches above 5kft. Breezy to windy conditions are also anticipated to develop across the forecast area starting later this afternoon. A low level jet (45-60kts) associated with the incoming shortwave trough will move over the forecast area, with moderate to high confidence (55-85%) that winds will mix down and impact many of our lower elevation areas across north Central Oregon, the eastern Gorge, and the Columbia Basin & adjacent valleys/foothills. Atypical for this setup and wind direction, strong west to northwest winds are also anticipated to develop through the Wallowa valley tonight through tomorrow. In the aforementioned areas, expect sustained winds of 25-40mph with gusts 40-55mph, while some ridges along the east slopes of the Cascades can also anticipate wind gusts between 50-75mph through tomorrow afternoon. A brief precipitation break will develop for the lower elevations Saturday while light to moderate snow and/or rain will continue across the mountains under northwest flow aloft. By Sunday morning, another front and shortwave passage will ramp up precipitation chances during the day, with light to locally moderate snowfall above 4kft in the mountains, and light rain elsewhere. Monday through Thursday: Overall, ensemble guidance is in good agreement of a progressive pattern consisting of several shortwave and frontal systems parading through the PacNW Monday through Thursday. ECMWF and GFS ensemble systems are also in a great agreement that these systems will be accompanied by a prolonged AR with IVT values peaking between 500 to 750 kg/m/s filtering into eastern OR/WA for at least a 48 hour period early to mid next week. What that translates to is a moderate to high confidence in (60-80%) heavy precipitation amounts at least across the Cascade crest and east slopes, as well as the Northern Blue mountains and the Wallowa mountains. That said, ensemble guidance is in disagreement over the timing and positions of the incoming systems each day, which results in a low confidence (20-40%) in the exact amounts of QPF that each area will see. But to provide an idea of the potential QPF amounts, the NBM gives the WA Cascade crest a 30-70% chance of at least 5 inches of QPF over a 72-hour period ending Thursday morning, and a 15-30% chance along the OR Cascade crest. Meanwhile in the northern Blues, likely owing to much of the precipitation falling out over the Cascades and west, NBM only shows a 20-50% chance of 2 inches of QPF, which drops to a 10-20% chance for 3 inches through Thursday morning. Due to the warm/mild nature of the incoming AR/airmass, much of the precipitation will be falling as rain across the mountain areas, which translates to rises along area rivers and streams. Of note, current river stage forecasts from the Northwest River Forecast Center place many rivers originating or along the WA Cascade east slopes into action stage by the middle of next week. Lawhorn/82 && .AVIATION...00Z TAFs...The winds are beginning to pick up ahead of the front with PDT/BDN/ALW already seeing sustained winds 10-13kts and gusts to 20kts. This has assisted with clearing out the FG/BR and low CIGs with the exception of YKM which is still IFR due to CIGs below 500 feet. Timing of the winds remains the challenge this forecast period, however, guidance does show that winds are expected to pick up across the remaining TAF sites within the next hour or two allowing all sites to go VFR by 00-02Z (60-80% confidence). Winds will be between 15-25 with some isolated 30 kts (PDT) sustained with gusts to 35 kts and higher. All sites are expected to stay VFR with only DLS seeing a slight chance (30-40%) of low CIGs after 20Z Sunday. 90 && .PRELIMINARY POINT TEMPS/POPS... PDT 40 51 38 52 / 30 40 40 80 ALW 41 50 40 51 / 50 50 50 80 PSC 41 55 39 52 / 10 10 10 70 YKM 38 55 34 50 / 40 20 20 70 HRI 43 55 39 53 / 10 20 20 70 ELN 35 48 32 44 / 60 40 30 70 RDM 32 49 31 54 / 30 20 10 50 LGD 38 46 33 44 / 80 70 70 80 GCD 34 45 32 47 / 50 40 40 80 DLS 47 55 44 54 / 70 60 70 90 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Wind Advisory until 10 AM PST Saturday for ORZ041-044-507-508- 510. Wind Advisory until 1 PM PST Saturday for ORZ050. WA...Wind Advisory until 10 AM PST Saturday for WAZ024-521. Wind Advisory from 7 PM this evening to 7 AM PST Saturday for WAZ026>029. Winter Weather Advisory from 7 PM this evening to 7 PM PST Saturday for WAZ522. && $$ .DISCUSSION...82 AVIATION...90

460 FXUS65 KREV 052024 AFDREV Area Forecast Discussion National Weather Service Reno NV 1224 PM PST Fri Dec 5 2025 .KEY MESSAGES... * Light showers ongoing near the Oregon border will continue through tonight with periods of gusty winds along Sierra ridges. * Dry and mild weather prevails elsewhere through much of next week. * A more unsettled weather pattern may emerge around the middle of the month, but confidence is low. && .DISCUSSION... A ridge remains parked over the eastern Pacific Ocean, deflecting any storms to our north that swing by. A couple of storms will pass by to our north between today and Wednesday next week. Then towards the end of the week, that ridge will finally start to breakdown and move east, allowing the storm track to shift further south. These shortwave troughs riding around the edge of the high pressure will deliver northern Washoe County, Surprise Valley, northern Lassen County, and Pershing County a 30-60% chance of light rain showers this afternoon and evening. The next round of showers in those same areas look to be around Wednesday. High temperatures will gradually warm up each day through this weekend and into next week, eventually bringing high temperatures into the 60`s in lower valleys and Sierra valleys by Wednesday. Winds will stay light (<20 mph) through at least Wednesday next week, though ridgetops could see gusts up to 35-50 mph through tomorrow. Next weekend as the ridge breaks down, we will likely be in for a pattern change with more active weather. Around 50-60% of the ECMWF Ens and GEFS members show signs of precipitation arriving during that time. We`ll monitor as it gets closer. -Justin && .AVIATION... Light rain showers are ongoing this afternoon across the northern portion of our CWA. These showers are expected to dissipate by 06Z tonight. Otherwise, light sfc winds and VFR conditions continue today and Saturday. -Justin && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$

480 FXUS66 KSTO 052117 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 117 PM PST Fri Dec 5 2025 .KEY MESSAGES... - Periods of clouds, mist, or fog continue in the Central Valley for the next few mornings - Seasonable temperatures and light winds are forecast over the next several days - Tonight - Early Sat. AM`s rain chances for Shasta County have lowered with only a 10-30% of measurable rain. && .DISCUSSION... ...Today... Current GOES-West visible satellite imagery illustrates the blanket of stratus in the Central Valley gradually eroding, with some high clouds passing overhead from the north. Visibilities have improved across the Central Valley this afternoon, but still see swaths of low clouds/stratus clouds over the Valley. We can expect another round of patchy dense fog and low clouds once again tonight into Saturday morning with best chances from Marysville southward again. Dry weather and seasonable temperatures are forecasted for the region, with 50s to 60s in the Valley and foothills, and 40s to 60s in the mountains for the daytime highs. Highs are trending several degrees cooler than initially forecasted due to the persistence of the fog/low clouds, keeping max temperatures from being fully actualized. ...Tonight-Sunday... A weak system passing to the north over the weekend may bring some isolated, light showers to the Shasta County mountains, however little to no impacts or accumulations are expected. Elsewhere, dry conditions will persist over the weekend with daily chances for fog, mist and low clouds especially in the Valley. High temperatures are forecast to be in the 40s to 60s across interior NorCal. ...Next Week... High pressure builds across the region next week, allowing for a gradual warming trend with high temperatures warming to the 50s to near 70 (mainly for areas outside of stratus/fog development). Dry conditions will continue through next week. Some ensembles are indicating a pattern change in mid December but there is a large amount of uncertainty as it is too far out in time. && .AVIATION... Lingering low cigs and mist across the Central Valley this afternoon and evening, although some sites may briefly return to VFR conditions. Another round of BF/FG and low stratus returns tonight after 03Z-12Z Saturday, with areas of MVFR/IFR conditions, locally IFR, particularly from Sacramento southward. Light and variable surface winds less than 12kts. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$

512 FXUS65 KMSO 052013 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 113 PM MST Fri Dec 5 2025 .DISCUSSION... KEY MESSAGES: - A prolonged period of winter weather lasting through at least the weekend - Heavy mountain snow, along with a wintry mix in the valleys will make for difficult travel conditions - Gusty westerly winds from Tonight into Saturday - Unsettled winter weather will continue into next week with potential for significant rainfall below 5000 ft midweek The next push of precipitation is beginning to move into north central and northwest Montana this afternoon. This feature will cause light to moderate snow for the majority of the region with the expectations being mainly rain for the lower valleys of north central Idaho, northwest Montana, Mission valley and Bitterroot valley. After the passage of this disturbance anticipated gusty westerly winds developing overnight causing downsloping effects especially in the broader valleys. The HiRes models continue to depict the development of snow bands developing during the evening hours. These bands will be capable of producing heavy snowfall (1 to 2 inch per hour rates) along with gusty winds with the greatest area of concerning being Seeley/Swan Valley south through the Sapphire range into southwest Montana. Multiple winter storm warnings and advisories are still in effect from the potential impacts from this next wave. Snow is expected to linger in the higher terrain, especially along the Montana/Idaho border on Saturday through Saturday. While the valleys experience off and on rain/snow showers but also gusty westerly winds throughout the period. Snowfall totals for the next 48 hours ending Sunday morning show the mountains along the Montana/Idaho border, Mission range and Bob Marshall wilderness should receive 1 to 2 feet of new snow. While the mountains of extreme northwest Montana, including Glacier and southwest Montana are expected to receive 6 to 12 inches of snow. Once again the valleys will be receiving a rain/snow mix during this timeframe along with downsloping effects so 48 hr moisture amounts appear to range from 0.20" to 0.60" with snow accumulations being in the 1 to 4 inch range. Another weak pulse of moisture appears to push through the Northern Rockies Sunday night causing an increase in the shower activity. The models continue to come in better alignment with a significant atmospheric river (AR) impacting the Northern Rockies late Monday through at least Wednesday. Snow levels will be rising to around 5000 feet in the north and 7000 feet in the southern part of the forecast area by Tuesday morning. Snow levels do appear to lower by a 1000 feet by Wednesday morning but then rise back up by Thursday. This AR event has the potential to bring near historic moisture amounts to the region for this time of year, especially along the Montana/Idaho border. The rainfall totals during this event appear to be between 1 to 3 inches with the heaviest amounts being over Idaho/Clearwater counties into northwest Montana. The valleys of Lemhi county and southwest Montana are expected to receive between 0.25" to 1.5" of rain. The areas above the snow level should anticipate 1 to 2 feet of additional snow. The biggest concern is the potential for ponding of water, significant increase in stream flows and rock/mud slides. This active weather pattern appears to continue for the latter part of the work week into next week as snow levels are anticipated to lower. && .AVIATION...Expect little to no improvement in flying weather conditions through the rest of the day at all regional terminal locations as the valley inversions, freezing fog, and low stratus hold firm and snow begins to fall. A surge of Pacific moisture is moving into the Northern Rockies increasing mtn obscurations and revamping precipitation intensities. Snow/freezing levels will remain the trickiest part of the forecast heading into the weekend. Snow will fall to most valley floors before slight warming increases the snow/freezing levels into Saturday. Defined snow bands and or squalls will accompany the surge of pacific moisture bringing localized major deteriorations to flying weather and periodic lowering of freezing/snow levels to valley floors. Gusty westerly winds increase into Saturday morning helping mix out some of the lowest stagnant layers but introducing some mehcanical turbulence and low-level wind shear. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...Winter Storm Warning until 5 PM MST Saturday for Bitterroot/Sapphire Mountains...Lower Clark Fork Region... Potomac/Seeley Lake Region. Winter Weather Advisory from 5 PM this afternoon to 5 PM MST Saturday for West Glacier Region. Winter Weather Advisory until 11 PM MST this evening for Butte/Blackfoot Region...Missoula/Bitterroot Valleys. ID...Winter Storm Warning until 4 PM PST Saturday for Northern Clearwater Mountains...Southern Clearwater Mountains. && $$

825 FXUS65 KBOI 052152 AFDBOI Area Forecast Discussion National Weather Service Boise ID 252 PM MST Fri Dec 5 2025 .SHORT TERM...Tonight through Sunday night...An atmospheric river in the Pacific is bringing anomously high moisture to the area this afternoon and evening, and will continue to drive the forecast through the short term. This afternoon and tonight snow levels have rising to 5-6 kft MSL in central Idaho and 7-8 kft MSL in SW Idaho and SE Oregon. While this will bring 4-8 extra inches of snow to mountains and high passes, most mountain towns in Idaho will be within 800 ft of the snow level. Those just above the snow level could see 1-2 inches of wet snow, compared to 0.3-0.6 inches of rainfall below the snow level. Lower elevations and low lands well below the snow level, especially SE Oregon and SW Idaho will see 0.1-0.4 inches of rain through this evening. Visibilities will be reduced within precipitation as clouds stay low and precip rates become moderate. The rising snow levels and wetter snow will help to improve road conditions at the tail end of the precipitation, so the Winter Weather Advisory will be allowed to end at the scheduled time around midnight. This evening through Saturday, in highlands, ridges, and open areas gust to 25-40 mph as precipitation clears out. This is driven by very strong winds aloft of 50-70 mph around 700 mb. A significant 130 mph flow is expected near the tropopause. The flow remains somewhat moist, allowing a persistent 50-70% chance of precipitation in central Idaho mountains through the weekend. Extra snow accumulation of 1-3 inches is possible above 4.5 kft MSL. A few CAMs show freezing rain in these showers, though the winds on Saturday will help mix the atmosphere reducing the risk to less than a 10% chance. On Sunday the flow briefly sources from the north, dropping snow levels to 4-5 kft MSL. Temps on Sunday drop a few degrees from Saturday. This brief flow switch also brings another pocket of moisture raising precip chances in lower elevations to 40% and higher elevations to 80% Sunday night. .LONG TERM...Monday through Friday...Forecasted to be much of the same from the short term. The upper-level ridge is still cemented in the eastern Pacific, with moisture riding overtop. Higher PoPs (60- 90%) are mostly limited to our northern zones, with lower chances (20-50%) for lower elevations. Beginning Thursday, the upper-level ridge axis looks to build further north/northwest, bringing higher heights overhead and pushing the moisture flux further north. Current long range models disagree to what extent the moisture may still exist along the northern higher elevation zones, thus they retain 20-40% PoPs Thursday. There is good agreement that by afternoon into evening Friday, our northern mountain zones will finally receive some respite. With the unseasonable, strong upper-level ridge in the eastern Pacific, well above average temperatures (10-15 degrees) are expected during the long term. A consequence of the above average temps will be higher snow levels. Snow levels will fluctuate with each passing shortwave, but generally stay in the 6.5-8kft range (highest in SE OR, lowest in central ID). This limits any additional snow accumulations throughout the long term to be above 6.5kft, with locations below that elevation generally just seeing rain. && .AVIATION...Widespread precip and low ceilings bringing widespread MVFR/IFR conditions with periods of LIFR. Precip continuing throughout the day, decreasing in coverage late this evening. Widespread concern of LLWS through Saturday morning. Snow levels: 5- 8 kft MSL (lowest in the W-cntrl ID mountains), becoming 4-5.5 kft MSL overnight. Surface winds: under 10 kts, except near KJER/KTWF W/ NW 8-12 kt gusting to 30 kt, and SE OR with W/SW 15-20 kt gusting to 30 kt. Winds at 10kft MSL: W/NW 30-55 kt. KBOI...MVFR/IFR in precip and low ceilings with a 30% chance of LIFR overnight into early Saturday morning. LLWS threat persisting until Saturday afternoon. Rain ending around Sat/05z. Surface winds: light and variable, becoming W-NW 9-14 overnight. Weekend Outlook...Scattered, lighter precipitation is expected Saturday and Sunday, primarily over higher terrain. Snow levels 4-6 kft MSL. Patchy fog in mtn valleys Sat/Sun mornings. MVFR to LIFR conditions in precipitation/fog with mountains obscured. Surface winds: SW-NW 5-15 kt, except 15-20 kt with gusts 25-40 kt Saturday across higher terrain and the western Magic Valley. Variable 5-15 kt Sunday. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Winter Weather Advisory until 11 PM MST this evening IDZ011-013. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise SHORT TERM...JM LONG TERM....CH AVIATION.....CH

991 FXUS65 KLKN 052002 AFDLKN Area Forecast Discussion National Weather Service Elko NV 1202 PM PST Fri Dec 5 2025 .KEY MESSAGES... Updated at 1156 AM PST Fri Dec 5 2025 * Light rain/snow showers are likely across Northern Nevada today through Saturday afternoon * Gusty winds in Eastern Elko County this afternoon into Saturday morning * Quiet conditions with warming temperatures return Monday, lasting through the new week as high pressure builds across the SW US && .DISCUSSION... (This afternoon through next Friday) WEATHER PATTERN OVERVIEW: Periodic snow and Rains showers will continue through Sunday morning across mainly Eastern Humboldt and Elko counties. A Quick moving upper trough transverses the westerly flow across the Pacific Northwest and the tail end of this system will clip northern NV this afternoon and evening with a few light showers lingering into Sunday morning. The best chances for precipitation with this system will be across the higher terrain of Elko and Humboldt counties and will be in the form of snow. Snow levels will start at about 7500 feet, and as the precipitation and cooler air moves in, snow levels across the northern tier will fall to about 5000 feet. However much of the cooler air will stay north of I-80 until after the best window for precipitation closes late Saturday night. Winds with this system will be elevated, but the area of coverage of the stronger winds will be limited to NE Elko County where NW winds of 10 to 25 MPH with gusts up to 35 MPH will be possible through Sunday morning. Precipitation amounts outside of the mountain ranges looks to be light with the valleys of Elko, N Eureka, Humboldt, N Lander and N White Pine counties seeing about a trace to 0.15 of mainly rainfall, snow amounts of up to a trace to 0.25 will be possible for the higher elevation valleys and I-80 passes. The big winners from this system will be the Independence, Jarbidge, and Ruby/E Humboldt Ranges as up to a foot of new snow will be possible across the peaks of each range. Sunday the upper trough exits allowing the development of a strong ridge of high pressure that will build in across the Great Basin shoving the storm track that has been across the Pacific NW north into Canada. This will bring quiet conditions, warming temperatures and lighter W to SW winds beginning Monday, and lasting through at least Friday. Temperatures for the week will start in the low to mid 40s for highs, warming back into the upper 50s to low 60s by Friday afternoon. Low temperatures Sunday morning start in the low 20s will also warm back into the low 30s by Saturday morning. FORECAST CONFIDENCE & DEVIATIONS: There is moderate confidence in the development and coverage of lower to mid elevation rain and snow showers across N NV tonight through Sunday morning. There is high confidence in the in the development of snow showers with accumulations possible across the high mountains of Elko County through Sunday morning. There is high confidence in the development of a strong ridge of high pressure across the SW US and Great Basin Regions that will bring quiet weather and warming temperatures Monday through next Friday. && .AVIATION... VFR conditions with Intermittent MVFR and IFR conditions are forecast this evening through Saturday as CIGs range between 1000ft to 3500ft and precipitation chances in the form of rain showers increase to 60% at KEKO, followed by KBAM, KWMC, and KENV. VCSH to showers will be possible Saturday for KELY however chances only reach 20%. There will be a period during Saturday night when there could be a transition of precipitation to snow for the above terminals, however confidence is low at this time to mention in TAF. KTPH is forecast to remain dry through this forecast period with CIGs SCT at 10kft to SKC. && .LKN Watches/Warnings/Advisories... None. && $$ DISCUSSION...98 AVIATION...98