850 FXUS66 KSEW 051758 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 958 AM 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. && .SHORT TERM /TODAY THROUGH SUNDAY/... Rain continues to move into the area from the northwest this morning, with the heaviest precipitation currently focused on the northern and southern Cascades. Overall, the forecast remains largely on track this morning, with no major updates needed. The remainder of the previous forecast follows below, with updates made to the aviation section. 14 Rain will continue all day, with the higher QPF focused in the Cascades and coastal regions. 2-3 inches are likely in the Cascades, with 1-3 along the coast and windward side of the Olympics. Snow levels will generally remain high throughout much of the day, but by the afternoon and evening, they will start decreasing. Along with anticipated convergence zone activity tonight, enough snow for a winter weather advisory is still on track for the Stevens Pass area, with higher amounts in the Cascades north of the pass and in through the Mount Baker area. Snowfall totals along Stevens Pass are likely to be between 5 to 10 inches, with periods of snowfall rates that could achieve at least one inch per hour tonight. Breezy conditions with wind gusts of 30 to 35 mph over the Cascade passes this afternoon could make for challenging visibilities and traveling conditions. Winds will also be breezy through Puget Sound, the Southwest Interior, coast and northern Olympic Peninsula today. The precipitation will continue into Saturday, but will briefly taper off for scattered showers into the evening. The next system will be right on its heels by Sunday morning. Highs will be back in the 50s through the weekend. Higher astronomical tides will peak today along the Pacific coast. The inner coastal areas will see peak tides on Saturday, though only minor coastal flooding will be possible. Coastal flood advisories remain in effect, with minor flooding most likely around high tide today and Saturday. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Rain associated with the next system will arrive Sunday morning and last into Monday. Another quarter to half inch of rain is expected in the lowlands, with 1-2 inches in the mountains. The primary point of discussion in the extended forecast will be a strong atmospheric river system that will take aim at Washington Monday through at least the middle of the week. Indications at this time are that a second atmospheric river will move in for the second half of the week, but not be as wet as the first one. During this time, significant rainfall is expected area wide, making for a very wet week. To put it in perspective, the total QPF expected between Monday morning and Friday morning for the Cascades and Olympics is between 7 and 11 inches. Areas from Seattle south could see 3 to 5 inches of rain. Whidbey Island may be the most rainshadowed location in the whole event yet still receive 2-2.5 inches of rain. See the hydrology section for more information on area rivers. 21 && .AVIATION... Northwest flow aloft will continue through today as a frontal system moves across Western Washington. Widespread LIFR/IFR conditions continue this morning with a warm front draped over the region and with substantial low level moisture in the area. LIFR/IFR cigs will continue for most areas through the remainder of the morning, with slow improvements to MVFR/IFR expected this afternoon. Vsbys will also remain lower this morning, ranging 2 to 4 statute miles for most areas. Stratiform rain this morning will become more showery this afternoon after a cold front moves through the area. A convergence zone is expected to develop around Snohomish County this afternoon into this evening, with additional post-frontal showers expected tonight. Localized improvements to VFR will be possible this evening in a post-frontal airmass. S/SW surface winds will increase this morning, peaking tonight. Gusts will range 20 to 30 kts for most areas, with localized gusts of 35 kts as well. KSEA... LIFR conditions continue at the terminal this morning. Cigs will then lift into IFR between 18-21z, before lifting further into MVFR by late afternoon. Light rain will persist at times this morning, with mainly drier conditions expected this afternoon outside of drizzle. A convergence zone will develop this afternoon and will remain north of the terminal. Primarily MVFR cigs tonight, but some brief improvements to VFR will be possible. Winds will increase from the S/SW to 10-20 kts this morning and will peak this evening through tonight. Gusts are expected to peak between 30 to 35 kts tonight. JD/14 && .MARINE... A weather system will move across the waters today. Winds will increase this morning, and peak in intensity this afternoon through early Saturday morning. Gale force wind gusts are expected for the Coastal Waters and western Strait of Juan de Fuca during this period. In addition, a strong westerly push through the Strait of Juan de Fuca will occur early this afternoon and continue to remain elevated through early Saturday morning. Localized gusts of 45 kts will be possible in the central and eastern Strait of Juan de Fuca during this period. Stronger southwest winds are also expected along the southern portions of the northern inland waters and near Bellingham Bay, with gusts of 35 kts. For this reason, have upgraded the Small Craft Advisory to a Gale Warning for the northern inland waters. SCA west winds are also expected along the northern periphery of Admiralty Inlet, and have issued a SCA for this region. Gusts may also peak briefly around 35 kts for Puget Sound tonight, with predominantly SCA winds this afternoon and tonight. Winds will slowly subside on Saturday. Additional weather systems are expected over the next week, the next being on Sunday morning, and a stronger weather system Monday into Tuesday. Further headlines will likely be required, with potential gales again with the Monday and Tuesday weather system. Seas of 4 to 7 feet this morning will build to 13 to 18 feet tonight into Saturday morning. Seas will then subside to 8 to 9 feet Saturday night into Sunday. Seas will build again late Monday into midweek with the next weather systems. JD && .HYDROLOGY... A series of wet weather systems will increase the threat of river flooding this weekend, especially into the first half of next week. West to northwesterly flow aloft with the first system today will put the area of greatest precipitation in the North Central Washington Cascades. Snow levels will initially range 6500 to 8000 feet today before falling to 4000 feet tonight and Saturday. As the flow aloft becomes more westerly to southwesterly the flood threat will shift to the flood prone Skokomish River late in the weekend. There`s still a wide variance in the possible precipitation amounts with an atmospheric river setting up through the first part of next week, but confidence is increasing in heavy rainfall across western WA, especially over the Olympics and Cascades. Confidence is increasing that we will see a widespread river flooding event on our hands beginning late Monday, throughout Tuesday and into Wednesday, with multiple rivers flowing off the Cascades and the Olympics reaching minor and moderate flood stages (potentially nearing even Major flood stage). Additional precipitation is also possible Thursday into Friday with continued westerly flow aloft. Uncertainty still continues to 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 start to elevate the landslide risk throughout the weekend, increasing rapidly early next week with the arrival of an atmospheric river. JD/Mazurkiewicz && .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. Winter Weather Advisory from 7 PM this evening to 10 PM PST Saturday for Cascades of Snohomish and Northern King 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 from 1 PM this afternoon to 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 from 1 PM this afternoon to 4 AM PST Saturday for 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 from 1 PM this afternoon to 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 from 4 PM this afternoon to 4 AM PST Saturday for Admiralty Inlet. Small Craft Advisory from 1 PM this afternoon to 4 AM PST Saturday for Puget Sound and Hood Canal. 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. && $$

163 FXUS66 KPQR 051754 AAA AFDPQR Area Forecast Discussion...UPDATED National Weather Service Portland OR 953 AM PST Fri Dec 5 2025 ...Updated aviation discussion... .SYNOPSIS...A steady succession of frontal systems will keep conditions wet through the weekend and much of next week. The most notable period continues to focus on Monday through midweek, when a prolonged atmospheric river may bring significant rainfall and rising rivers across southwest Washington and northwest Oregon. .DISCUSSION...Now through Thursday...A more robust frontal system is moving inland early this morning, bringing widespread rain to the region. This feature carries a stronger plume of moisture than yesterdays system, with integrated vapor transport values generally running in the 500-700 kg/ms range. This is enough to support persistent rainfall through the day, including areas farther south that were largely missed during the previous event. Rainfall from now through 5 AM Saturday is expected to total about 0.25 to 0.50 inches across interior lowlands. Totals will be notably higher along the coast, generally in the 1.0 to 1.5 inch range, with 2 to 3 inches common across the Coast Range and Cascades. Winds today will turn breezy from the southwest, with gusts most frequently reaching 25 to 35 mph through most of the day. Expect the frontal passage to arrive around 7-10 AM today. Showers linger into Saturday as a westerly flow pattern persists. Another frontal wave will arrive Sunday and bring yet another round of steady rainfall to the region. Ensemble guidance suggests IVT values with Sundays system in the 300-500 kg/ms range, producing a widespread soaking. Rainfall totals from Saturday through sunday are currently projected to fall in the 0.5 to 1.0 inch range across the interior lowlands, with 0.75 to 1.0 inches along the coast and 1 to 2 inches in the Coast Range. The Cascades are expected to receive roughly 1.5 to 3.0 inches, except for the Lane County Cascades where amounts are closer to 0.5 to 1.5 inches. Forecast confidence in the exact high and low ends of these ranges remains moderate. Widespread impacts are not anticipated through Sunday; however, if rainfall rates sustain around 0.2 to 0.3 inches per hour for several hours, a few faster-reponding basins, such as the Grays at Rosburg and the Willapa River, could rise quickly. Attention then turns to the Monday-Wednesday period, where models continue to suggest a multi-day atmospheric river. Over the past several cycles, ensembles have become increasingly consistent in highlighting two distinct surges of moisture: one centered roughly on Monday, and a second sometime Tuesday or Wednesday. Between these peaks, the moisture feed is unlikely to shut down completely, leading to a long-duration event rather than two isolated episodes. Ensemble IVT guidance continues to show a broad range but retains a strong signal for an impactful event. For the first plume on Monday, GEFS and ECMWF are similar, with members clustering around 600-650 kg/ms and higher-end solutions near 750-800 kg/ms. The second surge maintains mean values in the 500-600 kg/ms range with high-end members closer to 750-850 kg/ms. The precise timing and latitude of these plumes remain uncertain, but confidence continues to increase that the region will experience a prolonged period of moderate to heavy rainfall. Winds early next week may also trend breezy, but ensemble spread remains wide. Even moderate gusts in a 30-40 mph range could be sufficient to bring down isolated trees due to increasingly saturated soils. This remains a detail to refine as the event draws closer. Overall, the Monday-Wednesday period remains the primary focus for potential high-impact hydrologic (see hydrology section below for more details) and wind concerns. Confidence in a multi-day atmospheric river is rising, but exact rainfall totals and timing details still require several more forecast cycles to resolve. While rain is looking to continue through at least Thursday, rain amounts look much less Thursday and onward. ~12 && .HYDROLOGY...A series of frontal systems will keep conditions wet through the weekend and much of next week. The most notable period will be late Monday through late Wednesday, where a prolonged atmospheric river may bring significant rainfall and rising rivers across southwest Washington and northwest Oregon. Rivers draining the Coast Range and Willapa Hills have a 10-25% chance of reaching moderate flood stage and a 8-15% chance of reaching major flood stage. There is also the potential for flooding along small creeks and streams, as well as urban flooding. Flooding of the Willamette mainstem rivers is unlikely to occur (less than 10%). Probabilities for specific river points can be found at the National Water Prediction Service website. Periods of heavy rain will also increase the risk for landslides in areas of steep terrain, and debris flows over recently burned areas. && .AVIATION...Radar imagery and terminal observations as of late Friday morning depict a mix of IFR/low-end MVFR CIGs and VIS across all terminals as a warm front lifts over the region and brings rain and mist. Moderate to heavy rain at times are bringing brief reductions in VIS to 2-4 SM. Expect this trend to continue through this morning and early afternoon. After 21z Fri-00z Sat, rain will decrease and transition to post-frontal showers. Visibility should trend back up to VFR thresholds and CIGs should begin to lift toward high-end MVFR/low-end VFR. Expect west-southwesterly winds today across all terminals, around 10-15 kt with gusts up to 25 kt along the coast and 20 kt across the Willamette Valley. Winds will gradually weaken overnight as the system exits the area. KPDX AND APPROACHES...Low-end MVFR CIGs continue through the early afternoon with the warm front passage. Moderate to heavy rain at times may bring brief VIS reductions to 3-5 SM. After 21z Fri, rain becomes light and transitions into showers. CIGs will then trend toward high-end MVFR (above 2000 ft). Southwesterly winds 10-13 kt with gusts up to 20 kt today, weakening below 10 kt tonight. -10 && .MARINE...A frontal system will move over the waters today, with westerly winds increase to 15 to 25 kt with gusts up to 30 kt, strongest over the northern waters. Small Craft Advisories remain in effect across all waters including the Columbia River Bar beginning 4 AM Friday, lasting through Saturday evening. Seas of 4-5 ft early this morning will build to around 7-9 ft at 10-11 seconds by Friday evening as a northwesterly swell moves in with the next system. Will note that a very strong ebb may lead to higher seas of 10-11 ft in the Main Channel of the Columbia River Bar around 4-5 PM Friday. For the rest of the waters, seas likely (80% chance) build above 10 ft by late Saturday morning. There is also a 25% chance that seas build above 13 ft, with the highest chances north of Cape Lookout and beyond 10 NM. There is a 1-5% chance seas peak as high as 15 ft. The parade of fronts continue through the weekend and into early next week. Chances for widespread and frequent Gale force wind gusts of 34 kt or greater remain under 15% through early next week; however, chances for brief and isolated Gale force wind gusts are around 40-50% on Sunday and 50-70% on Monday. Seas are forecast to hover close to 15 ft from late Monday through late Wednesday, with a 10% chance seas peak around 17-18 ft. -10/23 && .BEACH HAZARDS...Coastal Flood Advisories remain in effect from for minor tidal overflow during high tide from 9 AM to 3 PM Friday and Saturday for the south Washington coast and Clatsop County coast in Oregon. Minor flooding up to 1 foot above ground level is possible during high tide in low lying areas near bays, sloughs, and the low reaches of the coastal rivers. Coastal residents in the warned area should remain alert for rising water and take appropriate action to protect life and property. -10 && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Coastal Flood Advisory from 9 AM this morning to 3 PM PST this afternoon for ORZ101. Coastal Flood Advisory from 9 AM to 3 PM PST Saturday for ORZ101. WA...Coastal Flood Advisory from 9 AM this morning to 3 PM PST this afternoon for WAZ201. Coastal Flood Advisory from 9 AM to 3 PM PST Saturday for WAZ201. PZ...Small Craft Advisory until 10 PM PST Saturday for PZZ210-251>253- 271>273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland

986 FXUS66 KMFR 051101 AFDMFR Area Forecast Discussion National Weather Service Medford OR 301 AM PST Fri Dec 5 2025 .DISCUSSION...A strong upper ridge remains southwest of the forecast area with a northwest flow over the area. At the same time a frontal boundary will slip far enough south to bring light to occasionally moderate rain to the area late this morning into this afternoon. With the flow from the west, the bulls eye of precipitation will be along the coast, coastal mountains and Cascades with lesser rainfall amounts in the Umpqua Basin, Rogue Valley and east of the Cascades. The main concern east of the Cascades will be moderate to occasionally strong winds over the higher ridges this afternoon with 700mb winds between 40-50 kts. There`s good agreement the front will weaken as it remains nearly stationary late this evening through Saturday. The net result will be decreasing precipitation late this evening with most hours and locations dry late tonight through Saturday. A warm front will move into the area Sunday with a net increase in precipitation with most centered west of the Cascades. Rainfall amounts Sunday will be light with higher amounts over northern Douglas and Coos County. The general consensus for most of next week keeps the bulk of the rainfall north of the forecast area. However intermittent light is expected in northern Douglas and Coos County on the southern fringes of the heavier core of rainfall which is likely to be mainly from about Eugene up to western Washington next Monday through Wednesday. It should be noted that during this time, snow levels will be above all the passes, therefore the concern for snow is next to zero. -Petrucelli && .AVIATION...05/12z TAFs...Ceilings have lowered over the last several hours as a frontal boundary moves south. LIFR ceilings are likely to be the predominate condition along the coast and just offshore with a reduction of visibility through the TAF period, Inland, west of the Cascades, MVFR ceilings will lower to IFR later this afternoon through tonight. East of the Cascades, VFR conditions will be the predominate condition, however the higher terrain could end up partly obscured after 18z. Stronger winds aloft could result in some turbulence along and east of the Cascades. Snow levels will remain higher between 8000-10000 feet. -Petrucelli && .MARINE...Updated 230 AM PST Friday, December 5, 2025...Winds will transition to south and southwest ahead of another front. Advisory strength winds today will be strongest near shore north of Cape Blanco. The combination of west-northwest swell, residual northerly fresh swell, and southerly wind seas will result in steep, chaotic seas into the weekend. Conditions remain unsettled through the first part of next week, with several fronts bringing periods of gusty south winds and a likelihood of high and steep seas. && .MFR WATCHES/WARNINGS/ADVISORIES... OR...None. CA...None. PACIFIC COASTAL WATERS...Small Craft Advisory until 4 PM PST Saturday for PZZ350-356-370-376. && $$

450 FXUS66 KEKA 050929 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 129 AM PST Fri Dec 5 2025 .SYNOPSIS...A deepening marine layer will return along the coast with patchy drizzle. King tides combined with tidal anomaly will continue to bring the threat of coastal flooding in low-lying areas around Humboldt Bay today. A series of frontal systems moving north of the area will bring a chance of light rain or sprinkles across the northern portion of the area through the weekend, especially for Del Norte and Humboldt counties. && .DISCUSSION...High pressure over the Northeastern Pacific has slightly "flattened" as a series of shortwaves and associated frontal systems move around the northern periphery of the ridge towards the Pacific Northwest. Downstream flow aloft will continue to bring increasing cloudiness to the area as a weak cold front traverses the Pacific Northwest. This should aid in a deep marine layer along the North Coast. Patchy drizzle has already been observed as of 09z this morning as the deepening marine layer and saturated profile confirms the previous model data. Overnight temperatures are forecast to run up to 5 degrees warmer compared with Thursday`s morning. High dew points in the mid 30s to mid 40s will preclude frost conditions across much of the interior valleys. With fronts approaching the area from the north, chances increase for light rain or sprinkles across Del Norte, Humboldt and Trinity counties this afternoon and well into the evening. Dry weather conditions are expected to prevail in Mendocino and Lake counties. Some blustery winds will continue over the coastal headlands and exposed ridges in Humboldt and Mendocino counties. Lingering light showers will continue across the northern portion of the forecast area 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 are expected. 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...(06Z TAFS)...Ceilings will continue to lower for coastal terminals into early Friday morning as a weather system passes to the north of the area. The marine stratus will deepen, with ceilings in the IFR to high LIFR range. Some drizzle may occur at coastal terminals early Friday. Interior valleys may also experience low clouds/fog. It is still unclear if lower ceilings will make it to KUKI, but there is a definite possibility early Friday. Through the day Friday ceilings are expected to raise and stratus is anticipated to push back toward the immediate coast. However, MVFR ceilings may persist through the day for coastal terminals. && .MARINE...Into Friday morning, northerly winds are expected to move closer to the Mendocino coast, but remain 15 to 20 kt with the strongest winds in the lee of Cape Mendocino. The swell remains fairly low, currently around 2 to 4 feet at 12 seconds and this is generally expected to continue through Friday. Friday afternoon and overnight a front approaching the area will bring a short period of light southerly winds to the northern inner waters with the outer waters turning westerly. Farther south, winds will remain northerly around 10 to 18 kt. Over the weekend winds become southerly north of Cape Mendocino, but only around 5 to 10 kt. Farther south, the northerly winds persist and are around 10 to 15 kt. This pattern is expected to generally continue through Wednesday with winds remaining fairly light as a series of weather systems moves by to the north of the area. Saturday, a larger northwest swell builds into the waters. Currently it looks to be around 6 to 9 feet at 10 to 12 seconds. This is expected to diminish to around 5 to 7 feet on Sunday and generally fluctuate around 5 to 7 feet at 12 seconds into early next week. -MKK && .COASTAL FLOODING...High astronomical tides are predicted to peak on today. High tides are forecast to be at 8.80 feet at the North Spit tide gauge at around 10:55 AM local time. High tides combined with surge and tidal anomaly will result in water levels between 9.1 to 9.3 feet MLLW (Mean Low Level Water). Minor coastal flooding around Humboldt Bay, including King Salmon and Jackson Ranch Road in the Arcata Bottoms, will be likely between 10AM and noon. A Coastal Flooding Advisory will be in effect from 10AM to noon on Friday. High tides are predicted to be at 8.63 feet at 11:44 PM on Saturday. This may cause minor flooding again on Saturday, with water level remaining nearly half of a foot above astronomical tides inside Humboldt Bay. -ZVS && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Coastal Flood Advisory from 10 AM this morning to noon PST today for CAZ103. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 11 PM PST this evening for PZZ475. && $$ 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

778 FXUS66 KMTR 052102 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 102 PM PST Fri Dec 5 2025 ...New SHORT TERM... .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... (18Z TAFS) Issued at 938 AM PST Fri Dec 5 2025 Patchy to areas of fog persist across the North Bay and East Bay valleys this morning and are forecast to improve between 19- 20Z. This will give way to mostly VFR conditions after low ceilings and visibilities improve. Onshore winds look to increase by this afternoon across the San Francisco Bay and Monterey Bay terminals before easing late this evening and into Saturday morning. This is when low ceilings and/or visibilities are expected again in the North Bay and East Bay valleys early Saturday morning. Any low ceilings and/or visibilities that do develop are expected to clear at a similar time as today. Vicinity of SFO...VFR through the TAF period. Offshore winds prevail this morning and are expected to become north- northwesterly by mid- to-late afternoon. Winds diminish overnight with moderate to high confidence of onshore winds returning by Saturday afternoon. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR through the TAF period. Light to southerly winds prevail this morning and are forecast to become onshore by early-to-mid afternoon. Winds diminish overnight and become southerly early Saturday morning. && .MARINE... (Today through Wednesday) Issued at 828 AM PST Fri Dec 5 2025 Northerly winds are increasing 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...RGass 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

408 FXUS66 KOTX 051749 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 949 AM PST Fri Dec 5 2025 .KEY MESSAGES... - Wintry mix Friday may result in a slick commute. 20-40% of 1" of snow in the northeast valleys. - Strong, potentially damaging winds in portions of Central Washington Friday night. Gusty winds in southeast Washington. - Periods of moderate to heavy mountain snow in the mountain passes through Saturday. - 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. Wintry mix for areas of Northeastern Washington and North Idaho Friday with snow in the mountains. 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 through Saturday: The active weather pattern continues with a strong 160kt zonal jet stream taking aim at the Inland Northwest today as a low pressure system tracks across British Columbia. Another round of warm, moist, isentropic ascent moves through the Inland NW today producing another round of precipitation reaching the Cascades early to mid morning, and then Eastern WA/North ID late morning into the afternoon. Snow levels start off low initially for the northern valleys (1500-2500 feet) but the warm advection will raise snow levels to 2500-3500 feet in the afternoon. Elsewhere snow levels will quickly be rising to 5000-6000 feet allowing snow to change to rain early at Stevens Pass, and for Lookout Pass by this evening. The next issue will be the winds tonight with a cold front passage. This will be especially true along the East Slopes of the Cascades into the Wenatchee area and Waterville Plateau as 850mb winds increase to an impressive 60-65 kts. The big question is will these winds mix down into the populated areas? Forecast soundings don`t show quite enough low level instability for widespread damaging wind gusts, yet with very strong winds above the surface and turbulent flow off the Cascades isolated damaging gusts are possible. Here are the HREF chances of various wind gust thresholds being met tonight: City 40+ MPH 50+ MPH 60+ MPH 70+ MPH Wenatchee 80% 45% 20% 5% Chelan 70% 5% 0% 0% Mattawa 75% 60% 30% 0% Ephrata 85% 60% 45% 0% Moses Lake 60% 15% 0% 0% Waterville 90% 35% 5% 0% Mission Ridge 100% 100% 95% 45% With this pattern having the potential for at least isolated damaging wind gusts, will be upgrading the Wind Advisory to a High Wind Warning and expanding to the Ephrata area. The HREF also showing gusts around 50 MPH for the Alpowa Summit area so will continue the Wind Advisory here as well and expand onto the Palouse. Also following the cold front snow levels fall to around 4000 feet allowing rain to change back over to wet snow at Stevens and Lookout Passes. Strong upslope flow behind the front will allow the snow to continue into Saturday. 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 4000-5000 feet supporting valley rain and mountain snow. The next one is much more significant arriving Monday Night into Tuesday with precipitable water 200-300% of normal. Strong upslope flow will provide added lift into the Cascades with significant slop- over precipitation into the Methow Valley, Plain, Leavenworth, and Wenatchee. Current indications from the ensemble means is for the atmospheric river to briefly move south into Oregon Tuesday afternoon and evening before lifting back over the area Tuesday Night into Wednesday and persisting into Thursday for more moderate to heavy precipitation. The QPF amounts the models are producing are impressive over this multi day period. The ECMWF Ensemble mean is producing 5-7 inches of precipitation along the Cascade crest, 4-5 inches for the Plain, Leavenworth, and Stehekin areas, and over an inch from Wenatchee up to Omak. The ID Panhandle will also see significant rains with 1-2 inches in the valleys and 2-4 inches in the mountains. 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. JW && .AVIATION... 18Z TAFs: IFR stratus with locally dense fog for KGEG due to a saturated boundary layer and light winds this morning. The next system is moving in with a strong upper level jet stream around 150-160 kts from west to east. Another round of precipitation will occur with a mix of rain and snow. Low level wind shear is shown in model soundings for KEAT/KMWH/KLWS/KPUW between 0z-6z Saturday 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. These potentially damaging wind gusts will likely not be long duration and sporadic given the stable boundary layer. The increased winds usher increased probabilities to bring improvement to the persistent stratus except far NE WA and N ID where the flow pattern favors upsloping flow. .FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence of widespread IFR and MVFR conditions across the region into Friday afternoon given more precipitation falling into an already saturated boundary layer. 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. /sb ----------------------- Confidence descriptors: Low - Less than a 30 percent chance Moderate - 30 to 70 percent chance High - Greater than a 70 percent chance For additional probabilistic information for NWS Spokane airports,please refer to the Aviation Dashboard on our webpage: https:/www.weather.gov/otx/avndashboard && .Preliminary Point Temps/PoPs... Spokane 38 35 44 35 43 38 / 100 40 30 20 80 50 Coeur d`Alene 39 35 43 35 43 38 / 100 80 70 50 90 70 Pullman 43 38 44 37 44 40 / 100 70 60 50 90 80 Lewiston 48 41 52 40 48 43 / 100 80 50 40 70 60 Colville 35 33 41 28 39 33 / 100 40 40 20 90 40 Sandpoint 36 33 40 34 40 37 / 100 80 90 70 100 90 Kellogg 40 35 40 37 41 40 / 100 90 100 80 100 90 Moses Lake 40 36 50 35 46 38 / 90 10 0 0 60 10 Wenatchee 45 38 50 37 45 39 / 90 60 30 20 70 20 Omak 37 34 43 32 40 34 / 90 40 20 10 60 20 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...Wind Advisory from 7 PM this evening to 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 Weather Advisory from 7 PM this evening to 10 PM PST Saturday for Western Chelan County. ID...Wind Advisory from 7 PM this evening to 7 AM PST Saturday for Idaho Palouse. Winter Storm Warning until 4 PM PST Saturday for Central Panhandle Mountains. && $$

710 FXUS66 KPDT 051716 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 916 AM PST Fri Dec 5 2025 .UPDATED AVIATION...18Z TAFs...BDN/RDM are at VFR and will continue to see VFR conditions through the period. DLS/PDT/PSC/ALW are all MVFR due to lower VSBYs 4-6SM due to BR and low CIGs below 3kft. YKM sits at IFR due to very low CIGs below 700 ft and 4SM due to BR. This will continue through 21-00Z as winds will pick up across all TAF sits assisting with the push out of the fog and the lifting of the CIGs. A warm front will come across the region bringing with it continued rainfall and an increase in the winds (80-90% probabilities). Timing of the warm front crossing will be the toughest part of the forecast, however, models show the front to move across between 21-00Z. Wind advisories have been put out across the many of the TAF due to winds nearing 30kts sustained and 35-40 kt gusts. BDN/RDM will also see higher winds 10-20 sustained with gusts of 25-30 kt. With the assistance of the winds, all TAF sites will see VFR conditions after 21Z (60-80%). 90 && .PREV DISCUSSION... /issued 408 AM PST Fri Dec 5 2025/ DISCUSSION... Key Messages: 1. Breezy to windy conditions this afternoon through Saturday afternoon. Wind advisories expanded both temporally and spatially. 2. Persistent rain chances through the next week combined with high snow levels will lead to rises on area rivers. Overview: The forecast for the next week can be succinctly described as warm, wet, and windy as a subtropical high in the Pacific combines with a remarkably persistent quasi-zonal to zonal jet stream and multiple frontal systems to direct several rounds of subtropical to tropical moisture into the Pacific Northwest. Headline updates: The main update to headlines was the expansion of existing wind advisories to include the Yakima Valley, Lower Columbia Basin of Washington, and the Wallowa Valley. Rain is beginning to overspread the forecast area again as low- to mid-level warm air advection (WAA) associated with a warm frontal passage this morning interacts with ample moisture. The result will be the best precipitation chances for the lower elevations through the remainder of the week. For mountain areas, especially the Cascade crest and northern Blues, precipitation chances will be more persistent into the weekend. The main talking point today is the anticipated breezy to windy westerly (southwesterly to northwesterly depending on the exact location) winds that are poised to ramp later this afternoon through tonight as a strong jet moves overhead. This afternoon through Saturday morning, the 00Z HREF places a persistent 8-12 hPa pressure difference between PDX and GEG -- often the threshold where advisory-level winds begin -- and an 850-hPa jet of 40-60 kts over the Columbia Basin. While the largely nocturnal nature of the event does reduce overall forecast confidence in persistent, widespread advisory-level winds through the entire advisory period, confidence is still high (70-95%) that peak gusts will exceed 45 mph in wind-prone locations. Moreover, per NBM calibrated probabilities, there is still a low-medium chance (20-50%) of reaching or exceeding warning-level gusts in the most wind-prone locations of the Columbia Plateau. Snow levels today will remain high enough (generally 5-8 kft) to preclude any concerns for winter weather headlines, though a cooler air mass tonight through Saturday night will present lower snow levels (4-5 kft) and at a medium chance (50%) of advisory- level snowfall for White Pass. Through the bulk of the next week, snow levels are then forecast to remain high at mostly 5-8 kft with periodic dips to 4.5 kft along the Washington Cascades. Lastly, will note a significant amount of precipitation is forecast for the mountain areas Monday through Thursday of next week. While confidence in precise amounts is still low, and will depend on the exact location of the jet stream and incoming frontal systems, the NBM places a 20-30% chance of reaching or exceeding 5 inches of liquid equivalent across the Oregon Cascade crest through the 72-hr period ending 4 AM Thursday, and an even higher 40-50% chance for the Washington Cascades. Since much of this precipitation is forecast to fall as rain, rises on area rivers are anticipated. Current forecasts from the NWRFC in Portland do place multiple rivers near or above action stage by the latter half of next week. && .PRELIMINARY POINT TEMPS/POPS... PDT 41 52 39 53 / 40 40 30 70 ALW 42 52 41 52 / 60 50 50 80 PSC 41 56 39 54 / 10 10 10 60 YKM 38 55 34 51 / 30 20 20 70 HRI 42 55 39 55 / 20 20 20 70 ELN 36 48 32 46 / 60 40 30 70 RDM 32 50 32 53 / 40 10 10 40 LGD 38 46 34 44 / 80 80 60 80 GCD 35 46 33 48 / 60 40 40 70 DLS 47 55 44 54 / 70 70 80 90 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Wind Advisory from 1 PM this afternoon to 10 AM PST Saturday for ORZ041-044-507-508-510. Wind Advisory from 1 PM this afternoon to 1 PM PST Saturday for ORZ050. WA...Wind Advisory from 1 PM this afternoon to 10 AM PST Saturday for WAZ024-521. Wind Advisory from 7 PM this evening to 7 AM PST Saturday for WAZ026>029. && $$ DISCUSSION...86 AVIATION...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