028 FXUS66 KSEW 082238 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 238 PM PST Wed Jan 8 2025 .SYNOPSIS...Surface high pressure will bring drier conditions to the region on Thursday, with patchy fog possible during the morning hours. Lowland rain, mountain snow, and breezy conditions return on Friday as a frontal system moves across Western Washington. Showers expected to linger through the weekend. Dry conditions return early next week as high pressure rebuilds. && .SHORT TERM /TONIGHT THROUGH SATURDAY/...Satellite imagery shows some of the low stratus over Western Washington has scattered and allowed some locations to see some blue skies. Dry conditions are expected to continue into Thursday as an upper level ridge sits over Western Washington. Residual moisture and light winds will promote the development of patchy fog and low stratus Thursday morning and should clear out by the afternoon giving way for some partly cloudy skies. HREF guidance hints that the thickest fog will likely form along South Puget Sound and the Chehalis Valley (60-80% chance of 0.25 mi visibility or less). High temperatures will be in the upper 40s to low 50s. An upper level trough will move over Western Washington on Friday bringing lowland rain, mountain snow, and breezy westerly winds. Snow levels will bounce between 3000 to 4000 ft on Friday, leading to a few inches of snow accumulation along Snoqualmie and Stevens Pass. Model guidance hints at the possibility of a Puget Sound Convergence Zone developing across the Central Cascades on Friday afternoon, which may lead to higher localized amounts of snowfall. Snow levels are expected to decrease below 3000 ft by Friday night. Precipitation is expected to continue into the weekend, with light showers possible primarily along the mountain ranges. .LONG TERM /SUNDAY THROUGH WEDNESDAY/...Slight chance of showers still remain possible early Sunday morning mostly along the mountain ranges. Drier conditions are expected to ensue starting late Sunday morning as an upper level ridge will build and amplify over the Pacific Ocean, with broad ridging settling over the Pacific Northwest by midweek. There is some disagreement in the exact strength of the ridge; however most models favor a moderate to strong ridge situated over the area by Wednesday. This upper level pattern will likely bring a few rounds of morning patchy fog to the region. High temperatures will be in the 40s and gradually warm up to near 50 by midweek. Low temperatures will be in the low to mid 30s. The next chance of precipitation may come as early as Wednesday night as some guidance brings PoPs back into the forecast. MGF && .AVIATION...High pressure will continue to build inland through Thursday as it slowly drifts eastward. A ridge axis to the west will track eastward, which will shut off north flow aloft over the terminals later tonight into Thursday. Ceilings this afternoon have improved to VFR for most main terminals (lower MVFR clouds with pockets of IFR remain in the Kitsap Peninsula but have been receding from north to south based on satellite). Cloud coverage will scatter (except in the Olympics and Cascades). Winds through the afternoon will remain light out of the north/northeast at 4 to 8 kt. Expect a decrease of winds tonight with weak gradients increasing the chance of either low IFR/LIFR stratus of fog across most of the terminals early Thursday morning (starting in the South Interior around 10-12Z and spreading region-wide by 16-18Z). Once the fog/stratus clears, VFR/few clouds are expected remainder of Thursday. Winds will slowly switch back to the south later Friday afternoon at 4 to 8 kt. KSEA...VFR mostly overcast ceilings early this afternoon will continue to scatter through the evening. Light north to northeast winds at 4 to 8 kt. Expect light winds under 5 kt tonight into Thursday (variable at times). IFR/LIFR probabilities are 30 and 20 percent respectively for the low stratus/fog potential Thursday morning. Best timeframe for any IMC conditions will be from 15Z through 20Z (descent chance it starts early and lingers longer). Once fog/stratus clears, few clouds/VFR for the remainder of the day with winds beginning to pick up out of the south at 4 to 8 kt. HPR && .MARINE...High pressure will continue to build inland today through Thursday as it progresses inland (keeping flow primarily offshore for most waterways). Morning fog is possible over portions of the Puget Sound Waters Thursday morning. Low pressure to the west will swing a frontal system Thursday night into Friday. This will be the next best chance of gusty west winds over the coastal waters and the Strait of Juan de Fuca. Most likely scenario is a windy period with gusts up to 25 kt with the fronts that pass through (which will also produce some precipitation). Once the system passes, it remains very quiet with no wind headlines expected after this system in the outlook period. Seas today continue to drop to 6 to 8 feet. Expect an increase up to 10 to 14 feet Friday/Saturday, before dropping under 10 feet Sunday and climbing back to 10 to 12 feet Sunday night into Monday briefly, then holding at 8 to 10 feet through next week. HPR && .HYDROLOGY...No river flooding is expected over the next 7 days. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$

338 FXUS66 KPQR 081811 AFDPQR Area Forecast Discussion National Weather Service Portland OR 1011 AM PST Wed Jan 8 2025 .SYNOPSIS...High pressure will largely result in dry weather across the region. The main exception to this will be on Friday when a front will bring widespread light valley rain and mountain snow to the region with a few showers lingering over the higher terrain into the weekend. A series of weaker systems are also expected to bring light precipitation to the region with another dry spell expected by Monday/Tuesday of next week. && .DISCUSSION...Today through Tuesday...A ridge of high pressure over the region will dominate through at least Thursday. This will bring dry weather and seasonably normal temperatures through at least Thursday night. Expect daytime high temps in the upper 40s to low 50s through Thursday with gusty easterly winds up to 40 mph during the afternoon and overnight hours within and near the Columbia River Gorge through Friday. These gusty easterly winds may reach the Portland/Vancouver Metro area during each afternoon, then retreat towards Gresham/Troutdale overnight with gusts up to 35 mph. Thursday night/Friday, a low pressure system will shift northeastward towards Alaska/British Columbia, dragging an extended frontal system into the Pacific Northwest. Timing of this system still remains in question, but most models have precipitation along the coast starting Thursday night with precipitation pushing into the Willamette Valley and Cascades by Friday morning. This system is expected to bring rain Friday, transitioning into showers by Saturday. The Cascades will see snow/rain until Sunday evening. Additionally,this system will lower high temps into the mid 40s Friday through early next week. High pressure is likely to return to the region by Monday, resulting in dry weather for the start of the week, at least until Tuesday. 42/~Hall && .AVIATION...This morning conditions have generally remained VFR with mid to high level cloud cover streaming overhead. That said, some low stratus/fog is present in the southern Willamette Valley but should dissipate over the next couple of hours (by 18-20z). Otherwise, expect VFR to prevail across the area through the rest of the daytime hours into the evening. Fog could reform in interior valleys 06-12z Thu as high pressure rebuilds overhead but east winds out of the Gorge will likely help to limit these concerns at immediate Portland area terminals. Best on HREF guidance the highest confidence in fog formation tonight is south of KSLE to KEUG. PDX AND APPROACHES...VFR expected through the period. A passing disturbance has lowered CIGs near 3.5kft this morning but these should rise into the early afternoon hours followed by just a few lingering high clouds (>10kft). Gorge winds redevelop 21-00z as high pressure builds overhead, helping to keep fog out of the terminal again tonight. -Schuldt/CB && .MARINE...A dissipating frontal boundary offshore is promoting 5-10 kt southeast winds across the coastal waters this morning, while a 8-10 ft westerly swell maintains low end Small Craft Advisory level seas. Latest available buoy data suggests model guidance may be slightly overdone with respect to this swell, which would tend to support allowing current headlines to expire later this morning as seas gradually subside to around 8 ft this afternoon and eventually to around 6 ft on Thursday. Winds will shift around to the north-northeast this afternoon as high pressure rebuilds overhead. Expect relatively benign conditions through Thursday as winds turn more offshore, though could see some localized stronger gusts of 15-20 kt out of gaps in the coastal terrain. Conditions deteriorate Thursday night into Friday as another front clips the northern waters and a larger swell arrives. After a brief period of southerly winds Thursday night, winds will strengthen out of the northwest and become gusty on Friday in the wake of the front. Likelihood of Gales has trended down with recent model runs (less than 10%) but another round of Small Craft headlines is likely as winds gust to 25-30 kt through Friday, The building westerly swell will also help to push seas back into the low to mid teens through early Saturday. Look for winds and seas to trend back down as high pressure builds back over the region Sunday through early next week. /CB && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory until 1 PM PST this afternoon for PZZ210. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland

262 FXUS66 KMFR 082227 AFDMFR Area Forecast Discussion National Weather Service Medford OR 227 PM PST Wed Jan 8 2025 .DISCUSSION...Quiet weather is in store for the next 24-36 hours. High pressure over the eastern Pacific Ocean will gradually nudge over the region Thursday into early Friday. A quick moving trough and front will knock down the ridge and pass through the area on Friday, bringing a quick shot of precipitation. The ridge will quickly rebound over the weekend, but the ridge axis will be offshore again, and this will allow for a few "inside sliders" Sunday into Monday. Eventually the ridge nudges back overhead early next week while one of the inside sliders undercuts this ridge and retrogrades westward over southern California. With the exception of Friday, this pattern will overall lead to dry conditions with minimal weather impacts. High pressure aloft is resulting in strong valley inversions, leading to persistent fog/low clouds in West Side Valleys as well as stagnant air across the region. An Air Stagnation Advisory is in place through Friday morning until the front arrives to mix out the stagnant air. Above the inversions, a thermal trough at the surface is bringing gusty northeast through southeast winds (15 to 25 kt), warmer temperatures and unseasonably low relative humidities to the higher elevations. This pattern will continue through Thursday night before a front arrives at the coast Friday morning. This front isn`t particularly strong, especially compared to the systems we experienced over the holidays, and it`ll be washing out as it moves inland during the day Friday. We do expect wetting rains along the coast and along and north of the Rogue-Umpqua Divide to the Cascades, but areas south and east will likely only get a few hundreths if that with this system. Snow levels will be above 5000 with this precipitation, so we don`t anticipate any winter weather impacts with this front. It will, however, provide enough mixing to clear out the stagnant air and bring some gusty winds to the coast, mountains and areas east of the Cascades. These winds don`t look headline worthy, but gusts of 25-35 mph will be common in these areas. In the northerly flow behind this front, gusty northerly winds will continue and this should keep stagnant conditions from returning until early next week. The inside sliders that follow on Sunday are likely to be dry, though some very light precipitation is possible across far northern areas Sunday afternoon/evening. High pressure returns by the early part of next week, and this is when we could see the return of persistent valley fog/low clouds and stagnant conditions. /BR-y && .AVIATION...08/18Z TAFS...Fog remains in the valleys this morning with visibilities down to 1/4 mile in a few areas. Some mid and high level clouds remain overhead with a weak inversion. High pressure is anticipated to build this afternoon into the overnight hours with a very strong inversion setting up over the region with temperatures up to 53 degrees F near 2000 feet and a few degrees above freezing at the surface. As a result, more dense fog with visibilities down to a 1/4 mile seems likely in many of the valleys. Spotty high clouds could keep visibilities varying from IFR to LIFR through the overnight hours. -Smith && .MARINE...Updated 200 PM PST Wednesday, January 8, 2025...Advisory level conditions are expected to persist through this evening across most of the waters. Residual west swell and breezy north winds will bring steep seas of 8 to 11 feet. While north winds (10-20 kt) continue tonight into Thursday, the swell will decay and conditions briefly improve. A cold front is expected to pass through the region on Friday. Steep seas are likely to accompany this front. Then, north winds strengthen Saturday into Sunday as high pressure builds offshore and a thermal trough develops near the coast. Winds may reach gale force south of Gold Beach during the weekend. -Spilde && .MFR WATCHES/WARNINGS/ADVISORIES... OR...Air Stagnation Advisory until noon PST Friday for ORZ023>026- 029>031. CA...None. PACIFIC COASTAL WATERS...Small Craft Advisory until 10 PM PST this evening for PZZ350-356-370-376. && $$ MNF/MAS/CZS

848 FXUS66 KEKA 082258 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 258 PM PST Wed Jan 8 2025 .SYNOPSIS...Dry weather is expected this week as high pressure dominates. Gusty NE winds continue in SE Lake County tonight. Chilly mornings are possible as skies clear tonight and Friday morning. && .DISCUSSION...High pressure continues to dominate the region, bringing mostly clear skies. These are not expected to last into the night, but could keep high temperatures similar to yesterday`s. Elsewhere, high temperatures are likely to raise a few degrees from yesterday as warming continues. Low level cloudiness or fog is once again possible in some of the interior valleys, though southern Mendocino and Lake largely stayed cloud-free and likely will again tonight. This will promote a colder night tonight by a few degrees, with 30s possible even to the coast. 20s are possible in the valleys of Trinity County. Models have been suggesting a warm up in the valleys during the day today and Thursday. Narrow valleys, such as the Trinity River valley, have strong inversions and persistent low cloud cover, and are less likely to see a significant daytime warmup. Larger valleys, like Ukiah and Lake County, see more sunlight and could break some of the overnight inversion and see temperatures in the 60s or perhaps the low 70s. A weak system moves into the Pacific Northwest on Friday, but most impacts remain well to our north, and likely will only bring cloud cover or a light sprinkle in Del Norte County. Some breezy northerlies at the coast are possible behind this system Friday and into the weekend. Typical areas, likes coastal headlands and higher elevation areas of the interior, will see the highest gusts with NBM showing the highest chance for gusts over 30 mph around Cape Mendocino. The airmass behind this system appears to be cold, possibly bringing near or below freezing low temperatures this weekend in the lower elevations, including the coast. Ensemble members continue to show high pressure dominating through early next week. JB && .AVIATION...Continued drying conditions and gentle offshore flow will allow for mostly VFR conditions to persist over the next 24 hours. There is a small chances (less than 15%) for some brief fog formation around Humboldt Bay overnight. Surface winds will be light for the most part. The exception will be Southern Lake County where NE winds aloft of 35kts will create a low level wind shear threat. High level clouds will begin to increase Thursday afternoon in advance of a weak frontal system. && .MARINE...Northerly winds have increased this afternoon, mainly in the outer waters. Wind gusts up to 25 kts can be expected over the outer waters into Thursday morning. The northerlies will trend down Thursday and part of Friday as a weak frontal system moves through and weakens the pressure gradient. Northerly winds will strongly rebound Friday afternoon behind the front. Gale conditions will likely develop in the southern waters early Friday evening, with expansion north Friday night. Northerly winds will further increase Saturday when gusts around 35 to 40 kts are forecast. Gale strength northerlies will likely carry through Sunday before weakening. A mid period WNW swell will be fading tomorrow afternoon as a long period WNW swell begins building in, building up to around 9 ft Friday. && .BEACH HAZARDS...A long period westerly swell will begin filling in late Thursday as a mid period swell fades. The swell will continue building Thursday night through Friday, up to around 6 to 8 feet at 16 seconds, and as the dominant wave group. A High Risk for sneaker waves can be expected by early Friday morning with these expected conditions. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 3 AM PST Friday for PZZ470. Small Craft Advisory until 3 AM PST Friday for PZZ475. && $$ 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

988 FXUS66 KMTR 082244 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 244 PM PST Wed Jan 8 2025 ...New SHORT TERM, LONG TERM... .SYNOPSIS... Issued at 310 AM PST Wed Jan 8 2025 Breezy to gusty offshore winds continue across the region, especially higher terrain of the North Bay. Additional gusty winds possible Saturday and early next week with quiet weather in between. && .SHORT TERM... Issued at 213 PM PST Wed Jan 8 2025 (This evening through Thursday) Offshore flow remains, but continues to weaken. As such, winds also continue to decrease across the region. Still seeing some gusts over 40 mph in the hills. Otherwise, another beautiful day across the Bay Area and Central. Offshore flow continues to promote sunshine and milder temperatures. It may be nice here, but we`re thinking of our colleagues and people currently being impacted by the extreme Santa Ana winds and deadly wildfires in SoCal. Relatively quiet weather again tonight with offshore flow. There`s a chance for some patchy fog in the N Bay valleys,but only in the 15-20% range. Thursday - generally speaking the same overall sensible weather. Sunshine, mild temps, dry airmass, and offshore winds. The lower confidence portion of the forecast with higher impacts will be the strength of the winds. 12Z model suite from this morning ramped up the offshore gradient from SFO-WMC again -11mb to -15mb. WRF guidance puts the peak gradient in the lowest 10% or in other words very strong for this time of year. As a result, have increased winds over the higher peaks of the N Bay. Gradient strength and pattern recognition shows gusts of 70-80 mph could happen again at Mt St Helena. Further examination through x-sections shows marginal mix down potential. Therefore, confidence at this point isn`t high enough to issued a Wind Advisory. If one were to be issued it would be for the N Bay Mts. && .LONG TERM... Issued at 240 PM PST Wed Jan 8 2025 (Thursday night through next Tuesday) Got some outdoor activities planned? Do them on Friday. Offshore gradient has weakened and any gusty winds will have eased. Temperatures will be in the 60s to lower 70s...solid chamber of commerce weather. Two potential weather impacts for the weekend into early next week: offshore winds again and frost/freeze. Weak upper level system swinging through the PacNW will promote several additional bursts of offshore flow bringing gusty winds to the higher terrain and foothills around the Bay Area. As for temperatures, interior Central Coast will see several nights of temperatures at or below 35 degrees with far interior locations reaching the upper 20s. Other sheltered valleys around the Bay Area could also see overnight lows dip into the mid 30s. Clear skies, dry offshore flow, and still long-ish nights will be a good set up for cooling. So, the question remains. Rain? Looking pretty dry through the end of January. CPC has the area in below normal rain through Jan 22 && .AVIATION... (18Z TAFS) Issued at 1005 AM PST Wed Jan 8 2025 Mainly offshore winds, dry conditions continuing in the 18z TAF cycle. It`s near high confidence VFR at the area terminals for much of the time with exception of KSTS where fog /LIFR-IFR/ may form early Thursday morning, low confidence but did add a tempo for 1/2 mile in fog, vertical visibility 200 feet. Vicinity of SFO...VFR. East to southeast wind near 10 knots decreasing to light and variable late today, possibly northwest 5 to 10 knots in the evening. Light and variable wind tonight and Thursday becoming northwest near 10 knots Thursday afternoon. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR. East to southeast winds 5 to 10 knots, becoming light and variable in the afternoon. Winds east to southeast 5 to 10 knots tonight and Thursday morning. && .MARINE... (Today through Monday) Issued at 953 AM PST Wed Jan 8 2025 Surface high pressure over the Great Basin will result in periods of offshore winds across the bays and coastal waters through late Thursday night. On Friday the high pressure system weakens while a low pressure trough moves eastward across the Pacific Northwest. Surface high pressure then rebuilds over the Great Basin during the weekend. This will bring a return of offshore winds to the bays and coastal waters over the weekend. Seas and gusty north winds gradually abate during the remainder of the week then increase again over the weekend. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ SHORT TERM...MM LONG TERM....MM AVIATION...Canepa MARINE...Canepa Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/nwsbayarea www.twitter.com/nwsbayarea www.youtube.com/nwsbayarea

133 FXUS66 KOTX 082256 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 256 PM PST Wed Jan 8 2025 .SYNOPSIS... Thursday will be a dry and cloudy day. Another chance for wintry precipitation is expected on Friday with the passage of a frontal system. Saturday and possibly Sunday have a good chance of being sunny across central and parts of eastern Washington. && .DISCUSSION... Tonight - Thursday: An upper-level ridge currently centered along 130W will drift eastward on to the WA Coast delivering a period of stable weather conditions for the Inland NW. Areas of low clouds currently trapped within the valleys and Basin will likely remain firmly in place. The one exception will be over the Palouse where increasing southeasterly winds in the boundary layer should help scrub out some of the lower clouds for locations like Moscow, Pullman, and Colfax. Temperatures will remain seasonably cool with highs in the 30s and lows in the 20s/30s. For any of the mountain valleys that experience brief clearing after dark and especially the benches above the low clouds, fresh snow and light winds will allow for strong radiational cooling and potential for temperatures to plummet into the teens or lower. Based on the 2PM satellite, this looks like it will be very localized. The higher terrain of the Cascades and Selkirks will carry the highest probabilities for sunshine and should mid-clouds decreasing in the Bitteroots with time. Friday: The ridge will be deflated with a robust shortwave dragging a cold front through the region. This front will pick up an appreciable moisture plume but will be a quick hitter with modest westerly flow. As such, there will not be much in the way of QPF in the lee of the Cascades and into Eastern WA. The Cascade crest will intercept over half an inch of QPF with the Idaho Panhandle receiving between 0.15-0.50" (highest amounts in the Central Panhandle Mountains). Precipitation will largely fall in the form of snow outside the lower Columbia Basin and L-C Valley which will be a rain/snow mix. As for impacts, the greatest impact will be on Stevens Pass where 5-8 inches of snow is expected with a 70% chance for at least 6". Forecast is calling for 3-5 inches for Lookout Pass and higher amounts in the mountains of southern Shoshone County. Lookout Pass carries a 15% chance for 6 inches or more. Snow for these passes will come in two waves...light amounts with the frontal passage then moderate to heavy snow showers with the post frontal air mass. The Puget Sound Convergence Zone will play a large role in exact amounts for Stevens Pass but could deliver snowfall rates of 1"/hour. We will also need to keep a close on the post frontal showers on the Camas Prairie. As flow shifts more northwesterly and lapse rates increase, US 95 around Winchester and Craigmont could be coping with periods of moderate snow showers. Winds will also become breezy on Friday in the mountains, across the southern Basin, and into Palouse and foothills of the Blue Mountains. This push of westerly winds will increase probabilities for scrubbing out low clouds but will likely not arrive until late Friday afternoon and evening and remain breezy through the night. Mean wind gusts from the NBM around Pomeroy, Pullman, and Anatone are between 35-45 mph. Similar speeds are being forecast in the Blues, Cascades and Bitteroots ridgetops which will bring the potential for blowing and drifting snow. Folks traveling along Hwy 12 between Lewiston and Dayton should be prepared for 40 mph gusts with a 50% chance for occurring. Wind gusts for the remainder of the Basin, Spokane-Cd`A, and Wenatchee Area will be in the 20-30 mph range. Saturday - Sunday: High pressure rebuilds off the coast and keeps the Inland NW under persistent northwest flow aloft. Weaker shortwaves dropping down the eastern flank of the ridge coupled with upsloping northwest flow will keep a threat for snow showers ongoing for the Idaho Panhandle mainly from I-90 southward. Climatologically, this is a favorable setup for snow showers between the Silver Valley and Camas Prairie with potential for a few inches of snow over time. Low clouds and fog could return to lowlands if the clouds even cleared at all. Confidence for low clouds and fog is low due to the northwest flow pattern and would not rule out some periods of clearing and potential sun breaks. Temperatures will remain cool with readings near normal. Monday - Tuesday: 100% of the ensembles indicate the upper-level ridge will build inland early next week. This will shield the PacNW of all precipitation chances and likely result in nuisance stratus and fog. The stable weather conditions will result in strengthening inversions with very small diurnal temperatures swings. Sunshine will be most prevalent in the mountains. Overall, should be little to no impact to travel outside fog and black ice overnight. /sb && .AVIATION... 18Z TAFS: Moist upslope flow will likely result in ceilings below 1500 feet through the TAF period for most sites with the exception of LWS which should remain above 2k ft. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence of continued IFR ceilings through the TAF period with moderate confidence of degradations to LIFR ceilings and visibilities tonight into tomorrow morning. ----------------------- Confidence descriptors: Low - Less than a 30 percent chance Moderate - 30 to 70 percent chance High - Greater than a 70 percent chance && .PRELIMINARY POINT TEMPS/POPS... Spokane 29 33 27 33 24 34 / 0 0 0 40 10 0 Coeur d`Alene 28 33 26 35 24 35 / 0 0 0 70 30 0 Pullman 27 36 29 36 29 36 / 0 0 0 80 50 10 Lewiston 31 41 33 43 34 44 / 0 0 0 60 50 10 Colville 26 32 25 33 20 35 / 0 0 0 50 10 0 Sandpoint 27 31 25 32 25 32 / 0 0 0 90 30 10 Kellogg 28 35 27 36 26 33 / 0 0 0 90 60 20 Moses Lake 30 36 30 38 26 41 / 0 0 0 10 0 0 Wenatchee 29 33 29 40 31 42 / 0 0 0 30 10 0 Omak 26 33 27 37 23 37 / 0 0 0 20 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$

515 FXUS66 KPDT 082221 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 221 PM PST Wed Jan 8 2025 .SHORT TERM... Tonight through Friday night...A large area of high pressure will steadily build into the Pacific Northwest through Thursday. This high will break down and move eastward through Friday morning. On Friday a weak trough, front and associated precipitation will move from west to east across the region into Saturday morning. POPs will increase general across the Cascades and nearby locations by mid-morning then spread everywhere by later in the morning to afternoon, before retreating back to the mountains by evening. Overall QPF will be upwards of 0.50 inches in along the crests of the mountains, with 0.25 to 0.50 inches in nearby locations and only a few hundredths in most lower elevation areas. SNow levels will initially be fairly high, ranging from 200 to 5000 feet in the Washington Cascades to over 7000 feet in the Oregon Cascades and 2500 to 3500 feet in the Blues and Wallowas. By Saturday morning, snow levels will decrease to between 2000-2500 feet in most areas. Snow accumulations are generally looking to be a few inches at this point, highest along the crest. Winds are expected to be relatively light through Friday but will then increase as the through and front approach into Saturday morning. Wind gusts in the 30 to 35 mph range, with gusts to 40 mph are possible, especially across the Columbia Basin, Simcoe Highlands, Kittitas Valley and Foothills of the Blue Mountains. NBM probabilities of wind gusts >=39 mph are 70 to 90 percent while wind gusts >= 47 mph are 50 to 70 percent during this time. So confidence is high in gusty winds, though they look to remain below advisory criteria. Otherwise, expect fog and/or stratus associated with the ridge, especially tonight in the normally favored locations. .LONG TERM... Saturday through Wednesday...Weather in the long term period will be fairly quiet aside from a couple of systems affecting the area Saturday and Sunday. A ridge will be centered out in the Pacific with our area in a generally northerly flow on the eastern side of the ridge. The Extreme Forecast Index shows little in the way of unusual weather. Saturday will see a system that arrived Friday departing the area during the day. Precipitation will be a chance of snow in the Cascades and eastern mountains with fairly light amounts of less than an inch. Snow levels will be around 2000 feet. The NBM probabilities give the mountains a 40%-70% chance of 1 inch of snow but drops off to 15%-30% for 2 inches. The lower elevations are not expected to get any rain or snow. Temperatures will be in the lower to mid 40s with lows in the 20s to lower 30s. As the system departs, pressure gradients will tighten and breezy west to northwest winds of 15 to 25 mph are expected in the Columbia Basin. As we get into Sunday, a weak wave will ride over the ridge into our area, bringing another slight chance to the mountains while again, the lower elevations stay dry. Snow levels will continue at 1500- 2500 feet, so precipitation will be a slight chance to chance of mountain snow. Amounts will be lighter than the previous system with only the highest peaks getting an inch of so of snow. NBM probabilities give only a 20%-40% chance of an inch of snow. Temperatures will be 2-3 degrees cooler than Saturday. Conditions will get even quieter Monday through Wednesday as the ridge expands and tilts eastward overhead as models bring a closed low to the southern California coast. Model clusters are in very good agreement Monday but by Wednesday, some differences develop about the ridge and the location and strength of the southern California upper low, but those differences should have little impact on our forecast. Not expecting any precipitation Monday through Wednesday. Models show temperatures cooling to the mid 30s to lower 40s on Monday. Models keep those temperatures in central Oregon and the mountains Tuesday and Wednesday while the Columbia Basin cools further to the mid to upper 30s, which hints at the possible development of low stratus and fog. Perry/83 && .AVIATION...(Previous Discussion) 18Z TAFs...Low stratus continues over parts of the Columbia Basin and have kept MVFR cigs at KYKM and KPSC for a few more hours. Otherwise have sct-bkn cigs at 040-080 through this evening. Low stratus expected return 03Z-09Z with MVFR/IFR cigs at all TAF sites except KRDM and KBDN. Kept vsby at MVFR at KYKM, KALW and KPDT but wouldn`t be surprised to see lower vsby at those sites. Did not have the confidence to add IFR or lower vsbys. Have other sites staying at VFR vsby. Winds will remain below 8 kts for the next 24 hours. Perry/83 && .PRELIMINARY POINT TEMPS/POPS... PDT 27 36 27 44 / 0 0 0 50 ALW 29 37 29 43 / 0 0 0 70 PSC 32 38 31 44 / 0 0 0 20 YKM 27 38 28 42 / 0 0 0 30 HRI 30 37 31 47 / 0 0 0 30 ELN 27 36 27 42 / 0 0 0 40 RDM 24 42 29 46 / 0 0 0 20 LGD 24 39 28 41 / 0 0 0 70 GCD 23 44 27 43 / 0 0 0 40 DLS 33 40 33 49 / 0 0 0 70 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ SHORT TERM...77 LONG TERM....83 AVIATION...83

708 FXUS65 KREV 081929 AFDREV Area Forecast Discussion National Weather Service Reno NV 1129 AM PST Wed Jan 8 2025 .SYNOPSIS... * Elevated east to northeast winds continue today and Thursday along the Sierra ridgetops. * An overall quiet pattern continues into next week aside from a weekend cool down as a dry front moves through the region. && .DISCUSSION... A high pressure system moves over the Pacific NW today, keeping us in this pattern of relatively benign weather. The NE flow will keep Sierra ridgetop winds elevated, but expect calm winds across the rest of the area. With said calm winds, we can expect a return of valley inversions. Additionally, expect afternoon high temperatures to rise up to 10 degrees above normal by Friday. This warm up will be short-lived, however, as a low to the north drops into eastern Nevada and Utah Friday night into Saturday. Amongst near-normal temperatures, this will also bring a tightened pressure gradient, resulting in increased wind gusts Saturday afternoon. The low pressure will settle into the middle of the country before splitting early next week. From there, a cutoff low is expected to pivot to the SW, keeping us in this pattern of NE flow for the foreseeable future. -Giralte && .AVIATION... VFR conditions expected area-wide through the weekend with winds light and variable. Sierra terminals may see increased turbulence due to the increased NE flow today. -Giralte && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$

172 FXUS66 KSTO 082114 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 114 PM PST Wed Jan 8 2025 .SYNOPSIS... Breezy north to east winds this week accompanied by dry weather and above-normal temperatures. Gusty north to east winds return by the weekend. && .DISCUSSION... Our gusty winds this morning continue to trickle down throughout the remainder of the morning and afternoon over the mountains. Our forecast pattern will see little change over the next several days with dry and breezy weather the main forecast highlights through the extended forecast (through next Wednesday). Ridging remains overtop Northern CA and will keep us dry with no forecasted precipitation observed. Our next round of gusty winds will begin on Saturday across the western portion of the Valley and over the Northern Sierra, tapering off Sunday morning. North to east gusts 25 to 35 MPH are forecasted with gusts up to 50 MPH possible over the Northern Sierra. Breeziest periods of winds in the Valley will be late Saturday morning into the afternoon and Saturday evening and overnight for the Northern Sierra. Valley NBM probabilities show around a 40-70% chance of gusts over 40 MPH mainly west and along Interstate 5, north of I-80. Be sure to exercise caution if operating a high profile vehicle or secure outdoor items. Temperatures warm today and tomorrow,particularly north of I-80 with Valley highs in the 60s and up to near 70 over the Northern Sacramento Valley. 40s to mid 60s are forecasted across the mountains to foothills respectively with highs cooling a few degrees this weekend. && .EXTENDED DISCUSSION (Sunday THROUGH Wednesday)... Eastern Pacific ridging expected to build inland and be the dominate synoptic feature as we enter next week. A closed low is also expected to develop in the Great Basin region and retrograde into SoCal by midweek. No precipitation is expected with this low for NorCal. Gusty north to east winds will likely develop as PGF increases over the area, however at this time the wind gusts look to not be as strong as our recent event for NorCal. Above normal high temperatures are expected, with upper 50s to low 60s for the Valley and 40s and 50s for the foothills and mountains. && .AVIATION... Mainly VFR conditions over interior Northern California for the next 24 hours except local MVFR/IFR conditions in BR for the Northern San Joaquin and Sacramento Valleys from 05Z to 22Z Thursday. Surface winds are mainly at or below 12 knots except for northerlies/easterlies 15-20 knots over the foothills and gusts up to 39 knots after 08Z Thursday over the Sierra Nevada Mountains. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$

967 FXUS65 KMSO 082007 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 107 PM MST Wed Jan 8 2025 .DISCUSSION... KEY MESSAGES: - Scattered light snow showers for western Montana through this evening. - Widespread moderate mountain snowfall this weekend, with periodic light valley snow impacts. Scattered light to moderate snow showers will linger over the Northern Rockies through this evening, with locations along and east of Highway 93 having a higher likelihood to see light accumulations. High pressure will begin building over the region late tonight, and remain in place through much of Friday. Partial clearing overnight tonight and tomorrow night, will increase the potential for patchy areas of dense fog each morning. Those that don`t experience the fog, will likely be socked in with low stratus. The next winter impact period will be this weekend. A shortwave trough of low pressure will move in from the northwest Friday afternoon, initially bringing the mountains and mountain passes light to moderate snow. Increasing winds at ridge tops and above will shadow out most valleys until the western edge of the trough moves to the east after sunset Friday evening. A light northwesterly flow Saturday and Sunday will be the period where the valleys of western Montana will see their best potential for minor to moderate impacts due to snow. The valleys of north- central Idaho will likely be too warm to see accumulating snowfall, aside from Grangeville. 48hr snowfall accumulations Friday afternoon through Sunday afternoon, will range from 3 to 6 inches at the passes and the mountains above 5000 feet 6 to 12 inches (Particularly the Mission and Swan Ranges). The foothills and valleys east and south of Bigfork in the northern Swan Valley have a 25 percent chance for seeing 6+ inches. All other valley locations in western Montana and Grangeville in north-central Idaho will have a 50 to 60 percent probability of seeing 1 to 2 inches during the same period. Another weak ridging pattern will setup over the Northern Rockies by mid-week next week, with increasing probabilities for the return of fog and stratus. Long Range Forecast: An increasing number of ensemble members (30% to 40%) are beginning to hint at a potential cold outbreak with arctic air sliding south out of Canada around the 18th. Stay tuned for further details and likelihood of occurrence. && .AVIATION... Light snow is shifting east and diminishing through the day into late evening. Expect mountain obscurations due to widespread lowered ceilings into Thursday morning. High pressure redevelops this evening and fog and low stratus is expected to return. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$

142 FXUS65 KBOI 082129 AFDBOI Area Forecast Discussion National Weather Service Boise ID 229 PM MST Wed Jan 8 2025 .SHORT TERM...Tonight through Friday night...Previous forecast remains on track with low-level inversion and patchy valley night/morning fog/stratus continuing under upper ridge through Friday morning. A trough will approach from the Gulf of Alaska later Friday and Friday night bringing snow showers and enough cold air aloft to mix out the inversion below and end the air stagnation. Snowfall Friday evening will total 1 to 3 inches in the West Central Idaho Mountains and Boise Mountains, with an inch or less elsewhere. The Snake Basin, including Boise and Twin Falls, are forecast to receive about a half inch. .LONG TERM...Saturday through Wednesday...A long fetch of north- northwesterly flow along the eastern edge of an amplified ridge over the Pacific will bring cold air into the region through early next week. A series of very weak embedded disturbances will lead to periods of snow showers over the northern mountains this weekend, with only light accumulations expected. Upper ridging expands eastward and becomes distorted by a prominent cutoff low over the southern California coast, but still intact enough to lead the development of inversion conditions in the valleys early next week. Temperatures will also be several degrees below normal, with even the lower elevation locations struggling to get above the mid-30s during peak daytime heating. && .AVIATION...Mostly VFR today, with areas of MVFR overnight due to fog. Low stratus and fog developing overnight in parts of Treasure Valley, western Magic Valley, and eastern Oregon, with a 30% chance of visibility below 2 SM at KBOI/KONO/KEUL, KBNO, and KJER after 09/09Z. Surface winds: variable less than 8 kt. Winds aloft at 10kft MSL: NW 20-35 kt. KBOI...Mostly VFR, with MVFR in fog possible (60% chance) overnight. Low confidence (30% chance) for IFR fog/stratus after 09/09Z. Surface winds SE around 5 kt today, becoming variable overnight. && .AIR STAGNATION...Air Stagnation Advisory will continue in the valleys through Friday morning due to light winds and mixing heights below 2000 ft AGL. A frontal system from the Gulf of Alaska should scour the inversion and end the stagnation late Friday. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Air Stagnation Advisory until 11 AM MST Friday IDZ011>015-028-029-033. OR...Air Stagnation Advisory until 11 AM MST /10 AM PST/ Friday ORZ061>064. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.twitter.com/NWSBoise SHORT TERM...LC LONG TERM....JR AVIATION.....JR AIR STAGNATION...LC

023 FXUS65 KLKN 082133 AFDLKN Area Forecast Discussion National Weather Service Elko NV 133 PM PST Wed Jan 8 2025 .SYNOPSIS...Fair weather under high pressure continues for the Silver State through Friday morning. Winds are lighter Wednesday afternoon though a few gusts are possible especially over central and east central Nevada both Wednesday and Thursday afternoon. Temperatures are seasonal this week with a slight increase each day as we head towards the weekend under persistent high pressure. && .SHORT TERM...Wednesday into Friday morning Northerly flow aloft in the eastern flank of the high pressure system to the west continues through the end of the work week. A relaxing pressure gradient will help to slow gusty winds back into the 20-25KT range Wednesday afternoon over the area. Temperatures will top out in the 30s Wednesday afternoon before dropping back into the teens and low 20s by early Thursday morning. On Thursday 500-mb model guidance has a west-east oriented shortwave ride the upper level flow across Utah. Vorticity associated with the wave will advect southward down the eastern border of the state, but with PW`s in the teens nothing more than some increased cloud cover for eastern portions of the state is anticipated. Under the quiet weather pattern temperatures Thursday afternoon and early Friday morning repeat the recent diurnal trend. .LONG TERM...Friday through next Wednesday Synoptic pattern defined by a high amplitude longwave trof over the heartland while persistent high pressure maintains its position offshore of the California coast with general north- northwest flow situated over the Great Basin over the forecast period. Shortwave moving thru the ridge brings light snow to portions of the forecast area as the attendant cold front moves into Nevada from the northwest Friday night before midnight. Latest progs continue to indicate PWATs of around 0.35 embedded along the front. Preceding atmospheric conditions look to be relatively dry however with the progs indicating dew points in the single digits Friday before the front approaches. All things considered, accumulating snowfall will be limited to locations in and near Elko County. Locations such as the Jarbidge Wilderness, Independence Range, and Ruby Mtns/E Humboldt Range can expect 1 to 4 inches at this time with around an inch or less expected for the valleys. Southwesterly surface winds during the day Friday turn Northwesterly Friday night in conjunction with the frontal passage. Winds will be gusty Friday night thru Saturday, easing Saturday night as the front progresses east-southeast. Gusts 30 to 35 mph are expected. Daytime high temperatures Friday will be in the upper 30s to upper 40s, with overnight lows in the low teens to low teens. Much cooler Saturday with post frontal air influencing the region. Daytime high temperatures reside in the upper 20s to upper 30s with with overnight lows in the mid single digits to mid teens. Upper impulses moving thru the ridge keep weather unsettled and cool into Monday with occasional light snow showers, again mostly situated in and near Elko County. Temperatures read a few degrees cooler than average. Weather currently indicated to be dry and fair Tuesday and Wednesday with temperatures also warming. && .AVIATION...VFR conditions in place at all terminals thru the next 24 hours. Breezes continue at KTPH and KELY with gusts around 25 knots. Light winds remain in place at KWMC, KBAM, and KEKO. Winds are expected to diminish across central Nevada Thursday evening. && .LKN Watches/Warnings/Advisories... None. && $$ 99/92/92