034 FXUS66 KSEW 211056 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 256 AM PST Wed Jan 21 2026 .SYNOPSIS... A strong upper level ridge maintains dry conditions across western Washington through the rest of the week. A weak system will pass through on Thursday for increased cloud cover. High pressure rebuilds Friday and into the weekend, with little in the way of rainfall chances well into next week. && .SHORT TERM /TODAY THROUGH FRIDAY/...Strong upper level ridge continues over western Washington for another day of dry conditions. Fog has already developed over most over the interior early this morning, with areas of freezing fog likely over the South Sound and the Chehalis river valley. High temperatures will remain in the mid to upper 40s this afternoon. A weak system will brush by the area tonight and into Thursday, which will result in increased cloud cover over the area. This system has weakened over the last couple of days, so not expecting much in any precipitation. High temperatures will cool slightly, with high temperatures in the low 40s. Overnight lows will also cool, with a more coverage of below freezing temperatures in the South and Central Sound. Ridging rebuilds into Friday which would continue the dry pattern, along with morning fog. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...Ensemble guidance continues to support upper level ridging over the weekend, which would maintain dry conditions over western Washington. Some of the models are showing the potential of a weak system late Sunday into Monday which could produce light precipitation over the area as the ridge slightly weakens. At this time, this system does not look impactful, with most areas still remaining dry throughout the long term. Mazurkiewicz && .AVIATION...Northwesterly flow aloft will continue through the TAF period as a ridge of high pressure remains situated along the West Coast. Satellite imagery shows fog across the south Sound and along the Chehalis River Valley, as well as across portions of the central and north Sound slowly expanding across the interior this morning. Conditions at the area terminals are primarily VFR for terminals outside of fog and IFR to LIFR for terminals in fog. Cold overnight temperatures have also led to the development of freezing fog in spots overnight, especially for areas around and south of KOLM. For terminals in fog, expect to see improvement back towards VFR conditions between 17-20Z. The exception is KOLM, which may briefly improve for a few hours this afternoon, but will likely see fog linger through much of the day. Surface winds for interior terminals will generally be light and out of the north, between 3-6 kts through the day, while KCLM and KHQM will see more easterly winds, increasing to 5-10 kts through the morning hours. Another round of fog and freezing fog will be possible for the area terminals on Thursday. KSEA...Conditions still VFR early this morning, with fog slowly creeping into the vicinity from the south. There remains roughly a 20-30 percent chance of LIFR conditions developing between 12-15Z for a few hours this morning with fog expected to make it into the terminal. Improvement to VFR expected between 17-20Z. Winds will remain light out of the north at 3-6 kt through the day. Guidance indicates another round of fog moving into the terminal on Thursday morning, with another 20-30 percent chance of LIFR conditions developing between 12-15Z. 14 && .MARINE... High pressure will persist across the waters today, with a thermal trough situated along the coast. This will continue to promote northerly winds across the interior waters and easterly winds along the Strait of Juan de Fuca and along the gaps in the coastal terrain. Winds look to stay below advisory thresholds. The biggest concern for the interior waters today and again on Thursday morning will be the development of fog which may bring visibilities down to 1 NM or less at times. A weak system will move into the coastal waters on Thursday and looks to briefly weaken the offshore flow, but does not look to have any other impacts at this time. High pressure will rebuild over the region in its wake while the thermal trough builds along the coast again. Another weak system may approach the waters late in the weekend into early next week, allowing for winds to shift back to the south, but again does not look impactful for the area waters. Seas will generally persist between 4-6 ft across the coastal waters through the end of the week. 14 && .HYDROLOGY... No river flooding is expected during the next seven days. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$

072 FXUS66 KPQR 211042 AFDPQR Area Forecast Discussion National Weather Service Portland OR 242 AM PST Wed Jan 21 2026 .SYNOPSIS...Dry weather is expected to continue through most of the weekend as high pressure stubbornly holds overhead. Gusty winds persist through the Columbia Gorge. Clear skies and light winds away from the Columbia River Gorge will result in frost and/or freezing fog formation for a decent swath of the interior lowland valleys and coast range Valleys. Near/below freezing temperatures in combination with any fog may lead to locally slick road conditions. Chances for precipitation return late this weekend into next week, but details on the exact timing and impacts remain rather nebulous at this time. && .DISCUSSION...Wednesday morning through Tuesday...Dry weather is here to stay through much of the weekend as ensemble guidance (GFS, Euro, and Canadian) are in good agreement that the ridge of high pressure will remain over the Eastern Pacific/Pac NW. However, ensembles indicate the heights will slowly lower over the PacNW each day, allowing a break down of the strong pressure gradients over the Cascades by late this week. Another day of gusty offshore/east winds is expected through the western Columbia River Gorge and into the eastern Portland metro with peak gusts up to 35-40 mph through the eastern Portland metro, including Troutdale, and up to 55-65 mph for windy locations east of Troutdale. As the pressure gradient slowly weakens each day, so will the extent and strength of gusty offshore winds through the Gorge. However, wind prone areas near the Gorge will continue to see breezy winds into the weekend. Satellite imagery early Wednesday morning depict scattered high clouds moving over NW Oregon and SW Washington on the north side of a cutoff low pressure system moving into central California. Other than these high clouds, mostly sunny skies are in store for the region through the end of the week. Under mostly clear skies, overnight temperatures will continue to be on the cold side with morning low temperatures near to below freezing across most of the region outside of the influence of offshore winds through the Gorge. Some high clouds through Friday morning will keep widespread apparent temperatures (often called wind chill or "feels like" temperature) mainly above 25 degrees, though known colder pockets could see parent temperatures fall below 25 degrees in the early mornings for a couple of hours. By Friday night, skies are expected to be mostly clear of high clouds, which will allow for peak radiational cooling, and parent temperatures could fall below 25 degrees over a wider area. This becomes a concern for a potential Cold Weather Advisory, which conditions are met when locations west of the Cascades see apparent temperatures at or below 25 degrees for at least 4 hours or more. At this point, there`s around a 60-70% chance of these conditions for most locations west of the Cascades except for the coast for Friday night/Saturday morning and about a 40-50% chance for Saturday night/Sunday morning. Will continue to monitor whether this threshold will be met for a widespread enough area and/or timeframe for the hazard to be issued. With the cold temperatures, freezing fog and low stratus concerns continue in the southern Willamette Valley, northern Cowlitz county valleys, and the Upper Hood River Valley each overnight through morning hours into the weekend. Any freezing fog that develops could lead to locally slick road conditions. Additionally, stagnant air will be a continued concern under the subsidence inversion, leading to air quality concerns into Friday. Mixing heights will remain low and transport winds will be weak through the week. Therefore, an Air Stagnation Advisory is in effect through Friday after which point there`s moderate confidence in improvement. The Portland Metro area from the West Hills eastward were not included in this advisory due to stronger winds from the Gorge maintaining a more mixed atmosphere. Looking at early next week, ensemble guidance continues to push back the return of precipitation to NW Oregon and SW Washington. Most ensemble members are in good agreement that a low pressure system will move through the NE Pacific and finally break down the strong high pressure Sunday into Monday. However, latest guidance suggests the low will weaken significantly before it makes landfall along our coast with only a 20-40% chance of precipitation now beginning late Sunday night, continuing into Monday afternoon. Higher chances for precipitation are for the far northern Oregon and SW Washington coast, Coast Range, and Cascades and the SW Washington lowlands. However, there are still a couple of items to keep eyes on as this system moves inland. First, a handful of ensemble members suggest that overnight/early morning temperatures will remain cold enough Sunday night into Monday morning to result in wet, non- impactful snow or rain/snow mix falling down to the Valley floor when precipitation returns. If this occurs, impacts would be minimal given air temperatures will be marginally freezing due to onshore flow, roads would be too warm to accumulate snow, and precipitation amounts would be limited in general. Second is precipitation type in the central Columbia River Gorge and Upper Hood River Valley as precipitation begins. If easterly winds continue into early next week, then colder air may linger longer for these areas. This could result in wintery precipitation, especially if the incoming moisture overlaps at the same time as the freezing air near the surface. These areas can remain much colder than other interior valleys like the Willamette Valley and southwest WA lowlands, and model guidance is generally too quick in scouring out the cold air. Specific details will become more clear as we get closer to precipitation returning. There is good ensemble agreement that weak transient ridging moves inland late Monday into Tuesday. Temperatures are expected to remain on the moderate side as onshore flow from the Sunday/Monday weather system will have scoured out the colder air and cloud cover is expected to remain over the region. However, this ridging is not expected to last long as there are higher chances for another round of precipitation to return sometime late Tuesday into Wednesday. -03/99 && .AVIATION...Persistent high pressure remains over the region, supporting mainly VFR conditions. An upper level low moving over California has sent some high levels clouds northwards and may inhibit widespread fog/stratus development, especially in sheltered areas of the southern Willamette Valley. Pockets of MVFR/IFR/LIFR conditions within low stratus/fog have redeveloped in the southern Willamette Valley and northern Cowlitz valleys as of 10z Wed, but they likely won`t become as widespread as previous mornings. Expect conditions to fluctuate between all flight levels through 16-19z Wed at KEUG. An offshore pressure gradient continues to support easterly winds at Portland- area and coastal terminals, and light northerly winds along the Willamette Valley. Stronger easterly gusts of 25-30 kt will continue at KTTD, with gusts up to 45-60 kt east of KTTD at the western end of the Columbia River Gorge. Winds will begin easing after 21z Wed - 00z Thu as the pressure gradient begins to ease. KPDX AND APPROACHES...VFR with increasing high clouds. Southeast winds around 10 kts. East winds remain breezy for east approaches with gusts to around 30 kt at KTTD. && .MARINE...High pressure inland and lower pressure over the coastal waters will maintain offshore easterly flow through Wednesday. High pressure builds offshore by Thursday, returning more northerly winds across the waters later this week. Winds generally remain around 10 kt or less, except areas downwind of gaps in the coastal terrain, where gusts up to 20 kt will be possible. Winds turn offshore again this weekend. Seas around 4 to 6 ft at 12-14 seconds continue through the week. Not much change to the sea state as a persistent weak westerly swell ebbs and flows through the week. -DH/03 && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Air Stagnation Advisory until noon PST Friday for ORZ109- 114>118. WA...None. PZ...None. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland

929 FXUS66 KMFR 211157 AFDMFR Area Forecast Discussion National Weather Service Medford OR 357 AM PST Wed Jan 21 2026 .DISCUSSION (Today through Tuesday)... Key Points: * Widespread precipitation-free conditions next several days - Morning fog/freezing fog possible for mainly westside valleys - Air stagnation advisories in place through Thursday * A Pacific closed low enters the region today/tonight - Changes the pattern through mid/late week - High pressure builds back in Sunday Further Details: The big story continues to be fog and freezing fog the next several mornings along with a stable airmass. Air stagnation advisories continue through Thursday which can lead to poor air quality as pollutants get trapped under stable air. A potential change in the upper levels may come today/tonight in the wake of a Pacific trough which will pass south of the forecast area before getting absorbed into the mean flow this weekend. The result will be northwesterly flow across the region Thursday through Saturday before high pressure builds back in Sunday. While the pattern does change, this will likely not lead to widepsread precipitation chances. While there may be increased mixing the next several days with this pattern change, the overall mixing heights remain low through the end of the week. In other words, don`t expect too much airmass change through this stretch. Looking ahead, the next reasonable chance for widespread precipitation may not come until middle of next week. The trend lately has been for dry conditions to prevail, even as precipitation chances come into the extended forecast...only to disappear once we get closer in time. A lot of this may be tied to climatology in the models for the extended forecast. January is shaping up to end on a dry note for many areas. That said, we are not in any record territory for driest month on record, but this trend could become notable for prescribed burn operations, especially areas with poor humidity recoveries overnight and above normal temperatures. -Guerrero && .AVIATION (12Z TAFs)... Another day of low clouds and limited visibility is likely for KRBG as the airmass goes unchanged within the Umpqua basin. Off shore flow and high clouds should keep these conditions away from KOTH. These high clouds should also keep both KMFR and KLMT in VFR conditions through this cycle. While confidence is high for KMFR to remain in VFR this cycle, there is a 10-20 percent chance for MVFR conditions this morning and again tonight into Thursday morning. -Guerrero && .MARINE...Updated 300 AM PST Wednesday, January 21, 2026...Below advisory seas remain in the forecast for area waters through today. Winds turn dominate from the north today, and speeds will increase through Thursday. These strong northerly winds will generate some steep wind waves Thursday night south of Port Orford and beyond 10 nm from shore. Seas will be relatively lower farther inland and to the north. These steep wind waves are expected to reach 8-10 feet at about 6 to 8 seconds Thursday night. These seas will likely remain hazardous to smaller crafts through Saturday morning. && .MFR WATCHES/WARNINGS/ADVISORIES... OR...Air Stagnation Advisory until 4 PM PST this afternoon for ORZ023- 024-026-029>031. Dense Fog Advisory until 10 AM PST this morning for ORZ023. Freezing Fog Advisory until noon PST today for ORZ024. CA...None. PACIFIC COASTAL WATERS...Hazardous Seas Watch from Thursday afternoon through late Friday night for PZZ376. && $$

155 FXUS66 KEKA 210804 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 1204 AM PST Wed Jan 21 2026 .SYNOPSIS...Dry weather and above normal daytime temperatures will continue through the next 7 days. Overnight and morning temperatures will remain chilly with patchy dense fog along the river valleys and around Humboldt Bay. && .DISCUSSION...High pressure over the area has weakened due to an elongated shortwave trough upstream and west of the California coast approaches. While mid- to upper-level high pressure remains over the area, a surface low will move toward the California coast today. This slight change in the weather pattern will promote the surface flow becoming more southerly which will support more onshore flow, resulting in a slightly deeper marine layer with some low pushing into the interior river valleys this morning through midday. The surface low will continue to track southward along the California coast Otherwise, dry weather and above normal daytime temperatures will persist. The ridge is expected to rebuild on Thursday and Friday leading to offshore flow. This dry, offshore flow will most likely reinforce the chilly overnight low temperatures. This will promote clearing sky conditions on Thursday, with mostly sunny skies across much NW California Friday and into the weekend. A weak shortwave trough will bring increasing cloudiness Saturday night and Sunday. Coastal stratus is anticipated to redevelop, with a slightly deeper marine layer along the North Coast. Inland however, generally dry conditions and above normal daytime temperatures are expected to continue through the next 7 days. After a long stretch of dry weather, long-range models are suggesting an increasing chance of precipitation from mid- to late next week. Stay tuned for updates as confidence of this weather pattern change increases. /ZVS && .AVIATION...A strong and persistent marine inversion has settled back in along the coast this evening with IFR fog and ceilings. That said, slightly more unstable air above will most likely prevent any dense fog with only a slight chance (30% chance) early Wednesday morning. Conditions will most likely lift to VFR during the day Wednesday for a couple hours in the afternoon, though there is a chance (about 35%) that IFR fog and clouds hang around all day with no reprieve. Midlevel MVFR to VFR ceilings will persist across the interior through the day Wednesday. /JHW && .MARINE...Generally light winds 10 kt or less and seas 6 feet or less are expected to continue into much of Wednesday as weak pressure gradients continue over the waters. Northerly winds will begin to increase in the afternoon and evening Wednesday as a weak low approaches the central and southern California coast while high pressure noses toward the Pac NW coast. Even with this synoptic scale set-up, surface wind fields appear only marginal near gale with gusts just near 34 kts in the outer waters by Thursday. The chance of much higher gusts over 34 kts is very low (20%). The primary hazard may end up being steep northerly wind waves which are forecast to build to 10 feet or more Thu evening and last into at least Friday evening. The fairly tranquil marine conditions over the last several days will be coming to an end for the outer waters. Deteriorating marine conditions will be hazardous for small craft. At this time, confidence in hazardous conditions for the inner waters is not as high with much greater mesoscale variability in space and time. The likely points for gales and large steep waves will be near Pt George and around or just downwind of Cape Mendocino. Hazardous northerly winds and waves should begin to shift westward on Saturday, though steep waves may through much of the day. /JHW && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 10 AM to 10 PM PST Thursday for PZZ470-475. Gale Watch from Thursday evening through late Friday night for PZZ470-475. && $$ NOTE: The full forecast discussion is now regularly issued between 10 am/pm and 1 pm/am. Additional updates will be issued as needed. Visit us at https://www.weather.gov/eureka Follow us on Facebook and Twitter at: https://www.facebook.com/NWSEureka https://www.twitter.com/NWSEureka For forecast zone information see the forecast zone map online: https://www.weather.gov/images/eka/zonemap.png

902 FXUS66 KMTR 211118 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 318 AM PST Wed Jan 21 2026 ...New AVIATION... .KEY MESSAGES... Updated at 245 AM PST Wed Jan 21 2026 - Late night and morning fog across the North and East Bay Valleys - Light rain across the Santa Lucia Range and portions of the Central Coast late Wednesday into Thursday - Seasonal temperatures and dry conditions Friday into next week && .SHORT TERM... Issued at 245 AM PST Wed Jan 21 2026 (Today and tonight) High clouds are currently obscuring lower level fog development but a few reports have started trickling in from the East Bay in Byron and Concord. As of 2AM, Byron is reporting less than 1/4SM visibility and fog while the Concord Airport is reported 1/4SM visibility and fog. There are some signs of fog developing in the North Bay Valleys with the Santa Rosa Airport reporting low clouds and 1SM visibility. Fog coverage tonight should be similar to last night with patchy, locally dense fog expected in the North and East Bay Valleys. Early morning commuters in these areas should allow extra time to reach their destination and be prepared for sudden changes in visibility. The upper level ridge that has been dominating our forecast for the last few weeks will be replaced by a cut-off low moving southwards down the California coastline today. The cut-off low will bring a few notable changes to our weather. The first is temperatures across the interior will return to cooler, more seasonal values with highs in the upper 50s to low 60s across the region. Morning low temperatures are expected to be in the low 40s to upper 40s with the higher elevations remaining in the upper 40s to low 50s. The second change will be increased rain chances late Wednesday into Thursday for the Central Coast. High resolution models are showing isolated showers starting late this evening into Thursday morning across the Santa Lucia Range, the Monterey Peninsula, and portions of interior San Benito County. Now, if any rain is able to make it to the surface, any precipitation totals are expected to be low. The current forecast grids show less than 0.10" of accumulated precipitation across the Central Coast. 90th Percentile NBM guidance (a reasonable "worst case" scenario) shows between 0.1-0.35" across the Central Coast with the max in the Santa Lucia Range. While showers are most likely to impact the Central Coast, we may see a few isolated showers as far north as Santa Cruz County and the South Bay. The NBM places a less than 5% chance of thunderstorms across southern coastal Monterey County with atmospheric conditions looking unfavorable for thunderstorm development. Models do show between 100- 300 J/kg of most unstable CAPE but thunderstorm potential is limited by poor moisture, poor shear, and poor 700-500mb lapse rates. The most likely scenario is that we will see isolated showers across the Central Coast, predominantly in the Santa Lucia Range, with the potential for isolated showers to drift towards the South Bay on Thursday. && .LONG TERM... Issued at 245 AM PST Wed Jan 21 2026 (Thursday through Tuesday) Isolated showers continue across the Central Coast through Thursday morning before dry weather returns. By late Thursday, the cut-off low will be to our southeast (offshore of San Diego and Baja California) where it will move inland and be absorbed into upper level troughing across the interior U.S. late Friday into early Saturday. Upper level ridging then rebuilds across the western U.S. through the remainder of the long term forecast. Widespread fog potential decreases by late this week as a shallow marine layer (approx. 1000 ft) is able to redevelop as the cut-off low moves through. Overcast conditions are still likely as low level stratus and the shallow marine layer rebuild across the region. High temperatures remain seasonal in the upper 50s to low 60s while portions of the interior Central Coast linger in the low to mid 60s. Morning low temperatures trend cooler starting Thursday with lows dropping from the 40s on Thursday to upper 30s to low 40s by Saturday. Sunday to Tuesday mornings look to be the coldest with lows dropping into the mid 30s to low 40s across the interior. Locally gustier offshore winds develop across the interior North Bay Saturday. Probabilistic guidance shows a 30-40% chance of gusts greater than 30 mph across the North Bay Interior Mountains. This drops to a 10-25% chance across only the highest peaks when looking at the probability of gusts greater than 40 mph. While this is a gustier offshore wind event, it should generally stay limited to the higher terrain. In the very long term, models continue to indicate a chance for widespread precipitation to return late January into early February. The CPC 8-14 day outlook shows a slight chance for above normal precipitation along coastal Sonoma and Marin Counties with near normal precipitation expected for the rest of the Bay Area and Central Coast. Models will come into better agreement as to the timing and intensity of any future systems as we get closer in time to late January so stay tuned to the forecast to see how this shapes up in real time. && .AVIATION... (12Z TAFS) Issued at 318 AM PST Wed Jan 21 2026 Patchy fog /LIFR-IFR/ this morning otherwise VFR today and tonight. A few showers developing tonight and Thursday morning. Vicinity of SFO...VFR. Mainly light wind. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR. A few showers tonight and Thursday morning. Mainly light winds. && .MARINE... (Today through Monday) Issued at 245 AM PST Wed Jan 21 2026 Gentle to moderate northerly breezes and moderate seas will continue through Thursday. On Friday winds will increase to a fresh northerly breeze along with building rough seas. Conditions will improve over the weekend as a light to gentle breeze settles in and seas gradually subside to slight Sunday through Monday. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ SHORT TERM...Kennedy LONG TERM....Kennedy AVIATION...Canepa MARINE...Canepa 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

336 FXUS66 KOTX 211129 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 329 AM PST Wed Jan 21 2026 .KEY MESSAGES... - Low confidence in a break of the quiet weather pattern by the end of the weekend into early next week. && .SYNOPSIS... Strong high pressure will dominate the weather this week, keeping the Inland Northwest dry. Dry conditions will persist until at least Saturday, with the potential for a return of light precipitation Sunday or Monday. && .DISCUSSION... Today through Thursday: Little change is expected over the next couple of days. A blocking high pressure ridge pattern will continue to dominate the weather pattern over the Inland Northwest. The ridge does weaken though and the ridge axis will retrograde a bit more offshore as well. This will place the region in a dry northerly flow pattern. The forecast is largely one of persistence with low clouds seeing very little changes. The stratus deck is reaching as high as 4,000-5,000 feet based on latest satellite imagery. The exception looks to be over the North Cascades where the stratus deck looks 1,000-2,000 feet thinner. The Methow Valley may be the best spot where clouds clear and the sun comes out because it is a little bit thinner there, but even there looks unlikely. Temperatures below the low clouds will see little diurnal variation with highs fluctuating from the low to mid 30s and to lows in the mid to upper 20s for most spots. Thursday night through Sunday night: A backdoor shortwave trough of lower pressure brushes across the region Thursday night into early Friday. Little to no moisture will accompany this wave. It will bring a weak surge of dry Polar Continental air that will push down the Okanogan Valley and Purcell Trench and across the Columbia Basin. This looks favorable to clear out the low clouds from the Canadian border southward. How far south this drier surge of air pushes is a bit uncertain though. Indications are that the sun will poke out across at least the Upper Columbia Basin and could see this clearing penetrate into the lower portions of the basin as well. Northerly winds will pick up across these areas on Friday. Expect sustained winds in the 10-18 mph range with gusts up to around 25 mph. This air mass will be a bit colder as well with temperatures at 850 mb cooling from 4-6 C below zero on Thursday to between 6-8 C below zero on Friday. Skies clearing Thursday night and cold air advection will set up a better potential for lows getting into the teens in the northern mountain valleys over this period. Then the northerly gradient weakens over the weekend. This would result in the potential for fog and low stratus to build its way back north, but uncertainty exists with how quickly that process would take place. Monday through Wednesday: The prognosis out in far extended portion of the forecast is for the longwave ridge of high pressure in the eastern Pacific to shift west over the region, but there is uncertainty with its strength and how long it resides over the Inland Northwest. One scenario with 40% of the ensemble members shows the ridge building in strong for early next week. This would result in continued dry conditions and would favor an expansion of low clouds. It doesn`t look like a favorable Air Stagnation period as developing stratus will prevent a strong inversion right at the surface for an extended period of time. The there is a second scenario comprising 45% of the ensemble members that has the ridge weaker and more progressive. This scenario would support a better chance for a more moist southwesterly flow into the region. Shortwave disturbances would bring the potential for precipitation, and this scenario would bring at least a small risk for freezing precipitation. The remaining 15% of the ensemble members has a less progressive and thinner ridge than places the Inland Northwest under dry northwest flow. /SVH && .AVIATION... 12Z TAFs: A low stratus cloud deck is entrenched over the Inland Northwest with widespread MVFR ceilings. The stable atmospheric conditions are courtesy of a strong ridge of high pressure. The ridge axis will be centered just off of the west coast through Wednesday, then will retrograde further offshore late Thursday into Friday. A persistence forecast will likely best verify for the next 24 hours with the stratus deck seeing little to no variation. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence in MVFR conditions with the low stratus cover. ----------------------- 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 32 24 33 19 30 16 / 0 0 0 0 0 0 Coeur d`Alene 33 22 35 17 31 15 / 0 0 0 0 0 0 Pullman 35 24 33 21 31 18 / 0 0 0 0 0 0 Lewiston 37 27 36 25 35 21 / 0 0 0 0 0 0 Colville 32 19 33 16 31 14 / 0 0 0 0 0 0 Sandpoint 31 22 32 17 29 16 / 0 0 0 0 0 0 Kellogg 33 24 33 16 27 13 / 0 0 0 0 0 0 Moses Lake 34 23 35 22 36 19 / 0 0 0 0 0 0 Wenatchee 33 26 34 24 34 21 / 0 0 0 0 0 0 Omak 34 24 35 21 34 18 / 0 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...None. ID...None. && $$

329 FXUS66 KPDT 210955 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 155 AM PST Wed Jan 21 2026 .DISCUSSION...The forecast is more or less status quo. A low cloud deck remains situated across pretty much the entirety of the forecast area below 4000 feet. Patchy fog can be observed in the Wallowa and John Day Valley, as well as portions of central and north central Oregon. Freezing Fog Advisories are in effect for north central Oregon and the Wallowa Valley through around late morning Wednesday. With a dry NW flow pattern over the PacNW, don`t expect this cloud deck to change much (outside of the fringes) until perhaps Friday, which will at the very least initiate a pattern change that in due time will eventually scourge out this gloom. Precip threats are pretty minimal in the near future, however global models do hint at an upper-level jet overhead during the day Friday. While moisture advection with this jet looks to be limited due to its more Arctic origin, this pattern could still bring in enough instability and surface winds to at least partially mix out the low cloud deck. Confidence in this occurring is only low-moderate (40- 50%), as guidance still overall suggests a dry forecast with only light winds generally less than 15 mph, but any kind of mechanical mixing would be welcomed just so we can see the sun again. Consensus across ensembles, however, is to introduce a more active, progressive pattern for the region starting late weekend and lasting around midweek. While nothing in the synoptic pattern suggests an impactful precip or wind threat, our primary issue with regards to this low cloud deck has been the presence of a stagnant, stable pattern, so this at the very least looks to be a brief break from that. Emphasis is on brief, however, as ensembles generally agree that ridging will return to the region midweek onward. 74 && .AVIATION...12z TAFs...Variable conditions currently across all sites, with MVFR at KDLS/KPDT/KYKM/KALW/KPSC and LIFR at KRDM/KBDN due to reduced ceilings of 200-300 feet. These conditions are expected persist, with dropping ceilings at KPDT/KALW leading to IFR ceilings of 800-900 feet this morning. Elsewhere, conditions will stay constant through the morning before improving to MVFR briefly for all terminals through the afternoon, with the exception of KRDM/KBDN only improving to IFR due to ceilings staying below 1kft. Upper level ridging and surface high pressure extends through the period, keeping conditions dry and winds light (below 10 kts). 75 && .PRELIMINARY POINT TEMPS/POPS... PDT 31 21 34 21 / 0 0 0 0 ALW 32 24 33 23 / 0 0 0 0 PSC 35 24 35 23 / 0 0 0 0 YKM 35 22 35 20 / 0 0 0 0 HRI 33 24 35 22 / 0 0 0 0 ELN 33 21 33 20 / 0 0 0 0 RDM 38 17 41 17 / 0 0 0 0 LGD 39 21 39 20 / 0 0 0 0 GCD 47 21 44 21 / 0 0 0 0 DLS 37 26 38 26 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Freezing Fog Advisory until 9 AM PST this morning for ORZ050. Freezing Fog Advisory until noon PST today for ORZ510. WA...None. && $$ DISCUSSION...74 AVIATION...75

150 FXUS65 KREV 210856 AFDREV Area Forecast Discussion National Weather Service Reno NV 1256 AM PST Wed Jan 21 2026 .KEY MESSAGES... * Light winds and valley inversions through Thursday will maintain hazy skies and air quality reductions for all valley areas with patchy freezing fog in some Sierra valleys and over Mono Lake. * A passing wave Thursday may bring gusty mountain ridge winds and low chances for showers to the Sierra and portions of western Nevada late week. && .DISCUSSION... Freezing fog remains locked in over Mono Lake this morning, even with some cirrus overhead. That`s expected to dissipate early Wednesday afternoon, likely around 12-1 PM. Valley inversions are still in place and likely will be through the end of the work week. A cut-off low is still on track to pass by to our south, sparking low end precip chances (20-30%) in Mono County Wednesday night through Thursday evening. Snow levels will be around 7500`, although even the most aggressive CAMs are showing snow amounts of 1" at most along the highest peaks and qpf is at most 0.10" in other parts of Mono County. So it`s very likely these showers won`t amount to much. But good to keep in mind if you want to go in the backcountry up there. Other than that, temperatures stay 5-10 degrees above normal through most of next week and winds remain light. Winds shift from the west to the north/northeast after Wednesday, staying northerly through the weekend. A very weak backdoor cold front looks to sneak on by to our east over Pershing/Churchill counties on Friday, dropping high temperatures on Saturday by 10 degrees but will quickly rebound Sunday and initiate another warming trend into next week. Long range ensembles are still showing a pattern change towards the end of next week. It looks like there could be multiple storms rolling through the Sierra and western NV based off of the ensembles and the GEFS IVT plume. This far out, confidence remains very low due to each new model run showing something slightly different. But just know there are signs that indicate a pattern change could be coming. -Justin && .AVIATION... VFR conditions and light surface winds continue for area TAF sites through tonight. Freezing fog has a 10-15% chance to form again this morning over KTRK, but the upper level clouds will likely inhibit it from forming. Haze in W.NV may lead to reduced slantwise visibilities this afternoon. A quick system moves through Thursday, delivering 20-30% chances for a light rain shower for KMMH. -Justin && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$

388 FXUS66 KSTO 202101 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 101 PM PST Tue Jan 20 2026 .KEY MESSAGES... - Dry weather prevails with Valley fog/low clouds - Warm and dry weather at higher elevations with periodically breezy offshore flow - Precipitation chances remain quite low for the weekend but minor cooling is still anticipated && .DISCUSSION... ...Today Through Thursday... GOES-West visible satellite imagery this Tuesday early afternoon depicts a large area of fog stretching from about Chico southward. The Dense Fog Advisory expired at noon, though patchy areas of fog remain throughout the Valley. Dry, cool weather continues for the majority of this week, with chances for fog and low clouds in the Valley and lower foothills each day. Highest chances from Chico southward, with high resolution models showing a 25 to 50% chance of visibilities less than 1/2 mile tonight into Wednesday morning. Use low-beam headlights when driving through fog, exercise caution, and slow down. At higher elevations, above normal temperatures continue with offshore flow. ...Friday - Early Next Week... Closer to the weekend, the upper level ridge will begin to break down as an upper low moves into southern California. This will bring widespread cooler temperatures to interior NorCal through the weekend. Precipitation chances have once again trended downward for the weekend, with less than a 10% chance everywhere for 0.01 inches of rain showers over the mountains. This weather pattern is likely to bring breezy north to east winds to the mountains briefly on Saturday though. Late in the weekend into early next week, ridging builds back into the area, which may mean a return to reduced morning visibilities in the mornings. && .AVIATION... Lingering patchy MVFR/IFR conditions in southern Sacramento Valley, Delta, and northern San Joaquin Valley through 21z Tuesday. FG/BR expected to re-develop after 06z Wednesday with similar aerial extent as today except coverage will be patchier in the northern Sacramento Valley. Surface winds will be below 12 kts in the Valley, with periodic east wind gusts of 10-15 kts in the Sierra and Southern Cascades until 18z Wednesday. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$

644 FXUS65 KMSO 211052 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 352 AM MST Wed Jan 21 2026 .DISCUSSION... KEY MESSAGES: - Strong valley inversions will persist for a couple more days - Colder temperatures on the way and break up of the low stratus deck Friday into Saturday - Uncertainty in the forecast for next week Not much will change in the forecast for today through Thursday as strong valley inversions will remain in place along with low stratus across north central Idaho into northwest Montana. Thursday night a modified arctic air mass will begin to infiltrate the western Montana causing some easterly winds. This push of colder air is not expected to be overly strong but enough easterly winds should help to scour out the low stratus deck that has been entrench across northwest Montana. The cold air along with clearing skies will cause temperatures to be rather cool by Friday morning with the majority of western Montana being in the single digits. The stratus deck over north central Idaho appears to hold on until some time on Friday once the easterly winds can make it passed the Montana/Idaho border. Friday and Saturday appears to be the coldest timeframe during the forecast period. The models continue to show that this front will be starved of any significant moisture so any shower activity will be extremely light and mainly confined to the Continental Divide. The models are about 50/50 on a week disturbance moving through the Northern Rockies Monday into Tuesday. Current guidance is only giving around a 40% chance of an inch of snow in the mountains. The far majority of the models show the ridge of high pressure building over the region by Wednesday causing strong inversions to redevelop with the threat of fog and/or low stratus. && .AVIATION...Sounding like a broken record here with low stratus and fog impacting the majority of north central Idaho into northwest Montana for the next 24 hours, mainly impacting KGPI. KMSO could experience some vicinity fog during the morning hours. While the remainder of the terminals should have fair flying conditions. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$

435 FXUS65 KBOI 211631 AFDBOI Area Forecast Discussion National Weather Service Boise ID 931 AM MST Wed Jan 21 2026 .DISCUSSION...Persistence through Friday morning, with cold air, low clouds, and patchy fog continuing below about 5000 feet MSL, and mostly clear skies (or cirrus clouds) with mild daytime temperatures above 5000 feet. Meanwhile, NBM keeps forecasting decreasing clouds and warmer daytime highs in the valleys. We don`t expect that to happen until possibly Friday when a dry cold front and upper level short wave trough come in from the north. No changes to current forecast. && .AVIATION...MVFR-IFR low clouds and fog will persist in valleys below 5-6kft MSL. Surface winds variable 10kt or less. Winds at 10kft: W-NW 10-20 kt. KBOI...MVFR-IFR stratus through the day. Surface winds variable or SE less than 10kt. && .AIR STAGNATION...Stagnant conditions remain in the valleys of southeast Oregon and southwest Idaho. Mixing heights will remain below 2000 feet AGL. Cooling aloft will weaken the inversion Friday, and light to moderate northwest winds behind a dry surface cold front will increase mixing, so we are hopeful that the current Air Stagnation Advisory will end on schedule at 5 AM MST Friday. Even a few hours of vertical mixing should clean the air before a new stagnation event begins about Sunday. && .PREV DISCUSSION... SHORT TERM...Today through Friday night...Low clouds and fog remain in the valleys generally below 5000 feet this morning and will persist over the next several days. The clouds may produce flurries at times. In the mountains, mostly clear skies expected with mild temperatures during the day and cold temperatures at night. Temperatures will remain well below guidance in the Snake Basin and have used persistence in the forecast as the NBM and most of the high resolution guidance cannot resolve the Snake Basin cold pool. Clouds should persist through Friday below 5000 feet. LONG TERM...Saturday through Wednesday...Dry conditions continue and persistence was used as the ensemble and NBM guidance remains useless in the Snake Basin. Cooler air aloft will begin to move into the area on Saturday which may help to clean out the low clouds and fog, and actually warm up temperatures in the valleys, although forecast confidence is low. A ridge builds into the area again by Tuesday, with warmer air aloft and a temperature inversion strengthening again. With persistence used, temperatures in the valleys remain below normal with above normal temperatures over the mountains. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Air Stagnation Advisory until 5 AM MST Friday IDZ011>014-016-028-033. OR...Air Stagnation Advisory until 5 AM MST /4 AM PST/ Friday ORZ061>064. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise DISCUSSION...LC AVIATION.....JY/LC AIR STAGNATION...LC/KA SHORT TERM...KA LONG TERM....KA

954 FXUS65 KLKN 210856 AFDLKN Area Forecast Discussion National Weather Service Elko NV 1256 AM PST Wed Jan 21 2026 .KEY MESSAGES... Updated at 1254 AM PST Wed Jan 21 2026 * Dry weather will persist through at least Thursday * High temperatures well above seasonal values each afternoon today through Thursday * A change in the weather pattern is likely Friday and Saturday && .UPDATE... Issued at 1254 AM PST Wed Jan 21 2026 No changes to the forecast are anticipated at this time. && .DISCUSSION... (This afternoon through Monday) WEATHER PATTERN OVERVIEW: A ridge of high pressure will amplify over California tonight. This ridge of high pressure will move eastward Wednesday and Thursday. A warming trend is expected today through Thursday. By Thursday afternoon, maximum temperatures across Northern and Central Nevada will be around ten degrees above normal for this time of year. A trough of low pressure will progress southward over Eastern Nevada Friday and Friday night, resulting in a slight chance of rain and snow showers in Nye and White Pine Counties. Northwesterly flow aloft will be responsible for colder temperatures Saturday and especially Saturday night. High temperatures throughout Northern and Central Nevada Saturday afternoon will be near seasonal values. Low temperatures across Northern and Central Nevada Saturday night will be around five degrees below normal for this time of year. Minimum apparent temperatures in the coldest valleys of Northern and Central Nevada Saturday night will be near zero degrees. An Eastern Pacific ridge of high pressure will move eastward over California Sunday. This ridge of high pressure will progress eastward across the Silver State Monday. A warming trend is expected Sunday and Monday. By Monday afternoon, maximum temperatures throughout Northern and Central Nevada will be six to eight degrees above seasonal values. FORECAST CONFIDENCE & DEVIATIONS: High forecast confidence regarding dry weather persisting through at least Thursday. High forecast confidence in high temperatures well above seasonal values each afternoon today through Thursday. Moderate forecast confidence regarding a change in the weather pattern Friday and Saturday. No deviations from the NBM model output. && .AVIATION... VFR conditions will prevail at all terminal for at least the next 24 hours. && .LKN Watches/Warnings/Advisories... None. && $$ DISCUSSION...84 AVIATION...84