671 FXUS66 KSEW 200439 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 839 PM PST Mon Jan 19 2026 .UPDATE... No changes made in this evening`s update. The previous discussion is below along with an updated aviation section: && .SYNOPSIS... Upper level ridge offshore weakening Wednesday night. Weak system moving through ridge Thursday going by mostly off the coast. Ridge temporally rebuilds Friday before another system tries to reach the area over the weekend into the first part of next week. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... Satellite imagery shows clear skies over most of the area this afternoon. Fog hanging tough over Thurston county and down the I-5 corridor in Lewis County. Temperatures in the sunshine in the mid 40s to lower 50s with mid 50s along the north coast. Temperatures in the fog still in the upper 30s. Little change in the forecast the next two days. High amplitude upper level ridge remaining offshore. Light flow in the lower levels over most of the lowlands. Models have been trying to reduce the cross cascade gradients for the last couple of days but it has remained in the -7 to -8 mb range. This will keep fog out of the Cascades foothills. Persistence forecast Tuesday and Wednesday with a little more fog coverage each morning. Thurston county staying foggy for most of the next 48 hours. Lows in the mid 20s to mid 30s with highs mostly in the 40s for the interior and lower to mid 50s coast. Upper level retrogrades and weakens a little Wednesday night into Thursday. This will allow a weak system to ride over the top of the ridge. System moving by to the west late Thursday with just chance pops along the coast. Another round of late night and morning fog for the interior. Cross cascade gradient weakening keeping the fog/low clouds intact longer over the interior. Highs will remain in the 40s with lows in the upper 20s to mid 30s. Felton && .LONG TERM /THURSDAY THROUGH MONDAY/... Extended model drying trend continuing Friday. Operational runs continue the drying trend through the weekend with the offshore upper level ridge rebuilding. Ensemble solutions much wetter in terms of number of solutions with precipitation. Number of wet solutions slowly increasing through the weekend. Sunday night into Monday ensemble solutions are pretty evenly split between wet and dry solutions. With the lack of any run to run consistency will keep slight chance pops in the forecast Saturday and chance pops for the most part Sunday and Monday. Given the model trends will not be surprised if Saturday turns out to be a dry day too. Highs in the 40s through the weekend then a couple of degrees warmer for Monday. Lows in the 30s Friday and Saturday, mid 30s to lower 40s Sunday and Monday. Felton && .AVIATION... Generally VFR this evening with dense fog south of the Puget Sound generating LIFR conditions at KOLM and near KBLI. Another round of fog and low stratus will blanket the western Washington terminals this morning under high pressure and weak flow, resulting in widespread IFR to LIFR flight conditions. Clearing to VFR is expected by early Tuesday afternoon for most terminals outside of KOLM, which will likely remain socked in by fog (there may be brief improvement to MVFR late Tuesday afternoon). Another round of IFR to LIFR fog and low stratus is on tap for tomorrow night. Winds through the period will generally remain light 3 to 7 kt out of the N/NE. KSEA...VFR this evening with another round of LIFR fog forecast to develop at the terminal, with greatest probabilities between 10z-19z Tuesday. Slow clearing to VFR will occur by early Tuesday afternoon, with another round of IFR to LIFR fog likely overnight into Wednesday morning. Winds will remain light out of the N/NE through the TAF period generally 6 kt or less. 15 && .MARINE... A ridge with high pressure will remain over the Pacific through much of the week. Winds will be light through the week (offshore at times with the thermal trough along the coast). A possible system may skirt the outer waters towards the end of the week, but another ridge will build behind it. There are no wind concerns in the forecast over the waters. Fog will be possible next couple mornings with the weak gradients (especially in the interior waters), with visibilities under 1 SM possible. Seas through the week will hold around 3-6 ft. HPR && .HYDROLOGY... No river flooding the next 7 days. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$

202 FXUS66 KPQR 200522 AAA AFDPQR Area Forecast Discussion...UPDATED National Weather Service Portland OR 922 PM PST Mon Jan 19 2026 Updated aviation discussion. && .SYNOPSIS...High pressure and dry weather continues through at least the middle of the week with breezy easterly winds through the Columbia River Gorge and eastern Portland/Vancouver Metro as well. As long as high pressure prevails, clear skies and light winds away from the Columbia Gorge will result in frost and/or freezing fog formation across most interior lowland valleys. Near/below freezing temperatures in combination with any fog may lead to locally slick road conditions. Lower confidence for fog/frost for locations that remain windy and/or have persistent stratus. Chances for precipitation return late week but details on the exact timing and impacts remain nebulous. && .DISCUSSION...Now through Sunday...Similar to the last several days a strong ridge of high pressure remains situated over the West Coast likely holding in place into Wednesday leading to dry weather and mostly clear skies across NW Oregon and SW Washington. The only exception is the central/eastern Columbia River Gorge and Hood River Valley where stratus has remained socked in for days, as well as portions of Cowlitz County and the southern Willamette Valley around and south of Eugene where diurnal low stratus and fog develop continues to take place. Breezy easterly winds are still in place through the Columbia River Gorge, surrounding terrain, and eastern Portland Metro this afternoon due to a strong pressure gradient across the Cascades due in-part to our current weather pattern. The pressure gradient from KPDX to KDLS has peaked around -9.5mb this afternoon leading to observed wind gusts of 20-35 mph through the Portland metro area, 30-45 mph across the eastern Portland metro area around and east of Gresham/Troutdale, and 55-75 mph at the known windy locations east of Troutdale, including Crown Point, and Corbett. Gradients are expected to slowly decrease tonight before largely leveling off through Wednesday. Peak wind gusts will respond be lowering as well but still remain breezy/gusty, especially in the late afternoon through overnight hours. Clear skies and light winds away from the winds from the Columbia River Gorge will lead to efficient radiational cooling across the area each night through the end of the week, dropping overnight lows to near or below freezing across the Willamette Valley, southwest Washington lowlands, and Upper Hood River Valley. High confidence in favorable conditions for widespread frost development, especially over grasses and metal surfaces. Freezing fog may also develop in some locations, particularly across the southern Willamette Valley and lower elevations of Cowlitz County where surface conditions are more moist and protected from the dry air filtering through the Cascade gaps. Any freezing fog that develops could lead to locally slick road conditions. Meanwhile, higher elevations above 1500-2000 ft but below 5000 ft will remain much warmer than the lowland valleys due to a strong subsidence inversion. Additionally, stagnant air will be a continued concern under this subsidence inversion as the winds decrease, leading to air quality concerns through at least mid-week. Mixing heights will remain low and transport winds will be weak. Therefore, an Air Stagnation Advisory remains in effect for most of the Willamette Valley due to this concern through 4 PM Wednesday. 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 ahead, the GEFS, ECMWF, GEPS and their respective deterministic models continue to indicate high pressure could remain in place over the eastern Pacific and Pacific NW on Wednesday into Thursday and possibly into the weekend. The majority of ensemble members indicate a trough moving through the central Pacific that will pinch off into a cutoff low and move towards California, undercutting the ridge of high pressure instead of breaking it down completely, thus leaving us in a drier Rex Block pattern. There remains a 15-25% chance of precipitation returning late Thursday through Friday, mainly for the coast and higher terrain features, with only a 5-10% chance for precipitation across the inland valleys - all in all dry weather is favored to persist. This weekend, the latest ensemble 500 mb cluster analysis indicate about a 25% chance of a shortwave pushing southwest through the Great Basin and into the PacNW and a 30% chance of a weak weather system moving in from the Pacific and breaking down the ridge. Both solutions produce an increased chance for precipitation Saturday into Sunday. However, that still leaves ~45% of ensemble solutions continuing at least weak ridging through the weekend with mostly dry weather. At any rate, ridging that continues Wednesday and beyond would be weaker than earlier in the week, which could lead to a moderating of daytime temperatures and a potential breakdown of the strong subsidence inversion. Additionally, about 15% of ensemble members suggest that overnight/early morning temperatures will remain cold enough 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 and roads would be too warm to accumulate snow. One location we need to keep a closer eye on when precipitation eventually returns is central Columbia River Gorge and Upper Hood River Valley. If easterly winds continue, 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 scouring out the cold air. Specific details will become more clear as we get closer to precipitation returning. -99/03 && .AVIATION...A persistent upper level ridge over the region will continue to yield widespread VFR conditions for most terminals through the period. Pockets of IFR/LIFR conditions within low stratus/fog may redevelop in sheltered portions of the southern Willamette and Cowlitz Valleys late this evening into tonight, as well as MVFR cigs in valleys east of the Cascade crest including at K4S2. 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 30-40 kt will continue at KTTD into tonight, with gusts up to 45-60 kt east of KTTD at the western end of the Columbia River Gorge. Winds will ease for a time overnight but gusts to 20-25 kt will remain possible at KTTD. Locally stronger gusts to 25 kt are also possible downwind of gaps in the coastal terrain, including at KONP. The pressure gradient is expected to ease tonight, reducing winds across the region before increasing again Tuesday morning. KPDX AND APPROACHES...VFR flying conditions expected through the period. Diurnal east-southeast winds at 10-15 kt will ease to around 5 kt after 8-10z Tuesday before increasing again by 18-20z. -19/36 && .MARINE...Strong ridging aloft continues to favor persistent offshore easterly flow through midweek. While winds are largely at 10 kt or less, areas downwind of gaps in the coastal terrain may see stronger flow with gusts up to 15-20 kt, mainly west of the mouth of the Columbia River. Seas remain below 10 ft at 10-13 seconds through the middle of the week. -03/36 && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Air Stagnation Advisory until 4 PM PST Wednesday 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

824 FXUS66 KMFR 200513 AFDMFR Area Forecast Discussion National Weather Service Medford OR 913 PM PST Mon Jan 19 2026 .UPDATE...Aviation Discussion updated. && .AVIATION...20/06Z TAFs...A stable air mass looks to keep a familiar pattern in the forecast. Valley fog with LIFR will become widespread in the valleys in Douglas and Josephine County then gradually improve to VFR Tuesday afternoon. However, expect fog or low clouds with LIFR to linger in Roseburg and Grants Pass. Fog is expected to briefly develop in Medford again early Tuesday morning. Confidence is low for got North Bend given the offshore easterly winds, so will monitor this and update the TAF as necessary. Other areas are expected to stay at VFR levels through the TAF period. && .PREV DISCUSSION... /Issued 222 PM PST Mon Jan 19 2026/ DISCUSSION...A stable air mass remains over northern California and southern Oregon. This will keep daytime highs above seasonal norms, cool nights, and uneventful weather in the forecast through much of the week. With poor atmospheric mixing continuing into midweek, a Stagnant Air Advisory remains in place through Wednesday afternoon. Fog is lingering in the Umpqua Valley and at Grants Pass this afternoon, and redevelopment is expected in these areas as well as into the Illinois Valley this evening into Tuesday. A Dense Fog Advisory for the Umpqua Valley and a Freezing Fog Advisory for the Illinois Valley and Grants Pass are in place. A thin layer of patchy fog did reach Central Point/north Medford and North Bend this morning, but coverage was brief. This pattern may also repeat on Tuesday morning. On Tuesday, an upper trough presses against the ridge before splitting and sending a cutoff low to the southwestern United States. This will weaken then flatten the ridge, bringing a period of northwest flow. This pattern change will help to cool daytime highs across the area to nearly seasonal levels, and some upper level disturbances may help to mix out stagnant air. Other effects look unlikely. At the very most, there`s a slight chance (10-20%) for light coastal showers on Friday. While a general pattern is noticeable in guidance for the weekend and beyond, uncertainty reigns in the details. An upper ridge looks to return towards the end of the weekend, but forecast 500mb heights are lower than current ones, indicating weaker high pressure and cooler temperatures. Long-term deterministic guidance shows variations in where the ridge axis is, as well as fronts either flattening or pushing the new ridge to the east in the following days. With those variations as well as unclear signals in ensemble meteograms, there`s little confidence to offer for when precipitation will return. -TAD MARINE...Updated 200 PM PST Monday, January 19, 2026...Below advisory seas remain in the forecast for area waters. Northerly winds increase slightly over outer waters into Tuesday morning, but are not expected to build steep seas. Winds turn southerly on Tuesday then back to the north on Wednesday, with gusts increasing into Thursday. This period of gusty winds may build steep seas for waters south of Coos Bay on Thursday morning, with areas of steep seas looking to last into Saturday morning as winds ease. -TAD BEACH HAZARDS...Updated 300 AM PST Monday, January 19, 2026...A low amplitude (3-6 ft), but long period (18-20 seconds) swell is expected to move into the coastal waters tonight and persist through Tuesday afternoon. This will increase the risk of sneaker waves on area beaches, especially on the incoming tide Tuesday morning. If you plan to visit area beaches, please be aware of the dangers sneaker waves pose to beach goers. Sneaker waves can run up significantly farther on beaches than normal, including over rocks and jetties. These waves can suddenly knock people off of their feet and sweep them into the ocean. The waves can also move logs or other objects which could crush or trap anyone caught underneath. While sneaker waves can occur at any time, the greatest risk is on an incoming tide. Please be aware of the tides if venturing out onto the beaches. NEVER turn your back on the ocean! && .MFR WATCHES/WARNINGS/ADVISORIES... OR...Beach Hazards Statement through Tuesday afternoon for ORZ021- 022. Air Stagnation Advisory until 4 PM PST Wednesday for ORZ023-024- 026-029>031. Dense Fog Advisory until noon PST Tuesday for ORZ023. Freezing Fog Advisory until noon PST Tuesday for ORZ024. CA...None. PACIFIC COASTAL WATERS...None. && $$

281 FXUS66 KEKA 192245 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 245 PM PST Mon Jan 19 2026 .SYNOPSIS...Dry weather and above normal daytime temperatures will continue through much of the upcoming week. Overnight and morning temperatures will remain chilly with patchy dense fog along the river valleys and around Humboldt Bay. && .DISCUSSION...Resilient high pressure continues to dominate the region, leading to dry weather and above-normal temperatures. Abundant clear skies are observed across NW California this afternoon, with the exception of coastal stratus that remains stubborn to scatter around Humboldt Bay. A shallow marine layer up to 2,000 feet is expected to redevelop quickly along the coast late this afternoon and evening, with low clouds lapping the coastal areas into Tuesday. Low tempearures tonight/Tuesday morning are forecast to remain chilly with areas of fog and patchy dense fog along the shelter valleys. If you are interested in catching a glimpse of the aurora tonight, your location matters! Low coastal stratus clouds will likely hinder viewing for those along the coast tonight. Meanwhile, clear to partly cloudy are expected for the interior areas, offering a much better opportunity between 10 PM and 2AM tonight. The 500 mb blocking flow pattern will continue to result in dry weather for NW California through the end of the week. A shortwave trough will undercut the block on Wednesday, resulting in a deeper marine layer with some low clouds pushing into the interior river valleys. Ensemble guidances shows the ridge rebuilding Thursday and Friday, with offshore flow strengthening. This dry offshore flow will most likely reinforce the chilly overnight low temperatures. Beyond Friday, global models are now trending drier across the region. NBM probability for light rain or drizzle (0.01 inch or more) is around 15-25% for Del Norte and northern Humboldt on Sunday. Probabilities for 0.1 inch or more is less than 10%. Generally dry and above normal daytime temperatures are expected to continue through the next 7 days. /ZVS && .AVIATION...(18Z TAFs)...LIFR and IFR conditions have persisted around Humboldt Bay over KACV trough much of the day on Monday. Conditions may improve some by late afternoon or early evening, however LIFR visibility and LIFR ceilings are expected to quickly redevelop by mid to late evening and overnight. Greatest disruption to airport operations appears to be highest for KACV where duration of 1/4SM in fog is forecast to be over 6 hours. The timing of 1/4SM in fog remains uncertain and statistical guidance has been utilized. Fog could also create disruptions to airport operations for KCEC as well, however confidence of long duration 1/4SM in fog is not as high. Otherwise, fog and LIFR ceilings in the valleys of Trinity, Humboldt and northern Mendocino counties will likely redevelop tonight and Tuesday morning. These LIFR conditions will pose a landing and take off hazard for smaller airports with no terminal forecast. Conditions should improve at these non-TAF terminals late morning and afternoon on Tue. Now for KUKI TAF, there are not any signs for LIFR in fog or even an IFR/MVFR stratus deck at this time and VFR with light wind is expected. && .MARINE...Northerly winds (strongest south of Cape Mendocino around 15 kt) will continue on a downward trend tonight through Tuesday. Steep northerly wind waves around 4-5 ft (also south of Cape Mendocino) are forecast to trend down tonight and Tuesday as well. A long period westerly to northwesterly swell will build to 2 to 4 ft at 18 seconds late tonight and early Tue morning, and then to 5 to 6 ft near 16 seconds for the remainder of Tue. A secondary swell group around 3 to 4 feet at 12 seconds from the west-southwest will also add to the total sea state for max significant wave heights around 6 to 8 feet on Tuesday. Pressure gradients remain loose and wind fields light Tue into Wed before high pressure rebuilds and gradients tighten Wed night-Fri. Northerly winds increase by Thu with high probabilities for gusts to 25-30 kt on Thu and lower chances for gale gusts over 34 kt in the outer waters. The main hazard may end being steep northerly wind waves which are forecast to build on Thu and eventually to reach 8 to 10 by Fri. These deteriorating marine conditions will be hazardous for small craft and at a minimum an advisory for small craft will be necessary. && .BEACH HAZARDS...A moderate risk for sneaker wave will arise during the early Tuesday morning hours. A Beach Hazard Statement, BH.S, has been issued for two separate arrival times of a westerly swell 4- 6ft with a period around 16-17 seconds. The earliest estimated arrival is 12z on Tuesday January 20th for Coastal Del Norte, Northern Humboldt Coast, and Southwestern Humboldt ending around 04- 05z Wednesday. The sneaker wave threat for the Mendocino beach zones will arrive around 15z on Tuesday January 20th, ending around 05- 06z. /EYS && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Beach Hazards Statement from late tonight through Tuesday evening for CAZ101-103-104. Beach Hazards Statement from Tuesday morning through Tuesday evening for CAZ109. NORTHWEST CALIFORNIA COASTAL WATERS... None. && $$ 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

852 FXUS66 KMTR 200539 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 939 PM PST Mon Jan 19 2026 ...New AVIATION, MARINE... .KEY MESSAGES... Updated at 1230 PM PST Mon Jan 19 2026 - Dry weather, cool mornings, and mild afternoons this week - Morning fog across the Delta, North Bay Valleys, and interior East Bay Valleys && .UPDATE... Issued at 755 PM PST Mon Jan 19 2026 It looks like the Northern Lights are going to be a bust tonight. The clouds are holding off, but the geomagnetic activity has plummeted from the G4 level observed this afternoon to less than G1 at the latest measurement. The issue is the orientation of the magnetic field generated by the strong coronal mass ejection. When it first hit earlier today, the incoming field was oriented south, which is opposite of the earth`s magnetic field, and allows for enhanced energy transfer into our magnetosphere. Europe was getting a good display thanks to their earlier sunset. In the early afternoon the orientation of the CME field flipped to northerly, in line with the earth`s field. This blocks the energy transfer and is a big hindrance to the geomagnetic storm and thus the aurora. While it`s still possible for the field to flip back southerly, the raw strength is also waning. It`s still worth taking a peek, but don`t hold your breath. && .SHORT TERM... Issued at 1230 PM PST Mon Jan 19 2026 (This evening through Tuesday) Very little change in day to day conditions anticipated through mid week. A ridge of high pressure remains just off of the Pacific coast that will continue to result in temperatures 5-10 degrees above average (up to 15 in the higher terrain). Overnight, we are expecting patch to areas of fog in the North Bay Valleys while tule fog (dense at times) is forecast to advect westward into the interior East Bay Valleys and Delta again either late tonight or into Tuesday morning. If driving or commuting in these areas; be aware of the potential for dense fog and be prepared for sudden changes in visibility, remember to slow down, and use your low beam headlights. Expecting a slight cool down on Tuesday as more widespread high clouds stream over the region, but only by a few degrees. Where mostly sunny sky conditions prevail, afternoon temperatures will warm into the mid 60s to lower 70s across the Central Coast and low to mid 60s elsewhere. That said, where fog lingers into late morning or early afternoon, expecting temperatures to only reach the upper 50s. && .LONG TERM... Issued at 1230 PM PST Mon Jan 19 2026 (Tuesday night through next Sunday) Dry conditions look to persist through much of the extended forecast. An upper level trough will develop over the north central Pacific between Tuesday night and Wednesday. A cut-off low will develop within that trough and move southward just off of the Bay Area/Central Coast, resulting in slightly cooler conditions and cloudier skies through late week. Thus, the greatest potential for rain will be across southern California and along the Santa Lucia Range on Thursday as a deeper plume of moisture advects inland to the south. However there is about a 20% probability of seeing greater than 0.01" and less than a 10% chance of that area seeing 0.10" over that area. A weak upper level ridge is forecast to develop by this weekend and into early next week. As a result, a slight warming trend is forecast, but not as warm as what we have been the past week. Longer range guidance continues to push back our next potential widespread rainfall. It is not until late January or early February that we forecast widespread rain to return to the region. && .AVIATION... (06Z TAFS) Issued at 932 PM PST Mon Jan 19 2026 LIFR/IFR vis and cigs are expected for the North Bay terminals as Tule Fog fills in in the vicinity of KAPC and valley fog develops near KSTS. Expect VFR conditions for remaining terminals to the south, including Bay Area terminals. Vicinity of SFO...VFR is expected to prevail through the forecast period with relatively weak offshore winds prevailing tonight and through the majority of the forecast period Tuesday. SFO Bridge Approach...Similar SFO. Monterey Bay Terminals...VFR is expected to prevail with weak but persistent offshore flow through the forecast period. && .MARINE... (Tonight through next Sunday) Issued at 932 PM PST Mon Jan 19 2026 Light north/northeasterly breezes will increase later in the week becoming moderate, especially across our northern outer waters. The weak upper level offshore system expected to move southeast through our outer waters this week will result in moderate northwest swell early Wednesday and then again Friday. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ SHORT TERM...RGass LONG TERM....RGass AVIATION...JM MARINE...JM 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

191 FXUS66 KOTX 192346 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 346 PM PST Mon Jan 19 2026 .KEY MESSAGES... - Dry conditions with lowland clouds and mountain sun through the week. - Moderate 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 under stagnant air, lowland clouds, and mountain sun. Dry conditions will persist until at least Saturday, with the potential for a return of light precipitation Sunday or Monday. && .DISCUSSION... Monday night through Tuesday: A strong upper-level ridge remains parked offshore the Pacific Northwest, with the Inland Northwest under the influence of a dry, stable pattern. Strong low- level inversions have kept the Inland Northwest under a blanket of stratus, with this trend continuing through the evening and into tomorrow. Some subtle changes are expected on Tuesday as a weak wave drops east of the Continental Divide. This is not expected to bring precipitation to the Inland Northwest with drier continental air filtering into the region from the northeast. Models show precipitable water values dropping from 0.25-0.30 inches this evening to 0.15-0.20 inches on Tuesday. Winds are expected to remain light and model soundings do not show the low-level inversions mixing out either. So while there may be some clearing across the Inland Northwest with this drier air, this does not seem to be robust enough of a system to bring widespread, continuous clearing across the region. Wednesday through Tuesday: The upper-level ridge offshore will remain the dominant weather influence for most of the week. Models do generally show it retrograding a bit Wednesday through Friday, which would open the door for weak shortwaves to slide through the Pacific Northwest. As of the latest model runs, none of these seem strong enough to result in precipitation or a push of strong winds though, continuing the risk for stratus and fog. By the end of the weekend into early next week, around 60% of model ensembles between the GEFS/EPS/GEPS begin to hint at a brief break of the blocking pattern as a series of systems work to flatten the upper-level ridge and eventually kick it eastward. This will bring increasing chances for precipitation (15% across central Washington up to 50% over the mountains) during the Sunday to Tuesday timeframe. The National Blend of Models (NBM) gives the mountains a 70% chance for one inch of snow from 4AM Saturday through 4AM Tuesday and a 20 to 30% chance for 1 inch across far eastern Washington and the North Idaho valleys. /vmt && .AVIATION... 00Z TAFs: The forecast largely continues persistence with widespread low stratus expected to remain in place under a strong upper-level ridge. Conditions will fluctuate between MVFR and IFR with light winds. Model probabilities are showing a 70% chance for improvement at KPUW/KLWS/KCOE around 21/22Z, but the confidence as stratus tends to be hard to scour out if there isn`t a strong kicker, like a drier strong push. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence in MVFR conditions or worse through the period. Low confidence in clearing occurring at KPUW/KLWS this afternoon. ----------------------- 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 25 36 22 34 23 35 / 0 0 0 0 0 0 Coeur d`Alene 25 36 22 35 23 35 / 0 0 0 0 0 0 Pullman 26 38 24 37 25 36 / 0 0 0 0 0 0 Lewiston 27 40 26 39 28 39 / 0 0 0 0 0 0 Colville 22 37 19 34 21 36 / 0 0 0 0 0 0 Sandpoint 25 35 22 33 23 33 / 0 0 0 0 0 0 Kellogg 27 38 24 36 25 36 / 0 0 0 0 0 0 Moses Lake 25 38 21 37 23 36 / 0 0 0 0 0 0 Wenatchee 26 37 24 37 26 37 / 0 0 0 0 0 0 Omak 25 38 23 36 25 36 / 0 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...Air Stagnation Advisory until 4 PM PST Tuesday for Central Chelan County-Moses Lake Area-Northeast Mountains- Okanogan Highlands-Okanogan Valley-Spokane Area-Upper Columbia Basin-Waterville Plateau-Wenatchee Area-Western Chelan County-Western Okanogan County. ID...Air Stagnation Advisory until 4 PM PST Tuesday for Central Panhandle Mountains-Coeur d`Alene Area-Lewis and Southern Nez Perce Counties-Lewiston Area-Northern Panhandle. && $$

284 FXUS66 KPDT 192307 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 307 PM PST Mon Jan 19 2026 .DISCUSSION...Current satellite imagery shows a low stratus layer across the Columbia Basin area extending to Central OR. While majority of freezing fog has lifted over North-Central OR and Foothills-Southern Blue Mountain of OR, the webcams are currently showing ongoing freezing/dense fog along US-97 between Cow Canyon and Shaniko. The northwesterly flow dominates the region with the upper ridge along the PacNW coast through work week. Thanks to the low stratus layer and temperature inversions, this will help keep high temps in the 30s and 40s. The boundary layer will remain dry from the ongoing subsidence, which will assist in lowering dewpoints and temps to near or below freezing during overnight hours. That said, freezing/dense fog could redevelop during early morning hours and night hours. Uncertainty still remain on the strength of the fog and extent, but we will monitor the forecast area and make any adjustments if need be. HREF raw ensembles show a 15-30% probability for visibilities less than 1/2SM but 30-40% prob during morning hours for tonight through early Tuesday morning, which might impact driving conditions. With the ongoing inversions, stagnant air conditions will continue for the next few days with low low transport winds (10 mph or less) and mixing heights around 1.5 kft or lower. Any pollutants, haze, and/or smoke may still be trapped near surface level thus resulting poor ventilation, keeping Air Stagnation advisories in place until late Tuesday afternoon. Feaster/97 && .AVIATION...00Z TAFs...Low stratus with several sites <2000 feet of CIG continue to impact sites, with the Central OR terminals seeing initial IFR conditions. IFR conditions are expected to last much of the period as the surface high pressures continue to hold the low stratus in-tact for the majority of the TAF period. Guidance hinting that we`ll get a break in the stratus in the last few hours of the period, but was cautious to include it for a longer duration given that guidance has not initial correctly for some of the terminals. We`ll see how guidance evolves going into the 06Z TAFS, but for now sub-VFR conditions will prevail for the next few hours. Winds remain light and variable. && .PRELIMINARY POINT TEMPS/POPS... PDT 22 35 21 34 / 0 0 0 0 ALW 25 34 23 34 / 0 0 0 0 PSC 24 38 22 36 / 0 0 0 0 YKM 22 39 20 37 / 0 0 0 0 HRI 23 35 22 35 / 0 0 0 0 ELN 21 35 20 35 / 0 0 0 0 RDM 20 45 18 41 / 0 0 0 0 LGD 24 43 22 43 / 0 0 0 0 GCD 25 49 26 49 / 0 0 0 0 DLS 26 39 26 39 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Air Stagnation Advisory until 4 PM PST Tuesday for ORZ041-044- 507-508-510-511. WA...Air Stagnation Advisory until 4 PM PST Tuesday for WAZ024- 026>029-521. && $$ SHORT TERM...97 LONG TERM....97 AVIATION...95

792 FXUS65 KREV 192008 AFDREV Area Forecast Discussion National Weather Service Reno NV 1208 PM PST Mon Jan 19 2026 .KEY MESSAGES... * Light winds and valley inversions will keep hazy skies and air quality reductions through the first half of this week with patchy freezing fog in some Sierra valleys. * Dry weather prevails this week with above average daytime temperatures and near average low temperatures. * A pattern change is possible for the latter half of the week allowing gusty mountain ridge winds to return though confidence is low. && .DISCUSSION... It`s gonna be a cool, calm, and collected start of the work week with light winds, valley inversions, and afternoon highs in the low to mid 50s and upper 40s for valleys and higher elevations, respectively. Valley inversions will create hazy conditions for W NV and freezing fog concerns for Sierra valleys. Most notably this will include Mono Lake where afternoon highs aren`t expected to reach must past freezing. Satellite imagery continues to show a clouded over Mono Lake, though some of the fog might lift a bit this afternoon. Other Sierra valleys, such as the Martis Valley and near Crowley Lake, can expect freezing fog in the mornings before dissipating by the early afternoon. A cutoff low off the coast of SoCal may bring a pattern change as early as Wednesday, though confidence remains low. The low-level feature still has plenty of wiggle room to meander, though recent models having gotten better at location and timing agreement. As of now, this brings light (<15% chance) shower chances to the Eastern Sierra. QPF and snow amount forecasts show a whopping 0.00-0.05" along the crests, though, despite snow levels around 7300`. Other than that, winds may also pick up enough to disperse valley inversions and freezing fog. The next item of note is the possibility for a backdoor cold front dropping in from the north. The 700mb GFS hints at increased easterly winds late Friday into Saturday, though the magnitude remains low at this point. If this pans out, expect impacts to backcountry recreation. -Giralte && .AVIATION... VFR conditions and light surface winds continue for area TAF sites to begin the week. The only exception is at KTRK where patchy and mainly shallow FZFG is expected to renew tonight into tomorrow morning (until about 15-16Z). Haze in W.NV may lead to reduced slantwise visibilities. -Giralte/078 && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$

042 FXUS66 KSTO 192012 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 1212 PM PST Mon Jan 19 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 have trended down for the weekend but minor cooling is still anticipated && .DISCUSSION... ...Today Through Thursday... Latest GOES-West visible satellite imagery depicts a large area of fog stretching from about Corning southward on this Monday afternoon. The Dense Fog Advisory has been extended in time through 2 PM this afternoon as dense fog and visibilities of 1/4 mile or less are still being observed. The region remains under upper level ridging over the next several days, with dry and mild weather prevailing for much of interior northern California. This inversion pattern is bringing daily chances for fog and low clouds in the Valley and lower foothills through the week, especially from Chico southward. High resolution guidance shows a 50 to 70 percent chance of visibilities less than 1/2 mile once again tonight into Tuesday morning. The fog and low clouds will delay some of the daytime heating in those lower elevations. Be sure to slow down, and use low-beam headlights if fog is encountered while driving. Elsewhere, above normal temperatures are forecast, along with offshore flow. ...Friday - This Weekend... Toward the second half of the week, the upper level pattern will feature a flattening ridge, with an upper low developing and moving into the southern California area which will bring slightly cooler temperatures for us up north by the end of the week and into the weekend. Precipitation chances have trended down for the weekend, with now only a 10 percent chance or less of 0.01" of rain showers over the northern mountains and southern Cascades. Confidence is higher in a minor cooling trend in temperatures, with forecast highs in the 50s to around 60 for the Valley. Ensemble guidance then indicats the upper level ridge building back in behind the trough, allowing for increased offshore flow. Another round of periodically breezy north to east flow can be expected late Friday and over the weekend as a result of this. && .AVIATION... Lingering IFR/LIFR conditions in central/southern Sacramento Valley, Delta, and northern San Joaquin Valley through 23z Monday. FG/BR expected to re-develop around 03z-06z Tuesday with similar aerial extent as today. There is some uncertain potential for FG/BR to reach further north, into Red Bluff, however FG/BR will be patchier that far north with only MVFR conditions expected. Surface winds below 12 kts in the lower elevations, with local E-NE wind gusts of 15-25 kts in the Sierra and Southern Cascades until 18z Tuesday. && .STO WATCHES/WARNINGS/ADVISORIES... Dense Fog Advisory until 2 PM PST this afternoon for Carquinez Strait and Delta-Central Sacramento Valley-Northern San Joaquin Valley-Southern Sacramento Valley. && $$

439 FXUS65 KMSO 191953 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 1253 PM MST Mon Jan 19 2026 .DISCUSSION... KEY MESSAGES: - Forecast challenges with valley fog will continue. - Uncertainty in the pattern change for the next 10 days. There is now some confidence that while 2 distinct waves drop south out of Canada bringing colder air masses, both systems will be moisture starved. High pressure and valley inversions will be the main theme through at least the 24-26th as of current model runs. The two waves, first on Tuesday and second Friday, will allow for a minor cool down, temperatures across the region may actually drop a couple degrees below normal by Friday, albeit only briefly with slow warming expected throughout the weekend. What is expected is a continuation on the current pattern, valley fog and low stratus improving during the afternoon but returning overnight. This pattern may persist into the following week, i.e. 26 Jan. The models, which for weeks have been trying to insert a pattern change, have completely backed away from demonstrating change as of the 12z Jan 19 runs. && .AVIATION... Little to no changes to the weather conditions for the next 24 hours. Fog and low stratus will continue to impact the valleys of north central Idaho into northwest Montana. KGPI is anticipated to have a stratus deck all day. KMSO could be impacted for a period of time this morning by fog. KSMN should expected hazy conditions, but at this time fog appears to have finally broken out of the area. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...ID...Air Stagnation Advisory until 4 PM PST Tuesday for Northern Clearwater Mountains...Orofino/Grangeville Region... Southern Clearwater Mountains. && $$

092 FXUS65 KBOI 200352 AFDBOI Area Forecast Discussion National Weather Service Boise ID 852 PM MST Mon Jan 19 2026 .DISCUSSION...Despite slight cooling aloft from a weak Canadian disturbance, mountain temperatures still rose above freezing for many sites this afternoon. This evening, mountains are now running a few degrees cooler than this time yesterday with the enhanced northerly flow. The valley cold pools and associated stratus/fog prevail, which has even expanded in some areas such as Harney County, Boise Mountains, Camas Prairie, etc. Patchy, dense, freezing fog can be seen on webcams in the Boise foothills, east-central Oregon, and portions of the Magic Valley, as well...and is undoubtedly depositing ice on roadways and sidewalks. There is low forecast confidence that Tuesday`s weak trough will erode much of the stratus deck. && .AVIATION...MVFR-LIFR below 5k-6k feet MSL in the Snake Plain and surrounding basins due to persistent low stratus and fog. Stratus/fog may reach KBNO overnight as it creeps westward. Lower mountains/foothills obscured. Surface winds: variable less than 8 kt. Winds aloft at 10kft MSL: NW 10-20 kt, increasing to NW-N 15-30 kt around Tue/15Z. KBOI...IFR-LIFR ceilings expected overnight, rising to MVFR-IFR by late Tue morning. Expect occasional snow grains out of the stratus. Surface winds: light and variable overnight, then NW around 5 kt Tue afternoon. && .AIR STAGNATION...A strong temperature inversion with light boundary layer winds will continue to support stagnant valley conditions across southeast Oregon and southwest Idaho. Mixing heights are expected to remain at or below 2000 ft AGL through Thursday morning, and therefore an Air Stagnation Advisory remains in effect until then. Cooling aloft should weaken the inversion late in the week as upper level disturbances arrive from Canada. && .PREV DISCUSSION... SHORT TERM...Tonight through Wednesday night...A strong upper level ridge remains the dominant feature over the region, maintaining a steep temperature inversion and stagnant conditions. Visible satellite imagery shows no significant changes to the persistent stratus deck entrenched across the Snake Plain and the lower valleys of southeast Oregon. No erosion has been observed, and the stratus is actually showing signs of expansion across southeast Oregon. This expansion is expected to reach the lower valleys of Harney County, including Burns, tonight and persist through the short term. A weak shortwave trough passing well east of the forecast area early Tuesday is unlikely to be strong enough to erode the stratus deck. Thus, widespread low clouds will remain trapped within the cold pools of the Treasure Valley, Snake Plain, and Baker Valley. Patchy dense fog is likely again during the late night and morning hours where the stratus intersects the terrain. An increase in mid-level clouds Tuesday morning could help produce flurries in the lower stratus-filled valleys as the higher clouds seed the lower deck. Models have poorly handled the stratus and resulting temperatures thus far, particularly the NBM which historically under-performs with valley inversion events. Consequently, the forecast weighs persistence heavily against statistical guidance. Temperatures will remain inverted, with valley locations struggling to warm out of the freezing range, while mountain locations above the inversion layer (roughly 5000 to 6000 feet MSL) experience mostly sunny skies and mild temperatures in the 40s and low 50s. Little change is expected through Wednesday as the ridge axis shifts slowly overhead, with valley stratus and fog heavily influencing daily high and low temperatures in the lower elevations. LONG TERM...Thursday through Monday...The latest model trends seem to be holding firm, as a cutoff low sets up off the California coast and a Great Lakes Low becomes the primary driver of weather over the CONUS. For us, however, this means insignificant weather in the deformation zone with some increased clouds and a redeveloped ridge off the PacNW coast. The Lakes low`s large pressure gradient moves into the mid-levels, and with some cloud cover and colder air aloft, this may be enough to briefly weaken or break the inversion on Friday and Saturday before that ridge returns on Sunday. The potential precip has been pushed back to Sunday/Monday, with the main component being warm and moist zonal flow setting up on Monday. This is at least a more reliable source of precipitation than the western edge of a Lakes low would be, but in the current forecast we are just on the southern edge of the moisture with some hints of ridging still off the coast. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Air Stagnation Advisory until 11 AM MST Thursday IDZ011>014-016-028-033. OR...Air Stagnation Advisory until 11 AM MST /10 AM PST/ Thursday ORZ061>064. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise DISCUSSION...SH AVIATION.....SH AIR STAGNATION...SH SHORT TERM...JDS LONG TERM....JM

821 FXUS65 KLKN 191955 AFDLKN Area Forecast Discussion National Weather Service Elko NV 1155 AM PST Mon Jan 19 2026 .KEY MESSAGES... Updated at 1154 AM PST Mon Jan 19 2026 * Dry weather persists thru the next several days * High temperatures will be warmer than seasonal values each afternoon thru Thursday * A change in the weather pattern is likely Friday and Saturday && .DISCUSSION... (This afternoon through next Monday) WEATHER PATTERN OVERVIEW: Upper level ridging and northwest flow continues to be the story for the next several days before finally breaking down some for the weekend. Local impacts look light, with minimal moisture availability currently indicated which will suppress any precipitation potential. The ridge breakdown is expected to allow a cooler air mass to enter Northeastern Nevada for the weekend, dropping daytime temperatures by around five degrees compared to late week. Model agreement is very low after Saturday, making it difficult to determine a clear picture, but the general indication still looks like a more active pattern takes hold for the end of the month. FORECAST CONFIDENCE & DEVIATIONS: High confidence for continued warm and dry conditions through Wednesday. Moderate confidence for ridge breakdown timing and impacts. Low confidence for conditions after Saturday. No changes were made to base NBM output. && .AVIATION...VFR conditions and light winds continuing at all sites through the next 24 hours. && .LKN Watches/Warnings/Advisories... None. && $$ DISCUSSION...94 AVIATION...94