ZSE Aviation Forecast Discussions

154 FXUS66 KSEW 011202 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 402 AM PST Thu Jan 1 2026 .SYNOPSIS... Systems spinning out of an upper level trough offshore moving through Western Washington later tonight into Friday morning and again later Saturday into Sunday morning. Upper level trough moving through Western Washington Monday. Another system reaching the area later Tuesday into Wednesday. && .SHORT TERM /TODAY THROUGH SATURDAY/... Satellite imagery shows high clouds over Western Washington early this morning. Fog formed before the high cloud cover arrived with visibility a half mile or less from Bellingham down the I-5 corridor through Lewis county. Temperatures at 4 am/12z were in the upper 20s to mid 30s. Light flow in the lower levels combined with a shallow but sharp inversion will keep foggy conditions intact through the morning hours. Weather system approaching from the south this afternoon with a small increase in the low level flow lifting the fog into a low cloud cover. Rain out ahead of the approaching system reaching the southern portion of the area late afternoon. Under cloudy skies highs will remain in the 40s. Rain spreading over Western Washington from the south overnight. Snow levels 5000 to 7000 feet. Easterly gradients will trap cold air in the passes creating the potential for freezing rain especially in Snoqualmie pass. Snow amounts with the southerly flow aloft will be light but with the freezing rain potential winter weather advisory will remain in effect for the Snoqualmie pass area into early Friday morning. Lows tonight in the mid 30s to lower 40s. Front dissipating over the area Friday with rain tapering off in the afternoon. Easterly gradients weakening with the cold air trapped in the passes scouring out in the morning ending the freezing rain threat. Highs near 50. Rain out ahead of the next system spinning out of the upper level trough offshore reaching the area Friday night. Trough offshore moving south and east into Saturday stalling the front over Western Washington Saturday. Rainfall amounts only a quarter of an inch or less. Snow levels remaining at least 5000 feet keeping the precipitation in the passes as rain. Coastal flooding is possible during high tides Friday morning. Better chance for coastal flooding over the weekend with higher astronomical tides, as well as the combination of lower pressure and increased winds and waves. At this time, minor to moderate coastal flooding is expected for both Saturday and Sunday. Major coastal flooding cannot be ruled out for the coast this weekend, particularly due to the stronger winds and increasing seas. Water levels look to rise up to a maximum of around 2 to 2.5 feet above ground level for most locations along the water this weekend. Felton && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Extended models still having trouble with the placement of the surface low associated with the front Saturday night into Sunday morning. One set of solutions has the low moving by to the west along 127W through Sunday morning. Another set of solutions has the low closer to the area with the low moving inland over Vancouver Island Sunday morning and a weak lee side surface low northeast of the Olympics. Olympia to Bellingham gradient as high as plus 7 mb on some of the solutions. If the windier solutions win out a wind advisory will be likely for Sunday morning over the interior. Even with the windier solutions the winds do not last very long with the low weakening and moving northeast. Upper level trough moving through Monday keeping at least chance pops in the forecast. Another system arriving later in the week with a majority of the solutions favoring a Tuesday night or Wednesday arrival. Felton && .AVIATION...Southwest flow aloft continues as an upper level disturbance lifting northward out of broad trough offshore approaches the region. Light low level offshore flow continues with widespread low level moisture trapped across the interior lowlands. LIFR/IFR ceilings and surface visibilities below 1SM at times will persist through the morning. Mid and high level moisture will increase through the day with IFR or low MVFR ceilings in light rain expected across the region this evening. KSEA...LIFR conditions in fog/stratus with visibility below 1SM expected to persist through around 18Z. High and mid level clouds will increase above it. There is low confidence in a brief period of VFR midday before rain develops after 00Z with ceilings lowering back to low MVFR or occasional IFR this evening. Surface winds light and variable. 27 && .MARINE... A system will move up from the south reaching the area tonight into Friday morning. A stronger frontal system will move through the waters Saturday into Sunday morning for increasing winds and seas. Another system will arrive Monday. Small craft advisory winds over the waters later Saturday night into Sunday with gales possible over the interior waters Sunday morning. Small craft advisory winds also possible over the coastal waters again Tuesday into Wednesday. Seas 5 to 8 feet building to 10 to 14 feet Saturday. Seas subsiding back down below 10 feet Monday. Felton && .HYDROLOGY... Multiple frontal systems moving through Western Washington into the weekend. The Skokomish River, starting from elevated levels, is forecast to exceed minor flood stage late Saturday night or Sunday morning. The river will recede back under flood stage Monday. No additional river flooding is expected into next week. Felton && .SEW WATCHES/WARNINGS/ADVISORIES... WA...Dense Fog Advisory until 10 AM PST this morning for City of Seattle-Downtown Everett / Marysville Area-Eastern Kitsap County-Eastside-Island County-Lowlands of Lewis and Southern Thurston Counties-Lowlands of Pierce and Southern King Counties-Lowlands of Western Skagit and Northwestern Snohomish Counties-Lowlands of Western Whatcom County-Middle Chehalis River Valley-Northern Hood Canal-Olympia and Southern Puget Sound-Port Townsend Area- San Juan County-Shoreline / Lynnwood / South Everett Area- Southern Hood Canal. Winter Weather Advisory from 1 PM this afternoon to 7 AM PST Friday for Cascades of Southern King County. PZ...Dense Fog Advisory until noon PST today for Admiralty Inlet- Northern Inland Waters Including The San Juan Islands- Puget Sound and Hood Canal. && $$

271 FXUS66 KPQR 011015 AFDPQR Area Forecast Discussion National Weather Service Portland OR 215 AM PST Thu Jan 1 2026 .SYNOPSIS...New year, new weather pattern! The high pressure ridge overhead which has maintained dry conditions the last few days is expected to finally degrades today. This will bring into the region relatively warmer, wetter, and active conditions through at least the weekend. However, due to a colder airmass trapped near the surface in the central Columbia River Gorge and Hood River Valley, freezing rain will be a noteworthy impact for these and other central Columbia Gorge adjacent valleys into Friday. && .DISCUSSION...Currently a ridge of high pressure continues to linger overhead facilitating dry and fairly calm conditions. The subsequent thermally induced trough is also resulting in a 5-8mb pressure gradient from KPDX to KDLS which continues to drive windy conditions through the Columbia River Gorge and other Cascade gaps with gusts at our typically "windiest" spots like Three Corner Rock and Corbett holding in the 35-60 mph range most of the day. This offshore gradient is expected to slowly ease over the 12-24 hrs but likely won`t go away completely as cooler air is continually reinforced in the Gorge and locally adjacent Cascade valleys - a variable likely to come into play once precipitation arrives today. Speaking of precipitation, as of 200 AM, radar and surface observations are showing light precipitation slowly spreading northward through the Willamette Valley and along the coast. This precipitation is brought to the region via an approaching closed upper-level low off the coast of southern Oregon and Northern California. This low will help to swing a warm- frontal boundary into the Pacific Northwest and result in rapidly rising snow levels. There continues to be a 4-6 hour difference within the models for the exact start time of light precipitation, which continues to provide some uncertainty to the overall forecast. At this time (200 AM) the HRRR looks to have the best handle on the incoming precipitation, but only time will tell if that continues to hold true. Assuming the HRRR remains accurate, then light precipitation should be expected around Salem, OR around 2-3 AM, the Portland/Vancouver Metro area around 4-5 AM and Kelso/Longview around 7-8 AM. Now, these are just best estimate start times and could easily be off by an hour or two. Given how light the precipitation appears initially, little impact is expected for the majority of the CWA. It should be noted that this overall set-up IE cold air that has been well established in the Central Columbia River Gorge as well as for Hood River County, combined with warm rain overrunning this cold air results in a very favorable pattern for freezing rain. Given that models are notoriously poor at scouring out cold air from these locations so with established cold/dry air in place and relatively warm precipitation expected to overrun said airmass, freezing rain with this system is very likely. The current 24 hour (4 AM Thursday-4 AM Friday)ice accumulation probabilities via the 00Z HREF show a 75-90% chance of at least 0.1" of ice accumulation for the majority of Hood River County. Also, there is a 40-70% chance to exceed 0.25" locally on the western side of the Upper-Hood River Valley. Overall, there is a high confidence in storm total ice accumulation values fall at least into the 0.1"-0.25" range. Given the overall set up as well as pattern recognition, portions of I-84 and WA-14 could easily some amount of ice accumulations. Therefore, will maintain a Winter Weather Advisory for the Central Gorge zones and Upper Hood River Valley from 10AM today through at least 10AM Friday. While the moderation presented in the forecast may still be a bit too fast Friday morning, the rapid decrease in QPF by the midday hours will help to mitigate additional impacts the rest of Friday. As we look towards the weekend into the start of next week, the specifics of the weather pattern become much more uncertain. Overall, ensemble guidance is pointing towards a fairly typical winter rain pattern for the PacNW continuing into Tuesday. Snow levels gradually lower back towards pass-level by Monday/Tuesday as well. Still, we`ll need to keep an eye out of the placement of individual shortwaves rotating around the larger trough feature over the eastern Pacific for added impacts like breezy winds. Beyond Saturday/Sunday embedded shortwave placement with in the large trough pattern becomes extremely uncertain among ensemble modeling systems. By the middle of next week there is decent consensus for us to migrate into a progressive WNW upper- level flow pattern once the larger trough feature previously to our east kicks into the Rockies. However, large variations exist regarding the exact amplification and longitudinal placement of trough features within this flow regime. At the very least we can be confident in more pervasive Cascade snowfall with each passing system Wed/Thur onward and near normal temperatures for this time of year. /42/99 && .AVIATION...Upper-level ridging has begun to weaken and will slowly shift eastward as a low pressure system lifts northward. Largely VFR flying conditions aside from brief periods of IFR/LIFR within fog/mist in the southern Willamette Valley within the next 2-3 hours. These conditions will to a MVFR/VFR mixture as steady rain spreads from south to north by 18Z Thursday. Around 22Z Thursday - 00Z Friday look for MVFR/IFR conditions along the Central OR coast and Willamette Valley terminals. Sheltered Cascade Valleys including the Hood River Valley are expected to trap sufficient cold air at the surface to produce freezing rain, though this is not anticipated to affect any TAF sites. Expect generally southerly winds across the airspace with locations north of KSLE,including KAST, maintaining easterly winds before becoming southerly around 06Z-08Z Friday, with KTTD being the exception and expected to maintain easterly winds throughout the TAF period. KPDX AND APPROACHES...VFR conditions expected to persist through at least 18Z Thursday. Light rain, approaching from the south, may begin as early as 12Z Thursday, but the majority of precipitation is expected to hold off until after 18Z-21Z Thursday. As the precipitation increases expect MVFR conditions, both the precipitation and lowered flight conditions are expected to persist through the remainder of the TAF period. Offshore flow will maintain gusty east winds up to 30 kt at KTTD, but much lighter winds around 5-10 kt are expected at KPDX. /42 && .MARINE...High pressure over the waters will continue to weaken as more active weather returns for the latter part of the week. Southeast winds around 10 kt or less continues into Thursday as a weak low pressure system off the northern California coast lifts northward. This will likely bring some breezier winds to the southern waters Thursday night, which could result in isolated southerly winds with gusts up to 25 kt through late Thursday night. Winds become offshore on Friday again as a stronger low pressure system develops farther off the northern California/southern Oregon coast. Southerly winds return by Saturday as well as increase across all waters on Saturday as this stronger system moves northward with gusts up to 40 kt. Therefore, have issued a Gale Watch across all waters starting Saturday. Though still a low probability (10-20% chance), a more compact surface low could lift across the coastal waters Saturday night with maximum gusts exceeding 48 kt. Seas are expected to continue to hover around 6 to 7 ft through Friday. By Saturday morning, an incoming fresh southerly swell is expected to push seas to around 14 to 16 ft with a period of 10 to 12 seconds. Guidance is also showing around a 10% chance for seas around 20 ft. Also of note, we are entering a perigean/king tide cycle. Therefore ebb currents are expected to be on the strong side, including near the Columbia River Bar, through January 4th. /42 && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Winter Weather Advisory from 10 AM this morning to 10 AM PST Friday for ORZ121-122. WA...Winter Weather Advisory from 10 AM this morning to 10 AM PST Friday for WAZ210. PZ...Small Craft Advisory from 1 PM to 5 PM PST this afternoon for PZZ210. Small Craft Advisory from 1 AM to 7 AM PST Saturday for PZZ210- 251>253. Gale Watch from Saturday morning through Sunday morning for PZZ251>253-271>273. Small Craft Advisory from 1 PM Friday to 7 AM PST Saturday for PZZ271>273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland

478 FXUS66 KMFR 011236 AFDMFR Area Forecast Discussion National Weather Service Medford OR 436 AM PST Thu Jan 1 2026 .DISCUSSION...Radar currently shows precipitation across the area moving north with the heaviest in Curry County. As of 4 AM, most of the rain is falling west of the Cascades with the highest 12-hour totals near Curry County and at Medford at ~0.25". Areas east of the Cascades mostly have less than a tenth of an inch so far. The shower activity will continue today and will focus on Curry and southern Siskiyou counties. Southerly winds will increase along and east of the Cascades this afternoon. Please read the detailed discussion below for more information on what else is ahead as we start the new year. && .AVIATION...01/12Z TAFs...A warm front is pushing north through the area, producing areas of light precipitation, some areas of MVFR ceilings and terrain obscurations, and rising freezing levels. Low clouds and fog with IFR/LIFR conditions in the Umpqua Basin and lower Rogue Valley near Grants Pass persist this evening, trapped under the increasing clouds aloft and a strengthening inversion. While there has been some clearing as the front approaches, full clearing of these areas is not expected until after the front passes tomorrow. By the evening, MVFR to IFR ceilings are expected to return to all locations. -BPN && .MARINE...Updated 200 AM PST Thursday, January 1, 2026...Overall, sub-advisory conditions are expected through this afternoon as seas remain swell dominated and light south winds persist. South winds trend slightly stronger tonight as a front moves into the area and seas hazardous to small craft are expected to develop. Then, a second front approaches from the west and conditions worsen late Friday morning through Friday night with gales possible across the outer waters and very steep and hazardous seas and gusty winds possible across the inner waters. Initially, gales are most likely across the waters south of Cape Blanco beyond 10 nm from shore Friday then may expand north of Cape Blanco for the waters beyond 10 nm from shore Friday evening and night. Models support winds remaining below gales across the inner waters but expect gusty, south winds and very steep seas, dominated by fresh south swell, to develop Friday night. Confidence is moderate in the strength and timing of these winds and seas on Friday and the track of this storm will be factors in which areas see the strongest winds and seas. Saturday and Saturday night, another stronger front moves into the waters and a low pressure nears the coast. This is likely to bring a second period of gales and very steep seas, with very steep seas lingering on Sunday. Winds may be strongest with this front and seas are forecast to peak Saturday night near 18 feet, dominated by wind seas and fresh south swell. South winds persist but trend lower on Sunday and very steep seas may continue through the day. Then, late Sunday night into Monday, models support steep seas with a mix of northwest swell and lingering fresh south swell. && .PREV DISCUSSION... /Issued 405 PM PST Wed Dec 31 2025/ DISCUSSION...From tonight into early next week, our area will be affected by a series of disturbances rotating around a broad, slowly east- northeastward moving upper level trough. The Air Stagnation Advisory has very recently been allowed to expire, with better mixing of the air mass due to a warm front lifting northward this evening. It will bring cloudy skies and increasing light rain chances overnight with snow levels above 8000 feet. Another effect is that some areas, especially in Josephine, Douglas, and western Siskiyou County will have very little cooling or even barely warmer low temperatures on Thursday in comparison to today`s high temperatures. Our area will be in the warm sector Thursday, then the associated weak cold front will follow late Thursday night. This will bring light to locally breezy (in the Shasta Valley and eastside) southerly winds with light rain likely. Our area looks to be between disturbances on Friday, though with the potential for moist southerly flow to wring out some light upslope rain for southern Siskiyou County, and increasing southerly winds for the Shasta Valley and eastside. A High Wind Watch for the Shasta Valley /PDXNPWMFR/ has been extended, now in effect from late Friday morning through Saturday evening. This is due to south winds that are likely to be either on the high end of Advisory or low end of Warning strength from Friday into early Saturday morning. The NBM shows a 40% probability of reaching 60 mph gusts in the Shasta Valley, which is a very slight decrease in comparison with yesterday`s 12Z model run. A brief break between disturbances should bring a slight decrease in speeds later Saturday morning, before winds ramp back up to around their previous peak of strength for Saturday afternoon and evening. South to southwest winds will also be strong at the coast, over the higher terrain, and east side, with the noteworthy potential of reaching Advisory strength at least in the Silver Lake to Summer Lake area of Lake County. Meantime, both the Friday night and Saturday into Saturday night disturbances, as well as a third low pressure system Sunday into Sunday night will support moderate to heavy precipitation for the coast, southern Josephine, and western and southern Siskiyou counties. Nuisance flooding of urban areas and creeks and streams is possible in those areas with 3 to 7 inches of rain in total forecast. Amounts will be lighter elsewhere, mainly up to an inch. A Winter Storm Watch /PDXWSWMFR/ for Siskiyou County above 5000 feet remains in effect, but has been shifted forward by 6 hours. It is now in effect from late Friday evening through Sunday evening. Snow levels will be around 6500 feet late Friday falling to around 5500 feet Saturday and around 4500 feet Sunday. 1 to 3 feet of snow are still forecast, with highest amounts on Mt. Shasta. Late Sunday into Sunday night, snow levels may drop down to Snowman Summit. Meantime, the southerly flow direction will not be favorable for the Cascades. But, they may receive a few to several inches of snow. Model confidence drops beyond Sunday, with differences in the characteristics and positioning of the waves in a splitting flow aloft. The highest probability Monday through Tuesday is for impactful weather to continue well to the south of our area, with lighter wrap-around precipitation having the highest probability of continuing in southern Siskiyou County. By Wednesday, a colder trough will be moving east-southeast from the Gulf of Alaska with an associated cold front. Less than half of GEFS model members have it arriving in our area before Thursday, with a smaller minority holding it off until Friday. When it does arrive, snow levels will at least be modestly lower with this system and the highest probability of precipitation will be for the coast and Douglas County northward. && .MFR WATCHES/WARNINGS/ADVISORIES... OR...CA...Winter Storm Watch from Friday evening through Sunday evening for CAZ080-082-083. High Wind Watch from Friday morning through Saturday evening for CAZ081. PACIFIC COASTAL WATERS...Small Craft Advisory from 4 PM this afternoon to 10 PM PST Friday for PZZ350-356-370-376. Gale Warning from 10 PM Friday to 7 AM PST Sunday for PZZ350- 356. Gale Warning from 10 AM Friday to 7 AM PST Sunday for PZZ370- 376. && $$

671 FXUS66 KEKA 010902 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 102 AM PST Thu Jan 1 2026 .SYNOPSIS...Light to moderate rain will continue through the day today, followed by a frontal system with moderate to heavy rain, high mountain snow, and gusty winds on Friday into Friday night. Chances for moderate to perhaps locally major coastal flooding increase Friday through Saturday. Bouts of rain and gusty winds are forecast to continue into the weekend and likely early next week. && .DISCUSSION...The first in a series of storm systems is now moving through northwest California producing light to moderate rainfall throughout the region. Up to 0.75" has been recorded in parts of Mendocino and Lake counties as of this writing with much less rain off to the north in northern Humboldt and Del Norte. Looking at the model guidance, this rain is on the wetter side of the model envelope through 06Z. Additional rainfall is expected through the day on Thursday as the area of low pressure moves northeast across California. This rain will help to prime the environment for what is to come Friday and into the weekend. A more potent front will approach the region on Friday, first bringing increasing southerly winds across the entire region. Ridgetop winds could reach advisory levels by late Friday morning across Humboldt and Del Norte counties, expanding inland through the day. The front will then rapidly move through the region during the evening or overnight hours Friday night with a narrow band of potentially very strong winds which could mix down to the coastal plain. Wind advisories have been issued for all coastal areas and coastal ridge tops. Wind advisories may also be needed into Lake County but confidence is not yet high enough to expand into that area at this time. There may be a quick hit of stronger winds to warning levels on the ridgetops near Cape Mendocino and a high wind watch is in effect for that area. Behind this front a secondary low will approach the northwest California coast within a more unstable, mixed atmosphere. It is highly likely that this low will bring another round of strong southerlies on Saturday, especially in Humboldt and Del Norte counties, and the winds could mix better down to the coastal plain and again bring strong winds to the ridgetops. In addition to the wind from these two systems, heavy rain is also expected. Guidance is now in very good agreement on a band of rain with heavy rain rates rapidly moving through the region in advance of the front. Total rainfall is not expected to be exceptionally heavy, around 1-3 inches across the region, but this rain should allow for many small streams to begin to rise. Quickly behind this front the rain will re-enhance as the secondary low approaches and an atmospheric river may aim toward Humboldt, Trinity, Mendocino, and Lake counties. Guidance continues to increase the rainfall potential and Saturday into Sunday. Overall rainfall during the Thursday through Monday time period could range from 3-6 inches across the region with locally higher amounts up to 8 inches. This heavy rain could easily result in small stream flooding and even main stem rivers reaching critical flood levels. Thus, a flood watch has been issued for all of Humboldt, Mendocino, and Lake counties. If these trends continue it will be highly likely that flood advisories and/or warnings will be needed this weekend into Monday. /RPA && .AVIATION...A shield of rain has spread over Northwest California with light to moderate rain rates at times. Rain will persist through much of Thursday. Southerly winds aloft will begin to increase on Thursday resulting in some wind shear at Ukiah, but otherwise mostly light winds are anticipated through the period. Mostly MVFR ceilings and visibilities are expected at the TAF sites however periods of IFR are likely in periods of moderate rain and where fog attempts to form in the interior valleys. /RPA && .MARINE...Southerly winds are now beginning to increase over the coastal waters as an area of low pressure south of the area moves north. This system will move inland on Thursday but another front will quickly approach the waters behind the departing system. Southerly winds will ramp up across the outer and southern inner water zones late Thursday night into Friday morning with gale force winds expected and a few storm force gusts possible as the front approaches Friday afternoon/evening. There is some uncertainty as to how much of this wind makes it within 10 nm of the coast north of Humboldt Bay, so this zone has not been included in the gale warning, but wind gusts to gale are certainly possible. Winds will decrease slightly early Saturday morning to possibly just below gale but then another low will approach, potentially stronger then the last, allowing winds to increase to above gale for most of the waters and potentially exceeding storm in the northern outer zone Saturday afternoon and evening. All of these strong southerly winds will allow seas to build and become very steep. Seas could exceed 20 feet by Saturday afternoon in the outer waters zone and some of these steep seas will propagate toward the coast. Winds will decrease overnight into Sunday morning as the low moves off to the north and moderate southerlies will then persist into Monday as stormy conditions continue. /RPA && .HYDROLOGY...A series of atmospheric rivers will bring an increased risk for urban and small stream flooding late this week, through the weekend and likely into next week. Mainstem rivers will also likely rise sharply and will need to be monitored for possible flood stage exceedance. Be on the lookout for watches, advisories, and warnings as this next heavy rain event unfolds. Stay alert and remember to never attempt to drive through water covered roads. Water may be moving much faster than you think. /RPA && .COASTAL FLOODING...A period of very high tides will continue through the 4th. The north spit tide gauge already recorded a 9.07 ft high tide Wednesday morning. The storm surge models continue to show over foot of surge, now verified at the north spit tide gauge as of 11 pm on the 31st, but higher amounts are possible with strong southerly winds expected to line up with the highest tides. High tides will likely reach 9.3 to 9.6 ft Thursday. A Coastal Flood Warning has been issued for Humboldt Bay. The storm surge model has been consistently modeling a high tide up to 10 ft at North Spit Friday and again Saturday. This scenario would bring 1 to 1.5 feet of saltwater onto normally dry ground around Humboldt Bay, and this is plausible if the strong winds, heavy rainfall and building high surf align. Outside of Humboldt Bay, the storm surge model is also showing over a foot of storm surge with at least advisory thresholds being met along the outer coast during high tide. Strong winds and large surf could cause waves to wash onto roads exposed to the surf including Highway 101 south of Crescent City, Pebble Beach in Crescent City, Moonstone Beach parking lot, Centerville Beach road and parking lot, low spots along Highway 1 on the Mendocino coast, and other near coast infrastructure. At this time surf isn`t expected to be exceptionally large, so elevated locations like the homes in Shelter Cove are less likely to be impacted but it isn`t out of the question as a possibility both Friday and Saturday at high tide if larger seas materialize. Because of all of these possibilities, a Coastal Flood Watch remains Thursday through Saturday for the entire coastline, and further warning issuance should be expected each day. Though the watch is in effect for the entire day, the flood threat is only 1-2 hours before and after the morning high tides. /RPA && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Coastal Flood Watch from 11 AM PST this morning through Saturday afternoon for CAZ101-103-104-109. Wind Advisory from 1 PM Friday to 10 PM PST Saturday for CAZ101>103-105-106-109-110-112. Coastal Flood Warning from 7 AM to 11 AM PST this morning for CAZ103. Flood Watch from Friday afternoon through Sunday evening for CAZ103>106-108>115. High Wind Watch from Friday morning through late Saturday night for CAZ104. NORTHWEST CALIFORNIA COASTAL WATERS... Coastal Flood Warning from 7 AM to 11 AM PST this morning for PZZ415. Small Craft Advisory from 4 PM this afternoon to 2 AM PST Saturday for PZZ450. Gale Watch from late Friday night through Saturday evening for PZZ450. Small Craft Advisory from 4 PM this afternoon to 6 AM PST Friday for PZZ455. Gale Warning from 6 AM Friday to 4 AM PST Saturday for PZZ455. Small Craft Advisory from 11 AM this morning to 2 AM PST Friday for PZZ470-475. Gale Warning from 2 AM Friday to 11 PM PST Saturday 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

705 FXUS66 KMTR 011246 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 446 AM PST Thu Jan 1 2026 ...New AVIATION, MARINE... .KEY MESSAGES... Updated at 1201 AM PST Thu Jan 1 2026 - High astronomical tides combined with storm surge will bring minor to moderate coastal flooding around high tide through Sunday - Daily rain likely through early next week - Strong southerly winds expected Friday night && .SHORT TERM... Issued at 1201 AM PST Thu Jan 1 2026 (Today and tonight) Light rain continues across the Bay Area as the new year begins. While the total rainfall over the last 24 hours has been less than 1", the troposphere has become totally saturated. The PW was measured at 1.38" on the 00Z sounding. That`s near the daily max, and in the top 0.3% of December soundings. The low level dry layer mentioned yesterday has been eliminated. In fact, the first dry layer is in the stratosphere. Despite the anonymously high moisture, rain rates were held in check by a lack of lift. We haven`t had a front move through yet to wring out the sponge. That will change this morning as an occluded front moves across the Bay Area and Central Coast. This will increase the rain intensity, and brings a slight to moderate chance of thunderstorms. High resolution models show the best chance over the Central Coast and South Bay around 4-7 AM. After the front moves through showers will become more scattered and the clouds will lift and lighten. There is a second round of showers possible in the afternoon as the instability rises with warmer surface temperatures under the new cold air mass. A NAM point sounding at Salinas valid at 11 AM shows some instability (41 J/kg surface CAPE), winds backing with height(16kt 0-1km shear), and good low level moisture (91% LowRH). One limiting factor is the high freezing level (7,500+ ft). Most of the instability is in the warmer air below this level. This will limit the amount of ice in the clouds necessary for static electricity build up, significantly hurting the chances for thunderstorms to form after the front passes. The other issues is drier air behind the front. Most likely we will get a break after the morning push of stronger rain, with only isolated to scattered showers expected for the rest of the day and into Friday. && .LONG TERM... Issued at 1201 AM PST Thu Jan 1 2026 (Friday through Wednesday) The mostly dry break now looks like it will continue through the majority of the day Friday before the main event of the week arrives Friday night. A strong cold front will quickly approach the coast, with southerly winds increasing to a strong breeze. These winds will pump a new round of tropical moisture, this time from the SW. With stronger winds and a lifting mechanism from FROPA, strong showers and thunderstorms are possible into Saturday morning. With the stronger forcing, these storms also have a marginal chance of hitting severe criteria. Even if storms don`t produce damaging winds, the synoptic flow will likely bring some wind impacts across the cwa. Gusts should reach 40-50 mph along the coast and in higher terrain. While not quite as strong as last week, some tree damage and power outages are expected. Southerly winds also produce storm surge thanks to the Ekman Transport. This surge will combine with the ongoing king tides to bring exceptionally high tides on Saturday morning, in particular. As the cold front passes, the 500 mb temperature will drop from around -16C to -23C. This will cause lapse rate to steepen, and could support deeper convection in the post frontal environment on Saturday. A reinforcing front is due on Sunday, bringing yet another round of heavier rain, but less damaging winds. While the rain intensity should start to lighten up next week, the pattern remains unsettled through the 8th or 9th. && .AVIATION... (12Z TAFS) Issued at 445 AM PST Thu Jan 1 2026 Light to moderate winds are expected through the TAF period. Expect mostly light to showers through the morning, with chances reducing int the late morning and early afternoon. Winds will stay southeasterly to southerly through the day for most sites. Light spotty showers return in evening and into the night for the more northern TAF sites before exiting into early Friday. CIGS will range from IFR-levels in some of the interior valleys to VFR heights in the more southern sites. Nearly widespread VFR returns into early Friday as the system exits. Vicinity of SFO...Showers continue to move through the area, causing slight reductions in visibilities with IFR/MVFR level CIGs. Expect mostly light to moderate easterly winds through the morning before winds become more southerly and breezy into the afternoon as CIGs scatter. Showers exit in the mid afternoon, but another batch of slight chances for scattered light rain arrives in the late evening but exit again into the late night. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...Moderate showers exit into the mid morning, with lingering light showers lasting into the afternoon. Expect mostly mid-level clouds through the TAF period. Winds stay light to moderate through the TAF period and range from southerly to southeasterly. Shower chances reduce and exit into the afternoon as cloud cover scatters. && .MARINE... (Today through Tuesday) Issued at 445 AM PST Thu Jan 1 2026 Breezy and showery conditions linger across the waters. Expect some reductions in winds into the night, but southerly winds rebuild into Friday and increase to gale force across most of the waters. These winds look to last through much of the weekend. Expect light to moderate rainfall to persist through the weekend, with a slight chance of thunderstorms early Thursday and again Friday into Saturday. Rain chances and breezy winds will continue into the beginning of the next work week. && .BEACHES... Issued at 859 AM PST Wed Dec 31 2025 Perigean spring tides (King Tides) will impact the region through Sunday. This is due to the combination of the full moon on 1/3, lunar perigee on 1/1, and perihelion on 1/3. In other words all three planetary bodies are lined up and close to each other. In addition to the high astronomical tide, the incoming low pressure system will bring strong southerly winds, generating some storm surge. The combination of these factors will bring minor to moderate coastal flooding to the low-lying areas near shorelines and tidal waterways during high tide through Sunday. At the San Francisco tidal gauge, high tide is expected to be 2.0 ft above normal at 8:41 AM Thursday, 2.2 ft above normal at 9:34 AM Friday, 2.2 ft above normal at 10:26 AM Saturday, and 1.8 ft above normal at 11:18 AM Sunday. These predictions include up to 1 foot of storm surge that will enhance the astronomical tide and flooding threat. High tide varies up to 90 minutes earlier or later along the Pacific Coast and through the San Francisco Bay, respectively. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Coastal Flood Advisory until 2 PM PST Sunday for CAZ006-505-506- 508-509-529-530. Wind Advisory from 1 PM Friday to 1 PM PST Saturday for CAZ006- 502>505-509-512-515>518-528>530. PZ...Small Craft Advisory from 3 PM Friday to 3 AM PST Saturday for SF Bay N of Bay Bridge. Small Craft Advisory until 9 PM PST this evening for Mry Bay. Small Craft Advisory from 9 AM Friday to 3 AM PST Saturday for Mry Bay. Small Craft Advisory until 3 PM PST this afternoon for Pt Arena to Pt Reyes 0-10 nm. Small Craft Advisory from 3 AM to 9 AM PST Friday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Gale Warning from 9 AM Friday to 3 AM PST Saturday for Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory from 9 AM this morning to 9 AM PST Friday for Pigeon Pt to Pt Pinos 0-10 nm. Small Craft Advisory until 3 AM PST Friday for Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm. Gale Warning from 3 AM Friday to 3 AM PST Saturday for Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory until 9 AM PST this morning for Pigeon Pt to Pt Pinos 10-60 NM. && $$ SHORT TERM...Flynn LONG TERM....Flynn AVIATION...Murdock MARINE...Murdock 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

536 FXUS66 KOTX 011219 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 419 AM PST Thu Jan 1 2026 .KEY MESSAGES... - Areas of freezing fog Thursday morning. - Active pattern begins late Thursday afternoon into Friday morning with a light lowland wintry mix. - Occasional rain and mountain snow Saturday through Wednesday. && .SYNOPSIS... A more active winter weather pattern returns heading into 2026 with potential for widespread light wintry mix from Thursday morning to Friday morning. Unsettled but mild conditions continue into the weekend and early next week. && .DISCUSSION... ...Wintry Mix for the region late Thursday morning into Friday... Wednesday night through Friday: High level clouds are increasing ahead of a weak system moving through. PWATs will increase from near normal currently to 190-220% of normal by tomorrow afternoon. The dry and cool air mass will slowly be augmented by increasing cloud cover from the south tomorrow morning and into the early afternoon. Precipitation type remains a challenge but the picture is starting to become a bit more clear in some spots. Expanding fog and low stratus in the mid Columbia Basin, western Palouse, and foothills of the blue mountains will trap in the cold near surface air before the onset of the precipitation, leading to light freezing rain. Temperatures in areas covered by fog or stratus have dropped to 21 to 25 degrees. These temperatures would likely stay below freezing tomorrow if the fog and stratus stick around through the late morning. Central and western Chelan County also have potential for wintry mix as a warm nose develops in the afternoon as top-down moistening occurs. Thus, winter weather advisories have been issued from 4 PM Thursday to 1 PM Friday. Ensemble guidance still favors light snow along the east slopes of the north Cascades and near the Canadian border. Downslope flow and relatively milder temperatures support higher confidence in mainly rain across far southeast Washington and the Lewiston area. Precipitation type and coverage becomes more unclear in the Spokane area, and southern portions of the northeast valleys. Confidence was too low to include the Spokane area in the winter weather advisory this evening. By late Friday morning, precipitation will be fairly limited to the Idaho Panhandle and near the Cascade crest. Temperatures will also warm into the mid 30s to 40s melting off any left over icy surfaces. This will allow for any remaining areas of lowland snow to change to rain. The Methow valley will be the exception where they can hang onto colder air but hi-res models show decreasing precipitation as southwesterly flow turns westerly bringing a pronounced rain shadow. Given a lack of strong forcing from this system, precipitation amounts are not expected to be overly impressive. Saturday through Wednesday: Unsettled conditions continue into the weekend as the deep trough off the CA coast moves northward and attempts to phase with a weak low in the Gulf of Alaska. Periods of light rain and mountain snow will continue through early-mid next week. Amounts look fairly unimpressive but the mountain passes could see minor travel impacts. Stevens Pass has a 55% chance of 12 inches or more from 4 PM Sunday to 4 PM Wednesday. For Lookout Pass, the chances are lower around 25%. Temperatures will stay above average in the 30s to 40s through mid next week. DB && .AVIATION... 12Z TAFs: Fog has expanded compared to previous nights under a strong low level inversion with IFR/MVFR conditions at KCOE, KSFF, KMWH, and KLWS. The arrival of high clouds ahead of an approaching weather system has made it more difficult to see its full extent and evolution via satellite though. Expect ceilings and visibilities to gradually increase through the morning. Light precipitation arrives from the south late Thursday morning/early afternoon. With surface temperatures around freezing, snow transitioning to freezing rain is expected for for KEAT- KMWH- KGEG. Precipitation at KEAT and KMWH will be very light. Precipitation is expected to begin as snow or a rain/snow mix at KSFF and KPUW before transitioning to rain. As precipitation arrives ceilings will drop to MVFR as the atmosphere saturates from the top-down, with probabilities for IFR conditions increasing above 40 percent after 06Z for all TAF sites except KPUW and KLWS. .FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: There still remains some uncertainty in precipitation type and timing of the transition from snow to freezing rain for KEAT- KMWH-KGEG. Dry air aloft ahead of the onset of precipitation will erode some of the warm nose currently present as precipitation works to saturate the atmosphere after 20Z. Due to this, there is higher confidence for light snow at the onset of precipitation for these locations. Models do eventually show the warm-nose aloft redeveloping Thursday evening, with some differences in how quickly this occurs. ----------------------- 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 34 31 37 34 42 37 / 30 80 70 30 70 70 Coeur d`Alene 38 32 39 35 42 37 / 20 80 90 40 70 80 Pullman 38 34 43 37 46 38 / 40 90 90 20 60 60 Lewiston 40 37 47 38 49 40 / 30 80 70 0 20 30 Colville 36 30 36 32 40 35 / 20 70 60 60 90 90 Sandpoint 36 31 37 35 40 37 / 20 80 90 70 90 90 Kellogg 41 33 40 39 43 38 / 20 80 100 40 70 80 Moses Lake 33 29 37 32 41 34 / 30 50 20 30 60 50 Wenatchee 30 29 34 34 39 32 / 30 40 30 40 70 60 Omak 33 29 34 33 38 35 / 20 40 20 40 80 60 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...Air Stagnation Advisory until noon PST today for Central Chelan County-Lower Garfield and Asotin Counties- Northeast Mountains-Okanogan Highlands-Okanogan Valley- Spokane Area-Wenatchee Area-Western Chelan County-Western Okanogan County. Winter Weather Advisory from 2 PM this afternoon to 4 AM PST Friday for Lower Garfield and Asotin Counties-Moses Lake Area-Upper Columbia Basin-Washington Palouse. Winter Weather Advisory from 4 PM this afternoon to 1 PM PST Friday for Central Chelan County-Western Chelan County. ID...Air Stagnation Advisory until noon PST today for Central Panhandle Mountains-Lewis and Southern Nez Perce Counties- Lewiston Area. && $$

704 FXUS66 KPDT 011127 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 327 AM PST Thu Jan 1 2026 .DISCUSSION... Key Points... 1. Freezing Rain for portions of the area today through tonight. 2. Additional precipitation, into the weekend, mainly for the mountains...with lower elevation rain and mountain snow. A complex forecast for today into tonight. As the area of high pressure that had been over the west moves eastward, moisture from California will move northward into Oregon today. While there is not a lot of moisture, QPF (liquid equivalent) values across the lower elevations are mainly less than 0.10 inches, with higher amounts over 0.50 inches and some areas even over 1.00 inch in the mountains through today and Friday in the mountains. Where the problem arises, especially across lower elevations, is that temperatures will remain steady or slowly rise today and then will finally rise more Friday and Saturday. With temperatures in the 20s in many areas, as the precipitation moves in, freezing rain looks to be the result. The other issue that remains, is guidance still disagrees on exactly how much QPF there will be with some guidance suggesting not very much and others suggesting more, but of course with freezing rain even a few hundredths can be enough to cause impacts. Winter Weather advisories are in effect and while it will ultimately end up being dependent on temperatures and QPF, a few hundredths of an inch to a tenth of an inch of freezing rain is possible across the advisory area. Beyond tonight/early Friday, the precipitation should end everywhere but the mountains during the morning on Friday and temperatures will rebound nicely. Then, an area of low pressure is expected to move northward up the coast into Saturday and precipitation chances will return Friday night into early Saturday, with the highest chances in the mountains. There will then be another shot Saturday night into Sunday as a trough moves onshore. FInally, by later Monday, it looks like drier conditions should result. Snow levels will initially be quite high, everywhere but the Washington Cascades. Across the Washington Cascades today they will be below 2000 feet but 3500 to 4500 feet in the Blue Mountains early and over 7500 feet in the Oregon Cascades. By afternoon, snow levels will be 6500-7500 feet everywhere, so any precipitation in the mountains will be rain except at the crests, though even in the Washington Cascades there could be some freezing rain accumulation before the transition to rain. By Sunday, snow levels will fall to around 400-4500 feet in the Washington Cascades and 5000-5500 feet elsewhere. During this time there could be 2 to 4 inches of snow at pass level in the Washington Cascades, less in the Blue Mountains and Oregon Cascades, though the could be higher amounts at the higher elevations. && .AVIATION... 12Z TAFS...Conditions range from VFR to LIFR currently. Expect all sites to deteriorate during the day and into the evening as FZRA impacts all TAF sites. Most sites are expected to be IFR/LIFR. Winds are expected to be light. && .PRELIMINARY POINT TEMPS/POPS... PDT 34 29 47 34 / 70 80 40 10 ALW 34 31 45 37 / 60 90 70 10 PSC 33 28 43 32 / 50 70 30 20 YKM 35 29 42 32 / 40 60 20 30 HRI 33 28 43 34 / 60 80 30 20 ELN 33 28 39 32 / 40 60 40 40 RDM 43 34 53 35 / 70 60 0 10 LGD 41 35 46 38 / 80 90 70 10 GCD 43 38 51 37 / 90 90 40 10 DLS 36 33 45 37 / 70 90 50 40 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Winter Weather Advisory until 1 AM PST Friday for ORZ041-510. Air Stagnation Advisory until noon PST today for ORZ044-507-508- 510-511. Winter Weather Advisory from 7 AM this morning to 1 AM PST Friday for ORZ044-507-508. Winter Weather Advisory until 1 PM PST this afternoon for ORZ511. WA...Winter Weather Advisory until 1 AM PST Friday for WAZ024. Air Stagnation Advisory until noon PST today for WAZ026>029. Winter Weather Advisory from 10 AM this morning to 4 AM PST Friday for WAZ026>029. Freezing Fog Advisory until noon PST today for WAZ028. Winter Weather Advisory until 4 AM PST Friday for WAZ521>523. && $$ SHORT TERM...77 LONG TERM....77 AVIATION...77

068 FXUS65 KREV 010857 AFDREV Area Forecast Discussion National Weather Service Reno NV 1257 AM PST Thu Jan 1 2026 .KEY MESSAGES... * High elevation snow (above 8500`) and rain showers linger along the Sierra today before pushing eastward into W NV. * Break in active weather Friday before a second, stronger system moves into the area late Friday night, continuing through at least Sunday. * Additional storms could keep valley rain and mountain snow chances going through early to mid next week. && .DISCUSSION... As of about midnight, light showers are pushing northward across W NV with light showers in the Sierra from the Tahoe Basin and northward. Mono county is a bit shadowed out this morning but as the low off the coast of SoCal tracks inland, the potential for spillover heightens. It`s quite cold out there, though we have significantly warmed up to 32 and above across some valley locations. Thus, the threat for freezing rain has decreased. However, spots may still be slick overnight and into this morning so exhibit caution when driving. Showers will hang on to the Sierra through about sunset today, with snow levels dropping below 8000` by or around noon. Expect lingering rain showers for the Sierra Front and W NV today, with any and all precip out of the area by midnight. We will see a break in precip through much of the day Friday before a second, colder storm moves onshore from the Pacific. Snow is expected to start in the Sierra of NE CA late Friday night (~1am Saturday), reaching the Tahoe Basin and parts of Mono county by around 5am Saturday. This system will continue through much of Sunday as well. For more details on amounts, rates, and snow levels, please see the avalanche discussion below. Sierra Front communities will likely see rain much of Saturday, though snow for foothill communities, like Virginia City, isn`t out of the question. Despite the lower snow levels, there remains a threat for flooding for much of NE CA with the CNRFC forecasting the Susan River to hit minor flood stage by Saturday. As such, we have issued a Flood Watch for the area from 11am Saturday through 4pm Monday. Please see the product for more details. Saturday looks to be the windiest day of the week with widespread gusts up to 40 mph. Some wind prone may see gusts up to 45-50 mph while ridge winds will gust in the usual 80-100 mph range. Active weather will continue through at least early next week with a potential third system on the heels of this second one, bringing impacts as early as Monday. -Giralte && .AVIATION... VFR conditions expected for Sierra Front terminals, though brief periods of MVFR will be possible due to -SHRA. Sierra terminals may drop to IFR/LIFR today due to -RA/-SN and low ceilings. Conditions are expected to improve after 00Z with most of the precip out of the area by then. From then onward, expect VFR conditions through much of the day Friday. Winds will be generally light but Sierra terminals may see isolated periods of LLWS. Additionally, all terminals can expect mountain obscurations due to precip and low ceilings. -Giralte && .AVALANCHE... Two storm systems will impact all avalanche center terrain through at least Sunday. * First storm through this afternoon: Snow levels will remain high this morning (over 9 kft) before dropping to 8 kft by noon and then to 7 kft as the precip wraps up. SLRs will be 6-8:1, bringing slushy accums of up to 6" for Mono county near Mammoth and a couple inches at most for the Tahoe Basin. Snowfall rates will remain under 1"/hr with SWE of 1.5-1.75" along the crests (0.5-1.5" elsewhere) and westerly ridge winds up to 50 mph. * Second storm early Saturday through Sunday: Snow levels start around 7-7.5 kft at the storm`s onset before dropping slowly below 7 kft through Saturday and much of Sunday. Up to 3` possible along the crests with a foot near lake level and along US-395. Heaviest snowfall rates will be Saturday afternoon (up to 1"/hr) and again Sunday afternoon (rates 1"/hr+). SLRs near 8-10:1 with SWE up to 3" along the crest near the Tahoe Basin (up to 2.5" Mono county). Ridge winds will be stronger with gusts up to 100 mph. -Giralte && .REV Watches/Warnings/Advisories... NV...Winter Weather Advisory until noon PST Thursday NVZ002. Winter Storm Watch from Friday afternoon through Sunday morning NVZ002. CA...Winter Weather Advisory until noon PST Thursday CAZ071>073. Flood Watch from Saturday morning through Monday afternoon CAZ071. Winter Storm Watch from Friday afternoon through Sunday morning CAZ072-073. && $$

413 FXUS66 KSTO 312109 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 109 PM PST Wed Dec 31 2025 For additional details on weather and expected impacts over the next 7 days, please visit weather.gov/sto/briefing. .KEY MESSAGES... - Moderate travel impacts Friday through Monday, from heavy mountain snow and wind. Minor travel impacts for the foothills and valley. - Unsettled weather pattern continues into next week. && .DISCUSSION... ...Today and New Years Day... The first wave of energy from an upper level system off the coast of CA is continuing to move north and east through the state this afternoon and evening. This brings precipitation chances to the region, with snow levels over 8500 feet. Precipitation will become scattered to widespread across the area, with forecasted amounts between 1 to 3 inches from today through tomorrow night. Highest amounts at higher elevations. Rain becomes isolated in coverage in the Valley, with continued widespread chances up in the mountains late Thursday and into Friday morning. Snow levels will start to decrease as we move into Thursday, with levels reaching 6500-7000 feet by Thursday afternoon and evening as colder air is wrapped around the system into CA. Temperatures will be in the 50s on Thursday within the Valley, and 40s at higher elevations. ...Friday through Monday... The main synoptic level system over the Pacific moves toward the coast on Friday bringing sufficient moisture and instability toward the region. Precipitation overspreads the region Friday through the weekend and continuing into the early part of next week. Moderate to possible heavy rainfall at times, with rain rates up to a half in per hour possible. Forecasted rainfall will range between 1 to 3 inches, with the highest in the foothills. Locally higher amounts can`t be ruled out if any area experiences training thunderstorm chances. These chances are low at this time. Thunderstorm chances increase Saturday and into Sunday morning as an instability axis sets up along the coast and into the Valley. MUCAPE reaches 500 J/kg, with sufficient moisture transport, and low level shear. A stray stronger storm can`t be ruled out Saturday afternoon/evening and again Sunday morning. This is where the potential exists for rainfall rates reaching a half in per hour around thunderstorms. Rain will continue into Sunday afternoon/evening and again early next week. As the system moves onshore, colder air will push down from the north helping drop snow levels. Friday into Saturday snow levels, remain around 6500-7500 feet and drop off toward 5000-6000 feet late Saturday and into Sunday. Latest guidance wants to push out the colder air moving down from the north toward Sunday and into Monday, which would cut into some of the snow totals. Accumulations are uncertain at this time but may range from 2 to 4 feet above 5000 feet. Locally higher amounts are possible at higher elevations. Winds could gust as high as 45 mph and cause dangerous travel conditions when combined with the heavy snow. If you plan to travel this week and into the weekend, make sure you have alternate routes, backup plans, and carry a safety kit with you at all times. Long range guidance looks to continue the feed of moisture and instability into the region mid next week bringing further precipitation, mountain snow, and breezy conditions. && .AVIATION... Visibilities improved today, with a few MVFR conditions lasting through this afternoon. Ceilings have increased, with a few locations near MVFR otherwise VFR. Rain will move in from the south this afternoon and evening becoming widespread later this evening and overnight. Ceilings drop to IFR/MVFR, with visibility reductions. Rain continues overnight and throughout tomorrow, with IFR/MVFR conditions. && .STO WATCHES/WARNINGS/ADVISORIES... Winter Storm Watch from Friday afternoon through Sunday morning for West Slope Northern Sierra Nevada-Western Plumas County/Lassen Park. && $$

870 FXUS65 KMSO 011116 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 416 AM MST Thu Jan 1 2026 .DISCUSSION... KEY MESSAGES: - Current: High pressure is reinforcing valley inversions, air stagnation today. - Still expecting a messy system tonight into Friday, though precipitation type may end up being snow initially, then mixed precipitation. - Mixed precipitation possible this weekend through Monday with black ice threat continuing. - Lower snow levels, breezy and unsettled Tuesday into next week. Valley cold pools were strengthened yesterday thanks to milder air streaming overhead combined with an upper level ridge overhead. Some locations struggled to get out of the 20s, especially with low clouds across northwest Montana valleys. The higher valleys were able to warm into the 40s and even a few 50s in spots like in Anaconda! Temperatures will generally be similar today as they were yesterday. Increasing cloud cover from a weather system over the southwestern U.S. will limit some heating. The current mesonet depicts mild temperatures, in the 30s, in the mid-slopes this morning. Even with the milder temperatures, the dewpoints are very low, single digits, signifying a decent dry layer in the lower atmosphere. This will do a few things...any moisture that moves into the region tonight, may be more a precipitation type of snow rather than mixed precipitation. Had to adjust the snow levels and temperatures down in many locations over the next 48 hours thanks to the cold pools in place and the incoming weather. The shortwave moving over Lemhi County this evening may overproduce snowfall, enough that a winter weather advisory may need to be warranted. Will let the day crew decide about this. Then tonight, moist westerly upslope flow will bring precipitation to north-central Idaho and along the Idaho/Montana border. Some of this precipitation may make it to the larger valleys (i.e. Flathead to Missoula) as light snow or mixed precipitation. One area that may hang on to snow with more accumulation than forecast, could be the US-12 corridor from Lowell east to Powell and Lolo Pass. Powell is sitting in the teens this morning, so there is a decent amount of cold air built up in that area. A bit of a lull in the precipitation is expected Friday night. Patchy fog or freezing fog is possible. A series of shortwaves, embedded in southwest flow, will move through the region over the weekend. These will bring snow or mixed precipitation showers. Night-time black ice will be a concern. Also an uptick with southerly breezes may allow for locations to moderate/weakening cold pools. Mountain passes could be snow-covered at times. Snow levels are anticipated to lower by Tuesday onwards as a deeper trough will move into the Pacific Northwest. This will allow for mountain and valley snowfall. The snowfall ranges for the Tuesday-Wednesday time period show 5 to 12 inches for the Idaho/Montana border mountains, and 3 to 8 inches in the Glacier Region. There are some timing differences with the speed of the trough. Looking further out towards the end of next week...there is a bit of uncertainty whether the colder trough scenario pattern lingers or will another stable, high pressure ridge build? The ensemble clusters are evenly split down the middle. About 47% lean towards keeping the trough over us, which would mean more snow chances. Among those that support the trough scenario, 87% of the GFS ensemble members agree, while only 28% of the European (ECMWF) and 35% of the Canadian members do. You may be wondering what the AI models are depicting? Both the AIFS (ECMWF- version) ensemble and the GFS AI/EAGLE ensemble seem to be siding more with the idea of a troughing over us Thursday/Friday. We shall see how it evolves! && .AVIATION...High pressure continues to enforce strong valley inversions and light winds. KGPI remains the primary site impacted by persistent LIFR stratus and fog. Incoming higher clouds may help prevent fog for other sites. A wave will bring a period of snow to Lemhi County/KSMN and north-central Idaho later this evening, generally after 2300Z/1500PST, and will bring lower ceilings and visibility through tonight. Mixed precipitation or snow showers are expected in the mountains across the region tonight into Friday. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...ID...Air Stagnation Advisory until noon PST today for Lower Hells Canyon/Salmon River Region...Northern Clearwater Mountains...Orofino/Grangeville Region...Southern Clearwater Mountains. && $$

820 FXUS65 KBOI 011030 AFDBOI Area Forecast Discussion National Weather Service Boise ID 330 AM MST Thu Jan 1 2026 .SHORT TERM...Today through Saturday night...Latest models are quite a bit wetter than before, with moisture originating all the way from the Pacific tropics. Pcpn also is delayed a few hours but there will be more of it. Winds looks too weak to scour the cold air out of the lower valleys in eastern OR and that means freezing rain in those valleys, with rain in the warmer valleys. We issued a Winter Weather Advisory for snow and freezing rain in the colder valleys of Harney and Malheur Counties today and tonight, and in Baker County only for tonight. The afternoon hours will become too warm for freezing rain, but for simplicity we issued only a single advisory. The main pcpn will come this afternoon through Friday morning as a warm front moves north, continuing in Idaho north of the Snake Basin later Friday. Drying Friday night and Saturday before the next Pacific trough spreads more light pcpn, mainly as rain, into our CWA Saturday night. .LONG TERM...Sunday through Thursday...Steady cooling through the period and continued wet as a Pacific upper trough moves slowly inland. That means gradually lowering snow levels, almost to the lower valley floors by Thursday. && .AVIATION...Precipitation spreading from S-N through the day. Mountains becoming obscured with widespread MVFR conditions in lowering ceilings and reduced visibility, with areas of IFR/LIFR conditions after 18Z. A 30% chance of freezing rain in the valleys of southeastern Oregon 15-21Z, and again tonight after 02Z. Snow Level rising to 4-8 kft MSL (highest south) by 00z. Surface winds: Variable less than 10kt. Winds aloft at 10kft MSL: SW 10-20 kt. KBOI...Rain spreading south to north after 19Z with ceilings becoming MVFR, then IFR after 04Z. Surface winds: Southeast less than 8 kt. Weekend Outlook...Conditions improving to VFR Friday through Saturday, expect fog possible early Saturday morning. Rain spreading west to east again Saturday night and Sunday. && .AIR STAGNATION...Air Stagnation Advisory will continue through at least Saturday morning with winds too light to scour the inversion. However, rain later today and tonight will act to cleanse the air of pollutants. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...Winter Weather Advisory from 8 AM MST /7 AM PST/ this morning to 5 AM MST /4 AM PST/ Friday ORZ061-063. Winter Weather Advisory from 10 PM this evening to 4 AM PST Friday ORZ062. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise SHORT TERM...LC LONG TERM....LC AVIATION.....LC AIR STAGNATION...LC

149 FXUS65 KLKN 010929 AFDLKN Area Forecast Discussion National Weather Service Elko NV 129 AM PST Thu Jan 1 2026 .KEY MESSAGES... Updated at 115 AM PST Thu Jan 1 2026 * Potential for freezing rain tonight into Thursday morning * Winds will be relatively light today, with afternoon gusts trending higher into the weekend * Valley rain and mountain snow this evening through Thursday * Dry on Friday, with more showers this weekend into next week && .UPDATE... Issued at 115 AM PST Thu Jan 1 2026 Rain showers reached Tonopah, Ely and Winnemucca earlier in the evening, and just began in Elko at around 1 AM. Expect showers to continue at times across Northern and Central Nevada the rest of tonight and through the afternoon and evening hours Thursday. There is a potential for either freezing rain or light snowfall in some valley and summit locations the rest of tonight into Thursday so travelers are urged to use caution. Forecast remains on track with no updates needed at this time. && .DISCUSSION... (This evening through next Tuesday) WEATHER PATTERN OVERVIEW: An active weather pattern is in store for the Silver State into next week as a series of shortwaves and weather systems impact the region. A very meridional pattern pushes the ridge overhead on Wednesday to the east this evening. Immediately replacing the ridge is a shortwave riding southwest flow in a larger ULT. Sub-tropical moisture advecting from the south will interact with the wave to increase precipitation chances across central and northern NV beginning later this evening. Precipitation is forecast to be mainly valley rain and mountain snow through Thursday, though there is a wrinkle of freezing rain in the forecast. Portions of eastern and southeastern Elko County, as well as isolated spots in Humboldt County are sporting sounding profiles that contain warm noses near the surface late this evening into the new year. Based on the early morning timing and lack of winter weather impacts so far this season a Winter Weather Advisory has been issued for freezing rain in southern and eastern Elko County tonight. Hazardous driving conditions may occur along I-80, US-93 and local roads that will impact the Thursday morning commute. Forcing and well above average moisture availability (PW`s of 0.55-0.65 inches) will make this New Years system a wet one for the region. Snow accumulations of 8-12 inches will be confined to elevations above 6000 feet. Central NV rainfall amounts of 0.10-0.25 are possible through Thursday with northern NV seeing potentially more as amounts will range 0.2-0.5 inches. Friday will be a brief respite from active weather though winds will begin to increase Friday evening. A tightening pressure gradient overhead will increase southwesterly wind speeds Saturday as a larger trough begins to encroach on the Great Basin. Precipitation chances increase Saturday through Monday though moisture availability isn`t quite as robust with this trough thanks to some Sierra scouring. QPF probs and storm totals bear this out though latest model runs do show an increase in snow and areal coverage early next week. The parent trough finally pushes through the area Tuesday with brisk zonal flow pushing into the area by later next week. FORECAST CONFIDENCE & DEVIATIONS: High confidence remains in light winds, valley rain, and mountain snow through Thursday. Ice was added to the Wx grids as up to 40% probabilities of freezing rain are possible tonight and Thursday morning for portions of northern NV, specifically Humboldt, and eastern and southern Elko Counties. && .AVIATION... A mix of precipitation is expected across Central and Northern Nevada the rest of tonight and through this Thursday evening. Most precipitation at TAF sites is expected to be rain, however some locations may see periods of mixed rain and or snow. Freezing rain is also a concern tonight into Thursday, with highest chances at KENV. CIGs and VIZ will likely be lowered to MVFR levels in precipitation, and possibly IFR in any moderate or heavy showers. Later today and overnight shower activity will taper off, though fog may be a concern in some areas tonight into Friday morning. && .LKN Watches/Warnings/Advisories... Winter Weather Advisory until 8 AM PST this morning NVZ033-038-039. && $$ DISCUSSION...96 AVIATION...96