245 FXUS66 KSEW 221632 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 832 AM PST Sat Feb 22 2025 .SYNOPSIS...An atmospheric river will set up over Western Washington, maintaining a wet weekend with heavy rain, gusty winds, and high snow levels across the region. After a brief break early Monday, a front will bring more rain gusty winds through Tuesday. High pressure rebuilds over the region around the middle of the week with mild and mostly dry conditions, though some shower chances linger near the coast. && .SHORT TERM /TODAY THROUGH MONDAY/...The current forecast remains on track with no planned updates this morning. 33 Previous discussion...The deep plume of moisture in an atmospheric river then sets up over the region into Saturday. This will bring heavy rain, high snow levels, and gusty winds at times. Temperatures will be rather mild in the strong southerly flow. A series of embedded impulses will serve as the focus for the heaviest rainfall. Not much change in the QPF from previous thinking with general ranges of 4 to 7 inches over the Olympics and 4 to 5 inches over the Cascades from Saturday through Sunday night. With the addition of high snow levels and existing snow, additional water will further add to the runoff into rivers. The HYDROLOGY section has more details about potential for flooding through the weekend and into early next week. In addition, gusty southerly winds will develop at times over the weekend. An initial round of gusty winds is expected on Saturday, peaking during the afternoon and evening. NBM probabilities highlight the coast and areas from Whatcom County and the San Juan islands south through around northern Whidbey Island and Admiralty Inlet for the greatest chance of gusts exceeding 45 mph (generally 50-80%). This may lead to localized power outages and tree damage and wind advisories have been issued. Breezy winds will still be expected elsewhere across the region, but with a lower likelihood of impacts. Another round of breezy winds are then expected on Sunday, especially for the same favored locations as Saturday. After a brief break Monday morning, the next weather system quickly approaches later in the day. A deepening low, expected to be around 980 mb, will approach the area before likely turning northeast toward Vancouver Island. Still a fair amount of spread in the ensemble guidance with the precise track of this low. However, confidence remains high that the associated front will slow and stall and maintain widespread rain during the afternoon and evening another weather system approaches the area Monday afternoon. Parent low with this feature, a 980-985 mb low, will reach 130W due west of the area then make a northeasterly turn. This will in turn increase the negative tilt of the front slowing its northerly progress down with the front stalling over Western Washington in the afternoon. With the low that far west best chances for gusty/possible advisory speed winds, along the coast and the Northwest Interior late in the day. Highs again in the lower to mid 50s with rain all afternoon. .LONG TERM /TUESDAY THROUGH FRIDAY/...Behind the front on Tuesday, expect abundant post-frontal showers (and perhaps evening a flash or two of lightning) and lowering snow levels that could bring some light accumulating snow back to the Cascade passes. Ensemble guidance then favors high pressure building over the region Wednesday and Thursday. This would bring increasingly dry conditions along with very mild temperatures with afternoon highs reaching the around 60. However there`s at least some chance of continued showers into Thursday, especially near the coast but also inland. Temperatures remain mild but showers may return late in the week. Cullen && .AVIATION...A mixed bag of ceilings and visibility this morning with scattered showers across western Washington. IFR conditions continue along the coast, with mostly MVFR to VFR conditions through the interior. Expect ceilings to bounce around a bit this morning before becoming largely MVFR to IFR this afternoon, perhaps as low as LIFR along the coast, as the next round of significant rainfall arrives this evening. Conditions will persist overnight into Sunday morning. South to southeast winds will increase this morning to around 10-15 kt, with gusts up to 25-30 kt possible. Strongest gusts will be along the coast and through the northern interior (BLI). As winds increase, some low level wind shear may be of concern. Wind speeds will begin to decrease late tonight between after 2Z-4Z Sunday. Surface flow will remain southerly with winds of 3-6 kt. KSEA...Ceilings have been bouncing between VFR and MVFR as rain showers move in and out of the terminal. A second round of precipitation is expected to begin moving in this afternoon and expected to persist through the remainder of the TAF period. Expect MVFR to potentially IFR ceilings and lowered visibilities with the rain. Winds will generally be south/southwesterly. Winds are expected to increase after 22Z, with wind speeds of 12-16 kt and gusts of 20-25 kt possible. Wind speeds will begin to gradually decrease after 3Z- 6Z Sunday below 10 kt. 29/62 && .MARINE...A series of frontal systems will keep conditions active across the area waters through the weekend. A Gale Warning is currently in effect across the coastal waters, and a Small Craft Advisory is currently in effect for the Western and Eastern Strait the northern inland waters, and Grays Harbor. Winds should begin to subside Saturday night into early Sunday morning. A stronger system is expected to move across the coastal waters on Monday. There is still uncertainty regarding its strength and trajectory; however winds in the coastal waters may approach high-end gale warning criteria. Winds will begin to gradually subside on Tuesday night below 21 kt. High pressure will build over the waters on Wednesday bringing calmer conditions. Combined seas are expected to increase to 14-17 ft today and then gradually subside to 10-12 ft by Sunday morning. Waves will build above 20 ft on Monday night through early Tuesday morning. Waves will gradually begin to decrease throughout the day on Tuesday afternoon and remain below 10 ft by the middle of the week. 29 && .HYDROLOGY...The potential for river flooding, urban flooding, and landslides remains elevated this weekend. Snow levels will increase to above 7000 feet Saturday night into Sunday with heavy rain falling over the Cascades and Olympics. This combination will lead to sharp rises on many area rivers and the potential for a few to reach flood stage. A flood warning is already in effect for the Skokomish River at Potlach, with the river expected to reach moderate flooding this weekend. The flood watch remains in effect for much of the remainder of Western Washington, with the primary exception being Jefferson, Clallam, and Whatcom counties. The flood potential outlook (ESF) covers these counties where river flooding is less likely but still a non-zero chance. Finally, urban flooding is possible late Saturday through early Sunday across much of the region with the heaviest rainfall over the area. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...Wind Advisory until 7 PM PST this evening for Admiralty Inlet Area-Central Coast-North Coast-San Juan County-Western Skagit County-Western Whatcom County. Flood Watch from Sunday morning through late Tuesday night for Bellevue and Vicinity-Central Coast-East Puget Sound Lowlands-Everett and Vicinity-Lower Chehalis Valley Area- Olympics-Seattle and Vicinity-Southwest Interior-Tacoma Area-West Slopes North Cascades and Passes-West Slopes North Central Cascades and Passes-West Slopes South Central Cascades and Passes-Western Skagit County. PZ...Small Craft Advisory until 10 AM PST Sunday for Grays Harbor Bar- West Entrance U.S. Waters Strait Of Juan De Fuca. Small Craft Advisory until 7 PM PST this evening for Admiralty Inlet-East Entrance U.S. Waters Strait Of Juan De Fuca- Northern Inland Waters Including The San Juan Islands. Gale Warning until 7 PM PST this evening for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From Cape Flattery To James Island Out 10 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From James Island To Point Grenville Out 10 Nm- Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm. Small Craft Advisory from 7 PM this evening to 10 AM PST Sunday for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From Cape Flattery To James Island Out 10 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm. && $$

454 FXUS66 KPQR 221318 AAA AFDPQR Area Forecast Discussion...UPDATED National Weather Service Portland OR 451 AM PST Sat Feb 22 2025 .SYNOPSIS...Active weather through early next week as a moderate to strong atmospheric river and multiple frontal systems bring moderate to heavy rain and periods of strong winds to the area today through Monday. Greatest flood concerns for coastal rivers, with ponding of water as the main concern inland. Quieter conditions expected mid to late next week. && .SHORT TERM...Now through Monday Night...Radar imagery shows light rain associated with a weak warm front spreading across northwest Oregon and southwest Washington as of early Saturday morning as an atmospheric river begins to take aim on the Pacific Northwest. Rainfall amounts have been limited to less than a tenth of an inch in most locations overnight, but a few locations on the central Oregon Coast have reported 6 hour rainfall totals exceeding a quarter inch. Shower activity will remain light and spotty through much of the day as the warm front departs the area, but precipitation will increase in intensity later in the afternoon with the arrival of a trailing cold front as precipitable water values surge above one inch. Expect rainfall totals from this evening through Sunday morning to range from 1.50-2.00 inches for coastal areas and the higher terrain, with amounts approaching 1 inch in the interior lowlands. The period of heaviest rainfall looks to occur during the day on Sunday as PWAT values remain above 1 inch and IVT values peak in the 500-750 kg/m/s range along the Oregon Coast. Rainfall Sunday afternoon will also be aided by forcing from a shortwave trough embedded in southwest flow aloft, along with an associated surface frontal boundary. Model QPF during the day on Sunday depicts an additional 1-2 inches of rain for the coast and higher terrain, with another 0.75-1.00" for the interior valleys through Sunday evening. Sunday night will bring a relative lull in precipitation between systems as transient upper level ridging passes overhead. The last in the series of frontal systems will then bring one more shot of moderate to heavy rain to the area on Monday, this time focused mainly along coastal areas. Those coastal areas could see another 1-2 inches of rain through Monday night, with an additional 0.50-0.75" looking more likely for area east of the Coast Range. The period of heavier precipitation will come to an end as an upper level trough crosses the region Monday night. Refer to the Hydrology section below for details regarding potential flood impacts from this event. Wind will be the other main forecast concern over the next few days as the series of seasonably strong frontal systems crosses the region. The first round of wind will come later this afternoon with the arrival of the cold front. Generally expect winds with this front to gust to 40-50 mph along the coast. It would not be out of the question to see a stray gust or two to 60 mph this afternoon on beaches and headlands, but do not expect these conditions to be widespread enough to warrant any wind headlines for the coast today. Gusty south winds will also spread inland to the Willamette Valley this afternoon and evening. Expect winds generally in the 25-35 mph range with a few gusts as high as 40 mph this afternoon and early evening. Sunday`s system looks to bring similar magnitude winds, with another round of 40-50 mph along the coast and 25-35 mph winds in the inland valleys. Monday`s system looks to bring perhaps the strongest winds of the event as models show relatively good agreement in a strong surface low bottoming out around 980 mb as it passes offshore during the day on Monday while tracking towards Vancouver Island. NBM probability for 60 mph winds increases to approximately 40 percent along the coast late Monday morning/afternoon. Do not quite have the confidence for a High Wind Watch on the coast at this time, but that may be a consideration in future forecast packages. Would expect the strongest winds to mostly be confined to beaches and headlands, with gusts more likely to be in the 40-50 mph range for inland coastal communities. Similarly, Monday`s system will present the best chance for advisory level winds in the inland valleys as NBM probs for 45 mph gusts increase to 15-30% from Portland to Eugene during the day on Monday. Will need to pay close attention to how models evolve with respect to the track of the surface low as a track closer to the coast will increase the potential for stronger winds across the area. Will also need to consider the impacts from saturated soils as that could contribute to the potential for downed weakened or dead trees over time. /CB .LONG TERM...Tuesday through Friday...Showers will be winding down across the area on Tuesday in the wake of the atmospheric river as high pressure begins to build in behind the departing trough. Could see some minor snow accumulations return tot e Cascade passes Monday night through early Tuesday as the passing trough drops snow levels down to around 4000 feet. Beyond Tuesday, WPC ensemble clusters strongly favor a ridgier pattern developing over the Pacific Northwest and western CONUS through much of next week, promoting a warmer and drier pattern across the region. This is reflected in the bulk of individual ensemble members which keep the area dry from Wednesday through Friday of next week. Likewise, the NBM mean depicts around a 75% chance for high temperatures to surpass 60 degrees in the Willamette Valley during the middle to latter part of next week. /CB && .AVIATION...Observations as of 11Z is showing light rain slowly moving eastward across the region. This will result in the widespread VFR between FL030 and FL050 to slowly lower towards a mixture of low-end VFR/high-end MVFR with bouncing cigs between FL025 and FL045. Look for these conditions to start manifesting around 15Z-18Z Saturday. Coastal locations will are expected to improve towards MVFR as precipitation spreads through 14Z-16Z Saturday. For the whole airspace, expect conditions to deteriorate towards IFR/LIFR starting around 20Z-22Z for coastal locations and towards predominately MVFR for inland locations starting around 00Z-03Z Sunday. Precipitation is expected to persist through the TAF period. Surface winds will generally be southerly for most terminals, strongest at the coast with gusts up to 40 kt and up to 30 kt for inland locations starting around 20Z Saturday. Also, strong upper level winds are also expected and is resulting in a LLWS threat via speed shear for the majority of the airspace starting around 20Z Saturday. PDX AND APPROACHES...VFR with FL030 to FL050 that will lower to a mixture of low-end VFR/high-end MVFR with bouncing cigs between FL025 and FL045 as precipitation spreads from west to east. Southerly gusts up to 30 kt starting around 20Z Saturday along with a LLWS threat via speed shear starting around the same time. /42 && .MARINE...A series of systems will lead to active weather across the waters through early next week. The first in a series of systems will bring about widespread southerly Gales with gusts up to 45 kt through tonight, along with high probability for isolated gusts up to 55 kt. The next system on Sunday will continue the southerly flow pattern, but is expected to be slightly weaker with SCA conditions with gusts up to 30 kt. The third and currently strongest system looks to maintain the southerly flow and bring Storm Force gusts up to 55 kt across all waters. In addition to the increasing winds, seas will behave in a similar manner. Current buoy observations are showing seas in the 13-15 ft range which is expected to persist through today. Seas will briefly subside on Sunday towards 10-12 feet, but this will be short lived as the aforementioned system on Monday/Tuesday will bring a very robust southerly swell, that when combined with the Storm Force winds will result in seas building towards 20-26 ft with peak seas likely around 26-28 ft Monday evening through early Tuesday morning. Given the active pattern there are multiple hazards that have been issued. A Hazardous Seas Warning will persist through very early this morning. A Gale Warning starting early this morning through Sunday evening. A Small Craft Advisory Sunday evening through Monday morning. Storm Watch starting Monday morning through Monday evening. /42 && .HYDROLOGY...A fairly long duration atmospheric river event will be enhanced by several systems crossing the region today through Monday, leading to multiple periods of moderate to heavy rain across the area this weekend through the early part of next week. In all, models have remained fairly consistent in depicting 72 hour rainfall amounts from this morning through Tuesday morning of 4-6 inches in along the coast and in the adjacent higher terrain, with 2-3 inches likely in the interior valleys. Amounts of 7+ inches are not out of the question in orographically favored parts of the Oregon Coast Range as well as the High Cascades. Rainfall looks to be fairly evenly distributed each day through Monday, with 1-2 inches of rain along the coast and in the mountains and up to one inch for the interior lowlands each period. This will certainly produce rises on area rivers. Expect to see the largest responses on some of the flashier rivers in the Coast Range, including the Grays, Wilson, and Siletz Rivers. Each of these locations show anywhere from a 20-40% chance of reaching minor flood stage late Sunday into early Monday, with the Wilson River at Tillamook notable showing a 20% chance to reach moderate flood stage in the most recent model run. Other coastal rivers show generally a 5-10 percent chance of reaching flood stage. Meanwhile, several slower responding rivers on the other side of the Coast Range are forecast to reach action stage Monday into Tuesday, but no inland rivers are currently forecast to reach flood stage. The primary impacts in lowlands will likely be related to ponding of water on roadways and poor drainage in low lying areas. Do not currently expect any widespread debris flow or flash flooding concerns as hourly rainfall rates look to max around around a quarter to perhaps a half inch, and therefore should remain well below thresholds on area burn scars through the duration of the event. Continue to monitor the forecast closely as relatively minor changes in forecast rainfall amounts could have significant implications on potential for potential river and areal flood concerns in the coming days. /CB && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Hazardous Seas Warning until 7 AM PST this morning for PZZ210- 251>253-271>273. Gale Warning from 7 AM this morning to 7 PM PST Sunday for PZZ210-251>253-272-273. Small Craft Advisory from 7 PM Sunday to 10 AM PST Monday for PZZ210-251>253-272-273. Storm Watch from Monday morning through late Monday night for PZZ210-251>253-271>273. Gale Warning from 7 AM this morning to 10 PM PST this evening for PZZ271. Small Craft Advisory from 10 PM this evening to 10 AM PST Monday for PZZ271. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland

765 FXUS66 KMFR 221749 AFDMFR Area Forecast Discussion National Weather Service Medford OR 949 AM PST Sat Feb 22 2025 .Updated AVIATION and MARINE Discussions... && .AVIATION...22/18Z TAFs...Widespread VFR prevails early this morning with a mid-level cloud deck moving in from the Cascades west. Patchy MVFR fog (visibility) has been in and out at Klamath Falls this morning, but should clear out by 19z. This afternoon and tonight, light rain and MVFR ceilings/vis will overspread the area from west to east as a frontal system offshore moves in. Gusty south winds will develop at the coast at North Bend, perhaps up to ~30kt. While t his could preclude low-level wind shear (LLWS), have decided to include in the TAF for the instances when the wind dies down at the surface at times. However, there is a higher probability of LLWS at RBG, MFR and LMT since surface winds in those locations are probably a bit lower. Have also bumped up the start time for LLWS for areas along the coast and west of the Cascades, beginning between 21z-00z this afternoon. -Spilde/BR-y && .MARINE...Updated 800 AM PST Saturday, February 22, 2025...An active weather pattern will cause very hazardous conditions this weekend into next week. South winds and steep seas will bring conditions hazardous to small craft this morning. Then, winds increase to gales this afternoon and persist into Sunday with very steep, hazardous seas, highest near and north of Cape Blanco. Since a coastal jet could form near Cape Blanco, the area of gales could expand south of the Cape. For this reason, we`ve included all zones in the gale warning. Another strong front will move through Monday with strong gales and possible storm force wind gusts with very high and very steep seas. Very steep seas persist into Tuesday, then things should calm down from Wednesday onward. The front on Monday looks stronger in the latest guidance, with solid gales and possible storm force gusts (>=55 kt), so we have added a storm watch. This front will build dangerous seas of 20-28 ft from Gold Beach northward, with seas peaking at 16-20 ft south of there. -Spilde && .PREV DISCUSSION... /Issued 405 AM PST Sat Feb 22 2025/ DISCUSSION...It is a quiet morning, with high clouds streaming aloft, and scattered areas of fog in valleys around the region. Just offshore, however, lurks the first of several systems that will pass through the region over the next several days. The leading edge of an atmospheric river(AR) will arrive at the southern Oregon and northern California coastline by mid day today. This plume of warm moist air will raise snow levels up to 7000 feet by this evening and bring widespread wetting rain to the region. Precipitation rates really pick up this evening into Sunday morning as model guidance is showing rain rates of about 1.5-2" over 6 hours around Curry County. Model values of integrated water vapor transport(IVT), a measure of moisture flow, is also on the stronger side, around 500 to 750 for about 24 hours. Ensemble situational awareness tools suggest these IVT values lie in the 98th percent for this time of year, which is notable and suggest a strong AR. The other thing that stands out is how much moisture is in the air. Precipitable water is anticipated to reach 1 inch by tonight. This would lie in the 99th percentile for this time of year based on sounding climatology for SPC and ensemble situation awareness tool. Our record values are right around 1.2 inches. Needless to say, this will be a very wet system for our area. Between Sunday into Monday, another upper level disturbance in this AR event will swing through region pushing the bulk of the precipitation farther north, although we`ll still see rain accumulate through Monday morning. The flooding risk is still expected to be minor/limited as this AR hits the region. Main stem rivers and streams will rise rapidly through Sunday, although none of the rivers are anticipated to reach action stage or minor flood. The one concern that we do have is snow melt east of the Cascades in south central Klamath and Lake Counties. That area got the brunt of snowfall from the event a few weeks ago. However, not much rain is anticipated to fall east of the Cascades. Plus, overnight lows will fall very close to freezing east of the Cascades, so the contribution of snowmelt overnight will be very limited. However, there have been events in the past of some small stream flooding east of the Cascades due to snow melt, so it`s just something to watch out for. Heading into Monday, models are now starting to resolve a quick- hitting negatively tilted trough sweeping through the region. At the surface, we now expect to see a rapidly deepening surface low passing within 130W, and tight sea level pressure gradients along the coast (from -8 to -10mb between NOrth Bend and Arcata). These are all the ingredients we typically look for in a strong wind event. A quick look at Ensemble tools shows significant wind speed concerns, from sustained multi-level winds around the 95th percentile in the NAEFS, and ECMWF extreme forecast index of between 0.8 and 0.9 in surface winds, confidence is very high for strong winds along the coast. Inland, gradients are still strong, but due to the trajectory of the surface low, mid-level winds are weaker and not as well aligned with the terrain. Despite this, strong winds re still expected for the typical trouble spots: the Shasta Valley, southern Rogue Valley, and much of the East Side, especially in the Summer Lake area. High Wind Watches have been issued for these areas, and details can be found at PDXNPWMFR. Various Wind Advisories may be necessary as well, but will wait on a few more model cycles before upgrading/issuing further headlines. Interestingly enough, winds will be the primary concern with this system, as precipitation will be much lighter than the previous systems, and snow levels are expected to remain well above 5000 feet. Tuesday evening will be the end of this AR event with high pressure building over the area. This quiet weather will persist into Wednesday with temperatures continuing to remain on the warmer side. Highs will be pushing the mid 60`s west of the Cascades with some upper 60`s in the river valleys closer to the coast. Temps will be a bit cooler east of the Cascades on Wednesday with highs in the mid 50`s. A low chance of rain returns on Thursday as an upper level wave quickly swings through the region. -BPN/Smith && .MFR WATCHES/WARNINGS/ADVISORIES... OR...High Wind Watch from Monday morning through Monday evening for ORZ021-022-030-031. CA...High Wind Watch from Monday morning through Monday evening for CAZ081-085. PACIFIC COASTAL WATERS...Small Craft Advisory until 10 AM PST this morning for PZZ350-356-370-376. Gale Warning until 4 PM PST Sunday for PZZ350-356-370-376. Storm Watch from late Sunday night through Monday evening for PZZ350-356-370-376. && $$

724 FXUS66 KEKA 221323 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 523 AM PST Sat Feb 22 2025 .SYNOPSIS...Chance of rain will increase today and peak tonight. Heavy rain is forecast for Del Norte and far northern Humboldt Counties tonight. Elsewhere, generally light rain is expected. A low pressure system will generate locally strong and gusty southerly winds over the headlands and interior mountains this weekend. Strong southerly winds will be possible again on Monday. && .DISCUSSION...A long fetch of deep layer moisture emanating from the subtropics (PWATS over 1 inch) will intersect the coastal terrain late today into tonight. Heavy rain is forecast for Del Norte and far northern Humboldt Counties tonight. Hourly rain rates around 0.30in/hr are probable (70-80% chance) in the interior of Del Norte from 8 pm Sat to 5 AM Sun. Deterministic convective allowing models such as the HRRR and ARW indicate localized hourly rates approaching 0.50in/hr, likely the result of topographic forcing. The brunt of this atmospheric river (AR2/AR3) will be aimed north of the area with Del Norte on the southern edge of the IVT plume max (500-600kg/m/s). Even though the duration of the AR is over 48 hours, heavy rain rates do not appear to last that long based on the latest HREF guidance. Even moderate rain rates (0.20in/hr) fall off during the day on Sunday. We still cannot rule out rainfall run-off impacts tonight. Minor flooding will be possible tonight into Sunday morning. Also, mud/landslides or rock falls will also be possible in the steep terrain. Slides will most likely impact highway 199 in Del Norte County and possibly highway 101 north of Klamath. For now will highlight this threat in a weather story graphic and social media post. Otherwise, rainfall be light to moderate for the remainder of the forecast area. Southern Lake and southern Mendocino may not get any measurable rain this weekend. Snow levels will remain quite high this weekend, above 6000 feet and temperatures will remain above normal even under thicker cloud cover. Gusty south winds will develop along North Coast this afternoon and evening as surface low pressure approaches the west coast and gradients tighten. Strongest winds will be over the coastal headland, especially Pt St George where gusts around 40 mph are probable. The gusty winds should persist through Sunday. A surface low is forecast to develop just outside 135W north of 40N Sunday as the quasi-stationary frontal boundary north of the ORCA border buckles and a surface cyclone develops and rapidly progresses NE outside 135W. Synoptic scale model guidance continues to keep the strongest and most damaging winds with this cyclone well offshore and just north of the forecast area, along the Oregon coast. Surface pressure gradients will tighten up again by Monday morning and stronger wind gusts to 50 mph are probable for the coastal headlands and interior ridges as a 60kt 925mb southerly speed max develops in advance of the boundary. All models have sped up the timing of strongest winds. ECMWF has been clustering around Monday afternoon/evening, but latest run has shifted earlier in the day. ECMWF ensemble mean wind gusts is over 50 mph for Pt St George and KCEC airport. In fact there are many members, 30% of 100, over 55 mph from 4 AM to 4 PM Mon. Looking at the NBM, 90th percentile max gusts are on the order of 55 to 65 mph over the interior mountains of Del Norte with lower probabilities for gusts to 55 mph for the Humboldt interior mountains; specifically Kneeland and Berry Summit. Wind this strong will make driving difficult and could knock down tree branches. We are leaning toward a wind advisory for this event. For now will hold off on hoisting an advisory multiple days out and wait to see how deterministic models and ensemble data sets trend. We will message the potential for hazardous winds in weather story graphic and social media posts. Precip will end on Tuesday as a broad upper ridging quickly springs back and holds into mid week (Wed). The ridge aloft with above normal 500mb heights will likely remain the dominant feature controlling NW California weather into late next week. Temperatures will remain above normal. DB && .AVIATION...Stratus has made periodic pushes toward the coastal terminals early this morning, bringing occasional LIFR/IFR ceilings. Stratus may linger until sunrise, when any remaining low clouds should lift and scatter out. An approaching system will bring increasing clouds and rain to the area. VFR ceilings will drop to MVFR by late afternoon or evening, while MVFR visibilities are possible during periods of moderate to heavy rain. Gusty southerly winds are forecast at CEC, perhaps as high as 35 kts, and are forecast continue into the night. At ACV, winds could occasionally gust to 25 kts this evening and overnight. LLWS will also be a threat at the coastal terminals this afternoon and overnight. Conditions remain VFR at UKI as the system primarily impacts Del Norte and Humboldt Counties, though a stray shower is possible overnight. JB && .MARINE...North of Cape Mendocino...Southerly winds will gradually increase today ahead of an approaching shortwave. Wind gusts of 20- 30 kts are likely through Sunday nearshore, with gale force gusts likely in the outer waters and around Pt St George. Seas will remain elevated this weekend, as steep wind waves of 7-9 ft at 8 seconds combine with a decaying mid-period westerly swell of 8-10 ft. Winds may diminish slightly Sunday night, but sharply increase again Monday morning as a stronger front arrives. Near-gale to gale force gusts are possible near shore, with strong gales of up to 45 kts possible offshore. South of Cape Mendocino...Light to moderate southerly breezes are forecast today, while seas are dominated by a decaying westerly swell. Seas are forecast to fall below 10 ft by the late afternoon, and remain below 10 ft into the weekend. Winds increase slightly Monday as a front passes to the north, with stronger breezes and steep seas possible. JB && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 6 AM PST Monday for PZZ450. Small Craft Advisory until 3 PM PST this afternoon for PZZ455-470-475. Gale Warning from 3 PM this afternoon to 3 PM PST Sunday for PZZ470. && $$ 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

317 FXUS66 KMTR 221726 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 926 AM PST Sat Feb 22 2025 ...New AVIATION... .SYNOPSIS... Issued at 229 AM PST Sat Feb 22 2025 Mainly dry weather is forecast through the period, with a general warming trend occuring. A few disturbances pass well to our north this weekend, which might bring some light rain to North Bay starting late Saturday and Sunday, and again on Monday. Mid to late week, an upper level low looks to form and cutoff somewhere over central or southern California. This may bring showers to the region, or favor more of the Central Coast depending on it`s placement. && .UPDATE... Issued at 838 AM PST Sat Feb 22 2025 Patches of stratus persist at the immediate coast with scattered high clouds over the rest of the region. The main forecast issues continue to be the warming trend for most of the forecast region through the next week, and the cut off low and resulting uncertainty that is expected towards the end of the next week. For now, the forecast remains unchanged. DialH && .SHORT TERM... (Today and tonight) Issued at 229 AM PST Sat Feb 22 2025 Picture from space this morning, shows a break between the high clouds over the region, showing pockets of stratus and fog along our coast and partially intruding into the North Bay region. Patchy fog and stratus will be possible for these areas this, and perhaps near Half Moon Bay and should mix out later this morning. Dry conditions will persist with a mix of mid and high level clouds. High temperatures look to be similar to yesterday`s. South Bay and Central Coast valleys should make it into the low to mid 70s, while other valleys rise into the mid 60s to near 70s. The coolest areas will be along the coast and in the mountains where highs top out in the upper 50s to mid 60s. && .LONG TERM... (Sunday through Friday) Issued at 229 AM PST Sat Feb 22 2025 Near zonal upper level flow for much of the region, with weak upper level ridging just to our south over southern CA. A series of disturbances pass to our north. Rain is favored to the north of the service area, though the North Bay counties may squeak out a couple hundredths of an inch late Saturday into Sunday and again on Monday. Dry weather is expected to persist elsewhere during this period, with the warming and drying trend continuing. Upper level ridging build back in midweek, which should should maximize our temperature growth. Mid to late week, a cut off low forms over the eastern Pacific and moves eastwards towards California. Ensembles and deterministic data continue to favor it entering central or southern California. PoP chances have decreased for the Bay Area, while chances increased slightly for the Central Coast due to a slight shift south in the model and ensemble data. Will need to keep an eye on this as it could affect temperatures, and PoP values will likely deviate some as we get closer to the event. Behind it, upper level ridging noes into California briefly on Saturday, with a trough forming off to its west. && .AVIATION... (18Z TAFS) Issued at 925 AM PST Sat Feb 22 2025 Fairly high confidence of VFR conditions to persist through the day and into Sunday morning. However, lower visibilities/ceilings around KHAF this morning, clearing by early afternoon only to return once again Sunday morning due to proximately to the coast. Also, KSTS may briefly see fog and low ceilings Sunday morning. Otherwise, light winds this morning will become onshore this afternoon and into the early evening before once again becoming light/variable. Onshore winds return Sunday afternoon. Vicinity of SFO...VFR. Mainly high clouds streaming in across the region this morning and will likely continue into Sunday morning. Onshore winds increase by early afternoon, yet with no notable gusts. Very low probability of low ceilings Sunday morning, will cover with SCT low level clouds. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR. FEW/SCT high clouds streaming across the region from the west-northwest. Onshore flow returns this afternoon. Winds go light/variable late this evening with drainage winds at KSNS early Sunday morning. && .MARINE... (Today through Thursday) Issued at 838 AM PST Sat Feb 22 2025 Winds and sea heights will remain relatively calm into early next week. A new, moderate northwesterly swell enters the waters by Tuesday of the upcoming week, causing seas to build up to 10 to 12 feet. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ SHORT TERM...KR LONG TERM....KR AVIATION...RGass MARINE...RGass Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/nwsbayarea www.twitter.com/nwsbayarea www.youtube.com/nwsbayarea

105 FXUS66 KOTX 221200 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 400 AM PST Sat Feb 22 2025 .SYNOPSIS... Warmer temperatures and rain will arrive this weekend as high temperatures warm into the 40s and low 50s. Runoff from rain and melting snow will lead to increased flow and minor flooding across southeast Washington and the central and southern Idaho Panhandle. Another weather system Monday into Tuesday will bring more rain and stronger winds. && .DISCUSSION... Saturday and Sunday: The first front of several to impact the Pacific Northwest between now and Tuesday is moving through early Saturday morning. Light rain due to warm air advection from the southwest will continue to move east across Washington and north Idaho through the early morning. Focus shifts to Saturday evening through early Monday as two systems accompanied by a moderate to strong atmospheric river impact the region. Models continue to be in good agreement with the ridge over the Western US to progressively flatten as the systems ride overtop. The first system will arrive Saturday afternoon and evening as a warm front lifts north across the Inland Northwest. PWATs increasing to 0.75+ inches as this front spreads north will support widespread rainfall, especially across the Cascades, far eastern Washington, and the Idaho Panhandle as strong westerly flow aloft favors orographic enhancement. There still remain differences in the onset of precipitation and exact amounts. A second surge of widespread precipitation will occur Sunday as a more compact low nears the northwest coast. This will keep the moist southwest flow directed into the Inland Northwest through the day on Sunday and into early Monday. Models have come into better agreement on the strength of the surface low, although the deterministic GFS remains slightly stronger and slower with the timing of the upper level shortwave and front as it moves through the Inland Northwest late Sunday into early Monday. The 48 hour precipitation total has trended upward with totals between 0.80 to 1.40 inches for the lowlands of far eastern Washington and 1.5 to 2.5 inches over the mountains which lies near the 90th percentile among the global ensembles. Additionally, winds have increased for Sunday night into early Monday as a cold front moves through the region with wind gusts 30 to 45 mph. IMPACTS: The combination of warmer temperatures, rain, and breezy winds will result in rapid snowmelt across the lowlands. If the current forecast verifies, rises in our flashier creeks and streams will be common across Spokane County and through the Washington and Idaho Palouse. Ponding of water in urban areas with poor or clogged drainage and field flooding will be of concern. It is advised to take proper precautions to mitigate flood impacts. Monday and Tuesday: Models continue to show a deepening surface low to slide northward along the Pacific Northwest coast on Monday. Models and their ensembles have been trending upward with the wind forecast with a 30 to 40 percent chance for wind gusts over 40 mph for Spokane and the Columbia Basin and and a 70 percent chance for wind gusts over 40 mph for Pullman. If the stronger winds were to pan out, saturated soils may exacerbate impacts with isolated to scattered tree damage. This system would also bring another round of widespread precipitation Monday into Tuesday. Snow levels look to decrease with a return to mountain pass snow. Currently, there is a 30% chance for Stevens Pass to receive 12 inches of snow. /vmt && .AVIATION... 12Z TAFS: The heavy rain system is passing through the area with precipitation, ceilings are at most MVFR status. TAF sites are expected to be VFR/MVFR with lowered ceilings due to precipitation. KMWH looks to get down to IFR at some point through the evening due to localized rainfall and low stratus. A rain break is expected late morning through early afternoon. A second round of rain will move around 00z. There is the potential for KGEG- KSFF- KLWS to see wind shear values of 30 knots or more at 2000 feet Saturday evening. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Moderate confidence in timing and location of upcoming precipitation, particularly with the second wave later in the TAF period. Moderate to high confidence of MVFR ceilings for all but KEAT through the night. Moderate to low confidence of wind shear values being greater than 30 knots difference at KGEG-KSFF-KLWS for Saturday evening. /JDC ----------------------- Confidence descriptors: Low - Less than a 30 percent chance Moderate - 30 to 70 percent chance High - Greater than a 70 percent chance && .PRELIMINARY POINT TEMPS/POPS... Spokane 44 40 50 38 49 38 / 50 100 90 90 50 80 Coeur d`Alene 44 38 48 36 48 35 / 70 100 100 90 50 90 Pullman 42 37 46 37 47 36 / 50 100 100 90 60 90 Lewiston 48 42 52 41 53 40 / 30 90 100 90 50 80 Colville 42 37 48 32 46 34 / 50 100 80 80 50 90 Sandpoint 42 39 45 37 45 36 / 90 100 100 90 60 90 Kellogg 43 40 45 39 47 37 / 90 100 100 100 60 90 Moses Lake 49 40 56 36 51 37 / 30 80 70 40 60 40 Wenatchee 42 39 49 36 45 35 / 50 80 70 50 70 60 Omak 42 36 46 33 45 34 / 60 90 70 70 50 70 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Flood Watch from this evening through late Monday night for Central Panhandle Mountains-Coeur d`Alene Area-Idaho Palouse-Lewis and Southern Nez Perce Counties-Lewiston Area- Northern Panhandle. WA...Flood Watch from this evening through late Monday night for Lower Garfield and Asotin Counties-Northeast Blue Mountains- Northeast Mountains-Spokane Area-Washington Palouse. && $$

737 FXUS66 KPDT 221738 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 938 AM PST Sat Feb 22 2025 Updated Aviation Discussion .AVIATION...18z TAFs...VFR conditions expected during most of the day. Light showers in the Basin will let up by the early afternoon, leaving sites with sct-bkn mid-level clouds, before an atmospheric river brings wind and rain to all sites starting this evening. Rain is expected to encompass all sites by 03z at the latest. Winds will be strongest at the foothills of the mountains, except for DLS, with rain expected to persist through much of the weekend, albeit intermittently. Gusts could reach 30 kts at some sites, with stronger winds expected during the day tomorrow. During rain, cigs will become ovc and drop to 3-6 kft for most sites. With gusty winds expected, LLWS is possible at some sites, with mentions included at PDT and PSC, but did scale back on LLWS from previous TAFs, as winds do look to be more unidirectional across models than previously thought. Evans/74 && .PREV DISCUSSION... /issued 423 AM PST Sat Feb 22 2025/ SHORT TERM...Today through Monday...Satellite and radar imagery tonight show a weak shortwave and frontal boundary pushing the last of very light precipitation across far eastern WA/OR, with some light showers developing just west of the Cascade crest. Otherwise, pockets of clear sky along the Cascade east slopes shows area of low stratus, with shallow fog in portions of the Yakima/Kittitas valleys. The shortwave trough and attendant front will exit the PacNW early this morning, setting up warm air advection under a west southwest flow aloft. The forecast area will see a brief break in precipitation into the early afternoon. Otherwise, snow levels will be on the rise behind the system exit, with snow levels expected to rise to above 6kft by mid-afternoon. Late this afternoon the next shortwave will arrive to the region while accompanied by a weak to moderate atmospheric river (AR) and surface warm front. A mild and moist airmass will filter in behind the warm front passage tonight, resulting in snow levels rising to above 7kft across the forecast area. This will facilitate mostly rain below the highest mountain peaks along the Cascade crest and eastern mountains through Sunday. Once again, there has been little change since 24 hours ago amongst guidance, with the expectation that there will be plenty of moisture to work with as the AR with this system will be centered along the 45th parallel. Both the GFS and ECMWF IVT ensemble suites show close to a 100% chance of IVT values greater than 250 kg/m/s making it east of the Cascade crest. Vapor transport at this magnitude will result in enough moisture for moderate to heavy precipitation accumulations along the Cascade crest and the interior northern Blues, with light to locally moderate accumulations in the lower elevations through Sunday afternoon. Sunday evening, the next shortwave trough is expected to quickly pass through the PacNW and exit by Monday morning, with the AR effectively ending early Sunday night. The NBM 48-hr probabilities ending Monday morning for precipitation accumulations shows a 95-100% chance along the Cascade crest/east slopes and a 70-90% chance along the interior northern Blues for 1 inch of rain accumulations. Looking at 2 inches or greater, chances are between 70-90% along the Cascade crest, with a 25-45% chance along the higher terrain of the interior northern Blues. In the lower elevation, there is a 60-80% chance of 0.25 inches of rain across central/north central OR, and the Yakima/Kittitas valleys; there is a 70-90% chance along the Blue Mountain Foothills, Grande Ronde/Wallowa valleys; there is a 50-70% chance across the remainder of the lower elevation zones. Breezy to locally windy conditions will also develop this afternoon ahead of the shortwave trough and warm front arrival this evening. Surface pressure gradients between the Blue Mountain foothills to the Lower Treasure valley will increase to around 10-12mb this evening and overnight, facilitating the strongest winds (gusts between 45-55mph) through the Grande Ronde valley and along the Blue Mountain foothills through Sunday morning (confidence 70-90%). From central OR to the Columbia Basin, locally breezy southwest winds will also develop tonight. There will be a brief period late tomorrow morning into the afternoon where winds will decrease behind the shortwave passage in the lower elevations, however a developing modest low to mid level jet will setup over the Columbia Basin. By late Sunday afternoon, winds will once again increase across the area as the next shortwave trough arrives and the lower to mid level jet winds begin to mix down. This will result in breezy to locally windy conditions (25-50mph gusts) across the lower elevations through Sunday evening, with winds decreasing by Monday morning. Early Monday morning, a brief window of dry conditions will develop across the forecast area as a transient ridge moves across the PacNW. However, by mid morning hours, a warm front will lift north across the forecast area through the afternoon, followed by the arrival of a compact and strong upper trough Monday evening through overnight hours. Snow levels will lower to between 4kft to 6kft (west to east gradient), allowing for moderate snow accumulations on upper elevation ridges above 5.5kft, with light snow down to pass level in the Cascades. Otherwise, moderate (0.25-0.5 inches) rain accumulations will be possible along the mid to lower Cascade slopes and the eastern mountains. Light to locally moderate (0.1-0.25 inches) rain accumulations. Winds will again be a concern Monday with the frontal passage and redevelopment of a low to mid level jet across the Columbia Basin. Wind gusts will increase across the lower elevations to 25-40mph, with locally 40-50mph in wind prone areas along the Blue Mountain foothills, central/north central OR, and ridges in the Columbia Basin. With the expected rainfall and subsequent snowmelt/runoff in the mountains, area rivers and streams will begin to rise Sunday, and are currently forecast to peak during Monday. At the moment, most rivers are expected to remain within bankfull through Sunday, though the Naches, Yakima, Klickitat, Walla Walla, and Umatilla rivers will begin to reach or just exceed bankfull by early next week. Smaller streams will also see rises, and those streams that have not been cleared of debris may see minor flooding into adjacent low lying areas. Lawhorn/82 LONG TERM...Tuesday through Friday night... Overview: A weakening upper-level low pressure system will likely (>90% confidence) become an open-wave trough as it passes over the forecast area Tuesday. Precipitation chances diminish through the day Tuesday as an upper-level ridge of high pressure builds over the PacNW. The forecast area will then likely (~75% chance) stay dry through Friday with temperatures running 5-10 degrees above normal. Uncertainty/Hydro: Wednesday through Friday, ensemble cluster analysis indicates roughly 25% of members suggest a glancing blow from a weak shortwave trough; this scenario would bring light precipitation to the mountains. Either way, hydrologic concerns should lessen through the period with no significant precipitation forecast. Winds: Widespread breezy to windy, locally very windy, westerly winds are forecast to slacken through the day Tuesday. Breezy southerly winds are then forecast Wednesday into Thursday through the Grande Ronde Valley and along the base of the Blue Mountains. Confidence in advisory-level winds Wednesday/Thursday is low (<40%), while confidence in advisory-level winds Tuesday morning is medium- high (40-80%) for central/north-central OR, the Blue Mountain foothills, Simcoe Highlands, and Columbia Basin. Plunkett/86 && .PRELIMINARY POINT TEMPS/POPS... PDT 60 47 61 43 / 20 70 80 60 ALW 53 45 57 42 / 30 90 90 80 PSC 58 45 62 41 / 10 70 70 50 YKM 49 40 57 36 / 40 70 70 50 HRI 59 47 63 42 / 10 60 70 50 ELN 46 37 52 33 / 50 80 70 50 RDM 59 46 61 40 / 20 60 60 40 LGD 45 37 48 37 / 30 80 90 80 GCD 52 40 53 38 / 10 80 80 50 DLS 54 45 58 43 / 60 90 90 80 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Wind Advisory from 4 PM this afternoon to 7 AM PST Sunday for ORZ049-507-508. WA...None. && $$ SHORT TERM...82 LONG TERM....86 AVIATION...74

316 FXUS65 KREV 220838 AFDREV Area Forecast Discussion National Weather Service Reno NV 1238 AM PST Sat Feb 22 2025 .SYNOPSIS... * A warming trend will result in spring-like temperatures this weekend into next week. * A pair of weak storms will bring increased winds and light showers to northeast California and northwest Nevada Sunday and Monday. * No significant winter storms expected through the end of February with a more active weather pattern likely to ring in early March. && .DISCUSSION... Springtime lovers rejoice! Your first taste of spring arrives today and will continue through next week. Afternoon high temperatures will remain comfortably in the 60s across Western Nevada while locations in Western Nevada Basin and Range will be flirting with 70. Sierra communities can expect highs in the mid 50s for the next week. Light showers and gusty winds will unfortunately (or fortunately, depends on your preference) accompany our spring-like temperatures Sunday into Monday. A brief system Sunday will constrain light showers along the OR border and NE CA, however, there is a 30% chance communities in the Tahoe Basin will see showers. Another brief system will primarily impact NE CA and the OR border Monday. Any accumulations with these two systems will be light. Additionally, snow levels remain above 7000 ft. Monday will be the windiest day with areas in NE CA and N Washoe County seeing a 50% chance of max wind gusts exceeding 50 mph. Ridges along the Sierra will also see strong wind gusts Monday (gusts 65-85 mph). Ridging builds back over the area Tuesday and will remain in place through the end of the week. However, another storm looks to be knocking on the door to ring in March. Stay tuned. -Giralte && .AVIATION... VFR conditions expected for all terminals through the weekend. Light rain showers possible for KTRK/KTVL early Sunday and into the afternoon hours, however, little to no accumulation is expected. -Giralte && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$

827 FXUS66 KSTO 221006 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 206 AM PST Sat Feb 22 2025 .SYNOPSIS... Weak system brings light showers and breezy southerly winds to the Sacramento Valley, foothills and mountains this afternoon into Sunday and then again on Monday. Dry weather and above-normal temperatures then continue next week. && .DISCUSSION... A band of mid to high level clouds is making its way across interior Northern California early this morning as per GOES-West Satellite imagery. Otherwise, clear conditions prevail elsewhere across the area. The clear and cool conditions may lead to patchy fog and low stratus development across portions of the southern Sacramento and northern San Joaquin valleys until around 9 AM. Spring-like temperatures return to the region today, with a 30 to 60% chance of the Valley seeing high temperatures greater than 70 degrees. Dry and warm weather is set to continue for the first half of the day as well before the first of two weak systems bring light, low impact precipitation to the northern third of the state. Beginning this evening into Sunday, the first system is forecast to bring between 0.45 to 0.95 inches to Shasta County foothills and mountains. Elsewhere, between 0.10 and 0.4 inches are forecast for the northern Sacramento Valley and adjacent foothills/mountains north of I-80. After a short break in precipitation Sunday PM into early Monday, the next wave will bring lighter amounts later that morning. Forecast precipitation amounts are in the range of a few hundredths to 0.25 inches mainly over Shasta County, however a few scattered showers may venture further south over the central Sacramento Valley and Sierra mountains/foothills north of I-80. Overall, impacts will be little to none, but a few isolated areas further north in Shasta County may see minor impacts such as slippery roads. Breezy southerly winds are also on the agenda for Monday, with gusts 15 to 30 mph in the northern/central Sacramento Valley and adjacent foothills, with gusts up to 40 mph over the Sierra. Above-normal temperatures will persist through this week and into the next, as upper-level ridging builds back over the Pacific Northwest ushering in a return to dry weather. && .EXTENDED DISCUSSION (Wednesday THROUGH Saturday)... Cluster analysis and ensemble guidance continue to support warm and dry conditions next week under upper level ridging. Daytime high temperatures will be trending above normal for late February /early March climatology. The NBM shows a 55 to 85 percent probability of high temperatures exceeding 70 degrees F throughout the lower elevations over the extended forecast period. As the ridging persists, a few locations may even see a chance at 80 degrees or higher later next week. Currently there is a 20 to 40% chance of exceeding 80 degrees across northern/central Sacramento Valley, with up to 40% around the Redding area. Light winds are generally expected with the exception of occasional periods of breezy north to east/downslope winds at times. Towards the beginning of March, a few ensembles show a low pressure system moving inland over Southern California which may bring a few isolated sprinkles to the Sierra, south of I-80. && .AVIATION... Brief periods of MVFR conditions possible across portions of the southern Sacramento and northern San Joaquin valleys due to BR until around 17z Saturday. Areas of brief MVFR conditions in showers across portions of the northern Sacramento Valley and northern mountains after 00z-06z Sunday. Otherwise, VFR conditions are expected. Surface winds generally under 12 kts. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$

283 FXUS65 KMSO 221057 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 357 AM MST Sat Feb 22 2025 .DISCUSSION... KEY MESSAGES: - Increased snowmelt and runoff Saturday into Monday, bringing the risk of minor flooding to low-lying and poor drainage areas and to small streams and creeks from potential ice jam releases - Widespread rain and high elevation mountain snow, Sunday into Monday. - Areas of freezing rain Saturday night through Sunday morning across western Montana with cold subsurface ground temperatures in place. No major changes this update. Light rain and snow have been reported over north-central Idaho. With temperatures near freezing, expect possible black ice if traveling this morning. A long duration (~48 hour) atmospheric river event remains on track to impact the Northern Rockies Sunday into Monday, delivering widespread precipitation and pushing snow levels above 6,000 feet. Warm, wet, and breezy conditions in the lower elevations will set the stage for rapid snowmelt, leading to runoff concerns and introducing the risk for minor flooding in low-lying and poor drainage areas across western Montana and north-central Idaho. Furthermore, the rapid thaw of small streams and creeks may lead to ice jam releases. Given rising snow levels and widespread precipitation, an elevated risk also exists for rock slides, particularly across north-central Idaho and along the ID- MT border, where confidence is high (90% probability) for widespread precipitation totals exceeding one inch. Higher peaks across the Northern Bitterroot, northwest Montana mountains, and Clearwater Mountains will see the highest precipitation totals of 2-4 inches. Finally, given the intensity of this system and changes to the snowpack, those planning winter recreation activities are encouraged to monitor avalanche forecasts at avalanche.org Another concern is the risk of icy conditions, particularly overnight Saturday night into Sunday morning. Although air temperatures may rise above freezing, many western Montana valleys still have subsurface temperatures below freezing. This could result in rain freezing on contact, creating hazardous conditions, especially on secondary roads with lingering snow cover. Travelers should be prepared for slick spots, particularly on untreated surfaces. Winter weather advisories have been issued across northwest Montana where our confidence is currently the highest for more widespread impacts to occur. The next Pacific disturbance is expected late Monday night into Tuesday. Snow levels will initially start around 5000 feet, but will drop down to 3500 feet Tuesday morning as a cold front moves through the region. By this point, the main moisture source will be cut off, but lingering snow showers will likely exist. && .AVIATION...Showers will persist across north-central Idaho and northwest Montana this morning, so expect periodic mountain obscuration. By Saturday night and continuing through Sunday night, an atmospheric river will bring rising snow levels and widespread valley rain, leading to a wet and active weather pattern. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...Flood Watch from 2 PM MST this afternoon through Monday afternoon for Bitterroot/Sapphire Mountains... Butte/Blackfoot Region...Flathead/Mission Valleys... Kootenai/Cabinet Region...Lower Clark Fork Region... Missoula/Bitterroot Valleys...Potomac/Seeley Lake Region... West Glacier Region. Winter Weather Advisory from 11 PM this evening to 8 AM MST Sunday for Flathead/Mission Valleys...Kootenai/Cabinet Region...West Glacier Region. ID...Flood Watch from 1 PM PST this afternoon through Monday afternoon for Lower Hells Canyon/Salmon River Region... Northern Clearwater Mountains...Orofino/Grangeville Region...Southern Clearwater Mountains. && $$

451 FXUS65 KBOI 221634 AFDBOI Area Forecast Discussion National Weather Service Boise ID 934 AM MST Sat Feb 22 2025 .DISCUSSION...Cloud cover this morning will thin out a bit in the afternoon as warm air begins to move in aloft. Temperatures today will be a few degrees warmer than yesterday for most spots, lowest sheltered valleys the continued exception as the light winds and minimal mixing will cap the warming potential. Current forecast for today is on track. Rain and snow arrive tonight and continue through Sunday with potential for hydrologic impacts the main concern at this time. The forecast will be updated with the latest information this afternoon. && .AVIATION...VFR, except MVFR/IFR in showers at MYL before 17Z. Widespread MVFR/IFR/LIFR with shower activity after 00Z as a storm system moves into the region. Mountains obscured. Surface winds: becoming SW-SE 10-25 kt. Winds aloft at 10kft MSL: WNW 25-40 kt. KBOI...VFR. Lowering ceilings in precipitation after 03Z. Mountains obscured after 03Z. Surface winds: SE 10-18 kt. Sunday Outlook...All flight categories expected Sat night/Sunday as widespread precip arrives. High snow levels favor rain at all terminals, except rain/snow mix at KMYL. Mountains becoming obscured. Surface winds: SE-SW SE 10-15 kt with 20-30 kt gusts Sunday. && .PREV DISCUSSION... SHORT TERM...Today through Monday night...Cloud cover has overtaken the forecast area as a weak, shortwave trough passes through this morning. Very light precipitation is falling across the higher terrain of northeast Oregon and west-central Idaho, mainly in the form of light snow. This trough will promptly exit by late this morning, yielding a brief break in precip with decreased cloud coverage. The next low pressure system is forecast to arrive tonight, spreading ample precipitation across Oregon and Idaho through early Monday. Precipitable water values will rank within the 95-99th percentile (high) for this time of year associated with a well- pronounced subtropical moisture fetch. Due to the origin of this moisture, snow levels will begin at roughly 3000-5000 feet MSL tonight and quickly rise to 5000-8000 feet MSL Sunday morning. The exception will be in east-central Oregon, the Weiser River Basin, and sheltered mountain valley locations, in which cold air near the surface will be slower to scour out. As a result of the intruding warmer air, there is a 10-15% chance of freezing rain developing overnight for those colder valleys before near- surface temperatures are able to warm above freezing. Otherwise, rain or a rain/snow mix is expected below 5k feet with the precip onset through Sunday morning, becoming all rain by mid- day Sunday. Higher mountain elevations, particularly in the favored upslope areas of southwest Idaho, should see notable snowfall amounts of around 6-12 inches through early Monday. Surface winds will become breezy Sunday afternoon, particularly in southeast Oregon, as the trough progresses eastward. Precipitation and wind gusts will taper off by Monday morning as this system exits and weak ridging develops. However, this ridge will be short-lived as the next trough approaches the area and creates strong southwest flow aloft. While temperatures will become noticeably milder today and Sunday with those first two Pacific troughs, temperatures will increase further on Monday due to the development of southwest flow. Surface winds will increase once again Monday, particularly near the NV border ahead of the incoming cold front. Overall, expect temperatures to be near normal this weekend, rising to several degrees above normal for Monday. The next round of precipitation will arrive Monday night, spreading additional rain and snow (60-90% chance) across the northern portions overnight into Tuesday. Snow levels will lower to 4000-5500 feet MSL with the accompanying cold front. A few inches of new snow can be expected for the mountains of west-central/central Idaho. LONG TERM...Tuesday Through Saturday...An upper level ridge is forecast to build over the west coast Tuesday. This will taper off the Pacific moisture stream over the forecast area with precipitation confined mainly to Baker County and the West Central and Boise Mountains Tuesday with snow levels around 4000 feet. An upper ridge will dominate Wednesday into next weekend with dry conditions prevailing and temperatures about normal to 5 degrees above normal. Forecast models do show another Pacific trough reaching the coast near the end of the period which could bring some precipitation (15-20% chance) to western and northern fringes of the forecast area. AVIATION...Mostly VFR. Local MVFR/IFR in valley fog and/or low stratus mainly near KMYL, KONO, KBKE, KTWF, and KJER early this morning. Low chance (15-25%) of MVFR in light snow for KBKE and KMYL through Saturday morning. Mountains obscured. Surface winds: variable 10 kt or less except E-SE 5-15 kt at KBKE and in the Snake River Plain from KBOI to KJER/KTWF. Winds aloft at 10kft MSL: W 20- 30 kt. KBOI...VFR. Low chance (10%) of MVFR ceilings Saturday 12Z-18Z. Surface winds: SE around 10 kt. Sunday Outlook...All flight categories expected as widespread precip moves in tonight and continues Sunday. Snow levels rising to 6000 to 8000 feet MSL. Mountains obscured. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise DISCUSSION...DG AVIATION.....MC SHORT TERM...SH LONG TERM....TL

186 FXUS65 KLKN 220921 AFDLKN Area Forecast Discussion National Weather Service Elko NV 121 AM PST Sat Feb 22 2025 .SYNOPSIS...A quick moving system clipping the northern tier of the Silver state Sunday afternoon look to be the only hiccup in the forecast as upper ridging brings a Springtime preview as near record high temperatures with quiet conditions move in for the week ahead. && .SHORT TERM...Saturday through Sunday Saturday looks to be quiet with a shortwave ridge transiting the Great basin region in the wake of a strongly positive tilted trough over the four corners. This ridge will be kicked east as a strong upper trough takes aim at the Pacific NW. Only to be replaced by more long wave broad upper ridging that will build in from the SW. As a result Saturday will see a jump in temperatures under mostly sunny skies, as highs will range from the upper 40s to upper 50s for most, the only caveat will be for Elko county as residual snow cover, meager as it is, will keep highs a bit lower than the rest ranging in the upper 30s to upper 40s. Overnight lows will see a east to west split, as cloud cover will begin to build across the west as the aforementioned upper trough moves in across the Pacific NW. Lows east of Battle Mountain will drop into the upper teens to upper 20s, while under the clouds to the west of Battle Mountain will see lows in the low to upper 30s for Sunday morning. Sunday will begin with clouds building across the Silver State, the good news is for most of NV the slow building of long wave ridging from the SW will keep the track of the upper trough well to the north with most of the state staying dry. However the tailing cool front will clip northern Nevada Sunday afternoon which will bring a low chance of isolated showers across the far northern tier of the state north of I-80. Snow levels Sunday will start at 7500 feet and look to rise to 8500 feet during the day, meaning any light precipitation that does fall will be mostly rain and totals only in the trace to 0.10, with the highest elevations seeing up to 1 of snow from this system. For now the main impact of this system will be for increased west to SW winds across Humboldt and Elko counties Sunday afternoon with speeds in the 15 MPH to 25 MPH with occasional gusts up to 35 MPH possible, wind across central NV wont be as strong running at 5 MPH to 15 MPH. This system will exit rather quickly Sunday night with quiet conditions returning state wide by Monday morning. .LONG TERM...Monday through next Friday Look for dry and warmer weather through the week as a combination of zonal flow and upper level ridging lasting through Thursday. Temperatures trend warmer each day reaching to near record highs. A shortwave disturbance Tuesday will help drop temperatures in northern Nevada along the state border, then quickly moving back to a warming trend the following day. Late Thursday into Friday, models are showing a trend of an cut-off low pushing south towards southern California, however there are discrepancies on the timing and position. This low is expected to be dry with temperatures staying on a warming trend. && .AVIATION...VFR conditions at all terminals over the next 24 hour period. && .LKN Watches/Warnings/Advisories... None. && $$ 98/97/93