970 FXUS66 KSEW 312240 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 340 PM PDT Tue Mar 31 2026 .SYNOPSIS... Cloudy conditions will persist today ahead of an incoming frontal system that will bring lowland rain, mountain snow, and breezy winds to the region on Wednesday. Showers will taper off over the mountains on Thursday before a high pressure ridge brings much warmer and drier conditions over the weekend and into early next week. && .SHORT TERM /TONIGHT THROUGH THURSDAY/... Upper level flow will continue to turn southwesterly today as a low pressure system lowers along the British Columbia coast. Clouds will continue to increase today ahead of this incoming system, with potential for light shower activity moving northward later this evening. Temperatures are on track to peak near normal today across the region, with highs in the mid to upper 50s across the lowlands. As the low pressure system continues to progress southward along the Pacific Coast, the storm system will swing a cold front across western Washington on Wednesday. Winds will ramp up early Wednesday morning, with the strongest wind gusts reaching 35-45 mph along the Pacific Coast, through the Strait of Juan de Fuca, and from Whidbey Island northward across the northern interior. Elsewhere, winds will be breezy, with gusts of 25-35 mph. Winds will remain elevated through the early afternoon before easing throughout the rest of the day. Precipitation will spread inland along the frontal passage Wednesday morning, with steady rain across the lowlands through the afternoon and showers continuing through the evening. The lowlands will see generally 0.25 to 0.75 inches of rainfall through Wednesday night. In addition, snow levels starting at pass level on Wednesday morning will rise to 4000-4500 feet throughout the day before falling below pass level once again early Thursday. This will result in about 4-8 inches of snow accumulation through the Cascade passes, and a Winter Weather Advisory has been issued. The parent low pressure system will shift inland over Oregon on Thursday, with potential for wrap around moisture to allow for continued light snow over the Cascades. Conditions will dry out across the lowlands on Thursday, with cloudy skies and some afternoon sun breaks. Wednesday and Thursday will see cooler temperatures, with highs peaking in the upper 40s to low 50s across the lowlands. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Models remain in good agreement over warmer and drier conditions settling over the western US into the weekend and early next week as a high pressure ridge builds over the region. A weak system may try to overrun the building ridge over the weekend and bring light rain to the north coast, but forecast models continue to trend drier. While there are model differences beyond the weekend, ensembles favor warm and dry conditions into early next week. Temperatures are expected to peak in the low to mid 60s over the weekend away from the immediate coast, with potential for some areas along the Cascade foothills to reach 70 degrees on Monday as warming continues. A pattern change looks to arrive towards the middle of next week, but the details remain uncertain at this time. 15 && .AVIATION... Southwesterly flow aloft as an system approaches western Washington tonight and into Wednesday. VFR conditions at all terminals this afternoon with high clouds streaming in overhead of the next front. Widespread rain will enter the coast around 10z with the return of MVFR/IFR ceilings. Rain will start to reach the interior around 12z-15z, with likely widespread MVFR conditions and some areas IFR (OLM, PWT). Westerly winds this afternoon turning southerly overnight and increasing to 8 to 12 knots for much of the area. Terminals like KHQM and KBLI will likely see stronger southerly winds, around 10 to 15 knots with gusts up to 25 kts. KSEA...VFR conditions this afternoon with passing high clouds. Westerly winds turning more southerly after 00z. Rain approaching the terminal early Wednesday morning (12-15z) with a 40% chance of MVFR conditions throughout the early morning. Will likely see bouncing from VFR/MVFR throughout Wednesday morning in passing rain showers. Southerly winds increasing to 8 to 12 knots Wednesday morning. Mazurkiewicz && .MARINE... Surface high pressure continues today with generally light winds over the area waters. A low pressure system will move over the area waters tonight and into Wednesday for increasing southerlies over much of the waters. A Gale Watch has been upgraded to a Gale Warning for higher confidence in gusts exceeding 35 kts over all of the coastal waters. A Gale Warning is also out for the East Entrance, where gusts and sustained will around 30 to 35 kts at times. A small craft advisory has been issued for the Northern Interior Waters and Admiralty inlet for enhanced southerlies. Broad high pressure will redevelop on Thursday and into Friday, bringing lighter winds and quieter marine conditions. Coastal seas remaining 3 to 5 feet throughout today. Seas will then build up to 9 to 11 feet Wednesday morning. Seas will remain elevated into Thursday before decreasing on Friday and into the weekend, back down to 3 to 5 feet. Mazurkiewicz && .HYDROLOGY... No river flooding is expected over the next 7 days. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...Winter Weather Advisory from 11 AM Wednesday to 11 PM PDT Thursday for Cascades of Pierce and Lewis Counties- Cascades of Snohomish and Northern King Counties-Cascades of Southern King County-Cascades of Whatcom and Skagit Counties. PZ...Gale Warning from 4 AM to 5 PM PDT Wednesday for East Entrance U.S. Waters Strait Of Juan De Fuca. Small Craft Advisory from 4 AM to 5 PM PDT Wednesday for Admiralty Inlet-Northern Inland Waters Including The San Juan Islands. Gale Warning from 1 AM to 11 AM PDT Wednesday 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. && $$

593 FXUS66 KPQR 312033 AAA AFDPQR Area Forecast Discussion National Weather Service Portland OR 132 PM PDT Tue Mar 31 2026 .SYNOPSIS...A weak trough will maintain light rain showers across the area through this evening. A stronger frontal system arrives Wednesday, bringing widespread rain, Cascade snow, and breezy south-southwesterly winds through Thursday. Accumulating snow along the Cascade passes will result in hazardous travel conditions from Wednesday to Thursday morning, especially along Santiam and Willamette Passes where snowfall rates may exceed 1 inch per hour. High pressure rebuilds Friday into the weekend, returning dry weather, sunnier skies, and a warmer temperatures. && .SHORT TERM...Today through Thursday night...Radar imagery as of early Tuesday afternoon depicts light scattered showers across northwest Oregon and southwest Washington as a weak trough brings moisture to the area. Chances for precipitation last through this evening and are around around 20-40% west of the Cascades and 40-60% across the Cascades. Winds gradually turn more southerly today ahead of the next system that will arrive tomorrow. The next robust system arrives on Wednesday as an upper level trough tracks southeastward from the Gulf of Alaska and swings a frontal system across the Pacific Northwest. This will return widespread rain, breezy southerly/southwesterly winds, and Cascade snow across the region. The majority of ensemble members from the high-resolution REFS suggests that precipitation from the initial warm front will begin along the coast early Wednesday morning (after midnight-2 AM). Precipitation will gradually spread inland and persist through Wednesday afternoon as the trailing cold front follows. Behind the cold front, precipitation turns showery and cooler air will filter in the area. Snow levels will gradually drop to 2000-3000 ft by Wednesday evening, resulting in accumulating snow along the Cascade passes and potential travel impacts. The Winter Storm Watches have been upgraded to Winter Storm Warnings for the Marion, Linn, and Lane County Cascades from 5 AM Wednesday to 5 PM Thursday. There is high confidence (70-80% chance) for 1 foot of snow or more along Santiam and Willamette Passes between 11 AM Wednesday to 11 AM Thursday. Based on REFS ensemble guidance, there is also a 25-50% chance for snowfall rates of 1+ inch per hour at any given hour during this time period along these passes, with the highest chances occurring between 11 PM Wednesday and 5 AM Thursday. Meanwhile, lower snow amounts are forecast north of the Marion County Cascades; therefore, Winter Weather Advisories were issued for the north Oregon and south Washington Cascades instead of warnings. If you have plans to travel through the Cascades, make sure to pack an emergency supply kit and refer to ODOT/WSDOT for the latest road conditions and restrictions. West of the Cascades, minimal impacts are expected from the rain and wind. The highest chances for 48-hour rainfall exceeding 1 inch ending Thursday afternoon are around 40-60% across the southern Willamette Valley and 70-90% for the coast south of Astoria. As the cold front pushes through on Wednesday morning/early afternoon, southwesterly winds will strengthen with gusts up to 20-30 mph for interior valleys, with stronger gusts of 30-40 mph for higher terrain and along the coast. Chances for stronger wind gusts along the coast (50+ mph) and across the Willamette Valley/southwest Washington lowlands (40+ mph) are around 10-25% at any given hour during the frontal passage. Another potential impact for the lowlands is a 10-20% chance for thunderstorms Wednesday afternoon/evening. Cooler air aloft behind the cold front will increase atmospheric instability, and model soundings support this with skinny CAPE profiles and CAPE values between 100-150 J/kg. Any passing thunderstorms may produce lightning, brief heavy downpours that reduce visibility, small hail, and locally erratic winds. Lowland rain showers and Cascade snow showers continue on Thursday but gradually decrease throughout the day as the system weakens and exits the region. Thursday night to Friday morning, clearing skies and calm winds will lead to efficient radiational cooling and temperatures dropping into the low to mid 30s across interior valleys. This would support frost development over vegetation and metal surfaces. Given that April 1st marks the start of growing season, we may need to issue Frost/Freeze headlines during this time. -10 && .LONG TERM...Friday to Monday...Ensemble guidance remains in agreement that upper level ridging will build over the Pacific Northwest, returning dry weather and sunnier skies through the weekend. Above-average 500 mb heights also occur during this time, suggesting warmer temperatures and afternoon highs reaching the mid to upper 60s by the weekend. There is also a 50-80% chance for high temperatures exceeding 70 degrees Sunday and Monday along the I-5 corridor, with the highest chances across the Willamette Valley. Will note that there is some uncertainty Monday onward as half of ensemble members maintain the upper level ridge over our area and dry weather, while the other half shifts the ridge eastward and returns slightly cooler temperatures and slight chances (15-25%) for precipitation. -10 && .AVIATION...West to southwest flow aloft with mid-level moisture will maintain mid to lower level clouds today. Weak low pressure will maintain chances for light rain showers inland, including cloud obscuration along the Cascades. Expect predominately VFR conditions through 08-10z Wed. Probabilities for MVFR increase across the area to around 50% afterwards as a robust frontal system approaches the region. Light rain is likely to begin spreading across the area by 08z Wed, with heavier rain arriving at the coast after 12z Wed. South to southeasterly winds are expected to increase into Wednesday morning as well, becoming gusty, especially along the coast. KPDX AND APPROACHES...Predominately VFR conditions expected with mid to high level clouds persisting through this evening. Around a 30% chance of light rain showers will also continue across the area. A robust frontal system will approach later tonight into Wednesday bringing rain and increasing probs for MVFR (40-50%) after 08z Wed. Southeast winds around 8-12 kt expected to increase through Wed morning. Southerly winds with gusts to 20-25 kt will be possible by 18-20z Wed. /DH && .MARINE...Southerly winds increase tonight into Wednesday morning as an occluding cold front approaches the waters. Have issued a Gale Warning for southerly winds gusting up to 35-40 kt from 2 AM to 11 AM Wednesday. Expect an abrupt westerly shift in winds behind the frontal passage late Wed morning. Wind waves are expected to build on Wednesday in response to the increasing southerlies, becoming steep and choppy, with significant wave heights building to around 12 to 14 ft, highest over the southern waters. Seas will likely fall back to around 9 to 10 ft Wed afternoon. Surface low pressure moves over the northern waters late Wednesday, as breezy westerlies ease overnight into Thu morning. An increasing west swell will also push into the waters Wed night into Thursday, building seas to around 11 to 13 ft with a period of 12 seconds. This will likely maintain Small Craft to marginally hazardous seas conditions into Thursday evening. Marine conditions are expected to ease later in the week as high pressure rebuilds and northerly winds return to the coastal waters by the weekend. Seas are expected to subside to around 5 to 6 ft later Friday through the weekend. /DH && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Winter Weather Advisory from 5 AM Wednesday to 5 PM PDT Thursday for ORZ126. Winter Storm Warning from 5 AM Wednesday to 5 PM PDT Thursday for ORZ127-128. WA...Winter Weather Advisory from 5 AM Wednesday to 5 PM PDT Thursday for WAZ211. PZ...Small Craft Advisory from 2 AM to 5 PM PDT Wednesday for PZZ210. Gale Warning from 2 AM to 11 AM PDT Wednesday for PZZ251>253- 271>273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland

285 FXUS66 KMFR 312004 AFDMFR Area Forecast Discussion National Weather Service Medford OR 104 PM PDT Tue Mar 31 2026 .DISCUSSION...Overall, the forecast remains on track and the main changes involved upgrading/updating various wind and winter headlines for the Wednesday system. Shower activity continues across the region this afternoon, focused mainly along and west of the I-5 corridor. Widespread clouds mixed with some spots of sunshine is resulting in near normal temperatures for the area. Overall, not much change is expected through the afternoon and into the evening. A big change is coming beginning late tonight and continuing Wednesday into Thursday. Models continue to show a strong upper trough moving southward from the Gulf of Alaska. The leading edge of this system will be a cold front that will approach the coast later tonight, and move onshore Wednesday. The upper level cold pool will then move onshore into Washington/Oregon Wednesday night into Thursday. Pressure gradients in advance of this system increase Wednesday afternoon, with mid-level winds peaking around 55 kt. It will be windy everywhere, with gusts of 20-30 mph common, even for West Side areas. We expect widespread peak wind gusts in the 40-50 mph range for areas from the Cascades eastward, perhaps 55 mph in some areas. Wind advisories have been issued for portions of Lake/Modoc counties where winds will be strongest. The Shasta Valley will be breezy at least, due to the fairly strong pressure gradient, but the mid level flow will not be aligned with the terrain, keeping winds there weaker than may otherwise be expected, but still close to advisory level strength. Peak gusts of 40-45 mph are possible, but we`ll forego an advisory for now. Strong winds are also expected along the coast, but should remain just below warning levels. The capes and headlands could briefly see gusts up to 60 mph, but overall, gusts in the 40-50 mph range are the more likely scenario. The main frontal band will be accompanied by a period of moderate rainfall with the heaviest precipitation from the coast to the Cascades from late Wednesday morning through the afternoon. We are NOT concerned about flooding with this event, other than some minor/typical nuisance ponding of water on roadways. Since river levels are very low for this time of year, most of the rain expected from this system will be beneficial/welcome. Amounts of 1-3 inches are likely along the coast, with 0.50-1.00 inch common inland to the Cascades with 0.25-0.50 inch over the East Side. Snow levels of 5000- 5500 feet Wednesday will drop to 2500-3000 feet by Thursday morning. It looks like a pretty healthy snow storm for the Cascades and Siskiyous with 6-12 inches common above 5000 feet. The Winter Storm Watch has been upgraded to a Warning for the Cascades. A Winter Weather Advisory remains in place for the Highway 97 corridor from Chiloquin northward for Wednesday night into Thursday morning and we`ve added the Warner Mountains of Modoc County and the mountains of western Siskiyou County to the Advisory as well. The heaviest snow will fall near Crater/Diamond Lakes and near Willamette Pass where it will be a bit colder, with NBM probabilities showing a high probability (>80%) of >12 inches of snow. At Crater Lake (~7000 feet), the 48-hour probability of >18 inches of snow ending Thursday evening is now nearly 100%! All in all, expect winter travel impacts in the mountains and over some of the higher passes, especially at Lake of the Woods by Thursday morning. Main I-5 passes should be OK, but some slippery spots could develop at Siskiyou Summit and/or around Mt Shasta City/Snowman Summit early Thursday morning. With the core of the cold pool shifting into northeast Oregon and Idaho on Thursday, showers and even an isolated thunderstorm or two will continue for a while into Thursday afternoon, but then diminish rapidly around sunset Thursday evening as high pressure builds in. It should be noted that models are still showing a fairly high probability (50-70% chance) that temperatures drop into the low to mid 30s for the west side valleys by Friday morning. So, that will introduce some frost/freeze risk. Greatest risk of that occurring is in the Illinois Valley (Cave Junction/Obrien/Selma). The probability of temperatures less than 28F, however, are quite low, generally 10% or less. Models are showing the upper ridge rebuilding across the area Friday into the weekend, so look for temperatures to rebound to above normal levels again (highs in the 70s again west side valleys) along with little to no chance at precipitation. -Spilde/BR-y && .AVIATION (18Z TAFs)... Conditions are going to generally deteriorate through this cycle with widespread precipitation starting tonight. Precipitation will spread west to east and continue through tomorrow evening. Isolated thunderstorms are possible but confidence was too low to include at any of terminals at this time. Expect widespread MVFR to IFR conditions to develop tonight and continue through Wednesday morning. Breezy wind speeds are expected as a front passes through the region tonight. && .MARINE...Updated 1230 PM PDT Tuesday, March 31, 2026...Conditions generally improve today with seas subsiding to around 4 ft. However, seas are forecast to become steep late tonight with south gales eventually leading to very steep seas through early Wednesday afternoon. A Gale Watch has been upgraded to a warning for all waters. Steep to very steep seas are expected to become swell dominated Wednesday night and build to a peak Thursday morning. A hazardous seas warning has been issued to account for this threat late Wednesday afternoon through Thursday morning. Advisory strength north winds are likely to return late in the week while seas remain steep. && .MFR WATCHES/WARNINGS/ADVISORIES... OR...Winter Weather Advisory from 8 PM Wednesday to 11 AM PDT Thursday for ORZ029-030. Wind Advisory from 11 AM to 11 PM PDT Wednesday for ORZ031. Winter Storm Warning from 5 AM Wednesday to 5 PM PDT Thursday for ORZ025-027-028. CA...Winter Weather Advisory from 8 PM Wednesday to 11 AM PDT Thursday for CAZ080-085. Wind Advisory from 11 AM to 11 PM PDT Wednesday for CAZ085. PACIFIC COASTAL WATERS...Gale Warning from 2 AM to 2 PM PDT Wednesday for PZZ350-356-370-376. Hazardous Seas Warning from 2 PM Wednesday to 11 AM PDT Thursday for PZZ350-356-370-376. && $$ MNF/JWG

068 FXUS66 KEKA 312051 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 151 PM PDT Tue Mar 31 2026 .SYNOPSIS...Isolated to scattered rain showers continue today ahead of a cold frontal passage tonight. Gusty south winds are likely tonight as a front moves approaches the area. Widespread rain returns Wednesday. Mountain snow and coastal small hail are possible Wednesday night and Thursday morning. && .DISCUSSION...Light to locally moderate rain showers continue to move across the area, primarily focused in Del Norte, northern Mendocino, and southern Trinity Counties. Increased instability this afternoon might be able to support a thunderstorm in a stronger shower, though confidence is low on this. A stronger frontal system moves through the PacNW tonight into Wednesday. Southerly winds will increase ahead of the main frontal passage Wednesday morning. The higher elevations of Humboldt and Del Norte could see gusts up to 50 mph. Coastal Del Norte could see gusts up to 45 mph. Further south, peak gusts of 30 to 40 mph are likely for much of Humboldt and western Trinity. Lake County will also be breezy, however this will mostly be in the afternoon with west winds of 30 to 40 mph possible. The highest mountains and coastal headlands could see locally higher gusts up to 60 mph. Widespread light to moderate rain is likely across the area. Periods of heavy rain are possible for the North Coast, and especially in the King Range and the mountains of Del Norte and northern Humboldt. Total rain amounts range from around 2.0-3.0" in Del Norte, 1.0-2.5" in Humboldt and Trinity Counties, and 0.25-1.00" in Mendocino and Lake Counties. This will largely be beneficial rain, but some minor impacts (flooding in poor drainage areas and mud/rock slides) are possible in Humboldt and Del Norte with the heaviest rain. Snow levels will drop with this system, down to 5,000-5,500 ft Wednesday morning during the period of most precipitation. This will bring some snow down to Scott Mountain Pass. Snow totals there range from around 2 to 6 inches, depending on how low snow levels drop. Snow levels continue to drop into Thursday, and could be as low as 2,500 ft as stratiform rain turns showery. While precipitation is likely to be meager by this point, some light snowfall is possible on the highest passes of Highways 3, 36, 199, and 299. A Winter Weather Advisory has been issued for the Trinity Horn above 4,000ft due to melted snow freezing overnight while snow levels plummet, creating icy, hazardous roads. Additionally, with much colder air aloft, atmospheric instability will increase, particularly along the coast. Showers capable of producing accumulating small hail are possible, along with isolated thunderstorms. Much cooler temperatures are expected Friday morning with widespread near-freezing or freezing temperatures. Temperatures will generally trend warmer as high pressure begins to rebuild into the weekend. JB && .AVIATION...18Z TAFs...Southerly winds will increase late Tuesday through Wednesday while rainfall moves in with an approaching front. Winds near 925 mb (2000 ft AGL) will increase to 40 to 50 kts from the S to SSW starting 13Z Wednesday. Ceilings will mainly hold to MVFR levels. A well defined front will create a sharp windshift to a westerly direction beginning around 17Z in Del Norte and then pushing eastward through the afternoon as it passes. && .MARINE...Southerly winds are increasing across the waters Tuesday ahead of a frontal system, while seas range in the 4 to 6 area. Southerly winds will further increase Wednesday morning when localized areas of gale strength gusts spread through the northern waters. There will be a abrupt shift in wind direction to westerly as the front passes late Wednesday morning and into the afternoon. A steep westerly swell will start building in Wednesday night, reaching 10- 14 feet at 12 seconds on Thursday. Westerly winds will ease Thursday before northerlies quickly strengthen starting Thursday afternoon. The northerlies increase more Friday, and localized gales are forecast south of Cape Mendocino Friday afternoon through Friday evening. Calmer conditions are forecast to begin by late Saturday. && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Wind Advisory from 8 AM to 1 PM PDT Wednesday for CAZ101- 102. Winter Weather Advisory from 8 PM Wednesday to 11 AM PDT Thursday for CAZ107. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 5 AM to 3 PM PDT Wednesday for PZZ450. Small Craft Advisory from 2 AM to 10 PM PDT Wednesday for PZZ470. && $$ 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

927 FXUS66 KMTR 311854 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1154 AM PDT Tue Mar 31 2026 ...New SHORT TERM, LONG TERM... .KEY MESSAGES... Updated at 1152 AM PDT Tue Mar 31 2026 - Seasonably cool conditions with rain chances through Thursday - Above normal temperatures and offshore flow return Friday and continue over the weekend && .SHORT TERM... Issued at 1152 AM PDT Tue Mar 31 2026 (This afternoon through Thursday morning) It only took 29 days, but it`s finally raining. A stationary front is offering an area of convergence for its tropical moisture tap. Rain shower activity will continue to drift south through the day as surface high pressure tries to nose in from the Eastern Pacific Ocean. A gale force low in the Gulf of Alaska will put a stop to that as it heads to the Washington/Canada border. The attendant cold front will bring us a winter-like feel with below normal temperatures, gusty conditions, and rain. Southwesterly winds will increase ahead of the cold front with northwesterly winds developing in the post-frontal environment. Widespread gusts of 20-30 mph can be expected with gusts up to 40 mph in the highest terrain. Rainfall totals are expected to be in the 0.10"-0.25" range with locally higher totals in the higher terrain of the North Bay and locally lower totals in the Interior Central Coast. Slick roadways can be expected due to the dry spell that has allowed oil to accumulate. && .LONG TERM... Issued at 1152 AM PDT Tue Mar 31 2026 (Thursday night through next Monday) The pattern will quickly change Thursday afternoon as upper-level shortwave ridging noses in from the Eastern Pacific Ocean. The short wavelength of the aforementioned trough and ridge will tighten the pressure gradient. Strong northerly winds will result, primarily affecting exposed areas like the higher terrain and marine environment. The SFO-WMC pressure gradient is expected to become negative Thursday night as the wavelength moves inland, resulting in offshore flow. At 5 AM Friday, the ECMWF Ensemble mean is forecasting the gradient to be -9.81 mb while the GEFS mean is forecasting the gradient to be -7.76 mb. The 2 mb discrepancy is due to the ECMWF Ensemble showing a stronger high and stronger low closer together than weaker features farther apart in the GEFS. This uncertainty is propagated through Friday and Saturday with the ECMWF Ensemble bottoming out at -10.96 mb at 5 AM Saturday while the GEFS is well on its relaxing trend at -5.24 mb. Nonetheless, a moderate offshore flow event can be expected Thursday night through the weekend with a 35 knot 925 millibar jet streak across the North Bay. This will translate to gusts of 40 to 50 mph in the higher terrain, namely the North Bay Interior Mountains, East Bay Hills, and Eastern Santa Clara Hills. The ridge will also send temperatures soaring back to well above normal. && .AVIATION... (18Z TAFS) Issued at 1104 AM PDT Tue Mar 31 2026 Mostly VFR across the region with ceilings between 5k-15k feet. Winds are light and variable this morning but will become west- southwest this afternoon with rain showers tapering off. Winds ease overnight becoming light and variable as rain showers return early Wednesday morning. The greatest potential for rain showers will be over the North Bay and Bay Area terminals through 18Z Wednesday, shifting southward later in the afternoon/evening. Along with the rain, ceilings lower to sub-VFR with the greatest potential for IFR across the North Bay. Vicinity of SFO...VFR. West-southwest winds increase this afternoon and early evening before easing overnight and into Wednesday morning. This is when we expect MVFR conditions to return to the region by around 12Z Wednesday. In addition, VCSH has been added to the TAFs around 12Z Wednesday with -SHRA returning by 18Z when we may see lower end MVFR ceilings at times of heavier rain showers. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR. Lingering rain showers will persist through about 21Z that may produce MVFR ceilings. Otherwise, expecting west-southwest winds at KMRY with the potential for northwesterly winds at KSNS this afternoon. Winds ease overnight with MVFR ceilings returning late this evening and likely to persist into Wednesday morning. Rain should stay to the north of the Monterey Bay Terminals, depending on timing of our next frontal system forecast to move through. && .MARINE... (Today through Sunday) Issued at 1104 AM PDT Tue Mar 31 2026 Gentle southwesterly breezes today will increase to become moderate to fresh tomorrow ahead of the cold front. Fresh to strong northwesterly breezes will develop in the post-frontal environment Wednesday night into Thursday morning. Strong northerly breezes will develop Thursday afternoon and persist into Friday. Moderate seas will build to become rough Thursday into Friday. Widespread hazardous conditions are expected Thursday and Friday. Conditions improve by the weekend. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ SHORT TERM...Sarment LONG TERM....Sarment AVIATION...RGass MARINE...Sarment 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

778 FXUS66 KOTX 312231 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 328 PM PDT Tue Mar 31 2026 .KEY MESSAGES... - Snow over passes will impact travel on Wednesday and Thursday. - Rises on smaller creeks and streams on the Palouse Wednesday and Thursday. - Lowland rain Wednesday and Thursday regionwide. && .SYNOPSIS... Tuesday will have quiet weather with cooler afternoon highs and below freezing overnight lows. Unsettled weather returns to the region Wednesday into Thursday with lowland rain, mountain snow, and breezy conditions. Weather trends warmer and drier Friday into the weekend. && .DISCUSSION... Today through Thursday: The storm approaching the Northwest will begin impacting the Inland Northwest by early Wednesday morning with additional precipitation from the Cascades to northern Idaho. Mountain snow and lowland rain will encompass the Wednesday through late Thursday period. Snowfall amounts above 4,000 feet in the Cascades will range from 4 to 10 inches with the highest amounts being near the crest locations. The Okanogan Highlands, the northern Idaho Panhandle mountains including Lookout Pass will see 4 to 8 inches. A winter weather advisory was issued for the Cascade Crest zone to highlight the accumulating snow above 4,000 feet. One tricky part of this forecast period will be the fluctuating snow levels. As precipitation moves into the area early Wednesday, snow levels will be slightly warmer (higher or rising) and thus making it more difficult to accumulate snow on roadways. Then, overnight into Thursday the snowlevels will decrease (lower, cool) allowing additional accumulation to take place. Across the region, lowland rainfall amounts will range from 0.25 inches to 0.75 inches over the span of 36 hours or so. Rises on some creeks and rivers is expected, but no flooding is anticipated for our major rivers. The Washington and Idaho Palouse looks to have a 50-60% chance for receiving near 0.75 inches of precipitation for the coming days, which will result in rises on local rivers and creeks in an already moist soil base. Overnight temperatures dipping into the mid to low 30s and daytime highs in the upper 40s and low 50s will maintain mild enough conditions to prevent most places from seeing snow accumulate on area roadways except at those higher elevation mountain passes. Winds will begin to increase early Thursday with the surface frontal passage, focusing on the southeast corner of Washington and the Blue Mountains. The ridgetops of Garfield and Asotin county carry a 60% chance of seeing wind gusts over 40 mph. Elsewhere across the valleys of central and eastern Washington and the central Idaho Panhandle wind gusts up to 25-30 mph will be common on Thursday. /Dewey Friday through Monday: A ridge pattern will build into the region behind the exiting Low. A period of dry, warming conditions is expected. Ensembles are showing the next chance for precip will be late Monday and Tuesday of next week. Another deep Low moving into the Pacific Northwest. Highs will climb from the 50s into the 60s and low 70s. Overnight lows will be in the 30s to low 40s. /JDC && .AVIATION... 00Z TAFS: Scattered showers will lift off the Washington Cascades and Northern Blue Mountains around 7-9Z, becoming numerous across central and Eastern WA and into the Idaho Panhandle by 16z. For all terminals, precipitation will be rain. Conditions deteriorate slowly through late Wednesday morning and Wednesday afternoon. For KGEG and KCOE, visibility less than 5 sm and 3 sm are 50% and 30% respectively. Likewise the ceilings have a 40 to 70% chance of developing below 3000 ft and a 20 to 30% chance 1000 ft or less. 71/PDT ----------------------- 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 35 49 36 48 32 53 / 10 90 100 60 10 0 Coeur d`Alene 36 49 36 45 34 51 / 30 90 100 80 30 10 Pullman 36 50 34 44 33 52 / 20 90 100 80 20 10 Lewiston 39 55 40 51 37 57 / 20 80 100 50 20 0 Colville 29 47 36 53 32 55 / 10 90 90 80 10 0 Sandpoint 33 45 36 43 34 49 / 30 90 100 90 40 20 Kellogg 37 50 35 40 34 48 / 40 90 100 90 60 30 Moses Lake 34 53 36 58 32 60 / 10 80 90 30 0 0 Wenatchee 36 48 37 53 36 58 / 10 80 80 30 0 0 Omak 33 48 39 58 34 58 / 10 80 90 60 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... WA...Winter Weather Advisory from 11 AM Wednesday to 11 PM PDT Thursday for Western Chelan County. ID...None. && $$

007 FXUS66 KPDT 312309 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 409 PM PDT Tue Mar 31 2026 .KEY MESSAGES... 1. Showers and isolated afternoon thunderstorms through Wednesday 2. Midweek mountain snowfall, Significant snow Oregon Cascades *Winter Storm Warning and Advisories Issued* 3. Drier and warmer conditions over the weekend && .DISCUSSION... Current radar shows much of the precipitation is traversing off to the north with a line of showers moving across the northern Basin and Yakima Valley. Ground observations are showing no accumulations with this line of showers so the showers are likely virga. Lingering showers are expected to persist through the evening with light accumulations along the foothills of the southern and northern Blues of 0.03-0.05 inches with 30-50% confidence while the eastern mountains will see 0.10-0.15 inches with 70-90% confidence and OR Cascades will see snow showers above 4500 feet with accumulations up to 2 inches with 70-90% confidence while the lower slopes will see 0.05 inches of rain. LREF raw ensembles show that there is 50-60% of the members in agreement that the northerly shift will bring with it 15-25% chances of isolated thunderstorms through Grant and Cook counties this afternoon. Wednesday ahead of the front, LREF shows 15% probabilities of isolated thunderstorms along the leading edge of the front. Isolated thunderstorms would form along the western slopes of the eastern mountains through Grant, Cook and into southern Umatilla Counties. Wednesday and Thursday models show a strong upper level low will move in off the coast of B.C. and ahead of it will be another front. Models show this system to be robust with increased chances of mountain snow, low elevation rain and increased winds. Clusters do show some deviation with the models with timing, however, all models show a robust front making its way into the region Tuesday night/Wednesday morning. The front will move across the region bringing snow levels to near 2000 feet. This will allow for some snow showers across a good portion of the region with the highest amounts being along the Cascades. A Winter Storm Waning has been issued for the east slopes of the Or Cascades with models showing nearly 10-15 inches of accumulation along Santiam Pass with 60-80% of the raw ensembles are in agreement. A Winter Weather Advisory has been issued for the east slopes of the WA Cascades through Snoqualmie Pass due to the areas seeing up to 7 inches of snow 60- 70% confidence. Tollgate and portions of the northern Blues will see 4-6 inches of snow as well with 30-50% confidence. The eastern mountains will see up to 1-1.5 inches with 60-80% confidence. The lower elevations models are showing QPF amounts nearing 0.15-0.30 inches with 60-80% confidence. There is some shadowing showing up in the models runs and portions of the western Basin as well as through central and north central OR will only see 0.05-0.15 inches of rain Wednesday through Thursday with 50-70% confidence. Lastly, winds will become a bit breezy as the front moves through Thursday brining 70-80% probabilities of 25-35 mph gusts across the region. Thursday night into Friday morning models show the next incoming system coming in from off the coast. An upper level ridge will set up over the region bringing warmer and drier conditions. Clusters show that the main difference between the models will be positioning of the upper level ridge. Looking at in house model comparisons, temperatures will be anywhere from 5 to 10 degrees above seasonal normal through the Basin and adjacent valleys and 10-15 degrees above seasonal average for the Oregon potion of the CWA. Temperatures will start off in the low to mid 60s before increasing and seeing upper 60s to low 70s in some areas. Confidence in the temperatures is 50-70% peaking Sunday. 90&& .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... VFR conditions across most sites however a slow moving band of rain showers and moisture stretching W-E across nrn Oregon has ceilings IFR and MVFR KBDN/KRDM respectively. The forecast is for these ceilings to lift at least one category through the afternoon before returning to MVFR levels into the evening. MVFR ceilings may also impact KDLS late Tuesday evening as light rain begins. Rain spreads over the region through Wednesday morning. Elsewhere, ceilings will hover between 5-7kft but ceilings will be reduced going by Wednesday morning with the next storm. Winds will stay light and below 10kts at all terminals through the period. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Scattered showers will lift off the Washington Cascades and Northern Blue Mountains around 7 9Z, For all terminals, precipitation will be rain. Conditions deteriorate slowly through the overnight and Wednesday afternoon. For KPSC, chances for ceilings below 1000ft ramp up to only 20% through 18z Wednesday morning, however go to around 80% for the MVFR category range. && .Preliminary Point Temps/PoPs... PDT 38 57 34 52 / 40 90 90 50 ALW 40 57 38 52 / 30 90 100 70 PSC 38 59 39 60 / 20 90 80 20 YKM 35 52 31 58 / 20 90 50 10 HRI 38 58 36 57 / 30 90 80 30 ELN 32 47 32 50 / 20 90 70 20 RDM 36 55 27 48 / 40 90 70 40 LGD 38 55 33 46 / 80 90 100 80 GCD 38 53 30 44 / 80 100 100 90 DLS 41 55 37 57 / 60 100 70 30 && .PDT WATCHES/WARNINGS/ADVISORIES... WA...Winter Weather Advisory from 11 AM Wednesday to 11 PM PDT Thursday for WAZ522. OR...Winter Storm Warning from 5 AM Wednesday to 5 PM PDT Thursday for ORZ509. && $$ DISCUSSION...90 AVIATION...71

573 FXUS65 KREV 312025 AFDREV Area Forecast Discussion National Weather Service Reno NV 125 PM PDT Tue Mar 31 2026 .KEY MESSAGES... * Snow showers above 8000 feet and valley rain today, with falling snow levels by mid week. * Wednesday into Thursday will feature a colder air mass and strong downsloping winds that will create travel impacts for land, air, and water. * The end of the week into the weekend will see a return of warmer temperatures and lighter winds. && .DISCUSSION... Precipitation has been falling around the region this morning, bringing wet roads across the Sierra, mostly in the Tahoe Basin as of this writing. We expect to see this continue, with periods of showers throughout the day. Snow levels are starting around 7500 to 8000 feet, and will begin to fall toward 7000 feet by sunset this evening. During the afternoon hours, some showers may be capable of producing lightning, especially over the Basin and Range today as 15- 25% chances for lightning appear in ensemble guidance. Overnight, this lightning threat shifts to the Sierra, highest (10-15%) west of the Tahoe Basin. As Wednesday arrives, a noticeable temperature drop arrives for overnight lows as the next weather feature drops in along the Alaskan coastline into the Pacific Northwest. The placement of this trough will allow not only colder air to filter in, but also bring strong to damaging downsloping wind gusts by Wednesday afternoon. Gusts of 100+ mph will reach Sierra ridges late Wednesday into Thursday, while ample mid-level dry air will be allowed to mix to the surface. Wind prone areas could see gusts up to 80 mph with gusts to 60 mph possible down to valley floors along the Sierra Front. Across the Basin and Range, winds will gust near 60 mph across Mineral County, while Pershing and Churchill will see gusts to 50 mph. This brings all kinds of concerns to the region, from bumpy flights in and out of area airports, to waves on Lake Tahoe up to 6 feet and up to 5 feet on Pyramid Lake. Blowing dust could be lofted over the Basin and Range as westerly winds cross dry lake beds and sinks. Recreating outdoors may prove difficult and uncomfortable with whipping gusts and cold temperatures across the entire region. Finally, there is also a risk of elevated fire weather conditions during the Wednesday into Thursday time period. We advise foregoing any activity that could create a spark, since winds are capable of carrying sparks, and we have already seen a couple small fires appear in Monday`s winds. This wind activity will remain overhead through late Thursday afternoon into evening. Snow levels will fall to around 3,500 to 4,000 feet by early Thursday morning, when the bulk of the moisture will have moved out over the Basin and Range, with only lingering showers across northeastern California. Shower activity will continue to advance eastward through Thursday, although the Sierra could continue to see lingering showers into the evening. Despite the lowering snow levels, recent warmth and high sun angle will keep roads mostly wet as opposed to allowing snow to accumulate. The only caveat would be the early Thursday morning commute, when the colder air may allow for some slushy accumulations along the side of area roadways above 7000 feet. Overall accumulations will be greatest along the Sierra crest where generally 6 to 12 inches will fall over Mono County. Expect up to 10 inches along the ridges overlooking the Tahoe Basin, with a 35% chance for Donner Pass to add up to 12 fresh inches of snow. Lake level could see accumulations of 1 to 4 inches with the higher accumulations along the western shore. Friday morning will be the coldest of the week. So, if you`ve already got outdoor plants popping out of the soil, you may want to consider protecting them by Wednesday night through Friday morning to keep them from wilting. As for showers, we could see some lingering showers over the Basin and Range, but the majority of the region will be on a warming and drying trend by Friday that will bring us into the weekend. Our longer range outlooks suggest that warming trend will be met with a drying pattern, although some guidance suggests we could be looking at another mid week system for next week, although confidence is low at this time. HRICH && .AVIATION... * SHRA will continue across KTVL and KTRK this afternoon, with periods of spillover into KRNO/KCXP/KMEV. Intermittent periods of showers will also appear over KMMH today. Amounts will be light for KRNO/KMEV/KCXP/KMMH while KTVL/KTRK could accumulate 0.5"- 1.00" of liquid water. LLWS and turbulence has been present over the Sierra terminals today, which will relax into the afternoon, and then intermittent periods of LLWS through 18z Wednesday. * Increasing westerly winds will become strong gusts Wednesday into Thursday, bringing more LLWS and turbulence with FL100 winds around 75-80 kts, mixing gusts of up to 40 kts to leeside valley terminals KRNO/KMEV/KCXP by Wednesday 21z and lasting through 15z Thursday. HRICH && .AVALANCHE... Two systems this week will bring rain and snow chances to all avalanche center terrain by Thursday. * Through early Wednesday morning: Snow levels are expected to drop below 7.5 kft for all terrain by sunset today, but coincides when precip will be wrapping up. SWE and snowfall values will be highest in ESAC terrain with up to 1.25" of SWE and up to 14" of snowfall; locally lower as you move northward with 0.5-1" of SWE and 4-10" of new snow. SLRs will be between 7-11:1. Chances for lightning today have decreased to 10% or less. * Wednesday - Thursday: Snow levels start out around 6.5 kft before rising slightly to 7-7.5 kft by sunset Wednesday night. As the cold air moves in, snow levels plummet below 5 kft by sunrise for the Tahoe Basin and by mid-morning for Mono county. Snowfall totals of 4-10" with locally higher (up to 16") in far northern reaches of SAC terrain. Otherwise, 4-10" for BAC terrain with 2-8" for ESAC terrain. SWE values around 1-1.25" for the Tahoe Basin, tapering to 0.2-0.6" for BAC and ESAC. SLRs a bit higher due to the colder nature of the storm, up to 9-12:1. -Giralte .FIRE WEATHER... Strong to locally damaging downsloping winds are anticipated for Wednesday evening into Thursday morning. A High Wind Watch is in effect for the Sierra and Sierra Front from Wednesday afternoon through Thursday morning. Westerly winds will bring 70 to 80 mph gusts to wind prone locations, such as Washoe Valley and favored canyons across Mono County. With the concentration of strongest gusts arriving overnight, this will lead to poor overnight recoveries Wednesday night. Recent warmth and eroding snowpack exposing areas of vegetation may have allowed some fuels to become receptive to sparks, and high winds could carry sparks into those receptive fuels. HRICH && .REV Watches/Warnings/Advisories... NV...Wind Advisory from 2 PM Wednesday to 11 AM PDT Thursday NVZ001- 004-005. High Wind Warning from 2 PM Wednesday to 11 AM PDT Thursday NVZ003. Winter Weather Advisory from 5 AM Wednesday to 8 AM PDT Thursday NVZ002. CA...Wind Advisory from 2 PM Wednesday to 11 AM PDT Thursday CAZ070. High Wind Warning from 2 PM Wednesday to 11 AM PDT Thursday CAZ071-073. Winter Weather Advisory from 5 AM Wednesday to 8 AM PDT Thursday CAZ072. Winter Weather Advisory until 5 AM PDT Wednesday CAZ073. && $$

472 FXUS66 KSTO 311954 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 1254 PM PDT Tue Mar 31 2026 For additional details on weather and expected impacts over the next 7 days, please visit weather.gov/sto/briefing. .KEY MESSAGES... - Potential for strong to severe thunderstorms in the northern Sacramento Valley and Sierra mountains/foothills this afternoon and evening. Primary hazards: 1 inch hail, weak tornadoes. - Winter Weather Advisory in effect from 5 AM Wednesday to 8 AM Thursday for the western slopes of the Sierra above 6000 feet. - A quick-moving system brings precipitation, thunderstorm chances, and breezy to gusty south winds to the area today through Thursday AM. - North to east winds develop on Friday, with dry and warm weather continuing into the weekend accompanied by Minor HeatRisk. && .DISCUSSION... ...Today-Thursday... A fairly progressive system brings scattered light to moderate rain, mountain snow, breezy to gusty southerly winds, and isolated thunderstorms (cells may be strong to severe) to the region today through Thursday AM. Snow amounts have trended up with the latest forecast and as a result, a Winter Weather Advisory is in effect from 5 AM Wednesday to 8 AM PDT Thursday for the western slopes of the Sierra above 6000 feet. Snow levels will be between 6500-7000 for most of the day on Wednesday, before lowering to 6000-6500 feet that evening. A few snow showers will linger over the Sierra Thursday morning, but the majority of precipitation will have exited the region. Currently 5 to 12 inches are forecast above 6000 feet, but higher accumulations are expected along the peaks. The threat for isolated thunderstorms exists through the Sacramento Valley and Sierra foothills today with probabilities around 15-25%. A few strong to severe isolated thunderstorms may develop across the northern Sacramento Valley and Sierra foothills this afternoon and evening as well. The primary threats being severe hail (1.00"+) as the primary hazard given sufficient CAPE and 0-6km shear along with chances for brief, weak tornadoes. Thunderstorm chances continue on Wednesday as well, mainly over Shasta County. Periodic light to moderate beneficial rainfall will continue today through Thursday morning, with the majority of accumulations expected over Shasta County, mountains, and Sierra foothills. Additionally, breezy southerly winds will accompany this system as well, with gusts of 25-35 mph in the Valley; strongest in the northern Sacramento Valley and NE Foothills. Stronger south- southwesterly wind gusts of 35-45 mph in the mountains will also be possible on Wednesday. ...Friday-Monday... By Friday, we will begin to dry out as the weather system moves into the Northern Plains and ridging builds over the eastern Pacific and Pacific northwest. This will allow for drying and north to east winds to develop across the area. Current NBM probabilities of 35 mph or more on Friday are around 60-90% along and west of the I-5 corridor. High temperatures are forecast to rise back into low to mid 80s in the Valley by Saturday and through early next week, prompting the return of Widespread Minor HeatRisk in the Valley on Sunday. && .AVIATION... General MVFR to VFR conditions over the next 24 hours across the area from -SHRA and additional cloud cover. Periods of IFR to MVFR conditions possible over the northern Sac. Valley from 18z Tues to 03z Wed from scattered thunderstorms over the area. South to southwest gusts 10 to 20 kts, up to 30 kts over the northeastern foothills into 12z Wed before increasing to 15 to 30 kts north of Interstate 80 through 18z Wed. Gusty winds 20 to 40 kts over the Sierra into 12z Wed before increasing to 35 to 45 kts through 18z Wed. && .STO WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from 5 AM Wednesday to 8 AM PDT Thursday for West Slope Northern Sierra Nevada. && $$

192 FXUS65 KMSO 311802 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 1202 PM MDT Tue Mar 31 2026 .DISCUSSION... KEY MESSAGES: - Significant closed low pressure system moving through the region Wednesday night through Friday bringing widespread snow and cooler temperatures. - High pressure returns this weekend, bringing warming and drying. The Northern Rockies will remain under a moist west-southwest flow through Wednesday ahead of an approaching Pacific trough. High mountain passes south of I-90, including Lolo, Lost Trail, and Homestake, may see nuisance snow accumulations through tonight, though impacts will remain localized. While widespread showers develop Wednesday, rising snow levels (5000 to 6000 feet) will limit accumulations to the highest terrain. The primary forecast challenge arrives late Wednesday night through Friday as the trough evolves into a closed low. While a cold front is expected to drop snow levels to 3000 feet by Thursday morning, uncertainty remains regarding the exact track and timing of the closed low. Small latitudinal shifts in the center of this feature will dictate where the heaviest precipitation falls. Current guidance favors a heavy, wet snow event for the Seeley/Swan and Butte/Blackfoot regions Thursday into Friday morning, where upslope flow and wrap-around moisture are most likely to overlap. Given the high-moisture content of snowfall, tree damage and power outages are a concern. However, because the exact position of these heavy precipitation bands often remains volatile until 24 hours before onset, residents and travelers should anticipate adjustments to the current Winter Storm Watches. On Friday, the system will exit the region, bringing continued light snowfall under northwest flow aloft and cooler temperatures. High confidence ( >80%) exists for a transition to a warmer, drier regime this weekend as a high-pressure ridge builds over the region. && .AVIATION...The Northern Rockies will experience periods of mountain obscurations and localized valley MVFR conditions through Wednesday as a moist west-southwest flow prevails ahead of an approaching Pacific trough. Primarily south of the I-90 corridor, including terminals near KMSO and KBTM, intermittent light snow will impact mountain passes through tonight, though valley floors should remain VFR. By Wednesday, a more widespread increase in shower activity is expected; however, rising snow levels to between 5000 and 6000 feet will transition most terminal impacts to rain, with snow-related IFR/LIFR risks and icing becoming increasingly confined to the higher terrain and mountain crests. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...Winter Storm Watch from Thursday morning through late Thursday night for Bitterroot/Sapphire Mountains...Butte/Blackfoot Region...Potomac/Seeley Lake Region. ID...Winter Storm Watch from Wednesday evening through late Thursday night for Southern Clearwater Mountains. && $$

528 FXUS65 KBOI 312019 AFDBOI Area Forecast Discussion National Weather Service Boise ID 219 PM MDT Tue Mar 31 2026 .KEY MESSAGES... - Light rain and mountain snow tonight and Wednesday. Isolated thunderstorms this evening. - Strong cold front Wednesday afternoon followed by colder air and significant rain and snow Wednesday night through Thursday morning. Snow level lowering to 3000-3500 feet by Thursday morning, with accumulation 3 to 6 inches, locally 9 inches, in Idaho north of the Snake Basin. Slight chance of thunderstorms Wednesday afternoon. - Very windy in the Camas Prairie and Western Magic Valley Thursday afternoon, with gusts to 45 mph from the west. && .SHORT TERM /Through Thursday Night/... Light rain and snow tonight with snow level remaining above 6000 feet MSL. Enough instability for isolated thunderstorms until sunset. A strong north Pacific cold front will pass through our CWA Wednesday afternoon followed by colder air, rapidly lowering snow level, and significant rain and snow Wednesday night, decreasing Thursday. A slight chance of thunderstorms as the front passes. Snow level lowering to valley floors in eastern Oregon late Wednesday night, and almost to valley floors in Idaho Thursday. The supporting deep upper level low, near 52N/143W this afternoon, is forecast to pass directly through our CWA Thursday, with cold air aloft producing enough instability for graupel showers, and a slight chance of thunderstorms in all areas Thursday. Becoming very windy in south-central Idaho Thursday afternoon with westerly gusts increasing to 45 mph. A Wind Advisory has been posted for the Camas Prairie and western Magic Valley. Decreasing showers, mainly of snow, Thursday evening, and becoming quite cold by Friday morning, with lows in the teens and 20s with only the lower southern Idaho Valleys staying above 30 degrees. && .LONG TERM /Friday through Tuesday/... Warming and drying is the story in the long term. As the upper low in the short term heads eastward, northerly flow on Friday keeps things a few degrees below normal for this time of year. A building high pressure ridge over the area will warm temps 5-10 degrees each day through Monday, until temps reach 10 degrees above normal early next week. Highs in the valleys will be in the low 70s, mid 60s in highlands, and upper 50s in mountain valleys and ridges. After a warm Tuesday, an approaching low pressure system makes landfall on the coast, hinting at a cool and wet pattern after the long term. && .AVIATION /18Z Tuesday through Wednesday/... Issued 1147 AM MDT TUE MAR 31 2026 Showers increasing across the area, bringing MVFR-IFR in mountains and near KONO. A 20-30% chance of thunder north and west of KMUO exists this afternoon as showers strengthen. Small hail/graupel are likely out of thunderstorms. Shower activity decreases tonight before more rain moves in tomorrow. Surface winds: becoming SW-NW 5-15 kt, gusts up to 30 kt possible near storms. Winds aloft at 10kft MSL: SW 25-35 kt. KBOI...VFR and overcast. Rain showers increase this afternoon with a 30% chance of thunder. Thunderstorms could produce small hail/graupel and wind gusts up to 25 kt. Surface winds: light and variable, staying generally SW-SE. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Wind Advisory from noon to 6 PM MDT Thursday for IDZ016-028. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise SHORT TERM...LC LONG TERM....JM AVIATION.....JM

360 FXUS65 KLKN 311934 AFDLKN Area Forecast Discussion National Weather Service Elko NV 1234 PM PDT Tue Mar 31 2026 .KEY MESSAGES... * Periods of valley rain and mountain snow beginning this evening, persisting through Wednesday * Changeover for northern NV locations from rain to snow early Thursday morning * Strong winds for northern and central NV Wednesday and Thursday afternoon * Fair weather conditions this weekend with a gradual warming trend && .DISCUSSION... (This evening through next Monday) WEATHER PATTERN OVERVIEW: The first of two weather systems is pushing into the Silver State this evening increasing precipitation across the area. PWat values in the 0.5-0.6 range are running about twice the daily average for March 31st meaning moisture availability over the area is plentiful for meaningful precipitation amounts. The first system is the warmer of the pair in which mainly valley rain and some highest elevation mountain snow will accumulate. The second wave, fast on the heels of the first, pushes into the Great Basin by Wednesday afternoon. This second system creates a tighter pressure gradient over northern NV Wednesday and eventually northern and central NV on Thursday to create criteria level winds needed for a Wind Advisory. In terms of moisture the best chances for meaningful precipitation will be over northern NV. Almost all precipitation that falls Wednesday will be in the form of rain but strong cold front pushes through the region Wednesday night. This will send snow levels crashing to below valley floors as a changeover to snow takes place over much of the area early Thursday morning. The unseasonably hot weather we have endured for much of March may inhibit accumulations in valleys somewhat. Current projections are a dusting to an inch along the I-80 corridor (amounts closer to 2 for summits and peaks). Higher valley amounts are possible in northern Elko County along US-93 and SR-225 where better moisture resides. 3-5 inches in locations such as Mountain City, Owyhee, Jarbidge, and Jackpot are possible. Model disagreement exists in shutoff of moisture. ECMWF guidance dries the system out sooner than its GFS counterpart on Thursday. Northern NV peaks and ridges could potentially see 1-2 feet of needed snowfall between the two systems this week. Behind the second wave ridging builds back into the SW CONUS beginning Friday. The weekend looks to be pleasant until gradually warming temperatures and fair skies. FORECAST CONFIDENCE & DEVIATIONS: High confidence remains in valley rain and mountain snow this evening through Thursday. Thunder was removed from Wx grids this evening and Wednesday as no appreciable model was indicating instability present, not even NAM. That combined with cloud cover today keeping temperatures somewhat subdued led to increased confidence in lack of convection with this system. NBM90 was also utilized in Wind and WindGust grids through 06Z THU. && .AVIATION... Upper troughing is pushing moisture across Nevada today, bringing in VCSH and -RA conditions to the northern terminals and moving southeast towards the central terminals this afternoon. VFR conditions will the be dominant category, however MVFR and lower conditions are possible with passing storm systems. Precipitation is expected to fall as rain throughout the day with much cooler temperatures behind the front. Any lingering precipitation may transition to snow overnight, however much of the moisture will have passed by then. Breezy westerly winds up to 10-15 kts with gusts as high as 20-25 kts across all terminals, dissipating this evening. More ongoing weather is expected to continue overnight into tomorrow morning as a stronger low pressure system moves in shortly after. && .LKN Watches/Warnings/Advisories... Wind Advisory from 10 AM Wednesday to 2 AM PDT Thursday NVZ030-031-034. && $$ DISCUSSION...99 AVIATION...97