####018012048#### FXUS65 KRIW 042016 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 116 PM MST Thu Dec 4 2025 .KEY MESSAGES... - Breezy to windy condition across parts of the state today with light snow increasing in coverage over western WY this evening. - The first significant snowfall for the mountains of western WY is on final approach. Periods of light to moderate snowfall will be possible tonight through Saturday afternoon across the lower elevations with moderate to heavy snow expected for the western mountains. - Widespread breezy to gusty winds are expected Friday afternoon through the overnight hours. Gusts of 25 to 35 mph will be common across the Wind Corridor with wind prone locations seeing gusts around 50 mph. - The upcoming week looks to see mild and dry conditions return to eastern WY with active weather possibly continuing across the west. && .UPDATE... Issued at 108 PM MST Thu Dec 4 2025 The overall forecast remains for the most part on track with only a few slight adjustments. Firstly, temperatures today will be near seasonable west of the Divide and on the warmer side of seasonable east of the Divide. Highs will range in the mid to upper 30s with some locations nearing 40 east of the Divide, temperatures west of the Divide will be cooler mainly around the upper 20s. Gusty winds have arrived at some locations this afternoon with gusts of 40 or more mph already occurring at Cody and Rock Springs. The upper Wind River Basin is also seeing some gusty winds currently with gusts of 30 to 40 mph. These winds are forecast to weaken slightly overnight but still remain windy through the overnight into Friday. As for the next few days the main focus continues to be the incoming system which will bring rounds of moderate to heavy snow across western WY. The previous discussion still does a good job of explaining the setup along with the timing of the system. Overall the forecast remains mostly unchanged with the only deviation being a slight shift in snowfall amounts. Western mountains are still expected to see anywhere from 10 to 20 inches with the higher elevations seeing 2 to 3 feet. As more hi-res models become available it seems there has been a slight increase in snowfall amounts across the Bighorns. Amounts look to have increased in coverage with much of the range north of Powder River Pass forecast to see 10 to 18 inches now. The other shift is over lower elevations of western WY this includes Jackson Hole, Star Valley, southern Lincoln County, and the upper Green River Basin. These locations have seen snowfall amounts drop slightly compared to overnight. A likely reasoning for this is the warmer temperatures that will be present Friday and Saturday. Forecasted temperatures at times may be flirting with the freezing mark with portions of Jackson Hole possible getting into the mid 30s. However, even with these slightly warmer temperatures, precipitation is still expected to fall as snow but accumulation may be hindered at times. Storm total amounts for these lower elevations look to range from 5 to 10 inches with lesser amounts of 1 to 4 inches nearby Pinedale and over southern Lincoln County. Winds increase during the afternoon/evening Friday across much of the state. This increase in winds combined with snowfall will likely make travel very difficult over portions of western WY Friday night through Saturday morning. Besides western WY, winds are forecast to increase east of the Divide with widespread gusts of 35 to 45 mph along the Wind Corridor from Casper to Rock Springs. An isolated snow shower or two may be possible Friday night through Saturday morning with most expected to remain dry. No additional winter highlights have been issued or changed. && .DISCUSSION... Issued at 343 AM MST Thu Dec 4 2025 10Z water vapor imagery shows strong north-northwest flow aloft with ridging over the Pacific and a broad trough to the east. An embedded weak disturbance is entering the northwest portions of the state. This will provide weak support for orographically-induced light snow chances (20%-40%) across higher elevations of Yellowstone National Park and the Teton Mountains through just after sunrise. Some breezy 20 to 30 mph winds will also be present from Rock Springs to Casper as the weak disturbance traverses the state through the morning. Seasonal temperatures are forecast today ahead of the incoming weather system. By the early afternoon, the first "wave" of this multi-day snow across the west and widespread gusty winds will approach. This first wave, currently (10Z) moving onshore over the Pacific Northwest, will mostly be a wind maker across the Absarokas (including the Cody area) , upper Wind River Basin, and across the Wind Corridor. This wind will be a result of a tightening pressure gradient ahead of the second "wave" and associated cold front later tonight. Gusty winds of 30 to 35 mph will be common across the aforementioned locations, with isolated gusts of 50 mph possible. Snow with this first wave will be confined to western Wyoming. Snow amounts this afternoon (from 11AM to 5PM) are forecast to be up to 0.5 inch across Jackson and Star Valleys and much of Yellowstone. The Tetons and high elevations of Yellowstone could see around 2 inches during this time frame. The second wave begins around sunset tonight as upper level divergence is enhanced over western Wyoming, thanks to being in the left exit region of a 125kt-150kt upper level jet. With abundant moisture filtering into the region and enhanced lift, due to orographics and upper level divergence, moderate to heavy snow is expected from sunset tonight through early Friday morning for the western mountains. During this time frame, snow amounts across the Teton, Gros Ventres, Salt River, and Wyoming Mountain Ranges and high elevations of Yellowstone range from 6 to 12 inches. As for the western valleys and low elevations of Yellowstone, snow amounts overnight tonight generally range from 1 to 3 inches. A lull in moderate to heavy snow is currently forecast between sunrise and midday Friday as the upper level jet shifts east over Wyoming. However, light snow will likely (90% chance) be falling during this time. Once the 125kt-150kt jet is overhead, the third wave begins early Friday afternoon and continues through Saturday morning. During this time, moderate to heavy snow is forecast across most of western Wyoming. Snow totals across the Teton, Gros Ventres, Salt River, and Wyoming Mountain Ranges range from 1 to 2 feet with the highest elevations seeing 3 feet. Thus, the Winter Storm Watch has been upgraded to a Winter Storm Warning beginning 5PM tonight and continuing through 2PM Saturday. Travel over Teton, Togwotee, and Salt River Passes could become very difficult, especially during both "waves". Winter Weather Advisories have also been issued for the Upper Green River Basin, the western Wind River Mountains, the Absarokas, Yellowstone, and Jackson and Star Valleys. Total snow amounts of at least 7 inches (80-90% chance) are forecast for Jackson and Star Valleys, Yellowstone, and the Upper Green River Basin. For these locations, the probabilities of at least 8 inches ranges from 40% to 80% over a 40+ hour period so opted only for Winter Weather Advisories at this time. Higher elevations of Yellowstone (Pitchstone Plateau) could see upwards of 2 feet, however, because these areas are largely untraveled, kept with the Advisory. Similar thinking swayed the thinking for the western Wind River MOuntains, the Absarokas, and the western Bighorns, with snow amounts between 8 and 12 inches. Locally higher amounts are possible (70%) across the highest elevations of these mountain ranges. It is important to note that gusty winds look to accompany the moderate to heavy snow, leading to reduced visibilities. With the strong upper level jet moving overhead Friday afternoon, winds begin to ramp up across the Wind Corridor and the Absarokas with frequent 25 mph to 35 mph gusts. This will likely (80-90% chance) translate to frequent gusts of at least 35 to 40 mph. Wind prone locations, such as South Pass and Muddy Gap, could potentially (50-80% chance) see gusts around 50 mph. Gusty 30 to 40 mph drainage winds across the upper Wind River Basin look to develop (90% chance) late Friday into Saturday as well. As the jet moves overhead, 700mb winds of 50kts to 60kts are forecast to develop over southern Wyoming, the Absarokas and the Upper Wind River Basin late Friday evening into the overnight hours. There is a 50% chance for wind gusts 60+ mph to occur in these areas as a result of the jet max moving overhead and mixing these stronger winds to the surface. Similar conditions look to develop through the rest of the Wind River Basin and northern Johnson County between 09Z and 12Z Saturday. These potentially high winds could last through Saturday morning, before gradually decreasing after 21Z Saturday. The upper-level jet begins to weaken and shift south during the day on Saturday, bringing an end to the impacts of the winter system. Ensemble guidance is in consensus that the northwest flow will persist Sunday into the early parts of next week, allowing for light snow to chances (30-80%) continue across the west. Elsewhere, dry conditions and a warm up to above normal temperatures is also looking more favorable. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1106 AM MST Thu Dec 4 2025 West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals. Light snow and MVFR conditions linger at KJAC late this morning. An improvement to VFR is expected early this afternoon though will have to watch trends closely for a possible extension of light snow impacts. Remaining terminals will be VFR through the afternoon with a gusty west wind at KRKS. More persistent snow will push into western Wyoming by sunset. This will bring deteriorating conditions at KJAC around this time, with IFR conditions expected by 01Z. KJAC is then expected to persist IFR through most of Friday morning. Confidence is lower on snow making it farther east, with KPNA having the best chance of MVFR conditions overnight. KRKS will continue to see a west wind through the period with gusts generally over 20 knots. Frequent mountain obscurations are expected through the period. East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals. Snow will have a more difficult time moving east of the Divide. The primary impact from this system will be strong wind at KCOD. Gusts will peak over 40 knots through this evening, dropping only slightly overnight. KCPR will see a southwest wind through the daylight hours today gusting to around 30 knots. Otherwise, terminals will remain VFR through most of tonight. Cloud decks will lower around 12Z Friday, with MVFR ceilings expected at KCOD, KCPR, and KWRL through the end of the period. KCPR will have the best chance of light snow late in the period and have included a PROB30 group to account for this. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .RIW WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from 5 PM this afternoon to 2 PM MST Saturday for WYZ001-002-008-013-014-023-025. Winter Storm Warning from 5 PM this afternoon to 2 PM MST Saturday for WYZ012-024. && $$ UPDATE...Dziewaltowski DISCUSSION...Gerhardt AVIATION...Myers ####018003856#### FXUS65 KLKN 042016 AFDLKN Area Forecast Discussion National Weather Service Elko NV 1216 PM PST Thu Dec 4 2025 .KEY MESSAGES... Updated at 1056 AM PST Thu Dec 4 2025 * Light rain/snow showers are likely across Northern Nevada this evening through Saturday evening * Gusty winds in northern Elko County Saturday && .DISCUSSION... (This afternoon through next Thursday) WEATHER PATTERN OVERVIEW: Models continue to track a weak shortwave riding upper level northwesterly flow into the area Thursday night. High pressure to the west continues to direct northerly flow in its eastern flank across the western CONUS. Vorticity with this system is mediocre at best, but frontogenesis over northern Elko County early Friday morning will help to initiate snow showers over the area. This FG is collocated with where highest snowfall amounts for valley floors exist in the Owyhee River Basin and along the northern NV border. Models continue to push accumulating snow further south into central NV valleys in northern Eureka and White Pine counties. Better moisture values continue to buoy this notion of snow further south though accumulation totals for valley floors continues to range from a dusting to less than inch. Better accumulations exist for Elko County high elevations and peaks where over a foot of fresh snowpack is forecast, especially for the Ruby Mountains and Jarbidge Wilderness Area. Current model run initiates snow over southeastern Elko County and northern Eureka and White Pine Counties sooner this evening, but also initiates a temperature warm up earlier Friday morning as winds back more westerly. This warmup will increase snow levels above 6500 feet and change precipitation for lower elevations to rainfall. A tighter pressure gradient over northeastern NV will create stronger surface winds Friday evening through Saturday. Cautious driving should be practiced along I-80 and US-93 in Elko County. Moisture advection from the west-northwest reinforces available moisture over the northern half of the state Saturday AM keeping chances for light shower activity over the area through Saturday evening before a dryout Sunday AM. This decrease in moisture is in response to the high pressure to the west encroaching on the SW CONUS. Monday evening into Tuesday a shortwave slides its axis along the northern NV border though lack of moisture and forcing over the region confines precipitation chances to the northern border. Models are beginning to resolve a large trough impacting the Great Basin towards the end of next week though timing and impacts are beyond the current forecast period. FORECAST CONFIDENCE & DEVIATIONS: High confidence exists in a weak system that will bring precipitation to northeastern and east- central NV Friday through Sunday AM. Moderate confidence exists in exact timing of snowfall and changeover to rain in the valleys as well as accumulation amounts for elevation regions and peaks in northeastern NV. Low confidence exists in the timing and impacts of a large upper level trough layer next week. No major grid changes are needed at this time. && .AVIATION... Intermittent MVFR and IFR conditions are expected Thursday afternoon through Friday as CIGs lower and precipitation chances in the form of snow and rain showers increase at KEKO by 03Z Friday, followed by KBAM, KWMC, and KENV between 04Z and 07Z. CIGs will lower to below 1000ft in the presence of rain and snow showers lowering VIS in the process. Precipitation at all terminals except for KTPH is forecast through Friday afternoon. && .LKN Watches/Warnings/Advisories... None. && $$ DISCUSSION...99 AVIATION...99 ####018004744#### FXUS63 KGRB 042016 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 216 PM CST Thu Dec 4 2025 Forecast discussion for routine afternoon forecast issuance .KEY MESSAGES... - There is a 50-80% chance winds will gusts over 30 mph north of Sturgeon Bay in Door County tonight. The highest chances will be near Deaths Door and Washington Island. - There is a 40-80% chance of light snow Friday afternoon and evening. Snowfall amounts around an inch or less are expected. Freezing drizzle may mix in briefly as precipitation ends Friday evening. - Below normal temperatures will continue through the weekend with moderating temperatures by the middle of next week, along with periodic chances for snow. && .DISCUSSION... Issued at 216 PM CST Thu Dec 4 2025 Persistent northwest flow across the region through next week will continue to bring intermittent chances for light snow and below normal temperatures for the forecast period. Snow Chances Friday... A fast moving shortwave will bring our next chance of snow Friday and Friday evening. Initially, a push of warmer air aloft will bring back cloud cover during the day Friday, along with some light snow across northern Wisconsin and over Lake Michigan. With the Bay of Green Bay still open, left some snow in the forecast for Door County as well, but was more pessimistic of snow getting elsewhere early in the day. As the cold air advection kicks up again on the back edge of the shortwave would expect snow to overspread the rest of the region with a round of snow. As things stand, best snow chances remain limited to portions of central and north-central, which may see around an inch or so of accumulation by the end of the day. The rest of the region will likely see lesser amounts closer to a half inch. Probabilistic guidance is in general agreement, with around 30-50% of exceeding an inch in portions of central and north- central Wisconsin, dropping off to around 10% as you move east. Finally, as snow tapers to an end Friday night, there may be a brief period of drizzle or freezing drizzle as ice crystals become scarce aloft. The potential for this drizzle will be fairly limited and short-lived, but a few slippery spots may still be possible. Snow Chances Saturday... Another fast moving shortwave will bring a clipper system through the region during the weekend. While the bulk of this system will pass south of our area, the northern end will again bring a round of snowfall through the region. Disagreement in the northerly extent of snow remains in the models, but even the GFS does bring a fast half inch to an inch to the region late Saturday night into Sunday morning. This change has increased confidence in accumulating snowfall during the overnight period for areas along and south of Highway 29. Again, expect some minor slippery stretches to develop. Snow Early Next Week... Finally, another more significant clipper will be possible early next week, mainly Monday night. This system has some better moisture and forcing accompanying it, which may make for a more widespread accumulating snowfall once again. Temperatures... Below normal temperatures will linger on through early next week, with highs generally staying in the teens. Low temperatures may be quite cold once again, especially Sunday night when we may again see widespread temperatures below zero. Fortunately, temperatures do show some moderation again through the week next week, which would bring temps back towards the mid to upper 20s. && .AVIATION...for 18Z TAF Issuance Issued at 1146 AM CST Thu Dec 4 2025 Clear, cold, but good flying conditions are expected for the afternoon to early afternoon period. Some mid to high clouds will arrive through the afternoon but no ceilings are expected until some lower clouds arrive overnight and bring some MVFR ceilings to portions of north-central Wisconsin. As the lower clouds arrive, some light snow will move into the region as well, although this will mainly be limited to north-central Wisconsin during the daytime period. Winds will be on the increase overnight as well, which will spread some LLWS from west to east through the morning period as well. Finally, the next round of light snow does appear to delay towards the afternoon, but a few flurries may make their way into portions of central Wisconsin and areas along the lakeshore by around noon. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....Uhlmann AVIATION.......Uhlmann ####018009835#### FXUS61 KLWX 042017 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 317 PM EST Thu Dec 4 2025 .SYNOPSIS... A reinforcing cold front will pass through the area this evening. Light wintry precipitation chances return late tonight through Friday as low pressure passes to the south. High pressure briefly returns this weekend before a pair of clipper-like systems impact the area early to mid next week. && .KEY MESSAGES... - Light but potentially high impact snow event becoming increasingly likely during the Friday morning commute. - Uncertainty remains in the northern extent of snow, but trends have been quicker and further north overall. && .NEAR TERM /THROUGH FRIDAY/... A reinforcing cold front will deliver another shot of Arctic air (likely the coldest thus far this season) late tonight into Friday. This sets the stage for a light but potentially high impact snow event that will likely affect the Friday morning commute. Confidence remains low in the northern extent of snow, but 12Z guidance has come into much better agreement on a quicker and further north trend. Ensemble members are more tightly clustered with the northern edge of the snow, but there is still some room for error. Certainty in accumulating snow is highest in the I-64 corridor, lower toward US-50/I-66, and even lower up toward I-70. It is possible areas near/north of I-66/US-50 see little to no snow depending on how tight the northern edge is. With the quicker and further north trend in guidance (and in upstream obs in TN/KY), opted to expand the Winter Weather Advisory northward into the Baltimore MD and Washington DC metro areas. This is supported by the latest rapid refresh guidance and extrapolation from upstream radar/satellite trends. Although amounts are expected to be light overall, especially further north, very cold temperatures in the 20s when the snow begins (and the time of day) will result in any snow sticking to all untreated surfaces. Even a light coating of snow results in very slippery and icy surfaces, especially elevated ones like bridges and overpasses. Despite the distant surface low passing over the Carolinas, mid to upper jet forcing is abundant with saturation as low as 850 mb. This is thanks for a 150+ knot upper jet. The lift overlaps the DGZ for a time, and these setups can in some cases "overperform" expectations due to the fluffy nature of the snow enhanced by the upper jet. This is probably why, in addition to the northward shift upstream, guidance has shifted north today. Snow looks to move into west-central VA around or just after midnight, then expands steadily northeastward through the night reaching the metro areas between 3-5AM. There will likely be a tight gradient in the northern extent of the snow as the best forcing is further south and dry air will have to be fought off further north. Amounts overall are expected to be light, ranging from a coating near I-70, to an inch or two south of I-66/US-50. The highest totals in a relative sense will be along the I-64 corridor and the higher elevations of west-central Virginia where as much as 4 or even 5 inches are possible. Steadier snow may end rather quickly mid to late morning from west to east. But, lingering flurries and perhaps freezing drizzle may develop, evident in forecast soundings that show drying aloft with weak low-level lift and saturation as well as surface temperatures hovering near freezing. The end time for the advisory was therefore left at 4PM, though if freezing drizzle does not materialize it may be able to be cancelled early. The freezing drizzle potential may linger Friday evening. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... Light to calm winds and lingering low-level moisture/cold air could result in lingering drizzle or fog Friday evening and night. With cold temperatures, slick spots may develop even in the absence of additional precipitation as any melted snow refreezes. High pressure will then nudge into the region to start the weekend. This will result in mainly dry weather and seasonably cool temperatures. An approaching shortwave in the northern stream could bring a return of flurries or a few snow showers to the Alleghenies Saturday night. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Not too much of a change in the overall pattern with broad longwave troughing across the eastern CONUS and ridging back toward the west. The northern jet stream will remain quite active with several perturbations set to work near or through the forecast area during the early and middle part of next week. The first set of disturbances to watch will occur during the Sunday into Monday timeframe. An upper-level trough axis will shift east out of the Ohio/Tennessee River Valleys with a shortwave passing to the north across the Great Lakes, and another shortwave passing to the south across the southern Appalachians region. Meanwhile, high pressure will remain wedged south along the eastern Appalachians. This will keep most of Sunday dry and cloudy with highs in the upper 30s and lower 40s (low 30s mountains). A cold front looks to drop through the area Sunday afternoon and evening, but may be fairly weak and moisture-starved as the main energy sources remain on either side of the region. Light wintry precipitation will work into the mountains Sunday afternoon with perhaps a few spotty showers further east Sunday evening into Monday as the trough axis swings overhead. Any precipitation will quickly wrap up east of the mountains Sunday night into Monday morning as the front works east and high pressure builds in from the Ohio River Valley. Stout Canadian cold air advection will filter into the area on north to northwest flow Monday marking one of the coldest days by far this late Fall/early Winter season. Highs Monday will struggle to get out of the low 30s in most locations (20s mountains). Lows Monday night are forecast to fall into the mid to upper teens with low 20s along the Chesapeake Bay and in the immediate Baltimore/DC city centers. A pair of clipper-like systems will traverse the area Tuesday through Thursday. Both of these systems look to swing across the Great Lakes driving a series of fronts through the region. Each storm system could deliver a period of light snow to the mountains with perhaps a rain/snow mix further east. Of course this will be dependent upon moisture availability and the overall track of the low as it drops south/east. Highest confidence for precipitation at this time appears to be over northwestern portions of the forecast area including the Allegheny/Potomac Highlands. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... VFR conditions are expected through this evening as winds diminish. Snow will move in quickly toward KCHO between 06Z-08Z, expanding NE toward the metro TAF sites by 08Z-11Z. Conditions steadily deteriorate to IFR or LIFR at KCHO, with IFR likely at IAD/DCA and perhaps up into BWI/MTN/MRB, but confidence is lower there. Winds will be light and generally out of the NE to SE through Friday, then calm Friday night. Freezing drizzle is possible once steadier snow departs between 14Z-18Z Friday, perhaps lingering well into Friday evening. Fog may develop Friday night. Therefore, improvements may be slow. VFR will return Saturday with light W/SW flow. VFR conditions likely persist Sunday into much of next week. Some temporary sub-VFR reductions are possible late Sunday into Monday and Tuesday through Thursday, especially over the mountains as multiple clipper systems pass through. Winds will remain light out of the north and northwest Sunday into Monday with speeds less than 10 knots. Speeds increase with gusts up to 20 knots in the wake of a front Monday afternoon. && .MARINE... Winds will diminish through this evening, becoming northeast overnight then southeast Friday. A period of light snow is likely with the highest confidence further south late tonight through Friday morning. Some patchy drizzle or fog is then possible through Friday night. Winds will be light and variable Friday night, then west to southwest Saturday less than 10 kts. A wave crosses aloft Saturday night, and that could bring briefly higher gusts to portions of the waters. Sub-SCA level north to northwesterly winds are expected through Sunday. SCA level winds look to return to the waters Monday through Thursday as a series of fronts pass through. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...Winter Weather Advisory from 4 AM to 4 PM EST Friday for DCZ001. MD...Winter Weather Advisory from 4 AM to 4 PM EST Friday for MDZ011-013-014-016>018-503>506. VA...Winter Weather Advisory from 4 AM to 4 PM EST Friday for VAZ053>055-057-501-502-505-506-526-527. Winter Weather Advisory from 1 AM to 4 PM EST Friday for VAZ025>027-029-030-036>040-050-051-056-503-504-507-508. WV...Winter Weather Advisory from 1 AM to 4 PM EST Friday for WVZ055-505-506. MARINE...Small Craft Advisory until midnight EST tonight for ANZ530>532- 538>542. Small Craft Advisory until 2 AM EST Friday for ANZ533-534-537- 543. Small Craft Advisory until 9 PM EST this evening for ANZ535- 536. && $$ SYNOPSIS...DHOF/EST NEAR TERM...DHOF SHORT TERM...DHOF LONG TERM...KLW/EST AVIATION...KLW/DHOF/EST MARINE...KLW/DHOF/EST