####018010863#### FXUS63 KBIS 101504 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 904 AM CST Wed Dec 10 2025 .KEY MESSAGES... - Another round accumulating snow is expected late this afternoon through Thursday night. Areas of freezing rain are also possible across the west and south central through late Thursday morning. - Below average temperatures are expected today through the upcoming weekend, with dangerous wind chills possible Thursday evening through Sunday morning. - More accumulating snow is possible across the west and south central Friday through early Saturday. && .UPDATE... Issued at 900 AM CST Wed Dec 10 2025 Very light snow continues to fall sporadically in the central and east under the low cloud deck. These clouds will slowly move east with surface high pressure and then the incoming next system. No major changes where made to the on going forecast. UPDATE Issued at 555 AM CST Wed Dec 10 2025 Low level clouds linger over northwestern and central North Dakota this morning. Flurries have be observed across portions of this cloud deck, and have added such to the forecast through the mid to late morning. Flurries and clouds should diminish from west to east as surface high pressure moves in this morning. Otherwise, this morning, gusty northwest winds linger over portions of the central North DAkota, with speeds broadly from 15 to 25 MPH and gusts up to 35 MPH observed. These winds, too, should diminish as high pressure moves in this morning. Other than the aforementioned update mentioned above, the forecast remains broadly on track. && .DISCUSSION... Issued at 415 AM CST Wed Dec 10 2025 Northwesterly flow is found over the northern Plains this morning. Light wintry precipitation lingers over north central North Dakota into the northern James River Valley, trailing along and behind a inverted surface trough associated with the clipper system that passed through North Dakota yesterday. A transient upper level ridge is expected to move through the northwesterly flow pattern this morning through much of the day, and will allow high pressure at the surface to move into the northwest. While this will help further erode precipitation and the somewhat gusty northwest winds that lingered overnight. Before that time light, non accumulating snow will remain possible over portions of north central North Dakota into the northern James River Valley through this morning. Clearing conditions are then anticipated through the late morning and afternoon as high pressure slides across North Dakota. Low temperatures this morning are from the lower single digits below north, to the upper single digits to mid teens above south. High temperatures this afternoon are forecast from the upper single digits to mid teens central, to the lower 20s to lower 30s west. Another round of impactful winter weather is expected early this evening through Thursday as another upper level wave passes through the northern Plains. Chances for precipitation will increase as strong 850-700mb WAA pushes in across the west, accompanied by decent FG forcing. At the fore of this system, periods of moderate to heavy snowfall will be possible across the west this evening through early tonight as the aforementioned FG forcing aligns with decent Q vector convergence. Then, in a similar setup to Tuesday, a ongoing WAA will cause a deep warm nose aloft, allowing for a switchover from snow to freezing rain across the west and south central overnight through late Thursday morning. During this transition, portions of southwestern and south central North Dakota may experience precipitation in the form of ice pellets, as the initially elevated nature of the warm nose aloft could allow for refreezing of falling liquid before it reaches the surface. CAMs remain somewhat discordant on the exact cessation time of the freezing rain, mainly due to differences in when the warm nose aloft erodes. A good majority of the CAMs favor an initial weak slug of CAA moving in out of the northwest mid to late Thursday morning, which will allow for a slightly quicker change-over to all rain and snow across the forecast area. A minority of CAMs instead favor WAA continuing through the late morning, early afternoon period which would allow freezing rain to continue across south central North Dakota for a little longer. In either scenario, the cold front associated with the low pressure system is then expected to move in out of the northwest, and facilitate a complete conversion to snow through the remainder of Thursday. As of the current forecast cycle, NBM 5.0 Calibrate probabilities has medium to high chances (50 to 80 percent) for at least 0.001" of ice accumulation across much of western and portions of central North Dakota, with probability dropping off quickly north of Highway 200. Chances for 0.10" are generally low (10 to 20 percent) across much of the same area, though a small area of medium (30 to 40 percent) can be found in south central North Dakota, mainly along and east of the Missouri River and south of I-94. This area would have the greatest residence time for freezing rain overall, not to mention the scenario where it lingers into the early afternoon mentioned above. With banding potential Wednesday afternoon and evening, and with the freezing rain overnight through Thursday morning, A Winter Weather Advisory is in effect across western North Dakota start 3 PM CST Wednesday, then expanded to include portions of central North Dakota starting 6 PM CST Wednesday, through 6 PM CST Thursday. With this update, we have opted to start the Advisory a little earlier across the west due to potential for moderate snowfall to start late Wednesday afternoon. After the cessation of freezing rain, lightly accumulating snow is then expected to continue across much of western and central North Dakota from the remainder of Thursday afternoon through late Thursday night, perpetuated by an incoming arctic cold front Thursday evening. When all is said and done, much of western and central North Dakota has medium to high (30 to 60 percent) probabilities to exceed 1.0 inches of snow through Friday morning, with low to medium probabilities to exceed 2.0 inches overall. The aforementioned arctic cold front will bring much colder temperatures and gusty winds starting Thursday night through Friday, and addition to the light snowfall through Friday morning. Low temperatures Friday morning are forecast from the mid teens below zero north, to around zero south. With these temps, with northwesterly winds with speeds from 15 to 20 MPH and gusts up to 30 MPH overnight, there are medium to high chances (50 to 80 percent) for dangerously cold wind chills below -30 across the northern portions of the forecast area Friday morning, mainly north of Highway 200 plus the northern James River Valley. That being said, a slightly faster progression of the cold front overnight could allow for this potential area to spread further to the south. High temperatures Friday morning are also very cold, with much of northwest and central North Dakota unlikely to rise above freezing. Saturday, if anything, will be even cooler across the north, though less windy than Friday. Low temperatures Saturday and Sunday morning are broadly forecast as low as -20 in north central North Dakota, up to around -5 in the southwest and south central. Despite the lack of winds, there are again medium to high for portions of northern North Dakota to experience dangerously cold wind chills both mornings, with the highest potential north central. High temperatures on Saturday are from -10 north central, to around 10 above southwest, then warming into lower teens east to lower 30s southwest on Sunday. Persistant northwesterly flow will allow for more opportunities for precpitation essentially each day over the weekend, though Friday through Saturday is currently looking like our best bet at the moment. Another low pressure system passing to the southwest of the forecast area will allow for medium to high chances (50 to 80 percent) for accumulating snowfall west and south central. NBM calibrated probabilities for at least 2 inches of snow through Saturday morning are high south and west of the river, with low to medium chances to exceed 4 inches in the far southwest for the same period. Looking ahead to next week, the warming trend starting Sunday is to continues, with forecast highs broadly back into the 30s and 40s by Tuesday. CIPS analogues lean toward near to above normal temperatures to continue through the end of the workweek. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 900 AM CST Wed Dec 10 2025 MVFR ceilings and flurries can be found over portions of northern and south central North Dakota this morning, including at the terminals of KMOT and KJMS. Conditions are expected to improve from west to east as high pressure builds in across the area. Late this afternoon through the evening, chances for precpitation and MVFR to IFR ceilings will increase from west to east as a low pressure system passes through the northern Plains. Periods of moderate snowfall are possible across the west early this evening through early tonight. A transition to freezing rain is expected late this evening and overnight across portions western and south central. Thursday morning through Thursday afternoon, another transition to all rain and light snow is anticipated. Northwest windS this morning remain moderately strong, with speeds broadly 25 knots and gusts up to 35 knots observed. As surface high pressure moves from the northwest this morning, winds are expected to diminish turn variable through the afternoon. As the aforementioned low pressure system starts to move into the area this afternoon, a general reorganization out of the south southeast is expected, with winds becomes somewhat gusty through the evening and overnight. && .BIS WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from 3 PM CST /2 PM MST/ this afternoon to 6 PM CST /5 PM MST/ Thursday for NDZ009-017-018- 031>033-040-041-043-044. Winter Weather Advisory from 6 PM CST /5 PM MST/ this evening to 6 PM CST /5 PM MST/ Thursday for NDZ010-019>021-034-035-042- 045-046. && $$ UPDATE...Smith DISCUSSION...Adam AVIATION...Adam ####018010526#### FXUS63 KIND 101504 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 1004 AM EST Wed Dec 10 2025 .KEY MESSAGES... - Rain moves through this morning; additions rain showers transitioning to a rain/snow mix is expected the afternoon - Wind gusts of 30 to 40 mph throughout the dayinto - Accumulating snow likely Thursday night into Friday - Arctic outbreak expected this weekend with low temperatures near or below zero...and potentially dangerous sub-zero wind chills && .FORECAST UPDATE... Issued at 1003 AM EST Wed Dec 10 2025 The forecast is on track so far for today as wet, windy, and cooler conditions overspread the state. Satellite and radar imagery show the bulk of this morning's rain pushing off to the south and east with leftover showers moving in from the west. Observations indicate winds have already shifted to the west behind the cold front with gusts approaching 40-45 mph at times. The main focus for today will be continued windy conditions, falling temperatures this afternoon, and the transition to a period of drizzle and snow showers. Steepening low level lapse rates as cold air advection moves in aloft support continued stronger wind gusts of 40-45 mph mixing down to the surface through the next several hours. The LLJ is expected to weaken some this afternoon, so expect a slow diminishing trend for wind gusts from 40-45 mph this morning to 25-35 mph by this evening. In addition to strong winds, cold air advection should keep temperatures near steady this morning in the upper 30s to near 40 before falling to near freezing later this afternoon and evening. Expect scattered to numerous rain showers this afternoon within the cyclonic flow pattern around an area of low pressure to the north. Thermal profiles on local soundings and CAMs indicate snow may mix in at times later this afternoon before dryer air pushes in tonight shutting off most of the precipitation. Best chance for a full transition to snow showers and lingering flurries will be in northeastern portions of the state, as additional moisture off Lake Michigan may saturate the lower levels and DGZ enough to support snow shower activity. Little to no accumulations expected, but a dusting is not out of the question north and east of the Indy metro area tonight. Overall expect a blustering, wet, and cool day across Central Indiana. && .SHORT TERM (Today through Friday)... Issued at 250 AM EST Wed Dec 10 2025 Today through Thursday afternoon: Central Indiana will now face a succession of Alberta Clipper lows over the coming days, the first of which reached the Great Lakes region last night, and the last of which will move through on Saturday. Todays low, will be strong, but will pass well to the north, keeping temperatures well above freezing (currently 42 in Indianapolis), minimizing overall impacts to central Indiana. Numerous showers are expected to pass through most of central Indiana throughout the morning hours ahead of a strong cold front. Total rain amounts for central Indiana are likely to be less than a quarter inch. Despite less overall impacts, the strength of this system will still have some, mostly due to strong winds. A robust jet streak will not be far off the surface around 50-60kt, but an inversion will keep the worst of the winds away from the ground; still gusts in the 30 to 40 mph range are possible throughout the morning. As the inversion breaks some late this morning into the early afternoon, a few gusts may exceed 40, but the jet streak should be east of central Indiana by the time greatest mixing occurs. The bulk of the lift will be east of the area by 15Z today, but there still will be some modest vorticity advection within the parent trough, along with modest lapse rates that likely will lead to scattered showers at times late this morning through the afternoon. This second round of precipitation will be undercut by some strong CAA during the afternoon hours, of which will likely lead to some mix of rain and snow at times. This should not accumulate to much of anything, but a quick light coating of slush within strongest showers is possible. Winds will continue to be gusty with the tight pressure gradient and cold advection promoting mixing down of stronger winds aloft. Wind gusts around 40 mph are likely, especially north. The strong push of CAA along with lingering stratus in the broader cyclonic flow will likely lead to scattered flurries this evening through early portions of tomorrow. These flurries likely will not cause any impact. That said, further NE, enhanced low level moisture downstream of Lake Michigan could allow for a few stronger snow showers to develop within this same synoptic setup. These snow showers still likely wont cause much impact but a dusting of snow is possible tonight into tomorrow in the Muncie, Winchester region. Thursday evening through Friday morning: As stated, central Indiana will remain in the path of strong upper level NW flow, and an efficient set up for quickly developing lows out of the Canadian Rockies. The second of these systems is expected to pass through late Thursday through Friday morning. The previous system brought through strong CAA, of which will sink the baroclinic zone southward placing central Indiana in a goldilocks zone for both cyclogenesis and temperatures cold enough for snowfall. This second low will be weaker than Wednesday's system, but will likely still have just as much forcing as it pushes across a strong baroclinic zone. These clipper systems along strong temperature gradients typically produce narrow corridors of moderate QPF, and this one is expected to be no different. The emphasis is on narrow, as this will lead to a wide range of QPF outcomes in certain locations, with still almost 48 hours until snowfall onset. This means take each forecast with some potential of error, as the greatest axis of snowfall could move 25-50 miles depending on where the baroclinic zone is placed following the cold push after today's system. Currently, this axis is most likely to be along the I-74 corridor. Model soundings showcase a deep isothermal layer as the low arrives between -6C and -10C. This isn't the most ideal temperature for efficient dendrite growth, and therefor SLRs are currently expected to be somewhere between 10-14:1 across central Indiana. This in combination with 0.2-0.3 inches of QPF puts the highest likelihood of snowfall to be between 2 and 4 inches. Slightly higher amounts are possible where the strongest frontogenetical forcing occurs as this forcing will likely be slightly further aloft and within more ideal DGZ temperatures. Forecast timing has a bit more confidence, as the margin of error is larger and ensembles have a tighter spread. Currently snow is expected to reach the Indiana border between 4-7PM on Thursday and continue through 10AM on Friday morning. && .LONG TERM (Thursday through Tuesday)... Issued at 250 AM EST Wed Dec 10 2025 Cold pattern to trend from unseasonable to anomalous this weekend, before moderation expected by end of the period...with additional light snowfall possible. H500 cut-off short wave to plunge slightly within polar flow this weekend...from south-central Canada, across northern and eastern Great Lakes. Paving a path for associated elongated arctic surface high pressure to build/track from North American Plains during the early weekend...to the Great Lakes/ Midwest by Sunday night. Vort max speeding around the bottom of the upper cut-off Saturday, from Quad Cities area into Ohio, will induce another clipper-type system. Additional light accumulating snowfall is likely for most of the region within perhaps a 15-hour period around the Saturday to Saturday evening timeframe. Bursts of moderate to perhaps briefly heavy snow are possible, especially north of I-70 which will be closer to supporting forcing. Arctic ridge to quickly build into central Indiana on the hind legs of Saturday's disturbance, with what should be clearing skies Saturday night promoting readings near/below zero. Very cold conditions...possibly approaching Indianapolis' record low of negative 4 degrees Sunday morning...should last into Monday morning, with highs Sunday held below 15F across most zones...and consecutive early mornings below zero for most locations north of I-70. Wind chill values to fall to around zero for many spots Friday night, yet only rebound Saturday to 5-15 degrees for most locations. Advisory criteria wind chills are currently forecast for both Saturday night and Sunday night across portions of the region...with wind chills during the day Sunday likely held below zero for some northern counties. Early workweek to feature noticeable moderation back to more reasonably cold levels...with Monday's max/min readings hopefully both noticeably higher than Sunday's marks. Low confidence in potential for freezing drizzle/rain given weak overrunning set-up with surface readings most likely in the 20s. Long term to end with temperatures possibly climbing above freezing. && .AVIATION (12Z TAF Issuance)... Issued at 631 AM EST Wed Dec 10 2025 Impacts: - Gusty winds 25 to 35kt tonight through this afternoon - MVFR ceilings with intermittent IFR within SHRASN. - Rain this morning, then mix of rain and snow this afternoon. Discussion: Gusty winds from 25-35 kts this morning through the late afternoon. Following dusk, gusts should begin to subside. Ceilings have quickly gone down to 2500, and will slowly decrease to 1500 throughout the morning. SHRA and SHRASN will develop late this morning through the afternoon, of which could push VSBY down to 4SM and CIGs to 800ft. Overnight, scattered flurries will be possible at KIND and KLAF, but confidence in occurrence is too low to include in this issuance. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...CM SHORT TERM...Updike LONG TERM...AGM AVIATION...Updike