Expires:No;;968797 FXUS63 KARX 072344 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 544 PM CST Wed Jan 7 2026 .KEY MESSAGES... - First of two systems moves into the region Thursday and into Friday with rain transitioning to snow. While there are some uncertainties with this first storm, there are some signals that a small area (deformation band) sets up and causes rain to transition to snow sooner, leading to a few inches of snow. - The second winter system moves into the region late Friday night and into Sunday morning with accumulating snow likely. There is a 30 to 60% chance of at least 1" of snow for the forecast area with the higher probabilities east of the Mississippi River. && .DISCUSSION... Issued at 135 PM CST Wed Jan 7 2026 Today-Saturday: Dry Today, Active Pattern for End of Week After a foggy morning, the low visibilities have improved for the entire forecast area. Skies have mostly cleared up, especially for areas south of I-94. Highs for today increase into the upper 30s to low 40s. Zonal flow aloft will transition to southwest flow on Thursday ahead of a cutoff upper level low moving into the Upper Midwest from the Desert Southwest. As the upper level low moves into the Central Plains, a surface low develops. With good warm air advection ahead of the surface low, precipitation will start off as rain for all locations by late afternoon/early evening Thursday then transition to all snow by mid morning Friday. Models continue to show a frontogenesis (deformation) band developing on the backside of the low. Comparing this possibility to sounding data, there is some agreement that this will happen. Soundings in southeastern Minnesota and western Wisconsin do begin as rain, however they transition to isothermal and the surface temperatures are right at or right below freezing. The uncertainty is exactly when and where this transition first occurs. While light snow is expected after the surface low moves off to the northeast and colder air filters in behind, if the frontogenesis band develops, then that area would see snow falling earlier. One caveat to the snow potential is that the best frontogenesis is present as the low is over the area. Once the low gets far enough away, the band loses its influence from the low and the better forcing gradually diminishes. Since the soundings are isothermal and are deeply saturated, the thing to watch will be if rates are high enough to lower temperatures enough to get all snow. This system could be a sneaky one as all models are showing a snow band with differences in amounts and location, as well as how long the precipitation type remains snow. Snow ratios with this system are higher, roughly a 7 to 10:1. Based on this information, snow totals with this first system are lower, mostly less than a half inch with potential for slightly higher amounts within that deformation band. Aside from the snow potential, there will be a decent amount of rain with this system with 0.5 to 1.0" forecasted across the forecast area. As this rain is falling on frozen ground, basement flooding may be possible so make sure to check your sump pumps. Ponding due to poor drainage will also be possible due to the frozen ground. While ice jams are not expected, any rivers or streams that do have ice on them, expect the ice to break up. The more ice a river has, the higher the chance of an ice jam as the river rises. The second storm to watch is for the weekend as two separate upper level features merge over the Upper Midwest/Great Lakes area. Heading into Friday, an upper level low develops over the Desert Southwest while another upper level low begins to form in the northern Plains. Ensemble and deterministic guidance continue to be in good agreement that these two features will merge together somewhere over the Upper Midwest. The southern system does have an associated surface low however, that low continues to remain off to the southeast, closer to the Ohio River Valley. Despite our distance from the surface low, there will be plenty of lift with the two phasing systems, a little increase in moisture, and compared to the Thursday system, temperatures aloft are cooler and so the precipitation type would remain snow through the entire event. The question then becomes, how much snow? Ensemble clusters again are in good agreement of the phasing occurring, however they differ on the amplitude of the resultant upper level feature and the location of it. Another factor to consider is the distance we are from the surface low. The closer in proximity to the low would increase snow totals across the region. In order for the higher snow totals to take shape, a lot of things would need to come together, such as the location of the surface low and how amplified the upper level feature is and how much moisture is able to make it northward. Ensemble members from both the GEFS and EPS are roughly in the 1 to 3" range however, that is for a 10:1 snow ratio. This weekends storm is looking to have snow ratios more drier, in the 12 to 17:1 range these snow totals, so this could result in slightly higher snow amounts, however our current forecasted snow amounts remain in the 1 to 3" range with the higher amounts east of the Mississippi River. Overall, there are two winter systems, one on Thursday evening into Friday and another Saturday into Sunday morning. The first system is mostly rain with snow falling towards the end of the event, however depending on if a deformation band forms and where that sets up, snow could be falling for a longer period of time over that local area. There will also be quite a bit of rain with this first system with rain totals between 0.5 and 1.0". This rain could cause some ponding on frozen ground and river rises that have ice on them. The second system will be all snow with cooler weather to follow for Sunday and Monday with highs in the 20s. Drier conditions return later Sunday and linger into early next week. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 544 PM CST Wed Jan 7 2026 Areas north of an EAU to ISW line could see restrictions as low as LIFR overnight and into Thursday morning with predominantly VFR conditions elsewhere. Conditions then slowly deteriorate to IFR or lower from south to north Thursday late afternoon/evening as a band of rain lifts into the region, which lasts into at least Friday morning. Southerly winds of 5-10 kts tonight become light in the morning and back to the northeast for the afternoon on Thursday. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...Cecava AVIATION...Skow