textproduct: La Crosse

KEY MESSAGES

- Rain changes to snow overnight bringing snow accumulations of 1-3" for areas north of I-94 with amounts of around an inch or less south of I-94. A brief period of freezing drizzle/rain will be possible in portions of west/north-central WI just prior to transitioning to snow tonight.

- Widespread rain and snow likely (60-80%) for much of the area Thursday evening and Friday. Any snow accumulations appear confined to areas north of I-94 at this time.

- Accumulating snow potential (60-80%) for the upcoming weekend with uncertainty remaining on the exact location of where the heaviest snow will fall.

DISCUSSION

Issued at 331 AM CDT Tue Mar 10 2026

Today - Wednesday: Rain Changes to Snow Overnight, Brief Period of Freezing Rain Possible

A notable pattern shift from the mild weather we have been seeing occurs by this evening and into the overnight as a surface cold front pushes into the region and ushers in some low-level cold air advection. In conjunction with this cold frontal passage, an elevated axis of theta-e pushes northward towards the local area during the late afternoon and evening which may result in some coverage of showers and maybe some isolated storms for areas south of I-90 in southwest WI and northeast IA. Cannot rule out a storm or two posing a marginally severe hail risk, primarily in Grant County, WI, with MUCAPE values in the 10.03z RAP approaching 1000-1500 J/kg coupled with steeper mid-level lapse rates to around 7-8 C/km.

Otherwise, as we head later into the evening and overnight, a lingering warm nose from the elevated axis of theta-e advection in combination with possible (distinct differences between NAM/HRRR) the lack of saturation in the dendritic growth zone poses a secondary headache as low-level cold advection works its way in the form of freezing drizzle/rain potential prior to a transition to snow. The degree of saturation between various models in the DGZ differs but either a drizzle or rain case would yield a risk for a glaze of ice. Overall, ensemble probabilities in the HREF are highest in west/north-central WI for a glaze of ice (20-50%) during the overnight period prior to sunrise. This follows the overall conceptual model fairly well as the upper-level trough axis would be beginning to move into southeast MN and northeast IA during this period which would aid in cooling the warm-nose left by the remnant theta-e advection. A big question that still remains with this potential though is exactly if road/surface temperatures will note any freezing prior to a changeover to snow as conditions have been mild for the past several days and if precipitation rates will be robust enough to result in any icing concerns as the period of freezing drizzle/rain concern would only be for 2-3 hours at any given location. Consequently, have held off on any Winter Weather Advisory issuance for now (outside of Taylor County) as confidence is simply not high enough for how any icing threat would materialize.

Eventually, the tricky warm nose will cool across the area resulting in a transition to snow during the early morning hours on Wednesday. General conceptual model in the 10.03z RAP has a primary axis of 500- 700mb frontogenesis moving through much of the area which presents in the CAMs as a band of light snow that moves through most of the local area. However, the 10.03z RAP depicts a secondary axis of frontogenesis in this layer that pushes through north-central WI that would keep the snow going for a longer duration in these areas. As a result, probabilities in the 10.00z HREF for 2 inches or greater are generally highest (50-90%) near and north of I-94. Given that there are some probabilities (40-70%) in northern Taylor County for amounts over 4 inches within the HREF. Have opted to issue a Winter Weather Advisory for Taylor County, considering the potential for snow accumulations of 2-3" with locally higher amounts in the northern portions of the county possible in conjunction with the aforementioned freezing drizzle/rain potential tonight.

Thursday into Thursday Night

The 09.00z deterministic models are in agreement that a shortwave trough in the northern stream will move east through the region. Like the past couple of days, there is some uncertainty on how far south the cold air will get. Some models suggest that the cold air might be as far south as Interstate 90. While other models keep the cold air north of Wisconsin 29. As a result, there is plenty of uncertainty on how far south the wintry mix or snow will get. In addition with the speed of the system, there is still uncertainty on how much residual moisture will be left by the time the cold air arrives.

High temperatures on Thursday will be primarily in the 40s. Low temperatures on Thursday night will range from the mid-20s to lower 30s.

Weekend

The models show that a baroclinic zone will be located somewhere over the Midwest, Ohio Valley, and Great Lakes. A surface low will be tracking along this boundary producing precipitation across the region. The strength of this low is highly dependent upon on how much the northern and southern streams interact this each other. In the models where there is little interaction, there is little cyclogenesis at the surface and the upper level wave remains more open. In the models where there is more interaction between the northern and southern streams, there is more cyclogenesis and this results in a stronger surface low and even the development of deformation band northwest of the surface low. The envelope of surface low tracks remain quite large ranging from New York to as far west as the Driftless Region. As a result, there remains plenty of uncertainty on precipitation type and wind strength. This system has the potential to be an impactful snow system, but there remains plenty of uncertainty on where that will occur.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 544 AM CDT Tue Mar 10 2026

VFR conditions are expected to begin the TAF period with decreasing cigs throughout the day. Showers will be possible at KLSE during the afternoon and into the evening hours with cigs continuing to decrease to MVFR after sunset across the entire local area (70-100% chance in the HREF). Overnight, rain will transition to snow prior to daybreak on Wednesday with cigs likely (50-80%) falling to IFR levels at precipitation onset. A period of freezing rain is possible in western Wisconsin prior to a full transition to snow before 12z which may result in a light glaze of ice. Otherwise, accumulating snow is expected around and after 12z with snowfall amounts of around 1" or less within the vicinity of the I-90 corridor. Snow will likely result in MVFR to IFR vsbys reductions across much of the area. Winds will remain around 8-12 kts throughout the TAF period from the east to northeast.

ARX WATCHES/WARNINGS/ADVISORIES

WI...Winter Weather Advisory from 7 PM this evening to 1 PM CDT Wednesday for WIZ017. MN...None. IA...None.