textproduct: La Crosse

KEY MESSAGES

- Milder temperatures today and Tuesday with highs in the middle 30s to upper 40s.

- Potential (30-60% chance) for a brief period of freezing rain near and north of Hwy 29 in north-central Wisconsin before switching to rain early Tuesday morning. This may result in some slick spots prior to temperatures warming above freezing.

- Snow likely (50-80% chance) Thursday and into Friday. Ensemble guidance has medium to high probabilities (40-80% chance) for 1 inch or greater of accumulations west of the Mississippi River during this period.

DISCUSSION

Issued at 300 AM CST Mon Jan 12 2026

Today - Tuesday: Above Normal Temperatures, Brief Period of Freezing Rain Possible in North-Central WI Tonight

GOES-19 water vapor imagery and RAP 500mb geopotential heights currently shows the local area in well established northwesterly flow with a system situated over portions of the Alberta and British Columbia that will likely move into the area overnight and into Tuesday. As for today, southwesterly surface flow and low-level warm advection will be the name of the game for today. As a result, ensemble guidance responds accordingly for temperatures as probabilities are high (50-90% chance) for temperatures to top the 40 degree mark for most south of I-94. Additionally, weak subsidence aloft and an absence of saturation will allow for skies to be mostly clear for much of daytime hours today. Consequently, looks like a fairly pleasant day as far as January is concerned.

The forecast becomes a bit more unpleasant as we head into tonight with the aforementioned shortwave perturbation pushing into in northern Wisconsin. Overall the forcing with this wave overnight isnt particularly strong with QG convergence and warm advection being the primary mechanisms. That being said, a stout warm nose at KMDZ in the RAP/HRRR overnight leads to some questions on if a period of freezing rain will be possible. Currently, the HREF has medium to high probabilities (40-70% chance) for at least a trace of ice north of Hwy 29. Not overly confident that this would manifest though given that very low-level saturation in the HRRR/RAP seems questionable as this dry layer under 900mb is quite pronounced which may limit drop size or even evaporate any precip altogether. Either way, there is certainly some potential for a brief period of freezing rain in north-central WI overnight.

Regardless, temperatures uniformly warm above freezing after daybreak so any wintry precipitation will transition over to plain rain after daybreak north of I-94. Highest probabilities (40-80%) for measurable rainfall will generally be north of I-94 throughout the day in the recent 12.00z HREF with quickly lowering probabilities south of I-94 measurable rainfall. As a result, outside of any potential freezing rain concerns prior to daybreak north of Hwy 29 in Wisconsin, not expecting much impact from this system. However, Tuesday will likely be another mild day with highs generally in the 40s south of I-94.

Wednesday - Friday: Seasonable, Accumulating Snow Potential Thursday Night and into Friday

During the pre-dawn hours on Wednesday, sharp cold advection will work its way in from the northwest in the wake of the departing shortwave from Tuesday. As a result, expecting temperatures to trend closer to seasonable for Wednesday through Friday with highs generally in the 20s to lower 30s. Would expect some flurries to light snow showers during the morning hours on Wednesday, however given that latest trends do not have steeper low-level lapse rates and a lack of low-level frontogenetic forcing, thinking that rates with any of these snow showers would likely not be conducive for any meaningful accumulation at this point. Additionally with the passing cold front and tighter surface pressure gradient, would except some breezier conditions during the morning on Wednesday with the EC ensemble having medium probabilities (30-70% chance) for wind gusts over 35 mph south of I-94 during this period.

The next system that will be worth monitoring moves into the area after late Thursday afternoon and continues into Friday as a more profound shortwave trough swings into the western portions of the area on Thursday. Overall there remains some distinct differences between the deterministic runs on both the timing and degree of intensity of this wave between the EC/GFS/Canadian, however all solutions push this wave through the area in some capacity. Fairly respectable QG convergence is present with this wave with a weak 600- 700mb frontogenetic signal in the 12.00z GFS Thursday evening. However, available moisture seems to be somewhat of a question with 850mb moisture transport being fairly limited in the 12.00z GFS along with precipitable waters being on the low-end at around 0.25" to 0.35". As a result, the grand ensemble (GEFS/EC/Canadian ensemble) has low probabilities (under 20%) for snow amounts in excess of 3 inches during this period. That being said, probabilities with the EC-AIFS ensemble has virtually every member with accumulating snow and high probabilities (40-80%) for an inch of snow or greater, with the highest probabilities west of the Mississippi River. So would say at this point confidence is high in some accumulating snow and thus have kept the likely NBM precipitation chance mentions during this period. However, the probability for more impactful snowfall is lower at this point.

This Weekend: Trending Colder

By the time the weekend rolls around, temperatures cool down further as cold advection behind the previous discussed shortwave pushes into the area. As a result, highs will likely tumble below normal for both days this weekend with the inter-quartile range for highs in the NBM ranging from the single digits to around 20 for highs on Saturday. Exactly how cold we get on Saturday night will likely be contingent on where the core of the arctic airmass associated 850mb temperatures ends up which has notable spatial differences in the GFS and EC. In the colder, GEFS scenario with 850mb temperatures of around -27C to -29C this would likely favor low temperatures to fall below zero area wide as shown in the 25th percentile NBM as opposed to a warmer scenario in the 75th percentile NBM which keeps lows in the single digits to lower teens. So certainly looks like we are in store for a reminder that it is January but exactly how cold we will get remains uncertain.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 501 AM CST Mon Jan 12 2026

VFR conditions are expected throughout the TAF period with mostly few to bkn upper-level clouds. Winds will remain from the west- southwest at around 5-10 kts throughout much of the TAF period but will increase slightly towards daybreak on Tuesday. Cannot rule out some LLWS towards the very end of the TAF period after 09z as the RAP/HRRR increases winds at 2kft to around 50-55 kts, however confidence was too low to mention in the TAF at this time.

ARX WATCHES/WARNINGS/ADVISORIES

WI...None. MN...None. IA...None.