textproduct: La Crosse

KEY MESSAGES

- Clipper system brings light snow beginning Thursday afternoon and into Friday. The bulk of accumulations will likely occur Thursday afternoon and into the overnight where 1-3" of snow is favored in southeast MN and western WI. Snow showers will move through the region on Friday bringing additional light accumulations.

- Below normal temperatures expected for the weekend and early next week with highs in the single digits and teens. Morning wind chills during this time frame will likely be in the teens to 20s below zero.

- Additional light snow chances (20-40%) on Sunday afternoon.

DISCUSSION

Issued at 241 AM CST Wed Jan 14 2026

Today: A Return To More Seasonable Temperatures

GOES-16 water vapor imagery and 14.06z RAP 500mb heights depict the local area in north to northwest flow this morning which will generally be the name of the game for the foreseeable future as we say goodbye to the warmer airmass that was in place for the past couple of days. As a result, temperatures will be noticeably colder today with highs in the teens to lower 20s expected across the local area. Winds will remain somewhat breezy behind the front this morning with the 14.00z HREF keeping decent probabilities (40-70% chance) for wind gusts over 30 mph south of I-90. However, winds will diminish further by noon.

Thursday - Friday: Clipper System Brings Periods of Snow

As we head into Thursday, the key feature to watch will be a fairly complex clipper system that will rotate through the area beginning on Thursday afternoon. The general conceptual model for this features an initial shortwave trough with a trailing surface low in western Ontario to the north. As this trough approaches the local area during the afternoon, weak theta-e advection from the west will establish a narrow low-level frontogenetic zone as shown in the 14.03z RAP. Consequently, much of the CAMs develop a quick moving band of snow that pushes from northwest to southeast through the local area during approximately the noon to 6pm timeframe. Overall would expect amounts with this initial push of snow to be under an inch as the 04.00z HREF only has medium probabilities (30-60% chance) for amounts over 0.5" through 6pm on Thursday assuming a 13-15:1 snow to liquid ratio. After this initial forcing departs, RAP/HRRR soundings suggest the potential for a loss of saturation in the dendritic growth zone during the evening which would suggest that a transition to a brief period of freezing drizzle could be possible before midnight. However, this would likely be short-lived as the core of the upper-level trough and sfc low push into northern WI which will aid in cooling thermal profiles aloft and switching us back to snow with the better forcing being focused along and east of the Mississippi River where guidance currently has higher forecast amounts.

As this surface low begins to depart east, we may observe a lull in precipitation for Friday morning ahead of the next feature with this system to watch being the surface cold front pushing towards the local area during the afternoon. A couple things to note with this will be an increase in winds with a tightening surface pressure gradient along with the cold advection moving in with the front allowing for better moment transfer of around 30-35 kts off the deck to the surface. As a result, the EC ensemble has fairly strong probabilities (40-90% chance) for wind gusts over 30 mph west of the Mississippi River Friday afternoon and evening. Consequently, depending on exact snow amounts overnight Thursday, this could lead to some blowing and drifting snow. Furthermore, low-level lapse rates ahead of the front steepen to around 7-8.5 C/km in the 14.06z NAM which will be coupled with some marginal low- level instability (around 10-30 J/kg of 0-3km CAPE). When the low-level frontogenesis associated with the front moves into this environment, could see some intense snow showers with this frontal passage that may quickly lower visibility when coupled with the gusty winds west of the Mississippi River. The snow squall parameter in the NAM does highlight portions of southeast MN and northeast IA during this period. That said, the more favorable environment for snow squalls would seem to be west/southwest of the local area in the NAM where the depth of the unstable layer in the low-levels is much more favorable, as opposed to in our local area where the more marginal instability would work to hinder snowfall rates within snow showers that develop.

In any case, seems like a complicated little system that moves through during this period with various parts to it. Overall, not expect overly impactful snow amounts as the recent NBM probabilities for over 3 inches are fairly low (10-20% chance) across portions of southeast MN and west-central WI at this point. However, given the increasing winds on Friday combined with the new snow, this could lead to some travel difficulties on Friday with any blowing and drifting that does occur.

This Weekend & Early Next Week: Below Normal Temperatures with Occasional Snow Chances

By the time the weekend rolls around, sharp cold advection behind the aforementioned cold front has swept into the region, ushering in fairly cold airmass with 850mb temperatures around the -20C mark with northerly flow aloft. Consequently, temperatures respond accordingly with the inter-quartile range for high temperatures on Saturday ranging from the single digits to upper teens. Overnight lows within the NBM inter-quartile range from the negative teens to single digits above zero into Sunday morning. By the time the daytime hours on Sunday rolls around, flow turns to the west which may "warm" us up a few degrees, primarily west of the Mississippi River with highs mainly in the teens with the 75th percentile NBM trying to sneak in some lower to mid-20s. This will be very short lived though as a shortwave will sneak across northern WI with surface cold front draped to the south ushering in reinforcing cold air into the region. Deterministic and ensemble guidance generally agree on keeping this airmass entrenched in the region through early next week, thus expecting temperatures to remain cold to start the upcoming work week.

As far as precipitation chances are concerned, outside of some lingering snow showers behind the initial cold front on Saturday, the main chances (20-40%) for snow will be associated with the aforementioned wave and sfc cold frontal passage on Sunday. Currently, accumulations would likely be on the low end at this point as precipitable waters generally around 0.25" or less in deterministic guidance would indicate limited moisture. As a result, the grand ensemble (GEFS/EC/Canadian ensemble) has medium probabilities (40-60%) for measurable snowfall but low probabilities (10-20%) for amounts of an inch or greater as this front works through.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1134 PM CST Tue Jan 13 2026

Stratus continues to be the source of much frustration in the aviation forecast. Large area of stratus hovering in the 2500-3500 foot range is present east of the Mississippi and into the MN arrowhead. While this was expected to be MVFR, many locations continue to report ceilings around 3200-3500 feet. Additionally, a large area of clearing has unexpectedly developed in SE MN and NE IA extending back to central MN. While additional stratus should shift southward from the MN arrowhead and NW WI overnight, have elected to keep RST/LSE with ceilings just above MVFR given continued uncertainty about if stratus will return from the north and if it will actually be at or below 3kft. As for other concerns, a few flurries may occur in our far east (MDZ/VOK/82C) overnight. Otherwise, expect continued gusts to 20-30 knots out of the northwest through midday Wednesday. Next widespread impacts still look to be after 18z Thursday.

ARX WATCHES/WARNINGS/ADVISORIES

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