textproduct: La Crosse

KEY MESSAGES

- Two major weather systems remain on target to impact the region with the first tonight-Friday morning and the second storm coming Saturday night - Monday morning.

- Storm #1: Very strong winds gusting up to 50-60 mph, strongest west of the Mississippi River. Light snow showers accompanying these winds could result in snow squalls and periods of whiteout conditions.

- Storm #2: A potentially historic winter storm is coming into focus for Saturday night into Monday morning. A widespread swath of 12-18+ inches of snow is looking more likely across a large portion of the forecast area, especially between I-90 and I-94. Strong winds Sunday afternoon and night could lead to blizzard conditions and localized tree and power line damage.

- Bitterly cold temperatures settle in for late Sunday into Tuesday before rebounding later in the week.

DISCUSSION

Issued at 300 PM CDT Thu Mar 12 2026

Tonight - Friday Morning: Winter Storm #1 | Damaging Wind Risk

A potent 993-mb clipper wave is digging along the ND/MT/Canadian border early this afternoon is on track to move into northern Wisconsin tonight. A 60-70-kt LLJ along the western and southern flank of this lower tropospheric cyclone has already brought 70-80 mph wind gusts to Montana this morning and these winds spread to the ESE through the afternoon and evening right behind a strong cold front. Preceding WAA/isentropic lift precipitation is spreading ahead of this surface low and arrives later this afternoon and persists into the overnight. There will be a sharp rain to snow gradient along the track of the surface low with snow amounts of 3-6 inches most likely north of Highway 29 and amounts falling off pretty quickly to the south.

The cold front reaches south-central Minnesota around midnight and the Mississippi River by 3am. The WNW winds increase quickly in the wake of the front with a strong consensus in the models that the strong CAA and mechanical mixing will steepen lapse rates to support the transport of the 60-70-kt LLJ to the surface. Explicit wind gust forecasts from the HRRR and RAP are in the 45 to 55 kt range with winds at the top of the mixed layer nearing 65 kts. The strongest winds look to be in the 3-5 hr period immediately following the frontal passage and then we'll see the isallobaric wind relax. While still blustery, winds should then slowly decrease through the rest of the day. The high wind warning has been extended into southwest Wisconsin where these gusts up to 60 mph are a possibility, but more limited to higher elevations and exposed locales.

There is also an increasing signal in the higher resolution guidance that vigorous snow showers/HCR features will wrap around the low and move through during the morning hours. Whether these showers reach the criteria for a snow squall remains to be seen, but any snow showers within the corridor of stronger winds will lead to rapidly degrading visibilities over short distances for those out driving Friday morning. For now, the impacts from these snow showers is covered in the wind warning/advisory products, but short-fused advisories or possibly even a snow squall warnings will be assessed through the night.

Saturday Night - Monday Morning: Winter Storm #2 | Heavy Snow

While the first winter storm tonight is respectable on its own, the second storm on its heels says "hold my beer" and has the potential to deliver a widespread 12 to 18 inches of snow with localized pockets of 24 inches not out of the question in addition to blizzard conditions. We've been watching this storm for many days and while the setup is downright textbook, there remains uncertainties in EXACTLY where the band of heaviest snow falls. The ensemble guidance has been narrowing in on our forecast area for the storm track, but we are still 2-3 days out and we need to expect that the storm track will wobble. Heck, the culprit upper level PV lobe is still over the northeast Pacific and doesn't move into the upper air network until tomorrow afternoon.

From an ingredient standpoint, the storm is a classic. A rapidly deepening meridional upper level trough and surface low, strong isentropic ascent and moisture transport over an elongated fgen band oriented along the low track that pivots directly over the forecast area, upright instability over the fgen zone that could lead to thundersnow on Sunday. There is still notable spread in the QPF values between the GEFS and EPS with the GEFS much more rambunctious with realizing the strong moisture transport over the front and producing a 12-18 hour window of 1"/hr snow rates. It is incredibly difficult to sustain snow rates this high for this long and casts uncertainty into whether these are even realistic. For reference, the record 2-day snowfall totals for La Crosse and Rochester are 18.5 and 20.1 inches, respectively. There are many ensemble members that are eclipsing these values.

There will be a sharp cutoff in snow amounts along the southern side of the snow band as a pronounced warm nose lifts northward into northern Iowa and southwestern Wisconsin. Areas that remain under the >+1-3C 850-mb isotherm will see their precipitation vary between snow, rain, sleet, and possibly freezing rain with impacts and amounts varying quickly over short distances. It won't be until Sunday afternoon/evening as the cold air advection ensues and the deformation band pivots southward that the precipitation type changes to snow over the southern forecast area.

Strong winds on the backside of the departing low and deformation zone will lead to blowing and drifting snow Sunday afternoon into Monday morning. The wetter nature of the snow early on combined with the winds could result in tree and power line damage as these winds increase and temperatures begin to fall. The winter storm watch for west of the Mississippi River highlights the risk for blizzard conditions and we will have to monitor trends in case an eastward expansion of blizzard wording is needed.

It goes without saying that travel may be impossible at times during this winter storm. The combination of high snow amounts and strong winds could make roads impassable, especially in open areas west of the Mississippi River.

Early Next Week: Bitterly Cold Temperatures

Stronger CAA trailing our weekend system sends temperatures plummeting back to values more typical of early February. Highs on Monday only reach into the teens with lows for Monday night falling below zero with a 20-30% chance of lows in the teens below zero given the fresh snow. This cold snap looks to only last a few days with highs rebounding back to near average by the end of the week.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1242 PM CDT Thu Mar 12 2026

Main taf concerns are MVFR and windy conditions tonight into Friday morning. Low pressure moves across the area this afternoon into Friday morning. Pressure gradient tightens this afternoon and ceilings lower into MVFR conditions after 02z Friday. Southerly winds will gust from 25 to 30 knots this afternoon. Then the winds switch to the northwest and gust are expected to increase to 45 to 55 knots at both RST/LSE taf sites by 06z Friday. Light rain will be possible at both taf sites this afternoon into early Friday morning and change over to all or mix in with snow around 06z Friday. With windy conditions and the snow showers on backside of low pressure. Visibility could be reduced to IFR conditions briefly at RST taf site in the heavier snow showers after 06z Friday. Conditions will slowly improve late in the taf period and pressure gradient slackens after taf period.

ARX WATCHES/WARNINGS/ADVISORIES

WI...Winter Storm Watch from Saturday evening through Monday afternoon for WIZ017-029-032>034-041>044-053>055-061. Winter Storm Warning from 7 PM this evening to 1 PM CDT Friday for WIZ017. Wind Advisory from midnight tonight to 1 PM CDT Friday for WIZ017-029-032>034-041>044. Winter Weather Advisory from 7 PM this evening to 1 PM CDT Friday for WIZ029. High Wind Warning from midnight tonight to 1 PM CDT Friday for WIZ053>055-061. MN...High Wind Warning from midnight tonight to 10 AM CDT Friday for MNZ079-086>088-094>096. Winter Storm Watch from Saturday evening through Monday afternoon for MNZ079-086>088-094>096. IA...High Wind Warning from midnight tonight to 10 AM CDT Friday for IAZ008>011-018-019-029-030. Winter Storm Watch from Saturday evening through Monday afternoon for IAZ008>011-018-019-029-030.