textproduct: La Crosse

KEY MESSAGES

- After a brief lull tonight into Thursday morning, a potent clipper races through the region Thursday night into Friday morning. The main impacts for 3-6 inches of snow look to be north of Highway 29, but the bigger story will be the strong winds that arrive behind the cold front. Winds could gust up to 60 mph and any light snow in these winds will result in whiteout conditions.

- A major winter storm is shaping up for Saturday night into Sunday night across the Upper Mississippi River Valley. There is high confidence (80-90%) in a band of 6-12 inches of snow with localized amounts of 18 to 24 inches (20-30% chance). The big question is exactly WHERE this band of heavy snow sets up. Combined with strong winds Sunday afternoon/night, travel may be impossible at times during this storm.

- Very cold temperatures settle in for the start of next week with sub-zero wind chills Sunday and Monday nights.

DISCUSSION

Issued at 145 PM CDT Wed Mar 11 2026

This Afternoon: Snow Departs

Our ongoing band of light snow departs through the early afternoon. Afternoon solar insolation coupled with lessening snow rates should result in minimal impacts for the rest of the day. Surface high pressure slides through tonight into early Thursday morning, bringing a brief lull in the weather before our next weather system arrives later Thursday.

Thursday Night - Friday AM: Snow in Northern WI, Strong Winds

A potent clipper wave digs across North Dakota and into northern Wisconsin late Thursday and Thursday night, departing by mid-morning Friday. Any locations south of the surface low see sufficient WAA to keep the attendant isentropic lift precipitation Thursday night fall as rain, with a sharp transition to snow along and north of the surface low track. There still exists a 2-3 county wide N-S spread in the storm track as the low traverses northern Wisconsin. This will play heavily into whether Clark and Taylor counties see impacts from the heavier snow band. The going forecast leans more on the track portrayed by the global ensembles (keeping the heavy snow along and north of Highway 29), which is similar to what has been depicted in the forecast over the last 24-36 hours.

Strong northwesterly winds race southward in the wake of the trailing cold front after midnight early Friday morning. A 60-70-kt 850-mb jet carves out the W/SW side of the departing surface low, with steepening boundary layer lapse rates tapping into this jet. The combination of this CAA and mechanical mixing should funnel these winds to the surface, it is just a question of how strong. Forecast profiles from the various global and convective models show the boundary layer fully realizing this 850-mb jet and explicit wind gusts from these models are pushing into warning levels (50-60-kts). It looks like these winds will be maximized immediately behind the cold front where the subsidence branch of the frontogenetical circulation and isallobaric wind will co-exist. Therefore, the strongest wind gusts look to occur in a 2-4 hour period. While still blustery, winds should then slowly decrease through the rest of the day.

Another outlier possibility--but something worth watching--will be if any snow accompanies this frontal passage and wind surge. Snow amounts do not look to be all that high (<1"), but any amount of snow that falls within these winds will result in near whiteout conditions and possibly necessitate the issuance of advisories or snow squall warnings.

Late Saturday - Sunday: Major Winter Storm Affects the Region

A winter storm that has been lurking in the longer range models for many days continues to have the local forecast area in its cross hairs. It truly is a matter of where, not if, we see a band of 6-12+ inches of snow occur. The forecast envelope is narrowing and an increasing number of ensemble members are focusing along the I-90 corridor. We are still just under 4 days away from this event and the model solutions are in remarkably good agreement for this range of the forecast. On the flip side, being four days out, the forecast still has time to shift appreciably in time and space.

From an ingredient standpoint, the storm is a classic. A deepening surface low, strong isentropic ascent and moisture transport over an elongated fgen band oriented along the low track and pivots directly over the forecast area. The NBM snow amount probabilities along I-90 are nothing to sneeze at: 90% for 6", 50-70% for 12", 10-20% for 24". And this is still 4 days out!

Strong winds on the backside of the departing low and deformation zone will lead to blowing and drifting snow Sunday afternoon into Sunday night. The wetter nature of the snow early on combined with the winds could result in tree and power line damage and if some of the more aggressive scenarios play out, blizzard headlines will be on the table.

It goes without saying that travel may be impossible at times during this winter storm. The combination of high snow amounts and winds of 30-40 mph could make roads impassable, especially in open areas west of the Mississippi River.

Cooling Temperatures

A surge of CAA trailing our weekend system sends temperatures plummeting back to values more typical of early February. Highs on Monday only reach into the 20s with lows for Sun/Mon nights in the single digits--locales that see the fresh snow likely seeing lows fall below zero. This cold snap looks to only last a few days with highs rebounding back to near average through the rest of the week.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1213 PM CDT Wed Mar 11 2026

Skies are beginning to clear from the west with improving conditions across much of the area. Where conditions are not already VFR, they should improve in the coming hours as the snow band moves off to the east into the early afternoon. Once the cloud deck departs, VFR conditions should remain across the area through the end of the period. Northwest winds will gradually decrease with gusts tapering off through the afternoon. Winds will eventually become light and variable overnight as the wind direction quickly backs to the south by tomorrow morning. Winds will again pick up late in the period, especially west of the river (including the KRST terminal).

ARX WATCHES/WARNINGS/ADVISORIES

WI...None. MN...High Wind Watch from late Thursday night through Friday morning for MNZ079-086>088-094>096. IA...High Wind Watch from late Thursday night through Friday morning for IAZ008>011-018-019-029-030.