textproduct: La Crosse

KEY MESSAGES

- Periodic showers today, transitioning to snow overnight into Wednesday. Snow accumulations most likely north of I-90 (60-90%) with the highest amounts expected in Taylor County.

- Gusty winds are expected tonight into Wednesday. Gusts of 45 mph are possible, highest west of the Mississippi River.

- Mild temperatures continue today, becoming much colder Wednesday through at least early next week.

DISCUSSION

Issued at 354 AM CST Tue Nov 25 2025

Periodic Showers Today Transitioning to Snow Overnight

A potent 500hPa shortwave trough ejects into the northern Great Plains today, sparking strong surface cyclogenesis that will eventually shift eastward into the Great Lakes region, moving through tonight into Wednesday. Periodic showers are possible throughout the day today (20-60%), most probable north of I-90, within a weak 925-850hPa warm air advection regime as the surface low and associated frontal system move into the region, providing enough lift within the saturated low levels for scattered precipitation. Shower potential increases this evening (60-90%) along a cold front before a quick transition to snow occurs tonight as strong cold air advection forces thermal profiles below freezing within the deformation zone. As a result, snowfall is expected for most tonight through Wednesday morning, although accumulations are expected mainly for areas along and north of I-90. However, there has been a southward trend of this system over the past 24 hours which has shifted the potential for higher snowfall amounts into our area.

The 25.01z NBM and 24.12z LREF ensembles now suggest 60-90% probabilities for greater than 1 inch of snow for much of the area although they maintain the highest probabilities generally along and north of I-90. The most notable increase in snowfall probabilities and subsequent amounts is across Taylor County where probabilities for greater than 4 inches of snow now sit at 60-80% (as compared to 20-40% 24 hours ago), likely associated with strong 800hPa frontogenesis situated of north-central Wisconsin as the main surface low moves through the Upper Mississippi River Valley. If the southward trend continues, these higher snowfall amounts may become more likely across more of the region. Overall, a general 1-3 inches is expected for areas along and north of I-90 with 2 to 5 inches possible in in Taylor County.

Gusty Winds Tuesday Night into Wednesday

A tightened pressure gradient associated with the aforementioned surface low, most notable on its western side, will increase the low level wind field as it moves through the region tonight into Wednesday. 925-850hPa winds increase to around 50-60kts which combined with cold air advection on the backside of the cold front should allow for efficient momentum transfer of these strong low level winds to the surface, leading to gusts of 40-45 mph across much of the region. The potential for these strong winds is highlighted in both the 25.00z HREF and 24.12z LREF which indicate 40-70% probabilities for 45 mph gusts. The strongest winds are expected west of the Mississippi River and begin to diminish Wednesday afternoon.

Given a lack of snowpack and lower snow totals for areas that are expected to see these stronger winds, not anticipating widespread impacts from blowing snow although some visibility restrictions may be noted at times. If the southward trend continues however, visibility restrictions and overall travel impacts will become more of a concern.

Mild Today Then Much Colder

Mild temperatures continue today under southerly flow. High temperatures reach into the upper 40s to low 50s for most. However, these don't linger for long as the strong cold air advection behind the surface low knocks temperatures down nearly 20 degrees by Wednesday, only reaching into the upper 20s to low 30s. These cold temperatures Wednesday combined with the previously mentioned gusty winds will lead to apparent temperatures in the teens.

Highs through much of the week will struggle to break 30F with very little spread in the 10th-90th percentiles of the 25.00z EC Ens and GEFS through Sunday, leading to high confidence in the current temperature forecast. More variation is introduced early next week, although the general consensus of the EPS/GEFS indicates temperatures are favored to remain below freezing, which is also highlighted in the 25.01z NBM mean.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 508 AM CST Tue Nov 25 2025

IFR to LIFR conditions are currently present across the region as a mixture of light showers, drizzle, and fog are impacting the terminals. This should continue for the coming hours with fog gradually dissipating by late morning with visibilities likely lifting back to MVFR/IFR (some high end LIFR may linger even longer for portions of SE Minnesota and NE Iowa). CIGs will likely stay in the IFR/LIFR range through tonight before gradually improving to MVFR by late in the period. Light rain is expected for much of the afternoon with some brief lulls possible this evening ahead of the next round of precipitation. Precipitation tonight will become a rain/snow mix with cooler air filtering into the area before turning to all snow later overnight. Visibilities with this precipitation will likely need to be adjusted going forward but have left them in the MVFR/IFR range as this seems reasonable for now. South/southwesterly winds this morning are expected to pick up through the afternoon, becoming more westerly by 00Z Wednesday. Winds will continue to increase after 00Z, peaking between 06-12Z with gusts of 35-40 kts out of the northwest likely.

ARX WATCHES/WARNINGS/ADVISORIES

WI...Dense Fog Advisory until 10 AM CST this morning for WIZ061. Winter Weather Advisory from 3 AM to noon CST Wednesday for WIZ017. Wind Advisory from 3 AM to noon CST Wednesday for WIZ032>034- 041>044-053>055-061. MN...Wind Advisory from midnight tonight to noon CST Wednesday for MNZ079-086>088-094>096. IA...Wind Advisory from midnight tonight to noon CST Wednesday for IAZ008>011-018-019-029-030. Dense Fog Advisory until 10 AM CST this morning for IAZ018-019- 029-030.