textproduct: La Crosse

KEY MESSAGES

- Winter Storm continues today through Sunday morning bringing moderate to heavy accumulating snowfall. 6+ inches of snow is expected for locations along and south of I-90. Areas over northeast Iowa and far southwest Wisconsin have a 40-80% probabilities of receiving 1 foot. Near blizzard conditions are possible west of the Mississippi River tonight through Sunday morning.

- Cold temperatures remain through next week with highs in the upper teens to mid 20s. Overnight lows fall into the single digits above and below zero Monday morning and Thursday morning.

- Additional periods of snow are possible (10-30%) through next week.

DISCUSSION

Issued at 415 AM CST Sat Nov 29 2025

Winter Storm Today Through Sunday Morning

A winter storm continues today as a 500hPa shortwave trough currently situated over the Intermountain West shifts east- northeastward, taking on a negative tilt as it progresses. At the surface, low pressure is located over the central Great Plains and is expected to continue northeastward throughout the weekend. 850-700hPa warm air advection has moved into the Midwest on the northern periphery of this low, initiating widespread snowfall across the region.

RAP/HRRR forecast soundings continue to depict a below freezing atmosphere such that snow continues to be the sole precipitation type expected with this event. These soundings also indicate the DGZ is generally situated within the 800-600hPa layer, on the higher end of this layer over northeast Iowa and southwest Wisconsin. Low to mid-level warm air advection and isentropic upglide on the 285-295K surface will be the primary drivers of precipitation through the day. However, various bands of frontogenesis continue to be depicted over northern Iowa into southwest Wisconsin within the RAP which would act to enhance snowfall rates across these areas.

Little has changed with regard to QPF and SLRs over the past 12 hours, so confidence remains high (75-95%) areas along and south of I-90 will see 6+ inches of snow with portions of northeast Iowa and southwest Wisconsin seeing upwards of 1 foot of snow under a prolonged period of 0.5-1 inch per hour snowfall rates owing to the aforementioned forcings.

The trend of increased surface winds owing to a closer track of the surface low continues, with the 29.00z HREF highlighting 70-100% probabilities of 35mph wind gusts beginning this evening through Sunday morning, strongest west of the Mississippi River. 29.00z HREF joint probabilities of 35mph gusts and visibility less than 1/4mi sit at 30-50%, indicating these winds combined with the moderate to heavy snowfall and blowing of the fresh snowpack could lead to near blizzard conditions at times. If these conditions occur, very difficult driving conditions would result.

Snow will taper off from west to east on Sunday, but there are some increased probabilities of light snow lingering through Sunday morning (10-20%), primarily along and east of the Mississippi River. Cold air advection under north to northwesterly flow steepens 0-2km lapse rates to 6-7 C/km, reaching into a modestly saturated DGZ. The breezy winds and any lingering light snow will shift eastward Sunday afternoon.

Cold Temperatures Through Next Week

Ensemble guidance continues to depict below normal temperatures through next week as northwest flow in the wake of this weekend's winter storm ushers cold air into the region. The coldest periods are expected Monday morning and Thursday morning as lows fall into the single digits above and below zero area wide, roughly 15 degrees below normal. However, the 25th-75th spread in the 28.18z EPS has increased as compared to previous runs for Monday morning, likely owing to potential cloud cover streaming in from the north on the backside of the winter storm that the EPS holds onto longer than other solutions.

Regardless, temperatures will still be cold for the foreseeable future. Thankfully, winds look to remain light through next week which will keep apparent temperatures above advisory criteria (-25F), although areas west of the Mississippi River may approach these values Thursday morning.

Precipitation Potential Next Week

Continue to see probabilities (10-30%) for several periods of additional light snow through the new week as various upper level shortwaves propagate through northwest flow. Monday night into Tuesday is the next shot at snow across our area, although the 29.00z LREF continues to depict a ~80% probability that the bulk of any snow stays to our south. If there is a northward trend, northeast Iowa into southwest Wisconsin would be the most favorable areas to see a period of travel impacts. After this timeframe, Wednesday and again Thursday see snowfall probabilities, but it remains too early to dive into much detail.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 534 AM CST Sat Nov 29 2025

Widespread snowfall continues moving northward this morning, overspreading the entire area over the next few hours. MVFR/IFR conditions turn to LIFR by mid morning as visibilities deteriorate in heavier snowfall. The heaviest snowfall is expected along and south of I-90.

Easterly winds today become north to northwesterly this evening, gusting 25-35kts at times. These stronger gusts could lead to further visibility reductions overnight as blowing snow becomes more of a concern. Gusts will be strongest west of the Mississippi River where near blizzard conditions are possible tonight through Sunday morning. Conditions slowly improve through the day Sunday as the winds diminish and snow shifts eastward.

ARX WATCHES/WARNINGS/ADVISORIES

WI...Winter Storm Warning until 6 AM CST Sunday for WIZ029-032>034- 041>044-053>055-061. Winter Weather Advisory until 6 AM CST Sunday for WIZ017. MN...Winter Storm Warning until 6 AM CST Sunday for MNZ079-086>088- 094>096. IA...Winter Storm Warning until 6 AM CST Sunday for IAZ008>011-018- 019-029-030.