textproduct: La Crosse

KEY MESSAGES

- A winter storm moves through the region tonight through Saturday night providing a prolonged period of accumulating snow. Probabilities for 6+" of snow are 70-95%, highest along and south of I-90 with areas along and south of Highway 18 in northeast Iowa and far southwest Wisconsin favored to see the highest totals.

- 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 Sunday night into Monday morning. - Low probabilities for additional precipitation through next week (10-30%), likely in form of snow.

DISCUSSION

Issued at 413 AM CST Fri Nov 28 2025

Winter Storm Tonight Through Saturday

A Winter Storm is expected to develop today across the central Great Plains as lee cyclogenesis sparked by a 500hPa shortwave trough currently situated over the Pacific Northwest propagates eastward. A belt of warm air advection associated with this developing low pressure system will lift northward tonight, which combined with a band of 800-700hPa frontogenesis in the warm air advection, is expected to initiate a prolonged period of snowfall through Saturday.

The southern shift in the low track seen in yesterday's model runs has since begun to trend back northward by a couple counties, which has increased snow amounts across the region. Thinking this variation stems from the primary 500hPa shortwave that is expected to drive this system finally moving onto the west coast of the United States, allowing it to now be fully sampled.

Probabilities remain high for 6+ inches of snow, generally 70-95% highest along and south of I-90. The 28.01z NBM remains the most bullish with higher probabilities, upwards of 50-80% for 12+ inches, as compared to the 28.00z LREF indicating 20-50% probabilities. However, these higher amounts seem plausible as 900-700hPa frontogenesis is depicted over areas south of I-90 Saturday afternoon which would bump up snowfall rates and subsequent amounts. As such, the highest snowfall rates, upwards of 1 inch per hour in the 28.00z HREF, and greatest period of impacts are expected during this time frame and the highest snowfall totals are favored over northeast Iowa into far southwest Wisconsin. Snowfall tapers off from west to east Saturday night into Sunday morning as the upper level trough and associated surface low shift eastward.

Cold Temperatures Through Next Week

Cold temperatures remain in place behind this weekend's winter storm, struggling to climb above freezing through next week. Sunday night will be the coldest, with lows in the single digits. Temperatures warm slightly Wednesday, into the upper 20s under southerly flow and warm air advection, but quickly cool down again Thursday. Some uncertainty remains regarding how the snowpack developing this weekend will influence temperatures, but confidence is high that they stay cold over the next several days.

Precipitation Potential Next Week

An active upper level pattern is expected through next week in the wake of this weekend's winter storm. Several waves propagate eastward across the United States through the week, promoting various periods of cyclogenesis and potential for precipitation. Quite a bit of variation exists amongst the ensembles through the week, so it's difficult to glean much for details at this time.

However, the next timeframe favored for precipitation potential across our area after this weekend comes Monday night into Tuesday morning. As previously mentioned, there's quite a bit of discrepancy amongst the ensembles, in this case regarding the track of a low pressure system developing across the central Great Plains. The majority of the 28.00z LREF clusters favor a southern track to this low, similar to the EPS solution, which would keep much, if not all of our area dry. Roughly 25% of the membership does suggest a more northward track though, towards the GEFS solution, which would bring higher probabilities of precipitation into our area. As such, precipitation probabilities sit around 10-30% during this time and with below freezing thermal profiles, snow would be the favored precipitation type.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 545 AM CST Fri Nov 28 2025

VFR ceilings are forecast for the rest of tonight and into the morning with a short period of MVFR ceilings possible--mainly east of the Mississippi River--during the early afternoon hours. Snow begins to overspread areas southwest of an RST to PVB line between 03-06Z, which could result in MVFR to localized IFR restrictions. These conditions spread further northeast throughout the night and persist through the day on Saturday before departing Saturday night. Northwesterly winds of around 5 kts this morning lessen during the day and back to the east after sunset and increase to 5-10 kts by sunrise Saturday.

ARX WATCHES/WARNINGS/ADVISORIES

WI...Winter Storm Warning from midnight tonight to 6 AM CST Sunday for WIZ053>055-061. Winter Weather Advisory from 6 AM Saturday to 6 AM CST Sunday for WIZ017-029. Winter Storm Warning from 3 AM Saturday to 6 AM CST Sunday for WIZ032>034-041>044. MN...Winter Storm Warning from midnight tonight to 6 AM CST Sunday for MNZ079-086>088-094>096. IA...Winter Storm Warning from midnight tonight to 6 AM CST Sunday for IAZ008>011-018-019-029-030.