textproduct: La Crosse

KEY MESSAGES

- A winter storm moves through the Midwest Friday night through Saturday night, providing a prolonged period of snowfall. Probabilities for 6+" of snow are 25-95%, highest (70-95%) along and south of I-90.

- 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 by the beginning of next week.

DISCUSSION

Issued at 159 PM CST Thu Nov 27 2025

Winter storm Saturday:

All eyes are on an upper disturbance off the Pacific Northwest coast this afternoon. Broad agreement across guidance that this feature will dive southeast toward the southern High Plains as an upper jet advances to the equatorward side of this feature as it approaches the Front Ranges of CO. This will result in lee surface cyclogenesis where CO/NM/KS/OK/TX meet Friday evening. As this occurs, upper low over the Great Lakes will shift eastward and an upper jet currently on the westward side of this low over the northern and central Plains will become oriented over roughly a MN to NYC axis. Additionally, broad surface ridge will build in the TN/OH Valley in the wake of this upper low with this shifting to the Piedmont on Saturday. With the right entrance region of the MN to NYC jet located over IA/MO, southern High Plains surface low should rapidly advance northeastward toward NE MO. Given the surface high to the east, southerly moist advection will be sufficient for widespread precipitation to develop as isentropic lift occurs on the 275-285K surfaces. Thermal profiles across the CWA are solidly below freezing, so any precipitation will fall as snow.

While snow is a certainty for areas along and south of I-90, remaining questions surround both how far north snow shield will extend and exactly how much will fall. Mesoscale features that tend to be needed to reach a foot of snow in this part of the country - frontogenetic banding or a persistent TROWAL - are conspicuously lacking in guidance outside of a frontogenetic band moving northward with the initial warm advection regime. Therefore, am expecting an extended period of light to moderate snow and have gone with the more conservative WPC numbers, which line up better with 27.12z modeled snow depth change, rather than the more aggressive NBM.

Due to collaboration concerns, have upgraded all counties within the Winter Storm Watch to a Winter Storm Warning west of the Mississippi and issued a Winter Weather Advisory for Wabasha County.

Cold week ahead:

A week of cold weather is expected in the wake of Saturday's winter storm. Based on the timing of when the surface high builds into the region, Sunday night should be the coldest of the bunch. Indeed, NBM highs are in the single digits above and below zero and would not be surprised to see all locations end up below zero once all is said and done. Silver lining is that breezy winds appear improbable during the cold snap so wind chills are favored to remain above -15.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1130 PM CST Thu Nov 27 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 beings to overspread areas southwest of an RST to PVB line between 03-06Z, which could result in MVFR to localized IFR restrictions. These spread further northeast throughout the night and persist through the day on Saturday. Northwesterly winds of 5-10 kts overnight lessen during the day and back to the east at around 5 kts after sunset.

ARX WATCHES/WARNINGS/ADVISORIES

WI...Winter Storm Watch from late Friday night through late Saturday night for WIZ041>044-053>055-061. MN...Winter Storm Warning from midnight Friday night to 6 AM CST Sunday for MNZ086>088-094>096. Winter Weather Advisory from midnight Friday night to 6 AM CST Sunday for MNZ079. IA...Winter Storm Warning from midnight Friday night to 6 AM CST Sunday for IAZ008>011-018-019-029-030.