textproduct: La Crosse

KEY MESSAGES

- Light snow moves into the region from the west overnight into Sunday morning with lingering snow through early Sunday evening. Accumulation of around 1-2" is expected with highest amounts west of the Mississippi River.

- More seasonable temperatures return through the week with above freezing highs favored (60-90%) Thursday. Occasional flurries may occur with the next chance for more notable precipitation appearing to be Thursday night into Friday.

DISCUSSION

Issued at 201 PM CST Sat Jan 31 2026

Light snow ahead Sunday

Late tonight into Sunday morning, an upper wave over NE MT breaks southeastward over the Upper Midwest with this feature over N central IA by sunrise Sunday. While snow onset may be delayed by very dry antecedent conditions in the mid and upper levels - as evidenced by the 31.12z MPX RAOB - lift associated with the shortwave and from response to the upper jet overspreading the Dakotas, NE, and western IA should lead to mid level saturation with temperatures in the DGZ and, consequently, light snow much like what is seen in the Dakotas early this afternoon ahead of this same upper wave. Lift may be enhanced early Sunday morning by transient 700/850mb frontogenesis but this will be short lived. Light snow should take a step down in intensity in the late morning and early afternoon before picking up again as a secondary wave approaches from the northwest during the later afternoon and evening. That said, amounts with the second wave look to be minimal as additional forcing via jet dynamics and frontogenesis do not look to be present with this round. Thus, snow amounts should remain light, with around 1-2" supported by the 31.12z HREF mean and 31.13z NBM mean. Given this low amount but high probability event, have gone notably higher than the typically low-in-this-scenario NBM PoP values (most areas closer to 100% rather than 30-80%) using other short term consensus values.

Aspect to watch for a bit more impact is potential for a short (1-3) hour period of freezing drizzle during the aforementioned low intensity snow during the late morning and early afternoon. Mid level descent on the back side of the initial upper wave may lead to loss of saturation in the DGZ before CAA in the lower levels allows for ice crystals to form there rather than in the 600-700mb layer. Should this loss of saturation occur while the low levels remain saturated and low level lift can be maintained, freezing drizzle would occur. Looking across progged soundings, locations and times with the combination of loss of mid level saturation, low level saturation with temperatures above -10C, and low level lift appear very limited with the potential exception of northeast IA. While 31.15z RAP would support a few hours of freezing drizzle, 31.12z HREF modeled soundings suggest the 600-700mb layer will remain near saturation through the afternoon. Have therefore continued to keep FZDZ out of the forecast but this will be the main aspect to monitor over the 36 hours as confidence in the light snow portion of the forecast is high.

Slow temperature moderation continues through the week, precip potential Thursday night, Friday

Good agreement across EC/GFS/CMC ensembles that our seemingly ceaseless northwesterly flow pattern continues through next week. That said, height aloft remain about the same or at least very slowly trend upward. NBM interquartile ranges for highs are around 5 degrees or less through the week, reflective of broad consensus on this pattern. Highs will tend to be in the 20s and, with occasional disturbances ejecting downstream, cannot rule out some periods of flurries eventually emerging in later forecast updates.

Only truly notable period of weather looks to be Thursday into Friday. Thursday, northwesterly upper advances over SK/MB with a surface low developing under the left exit region of this feature in western Ontario, resulting in a period of southwesterly winds at the surface in our CWA. The probable (60-90% per 31.13z NBM) result will be temperatures reaching above freezing during the afternoon. As the low shifts southeast to the Great Lakes and an upper wave dives southeast out of Canada, precip could (20-40%) develop in our forecast area. Given the probable above freezing surface temperatures and potential for westerlies at 850mb to keep temps there above 0C, will need to watch this period over the coming days as it may yield multiple precip types rather than another shot of just light snow.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1151 AM CST Sat Jan 31 2026

VFR conditions for the day, ahead of a weather system that should bring IFR visibility snow to the area beginning later overnight. Timing is still not exact, but overall feel IFR -SN should occur +/- 2 hours of that contained in the 18Z TAF issuances for KRST and KLSE. Some questions remain on how fast saturation will occur with dry air in place as the lift moves in.

IFR CIGS will likely follow later Sunday morning as continued saturation occurs over southeast MN. Lowest visibilities and higher snow totals of 1-2 inches look most favorable for much of the area southwest of I-94. Light snow (and probably IFR conditions) will persist for much of Sunday before existing east in the evening.

ARX WATCHES/WARNINGS/ADVISORIES

WI...None. MN...None. IA...None.