textproduct: La Crosse

KEY MESSAGES

- Additional 1" to 2" of snow expected through much of Sunday. Strong northwest winds in wake of higher snowfall chances Sunday night perpetuate travel impacts into Monday morning.

- A Cold Weather Advisory has been issued area wide for Sunday night through Monday morning as strong winds and cold temperatures result in wind chills of 25 to 35 below zero.

DISCUSSION

Issued at 344 PM CST Sat Jan 17 2026

Cold Sunday Night Through Monday Morning:

A troughing appendage to the upper level low, over the northeastern Great Lakes on GOES WV cyclonic rotation, is progressing south through the Upper Midwest, nearing a quasi- normal abutment to an enhanced upper level subtropical jet streak through the Mid-Mississippi to Ohio River Valleys. This synoptic confluence has strung the anomalously cold low level Arctic airmass east towards the Ohio River Valley with surface temperature observations in the teens. While the local forecast area will be somewhat spared from the coldest, minimum anomaly 850mb temperatures (OAX RAOB SPC Climatology) for now, subsequent digging and diving of an upper level trough on GOES-W over British Columbia & Alberta ushers in bitter, minimum anomaly 850mb temperatures across the Upper Mississippi River Valley Sunday night through Monday night.

Probabilities (60%) in the -25C isotherm at 850mb initial reaches the local forecast area Sunday evening (HREF), lingering 15% to 40% LREF probabilities through Monday night. Resultant confidence in surface temperatures below zero reach 100% initially Sunday night, sticking around through Tuesday evening. The intense low level cold air advection will also steepen low level lapse rates Sunday night into Monday morning, tapping into increased off surface winds with a tightening low level isoheight gradient from a deepening surface cyclone over the eastern Great Lakes. Long term ensemble (EPS/GEPS/GEFS 17.12Z) confidence for 30kt winds at 925mb reaches 100% Sunday night lasting through early Monday morning. Resultant sustained surface wind probabilities of 20kts result in wind chill probabilities reaching 100% for cold advisory criteria (-25F) Sunday night through Monday morning. Given the confidence and current forecasts, have issued a Cold Weather Advisory across the forecast area in collaboration with neighboring forecast offices Sunday night through Monday morning with wind chills from 25 to 35 below expected.

Snowfall Sunday:

An upper level trough on GOES-W water vapor imagery over British Columbia & Alberta digs and dives through the Northern Plains tonight from an enhanced upstream upper level jet streak on GOES derived winds, bringing additional snowfall locally for Sunday. Initial snow chances accompany low level frontogenesis along a meriodionally-oriented front advecting zonally across the forecast area early Sunday morning. Have increased PoPs compared to previous forecasts to account for this initial, higher potential farther south into northeast Iowa.

Subsequent widespread snowfall expected initially later Sunday morning lasting through Sunday evening. As the wave sags southeast, DGZ thicknesses decrease and shunt farther southwest as burbles of synoptic and frontogenetic forcing drive snowfall. Resultant HREF confidence for snowfall rates of 0.1" per hour decrease from 80% to 40% as precipitation chances approach the local forecast area. The transient nature of precipitation with limited moisture which was shunted southwest limits overall amounts and probabilities to 1" to 2".

Concurrent with highest snow chances exiting east, northwest winds gusting 30-40 mph progress from west to east across the forecast area, perpetuating winter impacts from blowing and drifting of fluffy snowpack Sunday night through Monday morning. The strongest low level cold air advection wanes through Monday morning, decreasing overall winds and accompanying winter impacts.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 558 PM CST Sat Jan 17 2026

The light snow will move east out of the area by 18.03z. Another round of snow will move into the area on Sunday morning. The snow will move into KRST around 18.15z and KLSE around 18.18z. This snow will produce IFR/MVFR ceilings and visibilities.

ARX WATCHES/WARNINGS/ADVISORIES

WI...Cold Weather Advisory from 3 AM to noon CST Monday for WIZ017- 029-032>034-041>044-053>055-061. MN...Cold Weather Advisory from 9 PM Sunday to noon CST Monday for MNZ079-086>088-094>096. IA...Cold Weather Advisory from 9 PM Sunday to noon CST Monday for IAZ008-009-018-019. Cold Weather Advisory from 11 PM Sunday to noon CST Monday for IAZ010-011-029-030.