textproduct: La Crosse

KEY MESSAGES

- Ongoing light snow remains on track with 1"+ of accumulations in spots. Increasing northwest winds this evening lasting into Monday morning will cause patchy blowing of lighter snowpack. Lower local snowpack compared to neighboring offices abstained issuance or expansion of Winter Weather Advisory but will require further monitoring as winds near this evening.

- Slightly warmer temperatures through midweek cease Friday as anomalous cold returns Friday and through the weekend. Current confidence for coldest temperatures Saturday morning. Headlines will likely be warranted.

- Measurable snowfall probabilities increase Tuesday night through Wednesday.

DISCUSSION

Issued at 140 PM CST Sun Jan 18 2026

Ongoing Snowfall:

Ongoing light snow seen progressing southeast through the forecast area this afternoon on radar, causing temporary reductions in visibilities below 2 miles at times. Overall forecast remains on track with 1" to 2" of snowfall expected.

A surface frontal boundary, evident in winds veering to northwest across Minnesota, exhibits initial gusts greater than 30kts 50-80 miles upstream of the local forecast area in central Minnesota as of 20Z.

Given the stronger winds and lighter snowpack, blowing snow concerns increase tonight. Given the higher snowpack measurements east of the forecast area in southern Wisconsin, neighboring forecast office hoisted Winter Weather Advisory while locally abstained as blowing snow expected to limited to patchy. HREF joint probabilities exhibit this confidence and climatology well as sustained winds remain near 20kts, limiting lifting ability of snowpack regardless of depth. Will require constant monitoring through the afternoon and evening regardless as patchy road impacts will occur.

Bitter Cold Area Wide Through Monday Night:

Coldest surface temperatures within the Arctic airmass seen well upstream into west-central Minnesota in the single digits. Expect these temperatures to cover the local forecast area tonight through Monday morning as northwest winds gusts 30 to 40 mph. Resultant wind chills from 25 to 35 below zero keep previously issued Cold Weather Advisory in place through Monday morning.

Cold Later In The Week:

A temporary reprieve in the anomalous cold expected through midweek as apparent temperatures hover a few degrees above and below zero. Eventually the cold returns this weekend with ECMWF (18.00Z) extreme forecast index of -0.85 from Saturday onwards suggesting "very unusual" cold is likely. Accompanying above 0 shift of tails bifurcate the forecast area suggesting a few member solutions suggest 99th percentile cold temperatures compared to Model climate for this time of year. Associated cumulative density function plots are limited to the day 5 forecast window so determining and deciphering specifics regarding shift of tails, i.e., extremities and outliers.

While all LREF members suggest the responsible Polar low advecting through southern Canada later this week in 100% probabilities for <504 dam 500mb heights bringing 100% probabilities for below zero 2m temperatures (EPS 18.00Z, GEFS 18.00Z) Friday night and Saturday night (EPS 18.00Z, GEFS 18.00Z, GEPS 18.00Z), strength and progression of the Low and subsequent High over the Upper Mississippi River Valley through the weekend presents inter/intra forecast model discrepancies. Evident in probabilities for the -20C isotherm at 850mb, seen over the forecast area with this weekends cold, varying in certainty from northern Wisconsin to central Iowa through next weekend. The highest pressure and longest lasting cold seen in the GEFS (18.00Z) with 80% probability for 1035 mb mean sea level pressure causing 75%+ probabilities for negative 2m temperatures Friday night through Sunday night. A stronger Low in the EPS (18.00Z), signaled in ECMWF dynamic tropopause heights to 850mb Friday night, forces the local high pressure farther east over the Great Lakes through the weekend, limiting probabilities for below zero 2m temperatures after Saturday night.

Resultant NBM 25th to 75th 2m temperature spread is 10-15 degrees early in the weekend and 5-10 degrees later in the weekend. Regardless, given the longer forecast hour and variable solutions, have kept NBM forecast through the weekend which keeps apparent temperatures straddling Cold Weather Advisory to Extreme Cold Warning criteria Saturday morning and nearing Cold Weather Advisory criteria Friday and Sunday mornings.

Snow Chances Return Tuesday Night Through Wednesday:

A Rocky Mountain Low quickly skirts northeast through the Central Plains Tuesday, bringing local snow chances initially Tuesday night. Long term ensemble confidence for 0.01" of QPF remains 100% as probabilities for 0.1" nears 50% in the GEFS (18.00Z) and 70% in the EPS (18.00Z). The higher QPF currently causes concern for Advisory criteria snowfall amounts but given the longer forecast hour and increasing fealty to the NBM, have kept NBM 20-50% PoPs in collaboration with neighboring forecast offices. Will require further adjusting as forecast hour nears and NBM catches up.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1131 PM CST Sun Jan 18 2026

During the overnight, the wind gusts will gradually decrease. KRST will likely see blowing snow reduce visibilities into the 1 to 2 mile range through 19.08z and then they should quickly become VFR. KLSE will occasionally see a few snow showers through 19.08z. These snow showers may briefly produce MVFR visibilities. Ceilings will be primarily MVFR through 19.15z and then become VFR.

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...Winter Weather Advisory until midnight CST tonight for MNZ086- 087-094-095. Cold Weather Advisory until noon CST Monday for MNZ079-086>088- 094>096. IA...Winter Weather Advisory until midnight CST tonight for IAZ008- 009-018-019. Cold Weather Advisory until noon CST Monday for IAZ008>011-018- 019-029-030.