textproduct: La Crosse

KEY MESSAGES

- A compact, but potent, band of snow affects northeast IA into southwest WI and north into central WI. Many locations will very likely (60-95%) see 3"+ of snow south/east of a Charles City to Tomah line while far southwest WI and adjacent parts of northeast IA will likely (60-90%) see some 6" values. A Winter Storm Warning has been issued for those areas favored to reach 6".

- While confidence in the placement of the heaviest snow band has increased enough for a Winter Storm Warning to be issued, the northern side of the snow band will see a sharp cutoff in snow amounts and impacts over just a few miles.

- Potential for additional light (<1") snow this weekend.

- Near or slightly below normal temperatures move in for the end of the week and early next week with these looking to rebound somewhat for next Tuesday and Wednesday.

DISCUSSION

Issued at 259 PM CST Thu Feb 19 2026

Band of snow tonight, heavy amounts likely in far SW WI and adjacent parts of NE IA

18Z WV satellite shows an upper low over the MN Arrowhead and a disturbance deepening over the KS/NE border. An upper jet is present from S CA to MO. At the surface, low pressure is present under the left exit of the upper jet with this being located in the Kansas City area.

Into tonight, with the upper jet advancing over IL/IN, surface low will shift east-northeast accordingly, becoming centered roughly in the Milwaukee area by 12z Friday. Southerly warm advection in the mid levels across the MS Valley ahead of the wave should lead to the KS/NE wave becoming an upper low that will pass just to the SE of our CWA. In concert with aforementioned warm advection, with northerly flow aloft on the back side of the MN Arrowhead upper low present, mid-level front will tighten with said frontogenesis providing a relatively narrow axis of enhanced lift from central IA into central WI. With robust forcing for ascent also being provided by the approaching upper low, should get over 0.5" of liquid under the strengthening mid-level front. With deep saturation through the DGZ, primarily snow should result with rates above 1" possible, although a short period of rain may occur before low level temperatures drop just a degree or two. Snow rates would likely be higher but, given much of the column is just below 0C and EPV* fields suggest a stable atmosphere, expect a wetter snow character overall and have moved forecast snow ratios toward the low side of consensus, closer to 10:1. As the upper low occludes over WI, axis of moisture should pivot from a SW-NE orientation to a more SSW-NNE orientation Friday morning, leading to increased snow duration in parts of central WI even as snow rates reduce as best QG forcing shifts over MI and dry air entrainment around 700mb occurs.

Big question for days has been where exactly the tightening mid- level front would be located as the upper wave moves northeast. 19.12z runs, including many short term models, have largely converged on central IA northeast into far SW WI with the aforementioned region at risk for a few extra hours with snow under the pivoting band extending into central WI. Have therefore issued a Winter Storm Warning for far SW WI (Crawford/Richland/Grant) and adjacent areas of IA (Clayton/Allamakee/Fayette) for the main band and Juneau/Adams for the pivot region. That said, with very dry air lurking around 700mb as seeing on lower level WV satellite channel, sharp northwest cutoff to snow amounts is expected. Thus, while locations from around Charles City IA to Tomah WI have a Winter Weather Advisory, snow amounts in these areas are highly uncertain, with only a few miles potentially separating minor (~1") accumulation from close to 5". Given this, any wobble in the location of the band may lead to a big chance in snow amounts.

Finally, the dry intrusion around 700mb may open up a short period of FZDZ on the northwestern edge of the band. Confidence in occurrence remains low as some guidance, for example the 19.19z RAP, suggests enough lift continues in the DGZ (rooted around 650mb) for potential seeding of supercooled droplets closer to the surface if ice crystals can make it through the dry intrusion.

Light snow this weekend

Pair of disturbances dive southeast out of Canada this weekend as northwesterly flow aloft returns after a welcome absence. These may kick off some flurries but accumulations look to be minor (19.13z NBM 95th percentile snow across the entirety of Saturday and Sunday is 1" or less).

Temperatures moderate next week

The dreaded northwest flow looks to be short lived as large scale height rises occur over the western two thirds of the CONUS and quasi zonal flow returns. Temperatures, having fallen to a bit below normal over the weekend, return to the mid 30s to mid 40s Tuesday and Wednesday.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1141 AM CST Thu Feb 19 2026

Band of snow is expected to occur tonight into early Friday, primarily south/east of a MCW-LSE-AUW line. Confidence is high enough to continue with definite mentions at LSE for several hours along with IFR conditions. Snow will probably (70%) skirt southeast of RST so have only included a PROB30 with MVFR mentions at this terminal. Winds will also ramp up after 06z Friday with gusts to 25-30 knots possible after sunrise Friday.

ARX WATCHES/WARNINGS/ADVISORIES

WI...Winter Weather Advisory from 8 PM this evening to 9 AM CST Friday for WIZ041-053. Winter Storm Warning from 8 PM this evening to 9 AM CST Friday for WIZ054-055-061. Winter Weather Advisory from midnight tonight to 9 AM CST Friday for WIZ034-042. Winter Storm Warning from midnight tonight to noon CST Friday for WIZ043-044. MN...Winter Weather Advisory from 8 PM this evening to 9 AM CST Friday for MNZ096. IA...Winter Weather Advisory from 8 PM this evening to 9 AM CST Friday for IAZ009-010-018-019. Winter Storm Warning from 8 PM this evening to 9 AM CST Friday for IAZ011-029-030.