textproduct: La Crosse

KEY MESSAGES

- Warm & windy today with west-northwest gusts from 30 to 35 mphthrough the afternoon and evening primarily along and north of Interstate 90.

- Very narrow, 50-75 mile, band of heavier snowfall remains possible Saturday morning and afternoon. Given very narrow forcing, highest amounts and exact location remains main forecast challenge as any shift in storm track shifts the band 100 miles north or south, 1 to 2 times the width.

DISCUSSION

Issued at 142 AM CST Fri Feb 27 2026

Warm & Windy Today:

Similar to previous forecasts, high (80%+) confidence for above normal temperatures across the forecast area today with daytime highs from the upper 40s to low 50s. Preexisting snowpack will influence weight of warmest temperatures being realized as a result of heat sink and increased albedo.

A tightening low level isoheight gradient within the warm sector of a strengthening extratropical cyclone shifting southeast through southern Canada increases west-northwest winds with gusts of 30 to 35 mph likely for much of the area. Higher fire weather concerns are mostly shunted south and west of the local forecast area, well within the warm sector, also locally influenced by preexisting snowpack.

Narrow Band of Heavy Snow Remains Possible Saturday:

Main forecast concern continues to be a narrow band of heavy snowfall through Saturday morning. As the main extratropical cyclone shifts east through Ontario, Canada tonight, it's estranged low level baroclinic boundary strewn from the Mid-Mississippi River Valley through the Northern Plains into the northern Rockies will foster the area for subsequent cyclogenesis. High resolution deterministic and ensemble (HREF/REFS) model disagreement seemingly stems from southern extent of cold front plunging through the Upper Mississippi River Valley this evening into tonight and subsequent location of cyclogenesis, low track, and accompanying frontogenetical band.

Collocation of accompanying enhanced frontogenesis with an extremely thick, 10k ft, and narrow, 100 mi, dendritic growth zone raises much concern for heavy snowfall rates producing higher snowfall totals in a narrow band across the forecast area. A more southern solution shunts higher moisture south of the forecast area whilst meager frontogenesis grazes the southern half of the forecast area. A more northern solution increases moisture availability and results in heavy snowfall totals locally. While most recent HRRR run (27.06Z) waned (halved) compared to previous run (HRRR 27.00Z), 0.4" PWATs progressing through the forecast area continue providing wettest 12 hour QPF values near 0.4". Similar QPF values seen in the RAP are exacerbated by collocation of enhanced frontogenesis with substantial, 10k ft, DGZ heights.

Regardless of which high/low resolution ensemble member you choose, all solutions suggest a narrow (~50-75 mi) band of enhanced snowfall rates with measurable snowfall from enhanced frontogenesis and stout, thick DGZ filaments of 7500'+ draped across the forecast area. On face value, nearly all HREF members abstain from warning level criteria snowfall amounts with 10:1 SLR calculations. However, enhanced forcing will likely provide closer to 20:1 SLRs, potentially doubling face-value totals.

However, while these calculations then near warning criteria locally, lack of spatial confidence combined with the very tight gradient for even /measurable/ snow and decreased forecast hour resulted in collaboration with neighboring forecast offices in hoisting a thin wafer WW.Y from southeast Minnesota into northeast Iowa and southwest Wisconsin. Very high (90%) confidence in the Advisory requiring a spatial update and modification during today's forecast period. Should HREF dProg/dt trends continue, a northern shift into the Interstate 90 corridor in central Wisconsin may arise, again.

Snowfall Sunday & Precipitation Chances Through Next Week:

Additional precipitation chances through Sunday have mostly remained south of the forecast area into the Mid Mississippi River Valley. Confidence will increase with Saturday's system progression.

As the low level baroclinic boundary lingers near the Upper Mississippi River Valley through early next week, slightly above normal temperatures are accompanied by precipitation chances. Eventual cyclogenesis in ensembles and select global models suggest heavy rain and convection potentially later next week.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1120 PM CST Thu Feb 26 2026

Initial temporary VFR-MVFR BR affecting smaller airports west of the Mississippi River Valley locally in northeast Iowa and southeast Minnesota at 26.06Z TAF issuance isn't expected to sink deeper into lower categories but remains immediate detail to remain cognizant of through the overnight hours.

Subsequent strengthening of nocturnal low level jet ushers in LLWS concerns from west to east. While stronger surface wind sites west of the Mississippi River are less likely to reach criteria, core of strongest low level winds expected to reach these sites. Therefore, have continued short window of LLWS at KRST TAF site until surface winds increase through the early morning hours. Surface winds increase slightly later at KLSE TAF site and therefore have continued LLWS mention into the morning hours. Strong surface winds continue into Friday night.

Narrow band of heavy snowfall expected Saturday morning. Exact location remains inherent forecast detail affecting aviation impacts. LIFR-VLIFR possible through Saturday morning where narrow snow band sets up.

ARX WATCHES/WARNINGS/ADVISORIES

WI...Winter Weather Advisory from 6 AM to 6 PM CST Saturday for WIZ053>055. MN...Winter Weather Advisory from 6 AM to 6 PM CST Saturday for MNZ086-087-094>096. IA...Winter Weather Advisory from 6 AM to 6 PM CST Saturday for IAZ009>011.