textproduct: La Crosse

KEY MESSAGES

- Warmer, more moist airmass raises nightly fog concerns for much of the area through late week.

- Confidence (60%) in anomalous warmth initially reaches the forecast area Friday, increasing (70%) for Saturday.

- Moderate confidence (50-70%) for light precipitation Saturday night through Sunday. Low confidence in exact location or potential for higher amounts (0.1"+).

DISCUSSION

Issued at 957 PM CDT Wed Mar 18 2026

Warming Into Early Weekend, Potential Nightly Fog:

Outside of nightly fog, a relatively quiet period of sensible weather is expected after ongoing mixed precipitation potential in central Wisconsin exits east of the local forecast area tonight. Main forecast detail will be advection of anomalously warm temperatures into the early weekend and subsequent potential preciptiation.

The two main phenomena that will have the largest impact on sensible weather locally will be the dense, climatologically thick snowpack observed and exact location of a relatively diffuse baroclinic boundary strewn northwest to southeast west of the Upper Mississippi River Valley tonight, flirting east/west over the forecast area as meager waves meander along it into this weekend. A farther northeast advection of the warm, moist airmass will increase nightly fog potential and degree of hottest temperatures into Saturday.

Confidence In Warmest Temperatures:

While our on doorstep for Thursday, NBM (18.19Z) probabilities for the 60 degree isotherm greatly increase (25-75%) initially Friday along our western peripheral counties and into southwest Wisconsin. Further warming into the weekend ushers in similar probabilities for the 70 degree isotherm locally. Although, high Interquartile Spread (25th-75th percentile) of 10-15 degrees over southeast Minnesota on Friday spreads across the forecast area on Saturday. Again, amount of melting and resultant albedo will be crucial, ultimate factor to monitor Thursday and Friday as the baroclinic boundary attempts to advect northeast through the forecast area with passing waves.

Low Confidence In Late Weekend Precipitation:

The synoptic pattern breaks through the end of the weekend, ushering in more normal daytime highs in the 40s to 50s through Sunday and low confidence in widespread precipitation potential with the passing cold frontal boundary Saturday night through Sunday. As potential cyclogenesis passes near the forecast area, confidence in precipitation potential (50-70%) agrees between long term global ensembles whilst disagreeing within respective ensemble runs. The GEFS (18.18Z) increased probabilities for 0.01" of QPF in 24 hours compared to previous run (18.12Z), 50-70% along and east of the Mississippi River, while the most recent EPS (18.18Z) decreased to similar probabilities in most recent run. Interensemble confidence for higher amounts (0.1"/24hr) increases northeast of the forecast area, lowest (<15%) in most recent EPS (18.18Z).

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 543 AM CDT Thu Mar 19 2026

High pressure will provide VFR ceilings and visibilities. The winds will be light and variable.

ARX WATCHES/WARNINGS/ADVISORIES

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