textproduct: La Crosse

KEY MESSAGES

- Potential for showers and thunderstorms both this afternoon/evening (10%) north/west of a Austin MN to Neillsville WI line and tomorrow afternoon/evening (30%) for areas north of I-90. Strong to perhaps severe wind gusts cannot be ruled out.

- Showers are likely (60%) late Tuesday night into Wednesday morning as a cold front slides southwestward. Additional showers may (40%) develop near this front during Wednesday afternoon as well.

- Mid to upper 80s highs are expected through Tuesday with considerable uncertainty Wednesday and Thursday due to the effects of the cold front. Temperatures stabilize in the upper 70s to mid 80s Friday onwards.

DISCUSSION

Issued at 118 PM CDT Mon May 25 2026

Low potential for afternoon/evening showers and storms, strong gusts next 2 days

17z WV satellite shows a weak shortwave over the IA/WI border and weak convection ahead of this in SW WI and a more substantial wave upstream over north central MN. At the surface, southwesterly winds with temperatures in the mid 70s and dewpoints in the mid 50s are predominant with these dewpoints stretching back into central IA.

This afternoon and evening, guidance values north/west of an Austin MN to Neillsville WI line depict around 2000 J/kg of MLCAPE with around 25 J/kg of MLCIN. Given the wave moving this way, would normally strive to add at least a 20% mentions for showers and thunderstorms this afternoon. However, examination of progged soundings shows, in addition to limited surface moisture described earlier, a large amount of dry air in the mid levels, in line with WV satellite readings extending westward into South Dakota. Additionally, best forcing with the aforementioned wave looks to remain to our north. Have therefore added some 10s to PoP grids but refrained from including thunderstorms in the forecast. Higher relative probability for a stray shower or storm may reside in southeast Minnesota this afternoon as a weak outflow boundary from the morning showers looks to be slowly pushing northward through Fillmore County per visible satellite. Should any convection develop, strong gusts could occur given the large (20-30 degree F) surface dewpoint depressions.

Tuesday afternoon and evening another weak disturbances moves eastward over MN/WI. While at least the southern half of the CWA looks to be capped due to the ridge aloft, areas north of I-90 may see showers and thunderstorms as, compared to today, there is a step upward in mid-level moisture and thus some updraft attempts may (30- 40%) survive and avoid dissipating due to dry air entrainment. ML outlooks are pointing toward a small risk for a severe storm - examination of shear profiles suggests well-organized convection is unlikely due to weak shear above 3km and thus a severe wind gust would be the concern with convection that develops.

Sagging cold front leads to additional precip

Tuesday night, upper ridge looks to weaken as a backdoor cold front pushes into the forecast area. As this occurs, some guidance suggests that an additional upper impulse will roll downstream. Have thus introduced likely (60%) mentions for precip Tuesday night and, should the upper support appear more probable, will need to raise PoPs further in future updates. As the backdoor front stalls in or just to the southwest of our CWA, additional precip may (40%) develop Wednesday.

Warmer than normal for the next week

As the upper ridge becomes centered just to our south, highs in the mid to upper 80s are expected Tuesday with a shot (40%) to reach 90, especially in the dry sandy soil areas around Black River Falls and Tomah.

Temperature forecast appears most uncertain Wednesday and Thursday due to the backdoor cold front and potential for precip and cloudy conditions. Have moved temperatures toward the warm side of non-NBM consensus blends, overall a few degrees cooler than 25.13z NBM which still shows a several degree split between raw and bias corrected components. Mid 80s and mid 70s are favored Wednesday and THursday, respectively.

For Friday onward, persistent ridging over the central CONUS should lead to temperatures above normal, in the upper 70s to mid 80s. Exact values are questionable given we'll be between the upper ridging and persistent troughing centered over far eastern Canada, but 25.13z NBM interquartile high temperature ranges, while large at 6-10 degrees, do tend to be in the upper 70s to mid 80s each day.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 635 PM CDT Mon May 25 2026

While TAF issuance suggests VFR through the 26.00Z TAF period, periodic storm chances could affect both TAF sites initially Tuesday morning lasting into Tuesday night. Given the ongoing local airmass, overall confidence in storm coverage and exact location remains low (<20%).

Additional low level wind shear impacts possible overnight at KLSE however surface winds are expected to remain elevated enough to abstain from meeting threshold. Should surface winds drop off, a near term amendment to include LLWS at KLSE will be warranted.

ARX WATCHES/WARNINGS/ADVISORIES

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