textproduct: La Crosse

KEY MESSAGES

- Isolated showers may impact Taylor and northern Clark counties Saturday afternoon (15% chance).

- Rain potential on Sunday increases heading south from the IA/MN border parallel (30-60%), highest just south of our forecast area.

- Very good (60-80%) chance for showers and thunderstorms Tuesday into Wednesday.

DISCUSSION

Issued at 1202 AM CDT Sat Jun 20 2026

Very small chance for a shower north of I-94 Saturday

Saturday afternoon, very weak upper disturbance may kick off a shower north of I-94. Limiting factor once again looks to be instability as most of this area turned over Friday evening and low level moisture recovery is not expected. Thus, while strong unidirectional shear remains in place with an upper jet aloft, actually getting an updraft to tap into that appears doubtful. This is reflected in recent runs of CAMs which all depict precip struggling to develop. Have therefore gone with only very low end mentions of showers (15%).

Waning potential for moderate rain in NE IA, SW WI Sunday

Upper wave currently over NV looks to continue to roll eastward through the weekend, forcing lee cyclogenesis in E CO with this feature moving east into central IL under the left exit region of an upper jet advancing over the southern Plains. Robust southerly moisture advection will occur across the lower and mid Mississippi Valley ahead of this low, leading to abundant precip across MO/IA/IL. First couple guidance cycles after the disturbance moved onshore have focused the trajectory along the lines of several previous runs of the operational GFS/EC, keeping rain just to the south of the CWA. That said, still some ensemble members bringing at least some rain to NE IA and SW WI. Have therefore attempted to tighten the north to south PoP gradient compared to NBM, removing most mentions between I-90 and a parallel defined by the MN/IA border. In any case, hazards seem unlikely as the 19.12z LREF now only depicts a 10-15% chance for our far southern counties to reach even 1" of accumulation and appreciable instability remains well to our south.

Thunderstorms Tuesday into Wednesday

While timing differences remain, rather notable agreement across guidance that a strong upper wave will dive southeast over or just to the northeast of the CWA Tuesday into Wednesday, bringing widespread precip. Continued northwesterly flow aloft following the pattern pause this weekend will limit opportunities for strong moist advection but, given cold temperatures aloft, should see some thunderstorms. Additionally, while upper winds are not as strong as they were this past Friday when convection overachieved in severity, may still see 40-50 knots of shear. Therefore, will need to continue to watch this period for another lower end severe thunderstorm risk day.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 623 PM CDT Fri Jun 19 2026

Showers and storms continue moving through the region this evening as an area of low pressure shifts eastward across northern Wisconsin. These showers/storms are expected to mainly impact areas along and north of I-90, bringing MVFR/IFR visibility and MVFR ceilings, before moving out of the area by 05z. Behind them, VFR conditions are expected, continuing through the overnight and into Saturday morning for most, although those north of I-94 have the potential to see MVFR ceilings develop through mid Saturday morning (40-60% per the 19.18z REFS). Gusty southwest winds continue over the next few hours, generally 20-30KT, before diminishing to less than 10KT overnight and veering to the northwest Saturday morning.

ARX WATCHES/WARNINGS/ADVISORIES

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