textproduct: La Crosse

KEY MESSAGES

- A chance (30-50%) for showers and a rumble of thunder in northeast Iowa and far southwest Wisconsin Friday morning.

- Warmer and windy for Saturday with potential (55%) for a 45 mph gust west of the Mississippi valley.

- Potential (15-30%) for rain returns Monday and Monday night.

DISCUSSION

Issued at 1131 AM CDT Thu Oct 8 2026

Shower, thunderstorm potential Friday morning

Early Friday morning, weak wave looks to slide southeast from SD into IA. Ahead of this wave, 850mb WAA will increase across IA, including over NE IA and nearby parts WI. Progged soundings suggest some elevated instability will be present as a result. Thus, good chance (30-50%) for some showers and thunderstorms to develop there Friday morning. With potential (20-40%) for MUCAPE to build to around 500 J/kg per 08.00z ECENS, cannot totally rule out a strong storm with a risk for hail. That said, shear through the effective layer of the storm appears to be weak (20-30 kts) and relatively warm temperatures at around 550mb look to limit instability. Therefore, am not particularly excited about the prospect for a severe hail report.

Warm and windy Saturday

Friday into Saturday, longwave trough moves over the Canadian Rockies with a southwesterly upper jet on the equator-ward side of this feature. Strong lee surface cyclone will develop as a result and, as this feature shifts eastward into Manitoba, 35-45 kt 850mb jet looks to develop from E NE to N WI, including over SE MN. The combination of mostly sunny skies, the strong 850mb winds for efficient mixing processes to tap into, and an increasing surface pressure gradient will lead to a breezy to windy day across the CWA, particularly in portions of southeast Minnesota west of the sheltered Mississippi valley. 08.13z NBM 24 hour probability for a 45 mph gust at the Rochester airport (where training data includes peak hourly gust information unlike most other grid points in the NBM) is 55%, so a Wind Advisory may be needed down the road. Have boosted winds above NBM using other consensus blends as it frequently has winds that are too slow on days with good wind setups. Additionally, the combination of the winds and efficient mixing bring the possibility of elevated fire weather conditions but the core of the stronger winds and drier air looks to remain to our northwest.

Low potential for rain Monday

GFS/EC/CMC in good agreement that the base of a longwave positively tilted trough will slide over the CWA Monday. This pattern usually suggests issues with sufficient forcing for ascent and moisture for precip and this looks to be no exception to this. Thus, this period will only have a low (15-30%) for precipitation and no hazardous weather is expected.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 636 PM CDT Thu Oct 8 2026

A warm front will move through the area on Friday. This will gradually lower ceilings into the 4-6K range during the afternoon. In addition, there could be some showers and maybe a few storms south of Interstate 90.

ARX WATCHES/WARNINGS/ADVISORIES

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