textproduct: La Crosse

KEY MESSAGES

- Heavy rainfall and flooding is expected this afternoon and evening generally for those along I-90 and south. Additional rainfall amounts of 1-3 inches are possible (30-60%).

- Strong to severe storms move through northeast Iowa into southwest Wisconsin this afternoon into this evening. The primary hazard is damaging wind, but a few isolated tornadoes cannot be ruled out.

- A wet holiday weekend is in store for the region as chances for showers and storms exist each day, though potential is greatest on Independence Day (50-80%). Additional rainfall amounts of of 1+ inches are possible Saturday through Monday (10-30%).

DISCUSSION

Issued at 156 PM CDT Thu Jul 2 2026

This Afternoon - Friday Morning: Severe, Heavy Rainfall, and Flooding Potential

A quasi-stationary boundary laid out west-east across the Upper Mississippi River Valley has been the primary catalyst for showers and storms last night and through the morning hours today. This is no different for this afternoon and evening as a shortwave lifts northeastward while a strengthening low level jet transports additional moisture into the boundary. At risk of sounding like a broken record, showers and thunderstorms are expected to develop in response to these forcings, but confidence in how things play out is low.

Of greatest concern at the moment is additional heavy rainfall and flooding potential this afternoon into tonight. Portions of southeast Minnesota have received 3 to 5 inches of rain through 12 PM CDT resulting in flooded roadways and streams. The 02.12z REFS suggests a 30-60% chance for amounts greater than 3 inches through Friday morning primarily along the Minnesota/Iowa border, but does extend into parts of western Wisconsin and further south into Iowa towards Dubuque. The 02.12z REFS/HREF LPMM also suggest some localized areas of up to 5 inches may occur. Additional river and street flooding will likely occur given the plethora of rain over the last several days. As such, have issued a Flood Watch to account for the potential.

Transitioning away from the heavy rainfall, storms that develop are expected to become strong to severe across northeast Iowa and southwest Wisconsin, south of the aforementioned boundary. SPC Meso Analysis suggests 2500-3500 J/kg of SBCAPE exist across this region along with effective bulk shear profiles exceeding 40kts. Given high PWAT values and strong mid-level flow, the primary hazard is expected to be damaging wind gusts although a few tornadoes also can't be ruled out given 0-1km SRH values of 70-90 m2/s2 and surface vorticity ingestion from the boundary spanning the region. Large hail remains a lower threat given poor mid-level lapse rates and warm temperatures aloft, but also can't be ruled out in supercells structures that develop.

Storms look to exit the region this evening with a bit of a lull overnight, but confidence remains low as various CAM guidance provides a multitude of solutions. That said, as we head into Friday morning, the 02.12z HRRR suggests that another storm complex moves through the region again bringing the potential for damaging winds though the strongest instability looks to be situated south of our area. The evolution of this complex will likely rely on how the rest of this afternoon plays out. That said, our area is highlighted in a level 2/5 slight risk for severe weather by the SPC.

Holiday Weekend - Next Week: Wet then Drier

Friday afternoon may ultimately end up dry depending on how the morning goes. Upper level ridging looks to build across the region, forcing shortwaves away from the area. Several of the CAM solutions fail to convect through the afternoon, though the 02.12z HRRR/RAP do suggest some potential (30-50%) for showers and storms as a shortwave sinks into the region on top of the ridge, primarily along and east of the Mississippi River. Independence Day sees far greater probabilities for showers and storms as a stronger shortwave/closed upper low traverses over the aforementioned ridge (50-80%).

Beyond the weekend, ensemble guidance is beginning to suggest that Monday into Tuesday should finally be a dry couple of days (knock on wood) as high pressure sinks southward into the Upper Midwest.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1240 PM CDT Thu Jul 2 2026

Showers and storms continue across the region this afternoon, generally along a line from central Wisconsin into northeast Iowa. Coverage of these showers and storms is expected to increase through the afternoon into this evening, but the greatest impacts look to be primarily be along and south of I-90. A bit of a lull in storm activity is possible overnight generally from 06z-12z, but there is a lot of uncertainty regarding this as model solutions vary quite a bit in timing/placement of storms. Showers/storms move eastward towards the end of the TAF period.

HYDROLOGY

Issued at 149 PM CDT Thu Jul 2 2026

Rainfall totals exceeding 3-5 inches have been observed across the Upper Mississippi River last night into today with some locations having received upwards of 7 inches. Additional rainfall in the 1-3 inch range is expected overnight (30-60%) generally along and south of I-90 per the 02.12z REFS/HREF. The 02.12z REFS/HREF LPMM even suggests upwards of 5 inches could occur. Areas that see additional rainfall through the afternoon into the evening will be at risk for additional flooding impacts and as such a Flood Watch has been issued for counties generally along I-90 and south.

ARX WATCHES/WARNINGS/ADVISORIES

WI...Flood Watch through Friday morning for WIZ041-042-053>055-061. MN...Flood Watch through Friday morning for MNZ087-088-094>096. IA...Flood Watch through Friday morning for IAZ008>011-018-019-029- 030.