textproduct: La Crosse

KEY MESSAGES

- Precipitation and non-severe storms continue through Tuesday. Strong winds will be main impact primarily in wind prone areas west of the Mississippi River Valley.

- More widespread (60%-80%) heavy rain and storm chances Wednesday morning through Wednesday night. Current low confidence (15%-30%) mainly west of the Mississippi River Valley Wednesday afternoon/evening.

- Low confidence in precipitation and storms through late week into the weekend. Expect current dry forecast Thursday to change some through midweek.

DISCUSSION

Issued at 120 AM CDT Tue Jun 16 2026

Shower & Non-Severe Storm Chances Spreading East:

A surface low evident in observations of cyclonic flow through central Minnesota continues east-southeast tonight through Tuesday, following the tight, closed area of mid-upper level cyclonic flow on GOES water vapor imagery loops, driving precipitation chances across the Upper Mississippi River Valley. Higher moisture north of the forecast area (INL 16.00Z RAOB) abates higher rainfall concerns locally with confidence for 0.1" of accumulations along and north of Interstate 94 in Wisconsin locally.

Main local impact will be stronger winds in susceptible areas west of the Mississippi River Valley from the enhanced low level cold air advection and lower isoheights translating stronger winds to the surface. Current confidence for 20 mph northwest winds gusting 30- 35+ mph through Tuesday morning in previously mentioned wind prone areas primarily.

Strong to Severe Storm Chances Wednesday:

Mid level synoptic confluence from an appendage of the large synoptic extratropical cyclone over Hudson Bay enhances an extended ribbon of mid level vorticity from the Canadian Rockies through the Upper Midwest Wednesday, causing cyclogenesis through the Upper Mississippi River Valley. While higher confidence for increased instability lies well south of the forecast area, separate surface lows north and south of the forecast area attempt to translate unstable air into the forecast area. Longer term deterministic models and ensemble counterparts allude to the northern low leveraging the 60 degree surface isodrosotherm through southwest and south-central Minnesota before weakening and subsequently relinquishing warm, moist air south of the forecast area. Therefore, exact track and northern extent of cyclogenesis affect local severe storm chances inherently intertwined with subsequent interaction between low center separation, phasing, and strength.

A stronger northern low or more northern solution would allow more unstable air to advect farther north, increasing local severe threat. Current confidence the northern low weakening while shifting east through central Minnesota keeps local storm concerns primarily west of the Mississippi River Valley, grazing 500 J/kg of MUCAPE across these counties through the early afternoon (NAM/GFS/EPS/GEFS). However, should a stronger or more southern solution to the northern low come to fruition, local storm threat could persist farther east, evident in individual EPS members advecting 1000+ J/kg of MUCAPE into southwest Wisconsin. Shear values would support all hazard types with linear storm mode or splitting cells should the frontal boundary slow down.

Machine learning severe hazard forecast models persist a hump of spatially relative higher (15%-30%) probabilities locally west of the Mississippi River Valley as a result.

Low Confidence Precipitation/Storm Chances Late Week Into Weekend:

While current NBM keeps a mostly dry forecast through Thursday, LREF confidence for measurable precipitation is moderate-high (50-70%) outside of the GEPS (<20%). While overall impacts expected to be minimal, steeper mid and low-level lapse rates from stronger cold air advection causes some storm potential. Given the longer forecast hour and limitations on forecaster editing away from the NBM, kept a dry forecast but expect that to change should current LREF confidence continue.

Storm and precipitation chances continues into and through the weekend as upper level diffluence permits mid level forcing to slowly shift east through the central CONUS. Longer forecast hour and limited synoptic forcing strength or signal limits overall confidence. Therefore, expect forecast to vary markedly through midweek.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1231 AM CDT Tue Jun 16 2026

VFR conditions currently present at the terminals. An area of showers and weak storms are moving east across the Upper Midwest early this morning that have produced some gusty winds with some of the stronger cores. While this activity does look to be on a downward trend overall, have included TEMPOs for the next few hours at the terminals to cover this potential. Another batch of showers moves through later in the morning, moving out by early to mid afternoon. Not expecting much in the way of visibility reductions with either round of showers as they should be light in nature but some MVFR stratus will accompany the second round of showers. Winds will pick up out of the west to northwest after 12Z with gusts to between 20-30 kts expected at the terminals. These gusts should taper off around 00Z with dry conditions expected from the afternoon through the end of the 06Z package.

ARX WATCHES/WARNINGS/ADVISORIES

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