textproduct: La Crosse

KEY MESSAGES

- A prolonged stretch of hot and humid conditions arrive for much of next week with daily heat indices in the 100-105 degree range for some or all of the area.

- Next chance for showers and storms comes Saturday night into Sunday, some of which could be on the stronger side.

- The risk for storms--possibly severe--beyond Monday becomes increasingly uncertain and tied to the strength of the cap and tracks of the previous storms.

DISCUSSION

Issued at 1240 PM CDT Fri Jun 26 2026

This Afternoon - Saturday: Last Few Days of Cooler Weather

A shallow upper tropospheric wave coupled with weak mid-level (700-500-mb) theta-e advection has brought clouds and scattered sprinkles to the region today, with these features gradually fading through the afternoon as the trough axis shifts into the Great Lakes and height rises ensue in their wake. This incoming shortwave ridge axis passes through on Saturday, bringing a pleasant start to the weekend with dry conditions and seasonal temperatures.

Saturday Night - Sunday: Storm Risk, Warming Up

As surface high pressure over the Great Lakes translates eastward, return southerly flow sets in overnight and into the day on Sunday, opening the door for a much warmer and more humid airmass to stream into the region over the ensuing 24-36 hours. Highs on Sunday top out around the mid-80s with dewpoints creeping into the upper 60s to low 70s, a taste of the weather to come for at least the start of next week.

Thunderstorms may form within the corridor of theta-e advection as it lifts northeastward through the region late Saturday night into Sunday. Latest trends point to a later arrival time than earlier progged, which could temper highs on Sunday if clouds linger too long. Early looks at the deterministic guidance shows some variability in the saturation of the warm nose--which will be key to whether storms can realize the 1500-2000 J/kg of MUCAPE situated above this cap. Therefore, PoPs remain in the 30-50 percent range on account of uncertainty in the coverage of any storms. If storms were to form, some linearity to the hodographs (arguably not oriented the best with respect to the line orientation) could promote cell organization and a hail risk.

Next Week: Summer Heat, Low Confidence Storm Risk

A longwave blocking ridge anchors itself across the southeast U.S. for the bulk of the upcoming week and will keep a fetch of warm and humid air in place across the region. Warmest heat indices areawide are favored for Monday (100-105+ degrees), after which confidence in the temperature forecast slowly degrades from north to south throughout the week on account of the potential influences of convection that will be tracking very close to or over the region within the southwesterly flow. The track of these systems is most favored from the Dakotas into northern MN and northern WI. However, this may be a scenario where each successive round of storms drives a little farther southward with each passing day, which would shunt the heat risk more into Iowa and southern Wisconsin by midweek. Regardless of how you slice the forecast, it will be hot and humid and heat headlines will be needed, it is just a matter of exactly what headline and where.

The stoutness of the cap (dictated by the exact placement of the ridge) will dictate how far southeastward each MCS can drive into the region before dissipating. Such details will be determined over the next few days and it may be a case where each round of storms plays a crucial role in the track of the subsequent convection. Damaging winds would be a main hazards with these storms as upscale growth is expected before they reach the area. However, there are a subset of solutions that have the ridge slightly farther southeast, which would favor storm development further into our local area and could introduce additional severe weather hazards.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1240 PM CDT Fri Jun 26 2026

Predominately VFR conditions are forecast for the TAF period outside of a low (20-30%) risk for shallow IFR/LIFR fog towards sunrise, favored in valley locations. Winds remain from the southeast at 5-10 kts through today, decreasing slightly tonight and increasing to 10-15 kts by midday Saturday.

CLIMATE

Issued at 1240 PM CDT Fri Jun 26 2026

Our anomalously warm and moist airmass will keep temperatures from falling much below the low to mid 70s Monday and Tuesday mornings, which are very close to the daily warm minimum temperature records across our area.

ARX WATCHES/WARNINGS/ADVISORIES

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