textproduct: La Crosse

KEY MESSAGES

- Small rain chances (20-30 percent) in northeast Iowa and southeast Minnesota this weekend.

- Above normal temperatures expected into Tuesday and then a return to more seasonable temperatures for the remainder of next week.

DISCUSSION

Issued at 1257 PM CDT Sat Sep 5 2026

This Afternoon and Evening

A weakening mesoscale convective complex (MCC) will continue to weaken as it moves east toward southeast Minnesota and northeast Iowa. As an outflow boundary (from last night's convection) moves south and southwest ahead of this MCC, surface-based CAPES will decrease from 2-3K J/kg to 1-2K J/kg. Still plenty of uncertainty on whether there will be any showers and storms. The CAMs indicate that there may be some scattered showers and isolated storms west of US Highway 14. At this time, kept the forecast dry, but will keep an eye on the trends this afternoon.

High temperatures this afternoon will range from the mid-70s to mid-80s.

Overnight Tonight

As the nocturnal jet intersects a front across western Minnesota and central Iowa, showers and storms will develop across southwest Minnesota and north-central Iowa. As their cold pools gradually coalesce, a MCC will develop. This system will dive southward into a 1-2K J/kg surface-based CAPES located over western Iowa.

Sunday

The MCC which develops to our west tonight will continue to move south into better instability across western Iowa on Sunday. Some of the CAMs suggest that maybe a few of these showers and storms might move into areas west of US Highway 52. Due to this, kept a 20-30 percent chance of showers and storms in the forecast. Even if they do, both the 0-3 km and 0-6 km shear are less than 20 knots; thus, not expecting any severe weather.

Tuesday into Wednesday

A vigorous shortwave trough will move east across the Northern Plains and Upper Mississippi River Valley. This will flatten the strong ridge. Showers and storms will be found along a cold front as it moves southeast through the region. With the better 0-3 km and 0-6 km shear being located in the wake of the front, not anticipating any severe weather.

High temperatures will range from the upper 70s to mid-80s on Tuesday and from the mid-70s to mid-80s on Wednesday. With zonal to northwest flow for the remainder of the week, temperatures will be near-normal.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 642 PM CDT Sat Sep 5 2026

VFR conditions into the early overnight. Showers and storms will move down into southern Minnesota and northern Iowa tonight through Sunday, however most of the rain should stay west of I-35. There is a low chance, 10 to 20%, that they can make it east of I-35. Due to the light southeasterly winds and saturated conditions near the surface, foggy conditions are expected to return by early Sunday morning and continue into the mid- morning. This will create MVFR to LIFR flight categories depending on how dense the fog can get. After any fog that develops dissipates, CIGS will stay around 15kft throughout the rest of the day with sustained southeast winds of 5 to 10 mph.

ARX WATCHES/WARNINGS/ADVISORIES

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