textproduct: La Crosse

KEY MESSAGES

- Dry conditions through Monday before rain chances return Tuesday through Thursday.

- Medium chance (40-60%) for rain amounts to reach or exceed 1.5 inches from Tuesday morning through Thursday morning.

- High temperatures will remain seasonal in the 60s to 70s.

DISCUSSION

Issued at 1255 PM CDT Sun Sep 27 2026

This afternoon through Monday: Fog Monday Morning - Dry Conditions

Visible satellite imagery early this afternoon depicts extensive cloud cover across much of the Upper Midwest. Must of this cloud cover is mid to low level clouds, which will aid in keeping afternoon highs a few degrees cooler today. There are some lingering light rain showers and/or sprinkles across portions of the area, but that activity should continue to wane through the afternoon.

High surface humidity along with surface high pressure and light winds will contribute in the development of fog and continued low clouds into Monday morning. The latest 27/12z HREF and REFS guidance both are showing high chances (60-80%) for visibility to drop down to 1 mile or less, with the higher potential across southeastern MN and west of the Mississippi River. Dense fog may even form as a result for some locations, which will lead to adverse driving conditions to start the day on Monday. Any fog that does develop should quickly dissipate after sunrise. Dry conditions are forecast the rest of the day and temperatures should be able to rise into the 70s for most locations with decreasing cloud cover into the afternoon.

Tuesday through Thursday: Rain Chances Return

An upper level low pressure system should be located over the Desert Southwest in the middle of next week. This low will begin to become cutoff on Tuesday into Wednesday, which should slow down its progression as it continues to move east and eventually northeast. Multiple sources of moisture, including the remnants of Hurricane Polo, will move in over the Plains into the Great Lakes region during this time frame. There remains a fair amount of uncertainty as to where the heaviest rainfall totals will fall this far north, but the consensus appears to be slowly leaning towards the higher totals remaining just to the south of the local forecast area. Even with that being said, higher totals could still reach into northeastern IA to far southern WI, but those details will be refined over the following few days. Ensemble forecast guidance suggests mean PWAT values of around 1.5-1.75 inches are possible which could lead to moderate to heavy rainfall rates. If the heaviest rainfall bands can get this far north, 2-3+ inches of rainfall from this multiple day system cannot be ruled out (10% chance or lower). If most of that rainfall occurs in a short duration or over areas that have seen plentiful rain recently, flooding may result.

Friday into the Weekend: Drier and Trending Cooler

The plume of deep moisture should get pushed off to the south Thursday into Friday as troughing attempts to dig south over the Great Lakes into the northeastern US. There is quite a large discrepancy on just how far south and how quickly the trough digs south out of Canada, which may have a pretty large impact on the weather going into next weekend. This feature will usher in a cold front, which will lead to cooler temperatures, just how cool is the main question. As of now, afternoon highs are forecast to be in the mid to lower 60s but overnight lows may drop into the lower 40s to 30s if the cooler solutions pan out.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 640 PM CDT Sun Sep 27 2026

MVFR to IFR cigs will likely persist through the evening as low- level moisture remains in place across the region. As winds begin to calm overnight, fog development will become increasingly like with the HREF and NBH highlighting southeast MN with higher probabilities for visibilities under 1 mile (40-60%). As a result, have opted to include a 1/2SM group at KRST to address this. 1/4SM remains possible, especially at KRST. However given the slightly lower probabilities in the HREF (20-40%) for 1/4SM visibilities, did have the forecast confidence to include in the TAF at this time. Winds will increase slightly during the daytime hours on Monday which in turn should aid in clearing out lingering fog along with aiding in diurnal mixing to lift cigs to VFR by afternoon.

ARX WATCHES/WARNINGS/ADVISORIES

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