textproduct: La Crosse

KEY MESSAGES

- Low chances (20%) for rain showers or thunderstorms across the south late this afternoon into this evening.

- Higher chances (50-80%) for rainfall are forecast on Thursday with no impacts currently expected.

- Much colder temperatures (mid-20s to mid-30s) expected on Friday night. This bring an end to the growing season for some, particularly north of I-94 (20-50% chance to fall below 28).

DISCUSSION

Issued at 1241 AM CDT Tue Oct 13 2026

This Morning through Evening: Cooler with some Rain Showers

A low pressure system should continue to dig south towards the southern tip of Nevada throughout the day. This feature will aid in providing more active weather later on this week, particularly on Thursday. Before that occurs, zonal flow should prevail throughout today over the Upper Midwest. At the surface, a cold front will move across the area early this morning and should be east/south of the forecast area by sunrise. Temperatures will be much cooler today compared to the last few days, with highs mainly in the upper 60s to lower 70s. The region should be under subsidence for most of the day until a secondary surge of mid level moisture reaches the Upper Mississippi River valley late this afternoon into the evening. The better synoptic scale lift should stay south of the forecast area, but there still remains the potential for a few rain showers or storms to develop across the southern portions of the area, mainly south of I-90. Strong capping will be in place so any showers or storms that form should be elevated. Mid level CAPE may be sufficient enough to develop some lightning and perhaps a few small hailstones, but otherwise minimal impacts are forecast with any shower or storms that develops today.

Thursday: Increasing Potential for Rain Showers

Cooler air will continue to filter in over the Northern Plains into the Midwest through the rest of the week with afternoon highs decreasing a few degrees each day. The aforementioned upper level low pressure system is forecast to become cutoff and should eventually lift northeast on Thursday. The cutoff low should become absorbed into a stronger trough that digs south out of Alberta and Saskatchewan on Thursday. As synoptic lift provided by the systems moves over the Midwest, plentiful moisture should be in place to generate precipitation throughout the day. Mainly light rain amounts are likely with this system, however, the latest 13/01z NBM does have higher probabilities for a half inch of rain (up to 30-50%) across the southern half of the forecast area compared to 24 hours ago. A cold front moving in from the northwest will quickly put an end to any precipitation on Thursday evening as cooler and drier air moves in in its wake.

Friday Night: Cold Temperatures Leading to Frost/Freeze

Broad surface high builds in the wake of the Thursday night's upper trough. Clearing skies and light winds after a period of post- frontal CAA will very likely (70-100%) lead to widespread frost, potentially (30%+) a freeze and, for areas north of I-94, a chance (20-50%) for a killing freeze with temperatures below 28. With some guidance suggesting some surface pressure gradient and thus light winds will be maintained Friday night will need to continue to monitor this period as there is still some uncertainty with regards to temperatures ending up a few degrees warmer than currently forecast.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 545 AM CDT Tue Oct 13 2026

MVFR conditions will persist throughout much of the morning as low-stratus lingers in the wake of a passing cold front overnight. However, as we head later into the afternoon, would expect some weak mixing to increase cigs to VFR thresholds and also work to scatter cloud cover some. IFR cigs may be possible (20-40%) as KRST has observed IFR reductions this morning. However, based on observational trends and increasing mixing after daybreak, these IFR cigs should improve to MVFR and eventually VFR by afternoon. As we head into tonight, some additional MVFR cigs will be possible (30-60% chance), mainly north of I-90. Winds will gradually shift from the northwest to the north throughout the TAF period and remain around 5 kts.

ARX WATCHES/WARNINGS/ADVISORIES

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