textproduct: La Crosse

KEY MESSAGES

- Chances (30-60%) for very light rain overnight Thursday night. Additional light rain chances (30-70%) for Saturday into Saturday night.

- Dry conditions to start the upcoming week give way to widespread rain potential for Tuesday and onward.

- Temperatures remain fairly steady over the next week with highs in the 60s to lower 70s.

DISCUSSION

Issued at 1015 PM CDT Thu Sep 24 2026

Very light rain overnight, light again Saturday afternoon into Saturday night

Belt of very light rain has been sliding eastward this evening ahead of a longwave upper trough seen on IR over MN as of 03z. Weak forcing overall and no instability to speak of has led to very low rain rates with many sites struggling to get to 0.01". Have thus continued to go with a moderate PoP but very low QPF forecast for the rain overnight tonight.

Short lived upper height rises will lead to a dry Friday but, by Saturday, another longwave ridge moves over the upper Midwest with a lead impulse slowly rolling eastward around midday and a second wave during the nighttime hours. Progged moisture remains an issue east of the Mississippi due the influence of a dry high pressure system in the Great Lakes and very dry mid-levels and somewhat dry conditions near the surface should eat into rain totals, if any. Farther west, enough moisture should (70-80%) sneak around the southwestern edge of the high to lead to light rain with weak forcing and lack of instability once again keeping rain intensity and concerns for hazards for those outdoors looking ahead to October very low.

Next Week: Mild, Widespread Rain Likely Tuesday

Continued southeasterly surface flow will allow for some ever so slight warming into Monday with highs potentially reaching into the 70s for more of the area. However, dry conditions on Monday will give way to increasing probabilities for widespread rainfall on Tuesday as a longwave trough and associated surface cold front will sweep through the local area throughout the day on Tuesday with already fairly high probabilities (50-70%) for rainfall amounts over 0.25" across much of the area in the grand ensemble (GEFS/EC/Canadian ensemble). Much of these higher probabilities are in part due to a strong axis of 850mb moisture transport surging north out ahead of this front with anomalous precipitable waters as shown in grand ensemble (GEFS/EC/Canadian ensemble) with respectable probabilities (40-70%) for precipitable waters over 1.5" on Tuesday. So could certainly see some healthy rainfall totals from this system, particularly if we can get some elevated instability to work its way into the region.

Forecast confidence begins to lessen as we head into Wednesday and beyond as this moisture fetch will battle against the northwesterly cooler and drier air in light of the aforementioned front. The key mechanisms for precipitation potential mid-week will be tied to a fairly robust upper-level trough ejecting into the south-central Great Plains during the second half of the work week. This system will likely see a bit of a "boost" in moisture as well given it will be ingesting moisture from the remnants of Hurricane Polo in the southwest CONUS. As a result, noting a footprint in the Shift of Tails of 0 in the EC Extreme Forecast Index QPF for Wednesday, suggesting there are a few EC members showing QPF reaching the 99th percentile of climatology for this time of year. Much too early to deduce if the local area may see additional rainfall from this feature as it may remain too our south, but something to monitor nevertheless.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1235 PM CDT Fri Sep 25 2026

VFR conditions are mostly expected through this TAF period outside of a possible rogue MVFR ceiling dip or some shower visibility impacts toward the end of the period. Lower stratocumulus deck overhead this afternoon will gradually thin heading into the evening hours, but meanwhile high level clouds will be spilling in from the west. West of the Mississippi River, ceilings will gradually decline Saturday morning as the next system approaches. Some light showers will be possible (30-50% chance) at RST by late morning. Generally southeasterly winds through the period around 10 knots or less.

ARX WATCHES/WARNINGS/ADVISORIES

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