textproduct: La Crosse

KEY MESSAGES

- A brief period of a wintry mix along and north of I-94 early this morning. Some light icing could occur in the pre-sunrise hours prior to temperatures warming above freezing. Impacts should be minimal.

- Windy and warmer today. Winds gusting to 40-45 mph in MN/IA, 30-40 mph elsewhere, peaking around midday. Temperatures warm into the 60s before rain spreads across the area from northwest to southeast in the afternoon and evening.

- More rain likely Thursday night (60-80% chance) for northeast Iowa and southwest WI with amounts generally between 1/4 to 1/2 of an inch or less.

- Warming into the weekend. Periodic rain is expected but any signal for heavy rainfall is of lower confidence at this time.

UPDATE

Issued at 616 AM CDT Wed Apr 8 2026

Breezy winds early this morning are expected to increase in magnitude as a low level jet strengthens across the Upper Mississippi River Valley. How strong the surface winds become as we head into the afternoon is the primary point of uncertainty, owing to the warm air advection associated with the low level jet and how much it hinders diurnal and mechanical mixing.

The 08.00z HREF/REFS supports the stronger gust potential, although the HREF does tend to be a bit overzealous when it comes to wind gusts. For example, in this current scenario, the 08.00z HREF paints 70-100% probabilities for greater than 45 mph winds across the region and even has a signal for gusts greater than 55 mph west of the Mississippi River, which from a conceptual model standpoint seems unlikely given the warm air advection regime. Currently thinking 35 to 45 mph gusts are most likely, strongest west of the Mississippi River.

All this said, opted to issue a short-fused Wind Advisory for late this morning into this afternoon after coordinating with surrounding offices for portions of southeast Minnesota and northeast Iowa.

DISCUSSION

Issued at 1245 AM CDT Wed Apr 8 2026

Wintry Mix Early this Morning Northeast of I-94

A band of rain showers has been lifting northeastward out of Iowa towards I-90 late this evening as mid-level theta-e advection intensifies on the backside of our departing ridge. With near or even below freezing wet bulb values at precipitation onset owing to our dry sub-cloud layer, there have been several reports over Iowa of snow/sleet mixing in with the stronger shower cores. Overall trends in the forecast remain on track with the main threat for freezing rain being northeast of I-94 with a light glaze expected by sunrise. Highest confidence in icy conditions is on elevated surfaces, but some untreated roadways could see slick spots for the morning commute. The freezing rain quickly departs after sunrise with rapidly warming temperatures through the morning.

Windy and Warmer Today, Rain in the Afternoon to Evening

The low-level jet cranks up with the aforementioned low-level warm air advection with wind speeds increasing to the 50-60kt range at 850 mb by sunrise. As daytime mixing commences around 8-10am, these winds will be quickly transported to the surface in the form of gusts in the 40 to 45 mph west of the Mississippi River and slightly lower gusts further east. Wind speeds decrease as the afternoon continues, and clouds and rain showers increase, all causing less favorable mixing conditions. Low- level theta-E convergence increases as the front moves across the area from west to east, thus rain chances are higher and more widespread heading into WI. Given the progressive nature of the front, rainfall amounts east of the Mississippi River should be around 1/4 to 1/2 of an inch. A token degree of instability south of I-90 could generate a rumble of thunder.

More Rain South of I-90 Thursday Night

The cold front that moves through this afternoon will stall to the south and be worked on by another shortwave moving through the northern stream of the split westerly flow Thursday late afternoon and night. This excites southerly low-level convergence flow into the front with strong moisture transport convergence and some instability near the I-80 corridor. Northeast Iowa and southwest WI are on the northern edge of the rain shield late Thursday afternoon and night. Amounts should taper off as one progresses northward towards I-90, but locations closer to Dubuque could see rainfall values in the 1/4 to 1/2 inch range depending on small nuances in the exact placement of the lower tropospheric front.

Warming into the Weekend, Periodic Showers into Next Week

Good consensus exists on a pattern evolution this weekend as a longwave trough forms in the western U.S. Beginning later on Saturday, a series of weather systems eject through the area in southwest flow from this trough as warmth and moisture build in. Precipitable water mean values in the 07.00Z Grand Ensemble are around 1 inch and the 07.00Z ECMWF Ens EFI has a good footprint for much above normal temperatures. Thus, the ingredients are there for heavy rainfall, although right now the model spread is dominating with lower predictability (10%) for any one location receiving over an inch in 24 hours. With the recent above average rainfall (300 percent of normal) over much of the area, rivers will be running elevated, so the heavy rain potential will need to be monitored. High temperatures look to be in the 70s Sunday and Monday, with the deterministic NBM providing realistic guidance. The probabilistic NBM guidance bias- corrected members are really jacking the distribution (7F warmer on average) - so not using the probabilistic T distribution for now. The pattern breaks by mid-week it appears.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 543 AM CDT Wed Apr 8 2026

Ongoing light rain will continue shifting eastward over the next few hours and should be east of our area between 13z-14z. Gusty south to southwest winds are expected today, with gusts of 30-40KT, strongest west of the Mississippi River. Gusts begin to diminish this afternoon as a cold front moves through the region, bringing another round of showers and perhaps a thunderstorm between 21z-06z. Winds will shift to the west- northwest behind the front, becoming 10-15KT with clearing skies.

HYDROLOGY

Issued at 1245 AM CDT Wed Apr 8 2026

The impactful crests on most rivers have passed and many locations are receding. Rains throughout the week should have little to no impacts on the current river trends. Our focus remains on the weekend and whether any of the ingredients in place can transpire into heavy rain and renewed rises on local rivers. Confidence is low on any such details, but with saturated soils and still elevated river levels, these bear watching closely.

ARX WATCHES/WARNINGS/ADVISORIES

WI...None. MN...Wind Advisory from 10 AM this morning to 4 PM CDT this afternoon for MNZ086-087-094-095. IA...Wind Advisory from 10 AM this morning to 4 PM CDT this afternoon for IAZ008>010-018-019-029.