textproduct: La Crosse

KEY MESSAGES

- One last cool day today followed by rebounding temperatures for Wednesday (highs in the 60s) and seasonable weather for the rest of the week. Even warmer for Sunday.

- Light rain/snow tonight into Wednesday morning, mixing with freezing rain towards central Wisconsin. Overall impacts should be limited in scope.

- Mostly dry during the day on Wednesday with another round of rain coming with a cold frontal passage late Wednesday afternoon and evening. Most areas should see less than 1/2" of rain.

- The potential exists for more rounds of rain over the weekend, possibly heavy as we look into early next week.

DISCUSSION

Issued at 1200 AM CDT Tue Apr 7 2026

Tonight: Wintry Mix

A ribbon of isentropic upglide/theta-e advection lifts northward on the backside of the departing ridge this evening, fueling a band of light precipitation. With surface temperatures west/south of I-94 staying above freezing overnight, any snow that does mix in will be brief in nature and not amount to any impacts. Further north and east, the 850-750-mb warm nose is progged to overrun a colder airmass and possibly result in a 2-5 hour period of freezing rain. Interestingly, the latest CAM runs are depicting drier profiles than their global counterparts. A look at some of the deterministic fields does show some weaknesses in the mid-level moisture profiles, so this trend bears watching through the day. Between moisture concerns, ongoing warm air advection, warm ground temps, and the short duration of the freezing rain threat, have refrained from issuing any headlines at this time.

Wednesday Afternoon/Evening: Another Round of Rain

Most of the day on Wednesday could be on the dry side with a few pop-up showers possible in the warm sector before a cold front approaches in the afternoon. With the mid to upper-level flow parallel to the frontal orientation, there could be some training storm motions along the front as it moves through. However, with the overall progressive motion of the front and limited mid-level moisture, precipitation amounts from this line are not expected to be overly impactful with only a 10-20% chance of seeing rainfall amounts over 1/2".

End of the Week into Early Next Week: Heavy Rain Threat

The lower tropospheric baroclinic zone slides down into Iowa and Illinois for Thursday as a trailing shortwave ripples along the U.S./Canadian border. Additional showers and storms are expected to develop along this frontal zone Thursday late afternoon and evening, some of which could spread across the forecast area within the corridor of WAA. Locations down towards Dubuque could pick up close to 1/2" of rain; however, the axis of heaviest rain should stay south of the forecast area.

A deep longwave trough carves out the west coast of the U.S. Friday into Saturday, bringing southwesterly flow across the region starting Saturday afternoon and persisting possibly as late as the middle of next week. A deeper fetch of lower to mid tropospheric moisture pumps northward with precipitable water values closing in on the 99th percentile of climatology for this time of year on Sunday. The exact placement of the heavy rain remains to be seen, but over a 72-hour period early next week there is a 20-50% chance of seeing over 2" of rain and a 5-15% chance of seeing over 3 inches, respectable percentages for being so far out. The "worst case" scenario depicted by the current guidance suite paints amounts over 4" across much of the area. Bottom line, the setup will favor heavy rain over the area, it is just a matter of where it falls.

Temperature Outlook

A pattern shift is in the offing after today as the surface ridge departs to the east. A Pacific airmass slides eastward in its wake, pushing highs into the lower 60s for most locales for Wednesday. With the region residing on the cold side of the surface baroclinic zone for Thursday and Friday, highs will be tempered in the mid-50s. As the aforementioned upstream pattern amplification occurs, temperatures respond in kind. There is strong agreement in the longer range ensembles that highs will surge into the 70s for Sunday and Monday, possibly warmer (25% chance of reaching 80 degrees) depending on the trajectories of our rainfall.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 538 AM CDT Tue Apr 7 2026

VFR conditions will prevail through much of the day with clear to mostly clear skies. Light winds will continue veering through the morning hours, becoming south to southeasterly by the afternoon, but will begin to increase increase this afternoon. Gusts of 15-20KT are possible for those west of the Mississippi River as we head into the evening. Conditions begin to deteriorate overnight as an area of rain/wintry mix moves northward through the region (40-80%) resulting in an area of MVFR ceilings, mainly west of the Mississippi River. A period of light freezing rain is possible in central Wisconsin between 08z-12z with the 07.07z NBM suggesting probabilities of 20-40%. Impacts should be minimal given warm ground temperatures, but elevated surfaces may see a light coat of ice. Winds further increase towards the end of the TAF period as the low level wind field increases, resulting in gusts of 25-30KT.

HYDROLOGY

Issued at 1200 AM CDT Tue Apr 7 2026

Crests are working downstream along the Black, Kickapoo, Lemonweir, Wisconsin, and Yellow rivers. With rainfall amounts tonight into Wednesday night expected to be 1/2" or less and most rivers having crested by the time this rain arrives, any impacts to the river trends will be minimal. It remains too soon to see how the potential for heavy rain later in the upcoming weekend would impact the rivers, but most rivers will have just receded and with soil moisture values still running high, they may be more sensitive and respond faster with the weekend rainfall.

ARX WATCHES/WARNINGS/ADVISORIES

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