textproduct: La Crosse

KEY MESSAGES

- Seasonable temperatures expected through Wednesday with highs in the middle to upper 80s.

- Slightly below normal temperatures to end the work week.

- Storms likely (60-80%) late Wednesday afternoon through the overnight. Storms will be capable of producing locally heavy rainfall with some potential (10-40% chance) for over an inch of rainfall north of I-90.

DISCUSSION

Issued at 242 AM CDT Mon Jul 6 2026

Today - Tuesday: Seasonable Temperatures, Small Storm Chances Tuesday

A fairly benign pattern is in store to bring in the new work week with weak ridging and minimal modification to the ambient airmass in place for today. As a result, with the clear skies overhead, light winds and small dewpoint depressions early this morning, cannot rule (20-30% chance) out some fog formation in both river valleys and areas west of the Mississippi River. Where fog does form it could be locally dense with visibilities of 1/4 mile in spots. However, any fog that does form will likely mix out quickly during the morning leaving mostly clear skies for the afternoon hours. Will have to watch if any remnant precipitation can sneak into the area during the late evening hours as a mid-level shortwave pushes through central MN. Much of the CAMs generally agree on decaying convection associated with this wave prior to reaching the local area due to it outrunning the instability axis. However, cannot fully rule out (under 10% chance) some remaining precipitation sneaking into southeast MN late this evening.

As we head into Tuesday, the main feature to watch will be a shortwave that will progress through the Dakotas and into central Minnesota during the late evening hours on Tuesday. As this occurs, some shower and storms chances (10-30% chance) are present north of I-90 during the late evening as lingering instability would suggest some potential for storms across central MN to persist into locations north of I-90.

Wednesday - Thursday: Storms Likely Wednesday Afternoon and into Overnight, Locally Heavy Rainfall Possible

The larger implication of how storms evolve on Tuesday and into Tuesday night will be how these storms modify the thermal gradient for storm development on Wednesday. Currently, deterministic guidance would suggest a frontal boundary that sets up somewhere in the north-central WI vicinity as an upper-level shortwave transverses through the region during the afternoon through the overnight hours on Wednesday. As this occurs, 850mb moisture transport is progged in the GFS to run somewhat perpendicular to the front suggesting a Maddox frontal pattern setup with the deep- layer shear vector running parallel to the aforementioned boundary. The key question outlined between the GFS/EC is the exact location of where this setup takes place.

Currently, probabilistic guidance in the NBM generally keeps the highest probabilities for an inch of rainfall or greater north of the local area in northern WI with only lower probabilities (10-40%) for an inch or greater of rainfall during this period in Clark and Taylor counties. That being said, the 90th percentile of the NBM across portions of Taylor County has rainfall amounts in the 2-3" range. So while most members keep the heaviest rain north of the area, the higher percentile solutions would suggest a scenario where the Tuesday and Tuesday night convection pushes the thermal gradient south. As far as any severe potential, cannot fully rule out some strong to locally damaging wind gusts with any storms if cold pool organization can take place. However, given fairly weak flow aloft and very warm cloud depths, the hail risk is extremely low with any storms. In any case, probabilities for showers and storms in the NBM are quite high (70-90%) during this period across much of the area. Consequently, while storms are likely across the area, confidence in the heavy rain risk remains low at this point.

Friday - This Weekend: Starting Cooler than Normal, Warmer Sunday

As we head into Friday, slightly cooler temperatures than normal temperatures seem plausible in the wake of the mid-week precipitation as northwesterly flow gets established across the local area aloft. However, would expect somewhat of a warm up as deterministic guidance uniformly agrees on developing a pronounced upper-level high pressure center over the Central Plains over the weekend. Consequently, seeing minimal precipitation chances across guidance at this point with subsidence building into the region as a result of this upper- level ridging.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 538 AM CDT Mon Jul 6 2026

MVFR to IFR fog this morning will quickly mix out by 13z resulting in VFR conditions for much of the daytime hours with only few to sct cumulus expected. Winds will generally remain light from the east/southeast at around 5 mph throughout the TAF period.

ARX WATCHES/WARNINGS/ADVISORIES

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