textproduct: La Crosse

KEY MESSAGES

- Scattered showers and storms this afternoon across western and central Wisconsin.

- Widespread showers and storms for Wednesday morning through the evening. Strong to severe storms are possible Wednesday morning in northeast Iowa and for more of the forecast area for Wednesday afternoon and evening. Hail is the main threat for any severe storm Wednesday morning with all storm hazards possible for the afternoon and evening severe threat.

- Periodic showers and storms from Thursday through the weekend with temperatures remaining in the 70s for most locations.

DISCUSSION

Issued at 114 PM CDT Tue Jun 16 2026

Today: Scattered Showers and Storms

A surface low situated over north central Wisconsin will continue to shift off to the east through the afternoon. This has helped to give way to increased precipitation chances across portions of the Upper Midwest. There is some instability, around 250 to 750 J/kg of MUCAPE, in place across the area, however there is little to no shear for storms to work with. These types of storms will pulse up and down due to this limited shear. Despite the limited shear, there could be some small hail with these storms. Another thing to watch out for is a ribbon of surface vorticity that is currently in northern Clark and southern Taylor counties. This coupled with the weak instability and limited shear could lead to some funnel clouds this afternoon across portions of western and central Wisconsin. These showers and storms move out of the forecast area by the evening.

Wednesday: Strong to Severe Storms Possible

Heading into Wednesday morning the low level jet begins to increase, around 35 to 45kts. At the same time, a surface low forms in the central Plains. With winds shifting around the south overnight, moisture advection really increases ahead of the low level jet with PWATs of 1.25 to 1.5". Ahead of this jet, moisture advection creeps into southeast Minnesota and northeast Iowa before the jet gets going. This will result in some showers for the early morning hours. Between 10Z and 12Z is when the low level jet begins to impact the forecast area, mainly northeast Iowa, and when instability builds in, with around 500 to 1500 J/kg of MUCAPE. With the elevated instability and good amount of shear SPC has gone ahead and put a slight risk for severe weather for Wednesday morning that just clips portions of northeast Iowa, with most of northeast Iowa in the marginal risk. It is all about timing and and how far north the low level jet can push to determine if we see severe storms in the morning. Regardless of the severity, there will be widespread showers and storms through morning across much of the forecast area. Total rain amounts are between 0.5 to 0.75" for areas south of I-90 with amounts closer to 1" for southern Clayton and Grant counties. With these being storms, the highest rainfall amounts could shift so while the general area may see around 0.5 to 0.75" through the morning, some areas could see over an inch due to the high PWAT values.

By the afternoon, another surface low comes down into the Upper Midwest from northwest Minnesota and the southern low fades into the northern low somewhere over our forecast area by the later afternoon. Short range models continue to suggest that our forecast area, particularly areas along and south of I-90 have a chance at recovering from the morning storms as dewpoints creep back into the low 60s. With strong 0-6km shear, around 55 to 65 kts, modest instability, between 1500 to 2000 J/kg of SBCAPE, and potentially minimal capping in place, strong to severe storms will once again be possible in the afternoon hours. SPC has went ahead and issued a slight risk for severe weather for areas generally along and south of I-90 for the afternoon storms as all hazards will be possible. There is uncertainty on how the morning storms will play a role in the severe potential for the afternoon, so stay tuned for updates on this potential. As there is potential for heavy rain during the morning hours and in combination with any storms that produce heavy rainfall over the same locations, WPC has issued a slight risk for Excessive Rainfall across the southern half of the CWA. The latest HREF LPMM has pockets of 1.5 to 2" of rain across the CWA so there is some potential for a bit of rain to fall on Wednesday.

Thursday-Sunday: Periodic Showers and Storms

West to northwest flow aloft remains in place through the weekend. A couple of waves pass through giving way to low shower and storm chances on Thursday and Friday. On Saturday, a surface low ejects out of the Central Rockies and shifts eastward. There remains some timing and location differences between the GFS and ECMWF but the general idea is that precipitation chances increase Saturday night and continue through Sunday. Temperatures through the weekend continue to remain mild as they stay in the 70s

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1234 PM CDT Tue Jun 16 2026

Widespread MVFR ceilings associated with an area of low pressure transiting the region will gradually lift to VFR and clear from west to east through the afternoon. Scattered showers will also accompany this low passage east of the Mississippi River though the afternoon, with a low risk (20-30%) for thunderstorms during this time. After a dry start to the night, showers and storms roll in after 06Z with widespread showers through the morning on Wednesday. Winds this afternoon will be from the northwest at 10-15G15-25kts, decreasing this evening and backing to the south shortly after sunset. These winds increase steadily after 06Z, reaching 10-15G15-25kts by mid- morning on Wednesday.

ARX WATCHES/WARNINGS/ADVISORIES

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