Area Forecast Discussion

KEY MESSAGES

- Severe thunderstorms are possible today, primarily across northeast Iowa and southwest Wisconsin. All hazards including heavy rainfall are possible.

- Quieter conditions are expected Friday through the start of next week with periodic chances for rain and cooler temperatures.

DISCUSSION

Issued at 107 AM CDT Thu Jun 11 2026

Today: Severe Thunderstorm Potential

Another day of severe weather potential is upon us as an upper level trough and vorticity maximum pivot through the area. A surface low develops over the Central Plains early this morning before lifting northward through the morning hours, shifting the warm front northward into our area while the surface low itself tracks directly over the Upper Mississippi River Valley. How far north the warm front eventually makes it is still a bit of an uncertainty and will be dependent on the location of any remnant outflows from yesterday's convection.

That said, current expectations are for the low and warm front to shift northward early this morning with 850hPa moisture transport associated with a strengthening low level jet in toe. Convergence on the nose of these features is expected to initiate convection across Iowa where MUCAPE values of 1500-2500 J/kg will exist per the 11.03z RAP, developing into a northeastward propagating MCS through the morning hours. 11.00z CAM solutions suggest this MCS largely remains south of our area, but those in northeast Iowa, especially those closer to the Mississippi River and those in far southwest Wisconsin would be most likely to see impacts from this morning system (60- 80%). This MCS would primarily pose a damaging wind threat with the potential for embedded tornadoes given a southwest to northeast oriented 0-3km shear vector.

As the low continues its trek northward through the day, instability continues to build across the Upper Midwest, most favorable along and south of I-90 where the warm sector is currently depicted to set- up. SBCAPE values of 1500-2500 J/kg are depicted in the deterministic guidance which will support thunderstorm development through the afternoon and evening hours with 40-60kts of 0-6km bulk shear, very favorable for severe storm development. All hazards are possible with storms that form through the afternoon with modest mid- level lapse rates of 7-7.5C/km, strong mid-level winds, and impressive low level curvature in model soundings resulting in 0-1km SRH of >200 m2/s2. The overall storm mode looks to be semi-discrete to linear throughout the day which would suggest damaging winds and tornadoes would be the primary hazards of these three, but can't rule out large hail especially in initially developing storms.

Heavy rain will also accompany the storms through the day as PWATs of 1.5-2 inches overspread our southern counties. These areas received generally 1-2 inches of rainfall yesterday per MRMS QPE with the 11.00z REFS LPMM suggesting another 1-2 inches could fall throughout the day with some low probabilities (20-30%) for greater than 2 inches. Those areas that saw higher rainfall totals yesterday and see multiple rounds of storms today could face some flash flooding potential.

Friday - Early Next Week: Periodic Rain Chances and Cooler

Quieter weather is expected Friday in the wake of the cold front and a more zonal upper level flow. However, a shortwave trough and cold front associated with a deep mid-latitude cyclone over Canada is expected to move through the Upper Midwest Saturday, bringing some potential for showers and thunderstorms throughout the day. Rainfall probabilities sit around 30-60% in the 10.19z NBM, highest over northeast Iowa into central Wisconsin where the greatest consensus amongst the model guidance suite exists. Beyond the rainfall potential, cooler temperatures are expected to move in behind the cold front with highs currently expected to top out into the mid to upper 70s Sunday through the beginning of the new week before a warming trend and additional rainfall potential develop by mid week.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 559 AM CDT Thu Jun 11 2026

VFR conditions currently present across much of the region with some patchy fog in some river valleys and low lying areas this morning. Another round of rain and storms is expected to move in from the southwest over the coming hours bringing MVFR CIGS and visibilities to the terminals (potential for brief IFR CIGs and visibilities in the stronger storms). The best potential for strong to severe storms generally looks to remain south and east of the terminals so have gone with VCTS and SHRA at the terminals in lieu of straight TSRA for now given the lower probability of thunderstorms along and north of I-90. Activity should gradually come to an end through the late afternoon and evening with conditions returning to VFR later in the period. As the surface low pressure moves to the north and east through NE Iowa and SW Wisconsin, winds will pick up this afternoon and turn to a more west/northwesterly direction as it passes.

ARX WATCHES / WARNINGS / ADVISORIES

WI...Flood Watch from noon CDT today through this evening for WIZ017-029-034. MN...None. IA...None.