Brief Outlook:
Severe thunderstorms are forecast across parts of the Upper Mississippi Valley, with risks of damaging winds and large hail on Independence Day. Check below for further details, timing and much more information.
States and Cities Impacted: Iowa (Des Moines, Cedar Rapids), Minnesota (Minneapolis, St. Paul), Wisconsin (Madison).
Detailed Forecast:
A weak surface low will develop eastward across the Upper Midwest during the afternoon and early evening as the northern Plains upper trough shifts east. Enhanced wind shear, with values around 25-35 knots in the 0-6 km layer, will support the development of organized storm structures, including a few transient supercells.
At the surface, instability values are expected to reach 1000-1500 J/kg, with temperatures warming into the upper 70s to low 80s. A cold front extending into western Minnesota and eastern Nebraska by midday will provide the focus for storm development. The interaction of this moist and unstable airmass with the advancing front will foster the development of severe thunderstorms capable of producing damaging winds and hail.