The NWS Storm Prediction Center has issued a

• Tornado Watch for portions of
  Central and Eastern Iowa
  Northern Illinois
  Extreme Southeast Minnesota
  Southern Wisconsin
  Lake Michigan
• Effective this Tuesday afternoon and evening from 230 PM until
  1000 PM CDT.
• Primary threats include…
  Several tornadoes and a couple intense tornadoes likely
  Widespread large hail and scattered very large hail events to 4
  inches in diameter likely
  Scattered damaging winds likely with isolated significant gusts
  to 75 mph possible

SUMMARY…Supercell thunderstorms will pose a threat for very large
to giant hail this afternoon and evening as they track eastward,
with the largest hailstones potentially reaching up to 3-4 inches in
diameter. The threat for several tornadoes will increase later this
afternoon and evening along a warm front, and any sustained
supercell will be capable of producing a strong tornado. Otherwise,
scattered to numerous severe/damaging winds may eventually occur as
thunderstorms consolidate into one or more bowing clusters, with
peak gusts up to 65-75 mph.

The tornado watch area is approximately along and 75 statute miles
north and south of a line from 60 miles west southwest of Waterloo
IA to 20 miles north northeast of Milwaukee WI. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU9).

PRECAUTIONARY/PREPAREDNESS ACTIONS…

REMEMBER…A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

OTHER WATCH INFORMATION…CONTINUE…WW 108…

AVIATION…Tornadoes and a few severe thunderstorms with hail
surface and aloft to 4 inches. Extreme turbulence and surface wind
gusts to 65 knots. A few cumulonimbi with maximum tops to 550. Mean
storm motion vector 26035.