The NWS Storm Prediction Center has issued a

• Severe Thunderstorm Watch for portions of
  Eastern Iowa
  Northern and Central Illinois
  Northwest Indiana
  Southwest and Southern Wisconsin
  Lake Michigan
• Effective this Tuesday morning and afternoon from 720 AM until
  200 PM CDT.
• Primary threats include…
  Widespread damaging winds and isolated significant gusts to 85
  mph likely
  Isolated large hail events to 1.5 inches in diameter possible
  A tornado or two possible

SUMMARY…An intensifying squall line will continue east into the
Watch area this morning through the midday. Severe gusts (60 to 85
mph) will likely become more prevalent and widespread as the squall
line matures through the late morning. An embedded tornado or two
is possible within the squall line.

The severe thunderstorm watch area is approximately along and 100
statute miles north and south of a line from 30 miles west southwest
of Dubuque IA to 80 miles east of Marseilles IL. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU3).

PRECAUTIONARY/PREPAREDNESS ACTIONS…

REMEMBER…A Severe Thunderstorm Watch means conditions are
favorable for 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. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

AVIATION…A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 75 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
28040.