The NWS Storm Prediction Center has issued a

• Tornado Watch for portions of
  Northeast and central Iowa
  Extreme southwest Wisconsin
• Effective this Monday afternoon and evening from 305 PM until
  1000 PM CDT.
• Primary threats include…
  A few tornadoes likely with a couple intense tornadoes possible
  Scattered damaging winds likely with isolated significant gusts
  to 75 mph possible
  Scattered large hail and isolated very large hail events to 2.5
  inches in diameter possible

SUMMARY…Supercell development is underway across northern Iowa and
these storms will spread southeastward through this evening. The
storm environment favors a few strong-intense tornadoes (EF2+), very
large hail (up to 2.5 inches in diameter) and isolated significant
severe gusts (75+ mph), especially where the supercells interact
with a modifying outflow boundary.

The tornado watch area is approximately along and 85 statute miles
east and west of a line from 10 miles west of Knoxville IA to 70
miles north northeast of Waterloo IA. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU0).

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.

&&

AVIATION…Tornadoes and a few severe thunderstorms with hail
surface and aloft to 2.5 inches. Extreme turbulence and surface wind
gusts to 65 knots. A few cumulonimbi with maximum tops to 600. Mean
storm motion vector 33030.