4-15-12 St. Paul, MN TPT Weather Radio (Tornado Watch) 3:45 pm

The NWS Storm Prediction Center has issued a Tornado Watch for portions of extreme northern Iowa southern Minnesota west central Wisconsin Effective this Sunday afternoon and evening from 340 PM until 1100 PM CDT. Tornadoes...hail to 2.5 inches in diameter...thunderstorm wind gusts to 70 mph...and dangerous lightning are possible in these areas. The Tornado Watch area is approximately along and 85 statute miles either side of a line from 50 miles south southwest of Redwood Falls Minnesota to 40 miles east southeast of Eau Claire Wisconsin. For a complete depiction of the watch see the associated watch outline update (wous64 kwns wou8). 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 177... Discussion...storms are starting to increase from nwrn IA into swrn MN in advance of a strong upper trough/vorticity Max moving newd toward the upper MS valley. Air mass along and south of the warm front extending across srn MN into wrn WI has warmed during the afternoon resulting in MLCAPE of 1000-1500 j/kg. Very strong winds aloft and associated intense vertical shear will aid in storm organization with potential for supercells to develop...especially as storms interact with the warm front. Large hail...damaging winds and a few tornadoes will be possible with stronger cells as activity gradually spreads/develops newd through the evening hours. Aviation...tornadoes and a few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 21045.