Sample severe thunderstorm watch page !http://www.spc.noaa.gov/products/watch/ww0300_radar_init_resize.gif! urgent - immediate broadcast requested severe thunderstorm watch number 300 nws storm prediction center norman ok 400 pm cdt wed jun 12 2013 the nws storm prediction center has issued a * severe thunderstorm watch for portions of northeast illinois northern indiana southern lower michigan northwest ohio southeast wisconsin lake erie lake michigan * effective this wednesday afternoon and thursday morning from 400 pm until 100 am cdt. ...this is a particularly dangerous situation... * primary threats include... numerous significant damaging wind gusts to 80 mph likely several very large hail events to 2 inches in diameter possible a few tornadoes possible the severe thunderstorm watch area is approximately along and 70 statute miles either side of a line from 40 miles east of findlay ohio to 60 miles south southwest of racine wisconsin. for a complete depiction of the watch see the associated watch outline update (wous64 kwns wou0). 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. && other watch information...continue...ww 298...ww 299... discussion...thunderstorms are expected to consolidate into a forward propagating convective system over the next several hours as a compact but progressive shortwave trough acts on a very unstable airmass across the upper midwest/lower great lakes region. ongoing convection near a surface low and warm front...from iowa east across northern illinois...exists where low level shear and ascent will contribute to a few more hours of tornado potential in watch 298. eventually storms will congeal into a large mass of convection with ascent and strengthening shear supporting a possible derecho or widespread damaging wind event. this transition is likely to occur across the chicago area and srn lake michigan into early evening. prior to this evolution the large hail and tornado possibilities will be greatest within the western portions of watch 300. with time...more widespread damaging wind potential will develop as the mcs races east across southern mi/northern ind...and into northwest oh through late tonight. aviation...a few severe thunderstorms with hail surface and aloft to 2 inches. extreme turbulence and surface wind gusts to 70 knots. a few cumulonimbi with maximum tops to 550. mean storm motion vector 28045. #weatherapp