AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 3:43 PM CDT SUN JUN 29 2014 TONIGHT AND MONDAY...FORECAST CONFIDENCE...MEDIUM https://fbcdn-sphotos-f-a.akamaihd.net/hphotos-ak-xap1/t1.0-9/10505401_668384479921789_1309336363833381253_n.jpg A decent 850-millibar warm air advection coupled with a weak short-wave trough will likely kick off widespread thunderstorms late afternoon and early evening across eastern Iowa. These storms are expected to affect southern Wisconsin mid-evening into early night. With median layer cape of around 1500 joules/kilogram and 0-6 kilometer bulk shear around 45 knots, some of the storms could be severe, mainly across the southwest half of the forecast area. Heavy rain is also possible with precipitable water values of around 1.75 inches, though storm motion and mesoscale convective system propagation vectors suggest things may be moving along quick enough to limit rain totals. Storms should wind down later in the night, with mainly dry weather possible Monday through early afternoon. The next round of storms will begin to affect the western forecast area by mid or late afternoon. All signs still point to a pretty solid severe threat later tomorrow afternoon and into the evening. Median layer convective applied potential energy will peak in the 2000-3000-joules/kilogram range, with 0-6 kilometer shear of 50-60 knots. With seemingly plenty of time for the atmosphere to recover and ideal surface front timing, confidence is increasing in this round of potential severe storms. Initial storm development Monday will likely be discrete supercells, eventually congealing into a line of storms later on. Severe storms that do form will likely produce large hail and damaging wind. Additionally, low-level shear will also support the possibility of a few tornadoes. Storms will also likely produce heavy rainfall with precipitable water values around 2 inches, though storms should be moving along at a good clip.
Posted on: Sun, 29 Jun 2014 23:23:12 +0000