Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 355 PM EDT Tue Jun 21 2016 Valid 00Z Wed Jun 22 2016 - 00Z Fri Jun 24 2016 ...Severe thunderstorms possible from the Northern High Plains to the Middle Mississippi Valley... ...Severe thunderstorms possible from portions of the Ohio/Tennessee Valleys to the Mid-Atlantic... ...Heavy rain possible over parts of the Upper Midwest, Ohio Valley, Upper Great Lakes and central Appalachians... ...Above average temperatures expected to continue for the western U.S... Scattered showers and thunderstorms are expected across the northern High Plains and Upper Midwest as a developing low pressure system tracks eastward. Convection is also expected near the Great Lakes, Ohio and Tennessee Valleys and across the central Appalachians as a warm front lift northward and across the central Appalachians and Mid-Atlantic as that portion of the boundary pushes south and east as a cold front. Conditions will be favorable for severe thunderstorms to develop over much of the Great Lakes/Ohio Valley and surrounding areas on Wednesday - the Storm Prediction Center has that area under a slight risk. Storms that fire up over northern Illinois/Indiana/Ohio and southern Wisconsin, Lake Michigan and Michigan have an enhanced and moderate risk for severe storms. as the system progresses the threat will shift to the central Appalachian and northern Mid-Atlantic for Thursday through Friday morning. Elsewhere, showers and thunderstorms will fire up over portions of the western and central Gulf Coast with a strong daytime heating component and onshore flow from the Gulf of Mexico. Easterly flow off the Atlantic and upper-level energy will aid in producing showers and thunderstorms over southern Florida through Wednesday evening. Showers will be possible across the Pacific Northwest ahead of an approaching cold front. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php