Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 417 AM EDT Tue Jun 21 2016 Valid 12Z Tue Jun 21 2016 - 12Z Thu Jun 23 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 Ohio Valley and the Upper Great Lakes... ...Above average temperatures expected to continue for the western U.S... A quasi-stationary front will extend from the Northeast/Northern Mid-Atlantic to the Ohio Valley westward to the Central Plains through Thursday. Showers and thunderstorms will develop along and ahead of the boundary from the Middle Mississippi Valley to the Mid-Atlantic and the Northeast moving off the Northeast Coast by late afternoon on Tuesday. The showers and thunderstorms will continue along the front from parts of the Ohio and Tennessee Valleys to the Mid-Atlantic on Tuesday afternoon until the showers and thunderstorms move off the Mid-Atlantic Coast by Wednesday morning. In addition, upper-level energy moving across the Upper Great Lakes into the Northeast through Wednesday evening. Rain will develop over parts of the Upper Great Lakes on Tuesday evening moving into Northern New England by Wednesday evening. Meanwhile, a wave of low pressure will develop over parts of the Northern High Plains that will move eastward to Middle Mississippi Valley by Wednesday evening. The associated upper-level energy will aid in producing rain over parts of the Northwest moving into parts of the Northern Intermountain Region into parts of the Northern High Plains on Tuesday evening ending overnight Tuesday. When the system moves onto the Northern Plains, showers and thunderstorms will develop over the Northern Plains into the Middle Mississippi Valley also overnight on Tuesday. By Wednesday evening, the showers and thunderstorms will move into the Upper Mississippi Valley and extend into parts of the Ohio Valley/Central Appalachians. Additionally, onshore flow off the Western Gulf of Mexico will aid in producing showers and thunderstorms over parts of the Western/Central Gulf Coast with a strong daytime heating component on Tuesday and Wednesday afternoon and evening. Also, upper-level energy over the Central Rockies and moisture along with daytime heating will aid in producing showers and thunderstorms, likewise, on Tuesday and Wednesday afternoon and evening. Furthermore, easterly flow off the Atlantic and upper-level energy will aid in producing showers and thunderstorms over southern Florida through Wednesday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php