Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 414 PM EDT Mon Apr 20 2015 Valid 00Z Tue Apr 21 2015 - 00Z Thu Apr 23 2015 ...There is a slight risk of severe thunderstorms for parts of the Mid-Atlantic to the Southeast... ...Heavy rain possible over parts of Maine... A front extending from the Lower Great Lakes to the Eastern Gulf Coast will move eastward off the East Coast by Tuesday morning. The system will produce showers and thunderstorms from the Mid-Atlantic to the Southeast that will likewise move eastward off the coast by Tuesday morning as well. Rain will develop over parts of the Northeast that will move into Southeastern Canada by Tuesday evening. The boundary will linger over Florida through Wednesday morning. Showers and thunderstorms will develop near the front through Wednesday morning over Florida. Light snow will develop over parts of the Upper Great Lakes/Upper Mississippi Valley through Wednesday. Rain will develop over parts of the Great Lakes that will expand into parts of the Ohio Valley/Middle Mississippi Valley by Tuesday evening. The rain will move eastward to the Northern/Central Appalachians to parts of the Tennessee Valley by Wednesday morning. In addition, upper-level energy moving over the Southern tip of Texas will aid in producing showers and thunderstorms through Tuesday evening. Another area of upper-level energy over the Central Rockies will move eastward to the Southeast by Wednesday. Showers and thunderstorms will develop over parts of the Southern High Plain with snow over parts of the Central Rockies on Monday evening. showers and thunderstorms will linger over parts of the Southern Plains through Wednesday. Elsewhere, a front over the Pacific will move onshore over the Pacific Northwest on Tuesday morning advancing eastward to the Northern Rockies by Wednesday. Rain will develop over parts of the Pacific Northwest Coast by Tuesday evening that will move inland to parts of the Northern Intermountain Region by Wednesday morning. Showers and thunderstorms will develop over parts of Northern/Central California on Tuesday evening tapering off to rain by Wednesday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php