Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 340 AM EDT Thu Apr 29 2021 Valid 12Z Thu Apr 29 2021 - 12Z Sat May 01 2021 ...There is a Slight risk of severe thunderstorms from parts of the northern Mid-Atlantic to the Tennessee Valley/Southern Appalachians through Friday morning... ...There is a Slight risk of excessive rainfall over the ArkLaTex region through Friday morning. ...There is a chance for record-breaking high minimum temperatures over the East and below-average temperatures over the Southern Rockies/Southern High Plains... A slow-moving front, spanning from the Northeast westward to the Ohio Valley and then southwest to the Middle/Lower Mississippi Valley and the Southern Plains will move off the East and Gulf Coast by Saturday. Showers and thunderstorms will develop along and ahead of the boundary from the Northeast to the lower Mississippi Valley through early Friday morning. The SPC has issued a Slight risk of severe thunderstorms from parts of the northern Mid-Atlantic to the Tennessee Valley/Southern Appalachians through Friday morning. The main hazards with the severe thunderstorms are frequent lightning, high wind gusts, hail, and possible tornadoes. The thunderstorms will have heavy rain associated with them. The WPC has issued a Slight risk of excessive rainfall over the ArkLaTex region through Friday morning. The heavy rain will produce scattered areas of flash flooding, with urban areas, roads, and small streams being the most vulnerable. Rain will develop over the Northeast/Mid-Atlantic on Friday morning, extending into parts of the Ohio Valley during the afternoon on Friday. The rain will end over the Mid-Atlantic/Ohio Valley by Friday evening. Wet snow will develop over parts of Upstate New York on Friday night. The rain will taper off over New England by Saturday morning as light snow moves into the higher elevations of Northern New England. Also, on Friday, the showers and thunderstorms will continue over parts of the Lower Mississippi Valley and the Southern Plains through Saturday morning. In the warm sector, south of the front, there is a chance for record-breaking high minimum temperatures over the Mid-Atlantic/Ohio Valley on Thursday morning. Meanwhile, an upper-level low over the Southern Rockies will move into Northern Mexico on Thursday. The cold air associated with the upper-level low will allow temperatures to be 10 to 20 degrees below average over parts of the Southern Rockies/Southern High Plains. Elsewhere, a front moving onshore over the Pacific Northwest on Friday afternoon will produce light rain over parts of the Northwest overnight Friday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php