Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 301 PM EDT Thu Apr 29 2021 Valid 00Z Fri Apr 30 2021 - 00Z Sun May 02 2021 ...A Marginal risk of severe thunderstorms is in effect from parts of the northern Mid-Atlantic to the Lower Mississippi Valley/eastern Texas 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 frontal boundary spanning from southern New England, across the Ohio and Mid-Mississippi Valleys and southwest to eastern Oklahoma/Texas will continue on with its slow eastward progression through the weekend. Scattered to widespread thunderstorms will develop along and ahead of this boundary over the next few days. Some of these storms will be quite strong, possibly severe, and may usher in hail, damaging winds and possibly an isolated tornado. The Storm Prediction Center has a Marginal Risk for severe storms in effect from eastern Texas to western Connecticut through Friday morning. These storms will also produce moderate to heavy downpours across portions of the Southern Plains and Lower Mississippi Valley and may lead to scattered areas of flash flooding, with urban areas, roads, and small streams being the most vulnerable. WPC has a Slight Risk for excessive rainfall in effect from northeast Texas to extreme southwest Tennessee. 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, while wet snow will develop over parts of Upstate New York 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. For areas south of this sprawling frontal boundary, warmer temperatures are expected. Several locations could tie or break high minimum temperature records for Thursday morning- especially across the Ohio Valley and Mid-Atlantic regions. Meanwhile, an upper-level low over the Southern Rockies will move into Northern Mexico on Thursday and will usher in cooler air to the region. This will allow daily temperatures to be about 10 to 20 degrees below seasonal average for the Southern Rockies and the adjacent 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. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php