Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 PM EDT Wed Mar 31 2021 Valid 00Z Thu Apr 01 2021 - 00Z Sat Apr 03 2021 ...Severe thunderstorms and flash flooding possible across the Southeast and Mid-Atlantic into tonight... ...Developing area of low pressure to bring wet snow across portions of Upstate New York and northern Vermont between tonight and Thursday... ...Record-breaking cold to engulf areas from the Lower Mississippi Valley to Northeast by Friday morning... A sharp cold front pushing into the Deep South and eastern U.S. will continue to help triggering bands of severe thunderstorms and heavy rain from the Deep South to the Mid-Atlantic. The area most susceptible to severe weather and heavy rain will be across the Deep South to the Carolinas through this evening. Meanwhile, a wave of low pressure developing along the front is expected to intensify rapidly as it skirts the Mid-Atlantic coast tonight, reaching the New England coast by Thursday morning. A cold air mass will be ushered into the Deep South and the East Coast tonight ending the threat of severe weather by then. However, as the low pressure system gains strength, wet snow is expected to expand across Upstate New York and northern Vermont later this evening into Thursday, where a few inches of accumulation is forecast to fall across many areas of Upstate New York with 8 or more inches possible over the Adirondacks as well as northern Vermont. Winter Storm Warnings and Winter Weather Advisories have been issued for these areas. On the warm side of the storm system, light-to-moderate rain will impact the Northeast tonight and move into northern New England by Thursday morning. The combination of warm temperatures, melting snow, and rain could cause rivers to rise and ice jams to form across northern Maine where Flash Flood Watches have been issued. Meanwhile, sharply colder air will surge into the eastern U.S. behind the low pressure system. A large area of Freeze Warnings is in effect across the Middle Mississippi, Tennessee and into the Ohio Valleys in anticipation of this cold surge. Temperatures 15 to 25 degrees below average and even colder wind chill values will enter the Southeast, Appalachians, and interior sections of the Northeast on Thursday. However, the coldest time period is expected to be on Friday morning as the center of a strong high pressure system settles over the Ohio Valley. This will allow for temperatures to drop into the 20s as far south as northern Mississippi and Alabama. This may lead to damage to early-season crops and foliage. Many record low temperatures are forecast to be tied or broken throughout the Deep South, Southeast, Mid-Atlantic, Tennessee and Ohio Valleys on Friday morning. Elsewhere, the western and central U.S. will have a tranquil end of March and beginning of April with virtually no precipitation in the forecast. A general warming trend will bring well above average temperatures along with dry conditions, leading to an increasing danger of wildfires across the northern Plains and central High Plains. The southern Plains and Pacific Northwest will be the only exceptions, with temperatures remaining slightly below average into Friday. For southern California, Wind Advisories are in effect today as Santa Ana winds develop behind a dry cold front. Wind gusts up to 50 mph could blow around unsecured objects and raise the fire danger across the region. Snell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php