Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 439 AM EDT Wed Mar 31 2021 Valid 12Z Wed Mar 31 2021 - 12Z Fri Apr 02 2021 ...Severe weather and flash flooding possible across the Southeast and Mid-Atlantic today... ...Developing area of low pressure to bring heavy snow across portions of Upstate New York and northern Vermont between Wednesday night and Thursday... ...Record-breaking cold to engulf much of the eastern U.S. from the Lower Mississippi Valley to Northeast by Friday morning... The final day of March will feature a strong cold front continuing to swing across the eastern U.S., producing areas of severe thunderstorms and heavy rain from the Southeast to Mid-Atlantic. Showers and thunderstorms are currently impacting the Lower Mississippi and Tennessee valleys this morning ahead of an approaching cold front. This activity is expected to push eastward and into the Southeast by this afternoon. Moderate-to-heavy rain may also develop across the Mid-Atlantic as an area of low pressure forms along the frontal system across the area this evening. Rainfall totals of 1 to 2 inches, with locally higher amounts, are forecast from southern Mississippi to the southern Appalachians. WPC has issued a Slight Risk of Excessive Rainfall that includes much of this region. Scattered flash flooding will be possible where repeating downpours occur. Much of this area has experienced well above average rainfall over the past few weeks, which will make soils sensitive to additional heavy rain. Flash Flood Watches are currently in effect across the Tennessee Valley for rainfall occurring this morning, with watches also extending across northern Mississippi and the southern Appalachians. Another hazard to contend with today will be severe weather. The Storm Prediction Center has issued a Slight Risk of severe thunderstorms from southern Mississippi to the central Carolinas. Damaging wind gusts will be the main concern, with isolated tornadoes possible particularly throughout south-central Alabama during the late afternoon to early evening hours. As a low pressure system gains strength Wednesday night into Thursday morning across the Northeast and southern New England, heavy snow is expected to develop across Upstate New York and northern Vermont. Cold temperatures surging into the region behind a cold front will set the stage for a potentially impactful spring snowstorm. Snow showers are forecast to taper off by Thursday evening, but not before over 4 inches of wet snow accumulates between the southern tier of New York and the Adirondacks, as well as northern Vermont. The heaviest snow is expected across the Adirondack Mountains, where up to a foot of snow is possible. Winter Storm Warnings and Winter Weather Advisories have been posted. On the warm side of the storm system, light-to-moderate rain will impact the Northeast Wednesday night 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. Flash Flood Watches have been issued here to highlight the potential hazard. Meanwhile, bitter and winter-like cold will be found across the eastern U.S. behind the aforementioned cold front. Freeze Warnings are in effect this morning across the Middle Mississippi and Tennessee valleys. 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 a strong high pressure system settles over the Ohio Valley. This will allow for temperatures to drop into the 20s as far south as the Mid-Atlantic and Tennessee Valley. This may lead to damage to early-season crops and foliage. Many record lows are forecast to be tied or broken throughout the Deep South, Southeast, Mid-Atlantic, Tennessee and Ohio Valleys. Elsewhere, the western and central U.S. will have a tranquil end of March and beginning of April with virtually no precipitation forecast. A warming trend will also lead to well above average temperatures to pair with the dry weather. The Southern Plains and Pacific Northwest will be the only exceptions, with temperatures remaining slightly below average through Friday morning. 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