Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 358 PM EDT Sat Mar 27 2021 Valid 00Z Sun Mar 28 2021 - 00Z Tue Mar 30 2021 ...There is an Enhanced Risk of severe thunderstorms and a Moderate Risk of excessive rainfall over parts of the Lower Mississippi and Tennessee Valleys through Sunday morning... ...There is an Enhanced Risk of severe thunderstorms over parts of the Mid-Atlantic and a Slight Risk of excecive rainfall over parts of the Tennessee/North Carolina border on Sunday into Monday morning... ...Strong cold front to bring gusty winds and heavy mountain snow across the Pacific Northwest and Northern Rockies beginning Sunday afternoon... A front extending from the Upper Great Lakes southwestward to the Southern Plains will move off the East Coast overnight Sunday. The system will produce showers and thunderstorms along and ahead of the boundary from parts of the Southern Plains eastward to the Mid-Atlantic through Sunday morning. Associated with the system, rain and snow will develop over parts of the Upper Mississippi Valley and the Upper Great Lakes through Sunday evening. The SPC has issued an Enhanced Risk of severe thunderstorms over parts of the Lower Mississippi and Tennessee Valleys through Sunday morning. The primary hazards associated with the severe thunderstorms are frequent lightning, severe wind gusts, hail, and tornadoes. SPC believes there will be a 10% or greater probability of EF2-EF5 tornadoes, severe wind gust 65 knots or greater, and two-inch hail in the enhanced region. The WPC has issued a Moderate Risk of excessive rainfall over parts of the Lower Mississippi and Tennessee Valleys through Sunday morning. The heavy rain associated with the thunderstorms will produce numerous areas of flash flooding. Some significant flooding is possible and many streams may flood, potentially affecting larger rivers. On Sunday, showers and thunderstorms will continue along and ahead of the front from the Mid-Atlantic to the Central Gulf Coast until the front moves off the coast overnight Sunday. The SPC has issued an Enhanced Risk of severe thunderstorms over parts of the Mid-Atlantic through to when the front moves offshore or Monday morning. The primary hazards associated with the severe thunderstorms are frequent lightning, severe wind gusts, hail, and tornadoes. SPC believes there will be a 10% chance of severe wind gust 65 knots or greater in the enhanced region. There will still be heavy rain associated with the thunderstorms, but the flooding threat will be lower with a Sight Risk of excessive rainfall over parts of the Tennessee/North Carolina border. Additionally, the rain will move into parts of the Northeast and Ohio Valley and then into the northern Mid-Atlantic. The rain will change over to snow on the backside of the precipitation shield over parts of the Northeast into parts of the Central Appalachians from Sunday afternoon into Monday morning. Meanwhile, on Sunday, a front will move onshore over the Pacific Northwest and advance eastward to the Upper Mississippi Valley southwestward to the Central Rockies by Monday evening. The strong cold front associated and the deepening area of low pressure in South-Central Canada will bring the threat of damaging wind gusts and heavy mountain snow. Snowfall amounts are expected to exceed one foot across parts of the Cascade Mountains. Winter Storm Watches and Winter Weather Advisories have been posted. The most widespread hazard, beginning Sunday, will be from gusty winds that extend from the Pacific Northwest through the Northern Great Basin/Rockies and into the Northern High Plains. High Wind Watches have been issued due to the potential for wind gusts to top 60 mph. This could lead to downed trees and power lines, as well as difficult travel for high-profile vehicles through Monday morning. On Monday, light snow will develop across parts of the Northern Rockies through Monday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php