Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 348 AM EDT Thu Oct 31 2024 Valid 12Z Thu Oct 31 2024 - 12Z Sat Nov 02 2024 ...Moderate to heavy snow over parts of the Southern Cascades and Northern Intermountain Region, with a second area over parts of the Upper Midwest on Thursday... ...Temperatures will be 20 to 25 degrees above average over parts of the Lower Great Lakes/eastern Ohio Valley and the Northeast/Mid-Atlantic... ...There is a Marginal Risk of severe thunderstorms over parts of the Ohio/Tennessee Valley and Lower Mississippi Valley and a Marginal Risk of excessive rainfall over parts of the Lower Mississippi Valley on Thursday... A wave of low pressure over the Upper/Middle Mississippi Valley will move northeastward to Southeastern Canada by Friday. The trailing front moves off the Northeast/Mid-Atlantic Coast by Friday evening, while the western end of the boundary slowly moves northward as a stationary front over north-central Texas by Saturday. Ahead of the front, temperatures will be 20 to 25 degrees above average over parts of the Lower Great Lakes/eastern Ohio Valley and the Northeast/Mid-Atlantic. On Thursday, moist air flowing northward over the Plains will extend into the Great Lakes, creating showers and strong to severe thunderstorms ahead of the front over parts of the Ohio/Tennessee Valley and Lower Mississippi Valley. Therefore, the SPC has issued a Marginal Risk (level 1/5) of severe thunderstorms over the Ohio/Tennessee Valley and Lower Mississippi Valley through Friday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a minimal threat of tornadoes. Furthermore, moderate to heavy rain will develop along the front over parts of Tennessee and Lower Mississippi Valleys. Therefore, through Friday morning, the WPC has issued a Marginal Risk (level 1/4) of excessive rainfall over parts of the Tennessee and Lower Mississippi Valleys. The associated heavy rain will create localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain. Moreover, the wave of low pressure will pull cold air over parts of the Upper Midwest, producing moderate to heavy snow over parts of Minnesota, extreme northern Wisconsin, and portions of the Upper Peninsula of Michigan. Furthermore, rain develops along the front from Central Appalachians to the Northeast on Friday morning, tapering off to scattered rain over parts of the Northeast by Friday evening. Also, on Friday, onshore flow off the Atlantic will produce scattered rain over parts of Florida. On Friday, the threat of strong to severe thunderstorms moves westward to the Southern High Plains as upper-level dynamics move over Southern California. Therefore, the SPC has issued a Marginal Risk (level 1/5) of severe thunderstorms over parts of the Southern High Plains from Friday into Saturday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a minimal threat of tornadoes Further, the showers and thunderstorms will create moderate to heavy rain over parts of the Southern Plains. Therefore, the WPC has issued a Marginal Risk (level 1/4) of excessive rainfall over parts of the Southern Plains from Friday to Saturday morning. The associated heavy rain will create localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain. Meanwhile, another front over the Pacific Northwest and California will move inland and dissipate by Thursday evening. On Thursday, the snow will become moderate to heavy over parts of the Southern Cascades and Northern Intermountain Region. Rain will continue over the Northwest and Northern/Central California through early Saturday. Light snow will continue over parts of the higher elevations of the Cascades, Sierra Nevada Mountains, Northern Intermountain Region, and Northern Rockies. Ziegenfelder Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php