Heavy snow over parts of Central Rockies Thursday night into Friday andsnow over northern Maine.There is a Slight Risk of excessive rainfall over parts of Southern NewEngland and northern Mid-Atlantic through Thursday morning.There is a Slight Risk of excessive rainfall over parts of the LowerMississippi Valley/Southeast/Southern Appalachians on Friday.There is a Slight Risk of severe thunderstorms over parts of theSouthern Plains into the Lower Mississippi Valley Thursday into Friday.A front extending southward along the East Coast moves eastward off theEast Coast by Thursday evening. Moisture pooling along the front will aidin developing heavy rain over parts of the Northeast and Mid-Atlantic.Therefore, through Thursday morning, the WPC has issued a Slight Risk(level 2/4) of excessive rainfall over parts of Southern NewEngland/northern Mid-Atlantic. The associated heavy rain will createmainly localized areas of flash flooding, with urban areas, roads, andsmall streams the most vulnerable. Rain will continue over parts of NewEngland into the Mid-Atlantic Coast on Thursday evening. Snow will alsodevelop over northern Maine and patches of rain/freezing rain over partsof northeastern New York State into parts of Northern New England.  Moreover, a second front extending from the Upper Midwest to SouthernCalifornia will move eastward to the Great Lakes to the Southern Plains byFriday evening. The system will produce snow from the Upper MississippiValley to the Central High Plains and a broader region of snow over partsof the Great Basin/Southwest/Central Rockies and Northern IntermountainRegion through Thursday evening. Additionally, rain will develop overparts of California through Thursday evening.Furthermore, a wave of low pressure over Southern California on Wednesdayevening moves eastward to the Central/Southern Rockies by Thursdayevening. The circulation around the low will aid in creating heavy snowover the Central Rockies through Friday evening. Additionally, snow willdevelop over parts of the higher elevations of the Southwest and SouthernRockies.By Thursday evening, the front will move into parts of the SouthernPlains, producing showers and severe thunderstorms. Therefore, the SPC hasissued a Slight Risk (level 2/5) of severe thunderstorms over parts of theSouthern Plains on Thursday into Friday morning. The hazards associatedwith these thunderstorms are frequent lightning, severe thunderstorm windgusts, hail, and a few tornadoes.On Friday, the associated front moves to the Middle Mississippi Valleyinto the Southern Plains. Moisture will pool along the boundary, producingheavy rain over parts of the Lower Mississippi/Tennessee Valleys,Southeast, and Southern Appalachians. Therefore, the WPC has issued aSlight Risk (level 2/4) of excessive rainfall over parts of the LowerMississippi/Tennessee Valleys, Southeast, and Southern Appalachians onFriday. The associated heavy rain will create mainly localized areas offlash flooding, with urban areas, roads, and small streams the mostvulnerable.Also, on Friday, the front will create showers and severe thunderstormsover parts of the Southern Plains, Lower Mississippi Valley, and CentralGulf Coast. Therefore, the SPC has issued a Slight Risk (level 2/5) ofsevere thunderstorms over parts of the Southern Plains, Lower MississippiValley, and Central Gulf Coast on Friday. The hazards associated withthese thunderstorms are frequent lightning, severe thunderstorm windgusts, hail, and a few tornadoes.Elsewhere, on Friday, an approaching front will create rain over parts ofthe Pacific Northwest Coast.