Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 357 PM EDT Sat Oct 01 2022 Valid 00Z Sun Oct 02 2022 - 00Z Tue Oct 04 2022 ...There is a Slight Risk of excessive rainfall over parts of the Central Appalachians through Sunday morning... ...There is a Slight Risk of excessive rainfall over parts of the Great Basin and the Central Rockies from Sunday into Monday morning... ...Temperatures will be 10 to 15 degrees below average over parts of the Mid-Atlantic... Post-Tropical Cyclone IAN will slowly dissipate near the North Carolina-Virginia border through Sunday evening. However, an upper-level low over the Mid-Atlantic will keep clouds and showers over the region through Monday. Moisture streaming inland off the Atlantic will produce heavy rain over parts of the Central Appalachians. Therefore, the WPC has issued a Slight Risk of excessive rainfall over parts of the Central Appalachians through Sunday morning. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, and small streams the most vulnerable. The threat of excessive rainfall decreases slightly to a Marginal Risk over the Mid-Atlantic on Sunday and the threat moves to the immediate Mid-Atlantic Coast on Monday. The clouds and rain will keep temperatures 10 to 15 degrees below average on Sunday. Meanwhile, a second upper-level low over the Northern Rockies will slowly drift to the Northern High Plains by Monday evening. Moisture circulation around the Upper-low will aid in producing rain over the Northern Rockies and showers/thunderstorms over the Central Rockies into the Southwest. Therefore, the WPC has issued a Marginal Risk of excessive rainfall over parts of the Northern/Central Rockies and the Southwest through Sunday morning. The associated heavy rain will create localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain and burn scars the most vulnerable. Furthermore, on Sunday, the tropical moisture streaming over the Southwest into parts of the Great Basin will produce showers and thunderstorms with heavy rain over the area. Therefore, the WPC has issued a Slight Risk of excessive rainfall over parts of the Great Basin and Central Rockies from Sunday into Monday morning. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, small streams, and burn scars the most vulnerable. On Monday, the threat of excessive rainfall decreases as the moisture flow is limited. However, there will still be showers and thunderstorms with the possibility of heavy rain over parts of the Southwest/Southern Rockies. Therefore, the WPC has issued a Marginal Risk of excessive rainfall over parts of the Southwest and Central/Southern Rockies on Monday morning. The associated heavy rain will create localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain and burn scars. Ziegenfelder Graphics are available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php