Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 308 PM EST Sat Nov 27 2021 Valid 00Z Sun Nov 28 2021 - 00Z Tue Nov 30 2021 ...There is a Slight Risk of excessive rainfall over parts of the Pacific Northwest through Sunday morning... \...Heavy lake enhanced snow downwind from the Great Lakes and snow for parts of New England and The Central Appalachians... ...Temperatures will be 15 to 30 degrees above average over parts of the Northern Rockies and Northern/Central High Plains... A plume of moisture will stream into the Pacific Northwest through Monday morning. The moisture will aid in producing heavy rain over parts of the Northwest Saturday into Sunday. Therefore, the WPC has issued a Slight Risk of excessive rainfall over parts of the Pacific Northwest 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 rain intensity will reduce slightly on Sunday and likewise, the threat of excessive rainfall will decrease slightly. Consequently, the WPC has issued a Marginal Risk of excessive rainfall over parts of the Pacific Northwest on Sunday into Monday morning. However, the associated heavy rain will create localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain. Meanwhile, low pressure over the Great Lakes will aid in producing snow over the Great Lakes into the Northeast/Central Appalachians through Monday. Downwind from Lakes Superior, Michigan, Huron, and Erie, the snow will be very heavy, including parts of Michiganâ€s eastern Upper Peninsula and the northern third of the Lower Peninsula, northeastern Ohio, northwestern Pennsylvania, and western New York State, likewise, through Monday. In addition, some parts of the Ohio Valley will have rain with this system. Also, moisture off the Western Gulf of Mexico and upper-level energy will produce light rain over parts of the Southern Plains/Lower Mississippi Valley through late Sunday night. Furthermore, upper-level ridging over the Northwest will allow temperatures to be 15 to 30 degrees above average over parts of the Northern Rockies and Northern/Central High Plains, expanding into parts of the Southern Plains and Mississippi Valley on Monday. Ziegenfelder Graphics are available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php