Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 240 AM EST Fri Dec 21 2018 Valid 12Z Fri Dec 21 2018 - 12Z Sun Dec 23 2018 ...Heavy rain possible over parts of the Northeast... ...Snow for the Cascades and from the Lower Great Lakes into the Southern Appalachians... ...Temperatures will be 10 to 25 degrees above average for the Northeast... A deep elongated storm over the eastern third of the country will lift northward into Eastern Canada by Saturday evening. The system will produce rain from the Great Lakes/Northeast southward to the Central Gulf Coast/Southeast that will end over the Southeast overnight Friday. The rain will end over New England by Saturday evening. Upper-level ridging ahead of a deep upper-level trough over the eastern portion of the U.S. will aid in bringing record high temperatures to parts of the Northeast on Friday. On the northwestern side of the precipitation shield, rain will change over to snow over parts of the Upper Great Lakes into parts of the Western Ohio Valley on Friday morning. The snow over the Upper Great Lakes will end by Saturday afternoon, while rain changes over to snow over parts of the Lower Great Lakes into the Central/Southern Appalachians by Saturday morning. The snow will end over the Central/Southern Appalachians by Saturday afternoon as snow begins over Northern New England. Meanwhile, a front over the Northern High Plains into parts of the Great Basin/Central California will move eastward to the Upper Great Lakes to the Southern High Plains by Saturday evening. The storm will produce rain and snow over parts of the Northern Plains that will change over to all snow overnight Friday as the snow extends from the Northern Plains into parts of the Upper Great Lakes by Saturday evening. Snow over the Northern Intermountain Region and rain over Northern California will slowly wane on Friday. In addition, rain and snow will be on and off over parts of the Pacific Northwest through Saturday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php