Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 259 AM EST Sun Dec 23 2018 Valid 12Z Sun Dec 23 2018 - 12Z Tue Dec 25 2018 ...Heavy snow possible for the Cascades, Sierras, and parts of the Northern Rockies... ...Heavy rain possible for Northern California Coast... ...The day after Christmas, winter weather may produce travel problems for the Central/Southern High Plains... A front extending from the Upper Great Lakes to the Tennessee Valley then southwestward to the Western Gulf Coast will move eastward off most of the Eastern Seaboard by Monday morning, Christmas Eve. The system will produce snow over the Upper Great Lakes/Upper Mississippi Valley that will move eastward to the Lower Great Lakes/Central Appalachians overnight Sunday and into parts of the Northeast on Monday, ending by Christmas morning. Rain will develop along the front over parts of the Tennessee Valley into the Lower Mississippi Valley on Sunday morning that will move eastward and expand along the front from parts of the Central Appalachians to parts of the Tennessee Valley/Central Gulf Coast by Sunday evening. The rain will move into parts of the Mid-Atlantic overnight Sunday and off most of the Mid-Atlantic/Southeast Coast by Monday afternoon. Meanwhile, a front moving onshore over the Pacific Northwest will move inland and dissipate by Sunday evening. Onshore flow off the Pacific will develop over the Pacific Northwest through Monday afternoon. Rain and higher elevation snow will develop over the Pacific Northwest/Northern California with snow extending eastward into parts of the Northern Intermountain Region/Northern Rockies on Sunday morning. Overnight Sunday, the snow will expand into parts of the Great Basin. Winter Storm warnings a posted for the Cascades and the Olympic Peninsula through early Monday morning. The rain and snow will start to wane over the parts of the Pacific Northwest on Monday evening, Christmas Eve, and ending over parts of the region by Christmas morning. On Monday, Christmas Eve, another front will move onshore over Northern California moving inland to parts of the Southwest/Southern California by Christmas morning. The storm will bring rain to Central California by Monday afternoon and snow over the Sierras overnight Christmas Eve. Later with the storm, rain and snow will move into parts of the Southwest/Southern Rockies Christmas night. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php