Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 249 AM EST Sat Dec 21 2019 Valid 12Z Sat Dec 21 2019 - 12Z Mon Dec 23 2019 ...Heavy rain for parts of Northern California... ...Heavy rain to develop over parts of the Central/Eastern Gulf Coast and Southeast... ...Temperatures will be 15 to 25 degrees above average over the Northern High Plains/Rockies eastward into the Upper/Middle Mississippi Valley and the Central Plains... Front moving inland over the Pacific Northwest advances to parts of the Northern High Plains/Great Basin by Monday morning, Christmas Eve. Associated moisture plume slowly moves southward along the West Coast until the plume gets to Southern California by late Sunday night. The system will produce rain over parts of the Pacific Northwest Coast and snow at the highest elevations of the Cascades on Saturday. On Sunday as the plume of moisture is centered more on Central California, rain and highest elevation snow will develop over parts of California and the Sierra Nevada Mountains. In addition by Sunday evening, weak onshore flow will aid in a return of rain and highest elevation snow to the Pacific Northwest into Monday morning. Meanwhile, an upper-level low over the Southern Plains will move southeastward to the Eastern Gulf Coast by Monday while intensifying. Circulation around the upper low will aid in pulling moisture off the Gulf of Mexico northward into the Tennessee Valley on Saturday and off the Atlantic on Sunday. The storm will produce rain over parts of the Central Gulf Coast while upper-level energy will aid in producing rain over parts of the Western Gulf Coast that will slowly recede into the Gulf of Mexico overnight Saturday. Also overnight Saturday, rain will develop over parts of the Central/Eastern Gulf Coast. On Sunday the rain will move into the Southeast and continue over the area through Monday morning. In the meantime, upper level ridging extending northeastward from the Southwest into the Central Plains will aid in allowing temperatures to be 15 to 25 degrees above average over the Northern High Plains/Rockies eastward into the Upper/Middle Mississippi Valley and the Central Plains by Saturday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php