Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 318 PM EST Wed Jan 18 2017 Valid 00Z Thu Jan 19 2017 - 00Z Sat Jan 21 2017 ...Heavy snow possible over the Sierras... ...Heavy rain possible over most of the West Coast... ...Heavy rain possible over the Lower Mississippi Valley into the Tennessee Valley... ...Snow possible over parts of Northern New England... Low pressure developing over Eastern Texas/Lower Mississippi Valley will lift northward to the Western Ohio Valley by Friday. The system will produce showers and thunderstorms over parts of the Western Gulf Coast and the Lower Mississippi Valley that will move eastward to parts of the Southeast by Thursday evening into Friday. During the day on Thursday, the showers and thunderstorms will extend as far north as the Western Ohio Valley through late Thursday night. Rain will develop along the boundary over parts of the Middle Mississippi Valley by Thursday morning that will move into parts of the Upper Mississippi Valley, Great Lakes, and Ohio Valley by Friday morning. In addition, upper-level energy will move over Northern New England overnight Wednesday produce rain and higher elevation snow over parts of the Northeast through Thursday evening. Meanwhile, a deep upper-level trough just off the West Coast will move inland to the Rockies by Friday. A plume of moisture will stream into parts of Central/Northern California that will move southward to Southern California by Thursday afternoon. Onshore flow will continue to move into California Thursday into Friday. The storm will produce rain and higher elevation snow over California into the Pacific Northwest as well as parts of the Great Basin and the Northern Rockies. Rain and snow will move into parts of the Great Basin/Southwest on Thursday moving eastward to the Rockies overnight Thursday into Friday. As the upper-level trough moves inland, snow levels will drop down to 5,000 ft over the Southwestern California mountains. Some of the snow and rain will be heavy at times over the West Coast. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php