Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 311 AM EST Fri Jan 26 2018 Valid 12Z Fri Jan 26 2018 - 12Z Sun Jan 28 2018 ...Heavy rain possible over the Northwest Coast... ...Heavy snow possible over the Cascades... ...Heavy rain possible over Central Gulf Coast... ...Snow possible over the Northern Rockies... An upper-level trough over the Northern Rockies will aid in producing snow over the region through Friday evening as the trough moves eastward to the Upper Great Lakes by Saturday evening. On Saturday, upper-level energy will move eastward from the Pacific Northwest to the Northern Rockies by Saturday evening as a surge of moisture moves inland over the Northern Rockies. The moisture and energy will aid in continuing the snow over the Northern Rockies through Saturday evening. In addition, onshore flow will aid in producing rain and higher elevation snow over the Pacific Northwest through Friday afternoon. Overnight Friday into Sunday, a plume of moisture will stream into the Northwest Coast producing rain, heavy at times over the coastal regions and snow over the Cascades through Saturday evening. As the moisture moves inland and upper-level ridge moves in over the Northwest Coast Saturday into Saturday evening the snow levels will rise over the area. Meanwhile, a front over the Northern Plains/Central High Plains into the Southwest will move eastward to the Lower Great Lakes/Ohio Valley into the Lower Mississippi Valley/Southern Plains/Western Gulf Coast by Saturday evening. Moisture from the Western Gulf of Mexico will stream northeastward into Southern/Central Plains ahead of the boundary, on Friday, that will stream into the Great Lakes by Saturday morning and into the Northeast by Saturday evening. The atmosphere will moisten on Friday as rain develops over parts of the Upper Great Lakes by Friday evening and light rain with some embedded thunderstorms develop over parts of the Southern Plains, too. Overnight Friday, rain will fill in along and ahead the front. By Saturday evening, the rain will move eastward to the Lower Great Lakes/Eastern Ohio Valley to the Central/Western Gulf Coast. The rain over the Central Gulf Coast into the Southern Ohio Valley will become heavy at times. A secondary cold front over West-Central Canada will move southeastward to the Upper Great Lakes to the Middle Missouri Valley into the Northern High Plains by Saturday evening. Light scattered snow will develop over parts of the Upper Great Lakes/Upper Mississippi Valley Saturday morning into Saturday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php