Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 238 AM EST Wed Mar 06 2019 Valid 12Z Wed Mar 06 2019 - 12Z Fri Mar 08 2019 ...Heavy snow for the Sierra Nevada and to a lesser degree over the other mountain ranges of the West... ...Heavy lake effect snow downwind from Lake Ontario... ...Temperatures will continue to moderate over the eastern two thirds of the country east of the Rockies with temperatures 10 to 25 degrees below average... An upper-level low off the Northwest Coast will have multiple impulses of energy rotate around the low moving across California while traveling to the Great Lakes and the Middle Mississippi Valley by Friday. The first impulse will be accompanied by a plume of moisture streaming into Southern California that will produce that will produce rain and higher elevation snow over California extending into parts of the Pacific Northwest and the Great Basin. Snow will extend into the interior parts of the Northwest and into part of the Northern/Central Rockies. The moisture will begin to wane over California overnight Wednesday and continue to wane into Friday. Likewise overnight Wednesday, the rain and snow will begin to taper off over California into the Great Basin while the rain and snow continue over the western third of the country through Friday. Meanwhile, as the first impulse moves into the Rockies, moisture from the Gulf of Mexico will move northward over the Southern Plains moving into the Middle Mississippi and Tennessee Valleys and the Ohio Valley by Friday. As the energy moves onto the Plains, snow will develop over parts of the Northern/Central Plains overnight Wednesday expanding into the Middle Mississippi Valley/Western Ohio Valley on Thursday continuing into the Ohio Valley and the Central Appalachians by Friday. On Thursday, rain will develop over parts of the Western Gulf Coast and expanding into the Lower Mississippi Valley as showers and thunderstorms develop by Thursday evening. The showers and thunderstorms will move into parts of the Tennessee Valley as rain develops over parts of the Southern Appalachians by Friday. Below average temperatures will persist over the CONUS east of the Rockies while continuing to moderate during the period. While the cold air is moderating, Freeze Warnings are in effect across the Lower Mississippi Valley to the Southeast on Wednesday morning as the cold low temperatures could harm vegetation. Elsewhere, lake effect snow will develop downwind from the ice free areas of the Great Lakes into parts of the Northeast, with higher totals downwind from Lake Ontario. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php