Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 413 AM EDT Fri Apr 20 2018 Valid 12Z Fri Apr 20 2018 - 12Z Sun Apr 22 2018 ...Heavy rain possible over parts of the Lower Mississippi Valley into parts of the Southern Plains... ...Heavy snow possible over parts of the Central Rockies... A storm over the Central/Southern Rockies will slowly move to the Southern High Plains by Saturday evening. The system will produce lower elevation rain and snow over parts of the Central Rockies/Great Basin that will slowly taper off by Saturday evening. Showers and thunderstorms will develop over parts of the Southern High Plains that will move eastward to the Southern Plains by Saturday morning moving into the Lower Mississippi Valley by Sunday morning. Rain will begin to develop over parts of the Central High Plains on Friday morning that will expand into parts of the Middle Mississippi Valley by Saturday morning into Sunday. Meanwhile, a front over the Eastern Pacific will move onshore over the Pacific Northwest early on Saturday morning moving inland to the Northern High Plains/Northern Intermountain Region by Saturday evening. Overnight Friday, rain and higher elevation snow will develop over parts of the Pacific Northwest moving into parts of the Northern Intermountain Region by Saturday morning. The rain will change over to snow over parts of the Northern Rockies by Saturday evening. The rain and snow will taper off over the Pacific Northwest into the Northern Rockies overnight Saturday. Elsewhere, an upper-level low over the Northeast and Southeastern Canada will aid in producing light snow over Northern New England through Saturday morning when the upper-level low moves to the eastern tip of Canada. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php