Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 432 PM EDT Mon Oct 03 2016 Valid 00Z Tue Oct 04 2016 - 00Z Thu Oct 06 2016 ...There is a slight risk of severe thunderstorms over parts of the Northern/Central Plains and High Plains... ...Heavy rain possible over parts of the Upper/Middle Mississippi Valley... ...Heavy rain possible over parts of the Cascades... ...Temperatures will become 10 to 15 degrees below average over most of the Western third of the U. S.... A deep upper-level low over the Northern/Central Rockies will move northeastward and deepen over the Northern Plains by Wednesday. The system will produce showers and thunderstorms from parts of the Northern High Plains into the Northern/Central Plains southward into the Southern High Plains that will move into the Mississippi Valley by Wednesday. Rain will also develop over parts Northern/Central Rockies and into parts of the Great Basin continuing into Wednesday. The rain will also move into the Northern High Plains early Tuesday morning into Wednesday. In addition, heavy snow will develop over some of the highest elevations of the Northern and Central Rockies also through Wednesday. Meanwhile, another upper-level low just off the West Coast of Canada will move southeastward to the Pacific Northwest reinforcing the deep upper-level trough over the West Coast. Onshore flow will develop over the Northwest starting Monday night. Rain will develop along the Pacific Northwest Coast and Northern California Coast on Monday evening that will move inland to parts of the Northern Intermountain Region by Tuesday afternoon. The rain will continue from the Northwest Coast to parts of the Northern/Central Rockies into Wednesday. Furthermore, a weakening upper-level low over the Northeast will move off the coast by Wednesday morning. The system will produce light rain over parts of the Northeast, ending by Tuesday evening. Additionally, onshore flow off the Atlantic will aid in producing showers and thunderstorms along parts of the Southeast Coast that will expand northward along the coast to the Southern Mid-Atlantic Coast by Wednesday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php