Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 242 AM EST Sat Nov 14 2015 Valid 12Z Sat Nov 14 2015 - 12Z Mon Nov 16 2015 ...Heavy rain expected for portions of the Pacific Northwest... ...Heavy snow expected across the higher terrain of the West Coast states... ...Below average temperatures expected today for the eastern U.S... A plume of Pacific moisture continues to stream into the northwestern U.S. along a nearly stationary frontal boundary, bringing widespread rain -- with snow falling at the higher elevations of the Olympics and Cascades. This precipitation is expected to continue through today, with another, stronger low pressure system forecast to approach the coast by tonight ahead of an amplifying upper-level trough. The next low pressure system will move onshore early Sunday morning, bring widespread precipitation to much of the West Coast. As the low pressure system and upper-level trough move inland, snow levels will lower in the Cascades and the Sierra Range. The same will eventually hold true for much of the Intermountain West as the frontal system continues to move inland Sunday into Sunday night. This system is forecast to produce heavy additional rainfall amounts of 1 to 4 inches through early Monday across coastal areas of the Pacific Northwest. Heavy snow will be possible at the higher elevations of the Olympics and Cascades, with snowfall totals of 8 to 16 inches forecast in the northern Cascades -- and 20 to 32 inches forecast in the Olympics. Please refer to products issued by local NWS Forecast Offices for details specific to your area. Moisture will gradually return to the plains over the next couple days as southerly flow increases. Scattered showers and thunderstorms are possible today. Showers and thunderstorms are forecast to become more numerous across the southern and parts of the central plains on Sunday as an upper-level disturbance passes ahead of the amplifying upper-level trough crossing the Four Corners region. Coverage of showers and thunderstorms will continue to increase into Monday, with showers spreading into the northern plains and Upper Great Lakes. Below average temperatures are expected again today across the eastern U.S. as an upper-level trough crosses the region. Afternoon high temperatures along most of the Eastern Seaboard will be 5 to 10 degrees below average. Lingering moisture across the Northeast will result in scattered rain and snow showers for some areas this morning, which should gradually diminish during the afternoon and evening. Warmer conditions will return to much of the East on Sunday. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php