Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 304 AM EDT Thu Apr 05 2018 Valid 12Z Thu Apr 05 2018 - 12Z Sat Apr 07 2018 ...Stormy weather expected throughout the Pacific Northwest and northern Rockies with potential for flash flooding in northern California... ...Heavy rain and severe weather possible in the lower Mississippi Valley... ...Springtime snow to be delivered from the Plains to the Mid-Atlantic... As things wind down across the East Coast, the West Coast will begins very active weather period. Light showers and higher elevation snow will be present across the Pacific Northwest and northern Rockies through this morning. By Thursday evening, an influx of moisture will bring showers and higher elevation snow as a frontal system approaches the coast--from British Columbia to northern California. This swath of precipitation is expected to endure into early Friday morning as the frontal system slowly moves toward the coast--however most of the precipitation across the Pacific Northwest will wind down. Another frontal system will approach the California coast on Friday--bringing heavy rainfall across central and northern California and will continue into Saturday. Moderate rainfall and higher elevation snow can also be expected across the Pacific Northwest. Flooding is a concern from Friday through Sunday. Thus, flood watches for this system are in place along the inland portions of the central and northern California regions. On Friday, upper level energy will eject from the Rockies and move across the central Plains and into the Mississippi Valley by Friday evening. With cold air in place, precipitation in the form of snow will sweep across parts of the northern and central Plains early Friday morning. By Friday evening, deep southerly flow will bring an abundant amount of moisture across the southern Plains into the Mississippi Valley. Meanwhile, a cold front will move south across the Tennessee Valley to the southern Plains. This front will act as a focal point for showers and thunderstorms across the lower Mississippi Valley. Heavy rainfall is expected with this cluster of thunderstorms in addition to severe weather. In addition to these hazards, the band of snow that impacted the Plains will move across the midsection of Missouri and continue across the Tennessee and Ohio Valleys. This cold front will stretch from the Mid-Atlantic to South Texas on Saturday morning. Showers and thunderstorms will be expected from the southern portions of the Mid-Atlantic to Southeast Texas. As cold air behind the front filters into the Mid-Atlantic, Ohio and Tennessee Valleys, rain will change over to snow. Elsewhere, lingering lake effect snow showers will be possible today.The surface low associated with the aforementioned cold front will lift into the Upper Great Lakes on Friday night. An increase in snow coverage is expected through the afternoon--but will decrease by Friday evening. As this cold front glides over the central and eastern portions of the U.S., much colder air will follow. High temperatures in the northern and central Plains along with the Upper Mississippi Valley will nearly 30 degrees below normal on Friday. This colder air will flow into areas from New England to the southern Plains by Saturday--with high temperatures ranging from 10 to 20 degrees below normal. Reinhart Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php