Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 300 PM EST Thu Jan 17 2019 Valid 00Z Fri Jan 18 2019 - 00Z Sun Jan 20 2019 ...Periods of heavy rain along with elevated flooding concerns persist for portions of California and Oregon... ...Major winter storm to impact the western and central states Friday and into the weekend... Precipitation continues to spread across the West as a strong winter storm system tracks toward the Rockies. Blizzard warnings remain in effect for the highest elevations of the northern portions of the Sierras where snowfall amounts in excess of three feet expected. Winter Storm Warnings and Winter Weather Advisories are also in effect for the surrounding areas, as well as, Washington, the Great Basin, the Intermountain West and the Central/Southern Rockies. Coastal areas will have an increased risk for heavy rainfall and flash flooding-- especially along the stretch of coast from northern California to northwest Oregon and a small area in southern California, particularly where the burn scars exist in the Los Angeles region. Precipitation will begin to wind down overnight as the front tracks further east. The upper-level trough responsible for the ongoing storm over the western U.S. will generate a new surface low over the western High Plains by Friday morning. This system is expected to produce a vast area of heavy snow, heavy rain with pockets of freezing rain to the south-central states and much of the East Coast. Some thunderstorms will also be possible across the Gulf Coast region. Heavy snow will begin by Friday evening over the Central Plains and then progress eastward by the weekend. Additionally, snow is expected across portions of the Northern Plains and Upper Midwest as a cold front drops south. Consult the WPC winter weather products and discussion for more information on this system. In the wake of the storm, an arctic surface high will plunge southward from Canada and result in frigid temperatures across the Plains and the Upper Midwest, with temperature departures on the order of 15 to 25 degrees below normal! Campbell/Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php