Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 259 AM EST Thu Nov 29 2018 Valid 12Z Thu Nov 29 2018 - 12Z Sat Dec 01 2018 ...Heavy precipitation is expected near northern California over the next few days with significant snowfall in the Sierra-Nevada into Friday morning... ...Active weather to impact the Plains and Mississippi Valley... A wet, active pattern is expected to continue through the weekend for the West, particularly in California. A frontal boundary approaching the West Coast is currently bringing heavy rainfall, with embedded thunderstorms, across California with heavy snow in the higher elevations. This will continue throughout the day today with lighter precipitation across the Pacific Northwest and Great Basin. As the frontal boundary, and upper level low, moves farther inland, precipitation will increase across the Great Basin/central Rockies while still maintaining across central and southern California. By Friday evening, California will begin to dry out with lighter showers and higher elevation snow in the Great Basin/central Rockies. However, another frontal boundary will approach the Pacific Northwest at this time--bringing more precipitation to the region in addition to northern California. Winter storm warnings will continue for the Sierra-Nevada through Friday morning, with total snow accumulations of over two feet expected above 7,000 feet. Wind gusts as high as 50 mph will also be a concern. Winter weather advisories are also in effect across the central Rockies and mountains across Utah and Arizona through Friday. Because of the recent burn scars and expected heavy rainfall over several days, flash flooding is a concern for parts of California. As such, flash flood watches are in effect in portions across the state. See WPC's excessive rainfall discussion for more information. A quasi-stationary front will drape across the Ohio Valley southward into the lower Mississippi Valley through Friday. This will become a focal point for showers and thunderstorms through the end of the week. By Friday evening and into Saturday, this front will lift northward as a warm front as it merges with an incoming occluded system from the Plains. Deep southerly flow ahead of the cold front will bring copious amounts of moisture from the Gulf of Mexico along with instability. This will bring widespread showers and thunderstorms in portions of the southern Plains and lower Mississippi Valley on Friday and Saturday. There is an enhanced risk of severe thunderstorms for Friday in this region along with a risk of localized flash flooding for the lower and middle Mississippi Valley. Farther north, snow is expected to develop across the northern Plains along with north-central Nebraska on Friday night. By Saturday, heavy snow will impact the South Dakota/Nebraska border through the Upper Midwest. See WPC's winter weather products for more details on this winter storm. Above average temperatures will be felt across the Plains and Southeast today--spreading eastward through the weekend. Much of the western U.S. will be below average due to the active pattern. By Saturday, the northern and central Plains will be 15 degrees below average with high temperatures in the mid 30s. Reinhart Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php