Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 341 AM EDT Wed Apr 12 2017 Valid 12Z Wed Apr 12 2017 - 12Z Fri Apr 14 2017 ...Heavy snow possible over parts of the Cascades and Sierras... ...Heavy rain possible over parts of the Pacific Northwest... ...Severe thunderstorms and heavy rain possible today near the Southern Rockies in New Mexico and Texas... An upper-level trough is forecast to remain over much of the West Coast through the end of the week, which will allow a surface front to slowly track through the Pacific Northwest, northern Great Basin and Intermountain West. Widespread rain, with periods of higher intensity, is forecast for much of coastal California northward to the Washington to the Northern Rockies; with snow for the higher terrain across that region. Heavy snow will likely occur in the northern Cascades and the Sierras over the next few days. Rain and mountain snow will spread into the Northern High Plains as the cold front crosses the Rockies by Thursday afternoon. Showers and thunderstorms will span from the southern Rockies to the Upper Midwest/Great Lakes region as a surface front slowly moves south and east through the central U.S. Some of the thunderstorms today across portions of New Mexico and western Texas may turn severe in addition to producing periods of heavy rain. The Storm Prediction Center has identified the western portions of the Southern Plains as having a slight risk for severe thunderstorm development. Refer to the SPC convective outlooks for additional information on severe weather. Embedded areas of higher rainfall will continue into Thursday across the Southern Plains and for the Midwest/Upper Midwest on Friday. Flash flooding may be possible for these areas. Showers and thunderstorms will accompany of the cold front as it pushes through the eastern states today and into Thursday. Precipitation will taper off once the front pushes offshore by Thursday midday. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php