Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 405 PM EDT Mon Mar 26 2018 Valid 00Z Tue Mar 27 2018 - 00Z Thu Mar 29 2018 ...Multi-day heavy rain and severe weather event for the southern Plains into the Mississippi Valley... ...Snow expected for the Cascades into the northern Rockies in addition to the southern Rockies... A very impressive upper trough will push across the West slowly over the next few days as deep southerly flow feeds copious amounts of moisture over the southern Plains and Mississippi Valley. At the surface, a dryline will drift eastward across Texas and southern Oklahoma today. Along this boundary, thunderstorms will form and move across central and north Texas. Some of these thunderstorms could be severe--thus, the Storm Prediction Center has issued an enhanced risk of severe weather through Monday night. Meanwhile, a cold front will push south across the middle and lower Mississippi Valley along with the southern Plains. The deep moisture from the Gulf of Mexico along with the frontal boundary acting as a focal point will fire off a line of thunderstorms along and ahead of the front on Tuesday morning in the middle Mississippi Valley into the southern Plains. This line will move south with the boundary through the day into the lower Mississippi Valley into northeast Texas. By Wednesday, this line will continue its southerly trek while rainfall rates increase as more moisture pools near the frontal boundary. A slight risk of severe thunderstorms will be possible on Tuesday and Wednesday throughout central to south/southeast Texas in addition to portions of the lower Mississippi Valley. A slight risk of excessive rainfall is possible for today for parts of the middle/lower Mississippi Valley into the southern Plains. This risk will increase to a moderate risk for Tuesday and Wednesday for parts of the lower Mississippi Valley, Southeast, and southern Plains. A steady stream of moisture will deliver precipitation across the Pacific Northwest this afternoon through Tuesday night. Rain and higher elevation snow is expected--with the snow concentrating along the Cascades and parts of the northern Rockies. The transport of moisture will weaken by Wednesday morning--however lingering precipitation will be possible for the Pacific Northwest and northern Rockies. Farther south, as the upper level trough intensifies across the Four Corners, moisture combined with lift along the terrain will yield snowfall across the central and southern Rockies--mostly in southern Colorado and New Mexico. Snow will begin in the central Rockies by early Tuesday morning and continue to move southward during the day. By Tuesday evening, most of the snow will occur in the southern Rockies. By Wednesday morning, snow will taper off. Reinhart Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php