Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 329 AM EDT Wed Mar 20 2019 Valid 12Z Wed Mar 20 2019 - 12Z Fri Mar 22 2019 ...Major to historic river flooding will continue across parts of the Mississippi and Missouri River Basins with areal flooding a threat across parts of the Northwest and Northern Rockies as well... ...A developing coastal storm is likely bring unsettled weather to the Mid-Atlantic and Northeast by Thursday... Despite dry weather, major to historic and catastrophic flooding will continue across parts of the Missouri and Mississippi River Basins due to rapid snowmelt as a result of heavy rainfall last week. Flood warnings and advisories remain in effect for parts of the region. Areal flooding is also a concern across parts of the Northwest and Northern Rockies/High Plains as warm temperatures this week are leading to accelerated snowmelt and the potential for ice jams. A cold front moving into California this morning and through the Southwest states by Thursday will bring increased chances for rain and mountain snows to California, the Central Great Basin, and into the Southwest/Four Corners region. Meanwhile, a couple of weak fronts moving through the Midwest will allow for mainly light rain from the Mid-Mississippi Valley to the Ohio Valley, with some light snows also possible across the Upper Great Lakes. The main sensible weather threat in the short range however will be with a developing coastal low pressure system off the Carolina coasts on Wednesday, tracking up the East coast the end of this week. Moderate to locally heavy rainfall is likely across the Mid-Atlantic states on Thursday shifting northward into the Northwest by Friday, with the potential for accumulating snowfall across portions of the interior Northeast as well. Santorelli Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php