Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 125 AM EDT Sat Apr 11 2020 Valid 12Z Sat Apr 11 2020 - 12Z Mon Apr 13 2020 ...Significant cold and snowfall across the northern and central Rockies moving into the Plains... ...Threat of heavy rain and severe weather expected to expand across eastern Texas toward the Tennessee Valley through this weekend... ...More record heat across Florida... A significant surge of cold Canadian air will continue to push southward and southeastward behind a cold front. By Saturday evening, much of the northern Rockies into the northern High Plains will be enveloped in snow as temperatures plunge into the teens tonight. This could challenge record lows over western Montana Sunday morning with lower wind chills. High temperatures will also be well below normal from the Rockies into the central Plains with temperatures during the day below freezing from Billings to Denver to Valentine after a mild Saturday with highs in the 60s. Winter storm watches, warnings, and advisories are in effect for areas of Montana southeastward to Nebraska then northeastward to Minnesota/Wisconsin for later Sunday into Monday for the next part of the storm. To the south, moisture from the Gulf of Mexico will return across the southern Plains as the lingering upper low approaches from the Desert Southwest. A surface low pressure system will gradually deepen over the central/southern Plains and move eastward toward northern Arkansas by Sunday evening. Rain will develop and then expand across eastern Texas toward the lower Mississippi Valley today along with an increasing threat of strong to severe thunderstorms. Farther north, rain will also expand across the central Plains into the Midwest today as the cold front moves in from the northwest. The cold air mass will begin to interact with the upper low in the South as well as moisture streaming up from the Gulf of Mexico to result in a rapidly intensifying low pressure system over the central Plains on Sunday. Rain is expected to continue expanding across the Mississippi Valley into the Ohio Valley as the severe weather threat across much of the Mid and Deep South continues to increase. By Sunday evening, areas in the Tennessee Valley may see locally heavy rain that could lead to flash flooding and ponding on roadways. To the north, snow and increasing winds will spread into the upper Midwest as the deep low pressure system continues to intensify. To the east, a surge of mild air will result in well above normal temperatures (but with rain/storms) for much of the I-95 corridor especially Monday. Across Florida, temperatures in the 80s/low 90s may again approach record highs. Fracasso/Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php