Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 410 PM EDT Mon Apr 20 2020 Valid 00Z Tue Apr 21 2020 - 00Z Thu Apr 23 2020 ...Showers and strong to severe thunderstorms possible for parts of the Northeast on Tuesday ahead of a cold front... ...A developing low pressure system is forecast to bring heavy rain and strong to severe thunderstorms from the southern Plains to west of the lower Mississippi Valley on Wednesday... A strong cold front associated with a deepening low pressure system moving across southern Canada will bring a quick round of precipitation across the Great Lakes into the Northeast for the next couple of days. Showers and thunderstorms are expected tonight from the Great Lakes to the central Appalachians ahead of the cold front. By Tuesday, the dynamics of the associated upper-level trough will help trigger strong to severe thunderstorms from the northern Mid-Atlantic to the southern New England before colder and drier air ushers into the region later in the afternoon and into the evening. Behind the front, some snow or mixed precipitation is forecast to linger in the vicinity of the Great Lakes as the cold air mass from Canada overspreads the Northeast and down into much of the East Coast through Wednesday. Meanwhile, a mix of light rain and snow is expected to slide across parts of California, the central Great Basin, and the Four Corners areas through Tuesday, as a broad upper-level trough moves across. This will set the stage for another low pressure system to form and deepen over the southern Plains. Showers and thunderstorms are forecast to increase in coverage across the central to southern Plains on Tuesday ahead of the system. By Wednesday, an increasing risk of severe weather can be expected from the southern Plains eastward toward the lower Mississippi Valley by the evening. Heavy rain could also lead to flash flooding in these areas especially by Wednesday evening. Elsewhere, a clipper low pressure wave is forecast to spread mixed precipitation across the upper Midwest into the Great Lakes on Wednesday. While portions of the northern and eastern portions of the country will be colder than average, the Florida peninsula will remain very warm behind a cold front. Warmer than average temperatures are also expected for much of the West, spreading eastward into much the Plains Tuesday and Wednesday. Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php