Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 419 PM EDT Tue Apr 07 2020 Valid 00Z Wed Apr 08 2020 - 00Z Fri Apr 10 2020 ...Unsettled weather spreads across the Southwest over the next couple of days as heavy rain causes flash flooding potential over southern California... ...Severe weather and flash flooding possible for the Ohio Valley into parts of the Mid-Atlantic before a strong cold front clears the region on Thursday... ...Significant snow possible for interior northern New England on Thursday... An anomalously deep upper-level low will be slow to move through the Desert Southwest over the next few days. A cold front ahead of the deep upper low will be nearly stationary across southern California through Wednesday morning. Pacific moisture streaming into southern California will bring the threat of excessive rainfall into the region, which could lead to flash flooding in the interior desert. For the higher elevations, more than of foot of snow can be expected especially along the southern Sierra Nevada. By later on Wednesday, the precipitation should edge farther east into Arizona and Utah. By Thursday, the upper-low is forecast to weaken as the precipitation begins to become more widely scattered and taper off across the entire Southwest. Farther east, showers and thunderstorms will be common as a pair of frontal systems traverse the eastern half of the country. The threat for severe weather and heavy rain in the Ohio Valley into the Mid-Atlantic should gradually ease this evening. However, another frontal wave will once again raise the severe weather threat farther south into the Tennessee Valley on Wednesday before a strong cold front arrives from the west Wednesday night. This strong front is forecast to sweep through the eastern U.S. on Thursday with strong thunderstorms possible across the Mid-Atlantic states in the morning hours. As the strong cold front moves rapidly off the East Coast on Thursday, a low pressure system is forecast to intensify rapidly near the New England coast. This will lead to strengthening winds across New England with accumulating snow likely to develop across the interior sections. In addition, some lake-effect snow will likely develop on Thursday downwind from the lower Great Lakes on the back side of the low pressure system. Meanwhile, a large cold air mass ushering across much of the eastern two-thirds of the country behind the strong cold front will bring much colder temperatures across the Plains even down into the Deep South later on Thursday. Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php