Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 357 AM EDT Tue Apr 07 2020 Valid 12Z Tue Apr 07 2020 - 12Z Thu Apr 09 2020 ...Precipitation and cooler weather continues for California into the Southwest over the next couple of days, with heavy rain causing flash flooding potential... ...Severe weather and flash flooding possible for the Ohio Valley to Mid-Atlantic Tuesday and for the Mid-South Wednesday... ...Warmth continues for much of the country through midweek but cooler temperatures return late week... An anomalously deep upper-level low will be in no rush to leave Southwest over the next few days. The resulting weather through week's end will be wet, cool and breezy. Today the upper low will continue to pump Pacific moisture into Southern California generating areas of rain and more mountain snow. There is a slight risk for excessive rainfall in portions of Southern California and Winter Storm Warnings remain in effect for the San Gabriel and San Bernadino mountain ranges. Wednesday should be more of the same in southern California with yet another round of valley/desert rain and mountain snow, but rainfall will begin to extend further east into the southern Great Basin and Lower Colorado Valley. The upper-low will begin to weak by early Thursday but scattered showers and cool temperatures will persist in the Desert Southwest. Farther east, showers and thunderstorms will be common as a pair of frontal systems traverse the eastern half of the Lower 48. Today is highlighted by a threat for severe weather in the Ohio Valley and Mid-Atlantic. These same regions will also be at risk for localized flash flooding within areas impacted by heavy thunderstorms. The severe threat will move south on Wednesday where the severe threat is forecast to take shape in the Southern Plains, Mid-South, and Mid-Atlantic. As a strong cold front sweeps through the eastern U.S. on Thursday, so will areas of thunderstorms that could become severe from the Gulf Coast to the Mid-Atlantic coast. Elsewhere, there is an Elevated to Critical fire weather threat over the Southern/Central High Plains through Tuesday, where downslope winds and low humidities will combine. A very warm temperature regime will look to last a couple more days from the front range of the Rockies to the East Coast. High temperatures will reach the 80s in parts of the Heartland and the South today. By Wednesday, portions of the Mid-Atlantic could make a run at 80 degrees. This abnormally warm stretch of weather will soon come to an end as a strong cold front travels across the eastern U.S. the second half of the week. It will be the equivalent of temperature whiplash in the Midwest as high temperatures drop from the upper 70s on Wednesday to the 50s on Thursday. The cold front is forecast to reach the East Coast by Thursday ushering cooler and breezy conditions by week's end. Mullinax Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php