Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 405 PM EDT Fri Apr 19 2019 Valid 00Z Sat Apr 20 2019 - 00Z Mon Apr 22 2019 ...Severe thunderstorms and areas of heavy to excessive rainfall will be likely across the Mid-Atlantic and Southeast through this evening... ...Locally heavy rain and some flooding concerns will exist across the Northeast on Saturday... ...New storm system moving into the West will bring some unsettled weather and cooler temperatures while the Plains see much warmer temperatures this weekend... A strong upper level low and associated trough crossing the Tennessee Valley this evening through tonight will lift northeast across portions of the central and southern Appalachians along with the upper Ohio Valley on Saturday. This will drive a cold front across much of the Mid-Atlantic states and Southeast through tonight as low pressure lifts up north up west of the Appalachians. The front will then pivot slowly up across the Northeast by late Saturday and into Sunday as the aforementioned upper low begins to slow down and meander over the Mid-Atlantic region through the weekend. In the short-term, widespread showers and thunderstorms, are expected across a large area of the East through this evening and well into the overnight hours from the Mid-Atlantic states south to the Florida Peninsula. Much of this region has already been highlighted for a threat of severe weather, including severe thunderstorms that will be capable of producing damaging wind gusts and a few tornadoes. The area of greatest concern will be across the Carolinas and northward up across central and southern Virginia where the Storm Prediction Center has placed this region in a Moderate Risk of severe weather. Already several Tornado Watches are in effect. In addition to the severe weather threat, many of these areas will see heavy to locally excessive rainfall, and as a result the Weather Prediction Center has highlighted a Slight Risk of excessive rainfall across areas of the Mid-Atlantic and Southeast. Locally several inches of rain will be possible, and thus there will be concerns for some flash flooding. On Saturday, as the front pivots up across the Northeast, the threat of heavy rain will lift northeast as well, and there will be some additional concerns for runoff problems and flash flooding. This will include areas of far northern New England in particular where there is a melting snowpack in place. On Sunday, there will still be a fair amount of unsettled weather from the Mid-Atlantic up across the Northeast with shower activity lingering, but the threat of heavy rain and severe weather will come to an end. Across the West, a cold front associated with an upper trough moving into the Pacific Northwest will drop southward into the Great Basin and the northern Rockies by Saturday. On Sunday, this front will continue to advance south across the Intermountain West while also advancing east out across the northern and central Plains. Low pressure will be developing in the lee of the Rockies on Sunday, and this will help drive plenty of warm southerly flow up across the Plains ahead of the front which will result in temperatures being well above normal. Some areas over the central and northern Plains will see high temperatures reaching well into the 80s with temperature over 20 degree above average for these locations. The Pacific Northwest and parts of the Great Basin should cool behind the aforementioned front, and there will also be an extensive area of cloudiness and some precipitation as well stretching from the Great Basin east across the central and northern Rockies and gradually out across the northern High Plains through Sunday. Precipitation amounts should be generally light to moderate, and there will be some very modest snow accumulations possible over the high terrain of the Rockies. Orrison Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php