Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Thu Sep 03 2020 Valid 12Z Thu Sep 03 2020 - 12Z Sat Sep 05 2020 ...Scattered severe thunderstorms are expected across parts of the Mid-Atlantic today.. ...Heavy rainfall and localized flash flooding will be possible across portions of the southern Plains, and also the central Appalachians and Mid-Atlantic... ...Record-setting heat and dry weather are expected to envelope much of the West going into the weekend... An upper-level disturbance advancing northeast across the Ohio Valley this morning will cross the central Appalachians and the Mid-Atlantic today and bring a threat of heavy showers and thunderstorms capable of producing localized flash flooding and severe weather. Much of the focus will be along and just south of a very slow-moving frontal boundary where a substantial amount of moisture and instability is expected to be in place. The Storm Prediction Center has indicated that there is an Enhanced Risk of severe weather across the central Mid-Atlantic in particular where there is expected to be concerns for damaging winds and a few tornadoes this afternoon. Meanwhile, this same front causing the concerns for heavy rainfall and severe weather in the Mid-Atlantic will be draped well back down to the southwest and weakening over areas of the lower Mississippi Valley and the southern Plains. The remnant boundary should be a focus for areas of showers and thunderstorms, and especially over areas of central and eastern Texas where a separate upper-level disturbance will be interacting with it. Locally several inches of rain will be possible from slow-moving showers and thunderstorms with very heavy rainfall rates that may exceed 2 inches per hour. This is expected to drive some concerns for flash flooding as a result. On Friday, a new cold front will be arriving from the Midwest and Great Lakes region which is expected to bring cooler, and much drier weather for much of the Eastern U.S. going into the weekend with temperatures trending down to either normal or modestly below normal for this time of the year. This boundary will settle down across the Gulf Coast states and will still be the focus for some showers and thunderstorms going into the weekend, but areas to the north will have a chance to dry out. A strong ridge of high pressure meanwhile will be developing over much of the Western U.S. for the end of the week and going into the weekend. This will set the stage for not only very dry weather, but also very hot temperatures including a likelihood of seeing record high temperatures. In some cases, the high temperatures are forecast to be as much as 20 to 25 degrees above normal, and this will foster many areas of areas of the Great Basin and especially the Desert Southwest seeing temperatures well over 100 degrees. Orrison Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php