Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Sun Aug 15 2021 Valid 12Z Sun Aug 15 2021 - 12Z Tue Aug 17 2021 ...Heavy rainfall and flash flooding are expected along a slow-moving frontal system in the eastern CONUS... ...Fred will reform into a tropical storm and impact portions of Florida into the Southeast with heavy rain and gusty winds... ...Another potentially record-breaking hot day for portions of the West, along with poor air quality and fire danger... Multiple weather features will continue to set up to the south of a typical summer jet stream focused along the northern U.S. and Canada. One area of concern over the next few days will be the eastern third of the U.S., with heavy rain and flash flooding expected. A frontal system is forecast to meander around the region and provide a place for above normal moisture to focus, causing possibly multiple rounds of heavy rain. Today and tonight, a Slight Risk of excessive rainfall is in place for the Southern/Central Appalachians and into portions of the southern Mid-Atlantic, where scattered flash floods are possible. The greatest flash flooding threat should move northward a bit with the front on Monday, over parts of the Ohio Valley/Central Appalachians and into the Mid-Atlantic. The area of troughing/low pressure in the eastern Gulf of Mexico that once was Tropical Storm Fred is expected to redevelop into a tropical storm later today. Fred is then expected to move northwestward and northward through the Gulf and is currently forecast to make landfall somewhere in the central Gulf Coast around Monday evening. Heavy rainfall and gusty winds can be expected along its track. Most of the rain may stay offshore of Florida today and tonight if the system takes a western track away from the Florida Gulf Coast, but by Monday into Tuesday, very heavy rain should begin over the Florida Panhandle and the Southeast. Slight Risks of excessive rainfall are in place for the scattered flash flooding threat. Another hazard early this week will be the hot temperatures, which will continue to be oppressive and possibly break daily record maximum and minimum temperatures across much of the western U.S. Excessive Heat Warnings and Heat Advisories are in place mainly in lower elevations of California and the Intermountain West as temperatures soar into the 100s. The heat is forecast to spread into the Northern Plains, with highs around 100F there as well. In addition to the heat, Air Quality Alerts are in place for the Northwest and into parts of the Rockies given smoke from fires and high ozone levels. Unfortunately, isolated dry thunderstorms and Elevated to Critical fire conditions remain a threat through at least Monday as well, which could worsen the ongoing fire situation in the West. Relief from the heat is expected in the Northwest Monday and Tuesday as a cold front pushes through and temperatures cool, but temperatures remain near 100F in the Northern Plains. Meanwhile, cooler temperatures are expected over portions of the Southwest into the Southern High Plains, along with the chance for rain and thunderstorms as monsoonal moisture continues to stream into the region. Flash floods are possible over the next couple days, and Flash Flood Watches remain in effect today over southern Arizona and New Mexico and into far western Texas. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php