Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 304 PM EDT Sun Aug 15 2021 Valid 00Z Mon Aug 16 2021 - 00Z Wed Aug 18 2021 ...Heavy rainfall and flash flooding are possible along a slow-moving frontal system between the eastern Ohio/Tennessee valleys and the Mid-Atlantic... ...Tropical Storm Fred forecast to make landfall over the western Florida Panhandle on Monday and bring the threat of heavy rain, gusty winds, and dangerous storm surge... ...More potentially record-breaking heat found across portions of the West and Northern Plains, 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 the main concern. A frontal system is forecast to meander around the region and provide a place for above normal moisture to focus, causing multiple rounds of scattered downpours. Through 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 expand northward a bit with the front on Monday and linger through the day on Tuesday over parts of the Ohio Valley/Central Appalachians and into the Mid-Atlantic. Moisture associated with Tropical Storm Fred may feed into this region by Tuesday as well. Tropical Storm Fred has redeveloped in the eastern Gulf of Mexico this afternoon and is expected to continue moving northward before making landfall somewhere in the western Florida Panhandle on Monday evening. Heavy rainfall and gusty winds can be expected along its track, as well as potentially dangerous storm surge for coastal regions near and to the east of landfall. Most of the rain may stay offshore of Florida tonight, but by Monday and early Tuesday, very heavy rain should impact parts the Florida Panhandle and later shift into the Southeast. Flash Flood Watches have been issued. As Fred weakens and pushes inland early this week, additional bands of heavy rain may extend as far north as the Southern Appalachians and East Tennessee. Another hazard to contend with through Tuesday will be excessively hot temperatures, which could break several daily maximum and minimum temperature records across much of the western U.S. and Northern Plains. 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. Dangerous heat is also expected throughout the Northern Plains, with highs well above average for this time of year and around 100F. In addition to the heat, Air Quality Alerts are in place for the Northwest and into parts of the Northern 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 on 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, with Flash Flood Watches remaining in effect today over southern Arizona and New Mexico, as well as into far western Texas. Snell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php