Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 319 PM EDT Mon Aug 16 2021 Valid 00Z Tue Aug 17 2021 - 00Z Thu Aug 19 2021 ...Tropical Storm Fred to bring heavy rain, gusty winds, and dangerous storm surge to portions of the Florida Panhandle this evening... ...Heavy rainfall and flash flooding are expected along a slow-moving frontal system over the eastern Ohio Valley, Appalachians, and the Mid-Atlantic this evening before moisture associated with Fred enters the region on Tuesday... ...Oppressive heat, poor air quality, and fire weather concerns continue for parts of the West and Northern Plains ahead of a potent cold front set to swing across the Northwest and Northern Rockies on Tuesday... Tropical Storm Fred is forecast to continue tracking northward and push inland across the western/central Florida Panhandle tonight and eventually into the Southeast. 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 the center of Fred. Flash flooding is a threat with the heavy rain, with a Moderate Risk of excessive rainfall in effect for portions of the Florida Panhandle and southeastern Alabama/southwestern Georgia tonight and a Slight Risk stretching farther inland. Flash Flood Watches have also been issued. Trailing bands of rain could affect the Florida Big Bend again on Tuesday and cause flash flooding issues, even after Fred's center has moved north. Tropical Storm Fred is currently forecast to weaken into a tropical depression by Tuesday morning and dissipate by Wednesday morning over the eastern Ohio Valley. As tropical moisture from Fred streams northward, it will feed into a frontal system lifting slowly northward across the Ohio Valley and Mid-Atlantic. While much of the eastern third of the U.S. should see rain and thunderstorms through midweek, the front will provide an additional place for the moisture to focus, enhancing rainfall totals and the possibility of flash flooding. A Slight Risk of excessive rainfall is in place through tonight from eastern portions of the Ohio Valley through the Central Appalachians and portions of the Mid-Atlantic, where scattered flash floods are possible. Then on Tuesday, as Fred moves farther inland along with its associated moisture plume, a large Slight Risk of excessive rainfall stretches from the Southeast to New York State. In addition, a small Moderate Risk area is delineated for parts of the Southern Appalachians Tuesday into Tuesday night, as several inches of rain could occur in mountainous areas that are particularly sensitive to heavy rainfall. Another day of heavy rain is possible on Wednesday from the Mid-Atlantic to the Southern Appalachians as the tropical airmass in place refuses to exit. Another day of hotter than normal temperatures is forecast for much of the West into the Northern Plains today. Highs topping 100F across much of California, the Central Great Basin, and into the Northern High Plains have led to the issuance of Excessive Heat Warnings and Heat Advisories for portions of these areas, and some daily records have the potential to be set once again. The heat will not be the only threat for these areas, as Elevated to Critical Risks of fire weather are in place today and Tuesday, along with the potential for additional fire ignitions from dry thunderstorms. Air quality is already an issue over much of the Northwest given smoke from fires and high ozone levels. However, cooler temperatures creeping into the Pacific Northwest tonight is a sign of what is to come on Tuesday and Wednesday--a potent cold front pushed by an upper-level low that will bring cooler and refreshing air to the Northwest, as well as increasing rain chances especially for the Northern Rockies on Tuesday. Meanwhile farther south, 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. A few strong to severe thunderstorms are also possible. Meanwhile, above average temperatures with highs into the upper-90s and low triple digits are expected to remain across the Northern Plains and Upper Midwest through at least Wednesday. Snell/Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php