Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 325 PM EDT Thu Aug 15 2024 Valid 00Z Fri Aug 16 2024 - 00Z Sun Aug 18 2024 ...Flash flooding and severe weather threat will stretch from the Great Lakes through the Ohio and Tennessee Valleys to the Central/Southern Plains over the next couple of days... ...Dangerous heat anticipated across the Southern Plains and Lower Mississippi Valley... The slow-moving frontal system traversing the central United States today will continue to push towards the East over the next couple of days. Showers and thunderstorms are forecast to spread from the Great Lakes through the Ohio and Tennessee Valleys to the Central and Southern Plains. Ample moisture and instability in the warm sector will support isolated to scattered severe thunderstorms, and the Storm Prediction Center has issued a broad Marginal Risk (level 1/5) of severe thunderstorms for this area on Friday and Saturday with an embedded Slight Risk (level 2/5) area over a portions of the Central Plains on Friday. The main storm hazard will be damaging winds, but large hail will also be possible in severe storms in the Central Plains. In addition to severe thunderstorm hazards, heavy rain may lead to localized instances of flash flooding, especially in areas with repeat/training storms. Precipitation will spread towards the East Coast and into the Southeast over the weekend as the system progresses. Heat will remain the main weather story for much of the south-central U.S. through at least this weekend. High temperatures near or above 100 degrees will be common throughout the Southern Plains and Lower Mississippi Valley. High temperatures and humidity will combine to produce dangerous heat indices that could reach up to 112 degrees. Overnight lows won't provide much relief from the heat, lows are forecast to only drop to the mid-to-upper 70s, which could break several daily records for warm lows. This level of heat can affect anyone without effective cooling and/or adequate hydration, so it will be imperative to follow proper heat safety and check on vulnerable individuals. Elsewhere, some showers and storms will continue over New England as an upper-level low churns over Nova Scotia. To the south, portions of Central and South Florida will see scattered storm chances over the next couple of days as a cold front slowly pushes through and stalls near the Florida Keys. In the West, some thunderstorms will be possible with a shortwave passing over portions of the northern Great Basin and Northern Rockies. Monsoonal moisture and storm chances are set to return to the Southwest and central Great Basin by Saturday, where isolated flash flooding is the greatest concern. Forecast high temperatures are expected to generally be around average along the East Coast, slightly below average in the Great Lakes/Upper Midwest, above average in the northern/central Plains, and below average in the Northwest. Dolan/Snell Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php