Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 303 PM EDT Thu Sep 18 2025 Valid 00Z Fri Sep 19 2025 - 00Z Sun Sep 21 2025 ...An upper trough across the northern/central Plains and Mississippi Valley will bring chances for severe storms and isolated flooding potential through Friday... ...Tropical moisture from Mario pushes into the Southwest, with flash flooding possible through Friday... ...The Ohio and Tennessee Valleys will see high temperatures as much as 5-10 degrees warmer than average as afternoon highs reach the 90s... The upper-level low that has stalled over the Central U.S. the past few days will gradually start to disassemble and move a bit eastward towards Eastern U.S. Although, threats of heavy rainfall and flash flooding will slowly diminish, remnants of the mid-level moisture and passing cold front will continue to bring chances for showers and thunderstorms over central/lower Mississippi Valley and parts of the Southern Plains. In addition to showers and thunderstorms, there is a chance for gusty/damaging winds and hail. Therefore, combining some of these favorable convective conditions with the sufficient unstable boundary layer, Storm Prediction Center has issued a Slight Risk (level 2/5) for Severe Thunderstorms over portions of Missouri to southern Plains. Although mid-level moisture will gradually diminish, there is still a Marginal Risk (level 1/4) for Excessive Rainfall and isolated flash flooding. Remnants of Mario continues to impact California, Southwest, and parts of the Southern Rockies through Friday. Due to rainfall totals possibly reaching 2-4" with rainfall rates at >1-2"hr, Weather Prediction Center has places parts of California (mostly central and southern California) under a Slight Risk (level 2/4) for Excessive Rainfall and localized flash flooding. In addition, several parts of the Southwest has been under a Flood Watch through Friday; follow your local weather forecast office for specific information. With sufficient tropical moisture and favorable unstable environment, Storm Prediction Center has placed a Marginal Risk (level 1/5) for Severe Thunderstorm over parts of the Southwest and southern California. The mid-level tropical moisture over southern Florida is slowly diminishing as we head into the weekend but still expect chances for some scattered showers and thunderstorms from the remaining moisture through Friday. With the chance for some occasional heavy downpours and rain rates between 2-3"/hr, Weather Prediction Center continues to have a Marginal Risk for Southeast Florida through Friday, with a chance for isolated flash flooding over flood prone urban areas. Below normal temperatures over the northern/central Plains, parts of the upper Mississippi Valley, the Southwest, and California will gradually become close to normal by Saturday as a zonal pattern start to set in. As the upper level ridge start to build over the Great Lakes, Ohio and Tennessee Valleys, temperatures will start to gradually climb into the upper 90s and low to mid 90s, which will be between 5-10 degrees above normal. Oudit Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php