Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 352 AM EDT Wed Oct 04 2023 Valid 12Z Wed Oct 04 2023 - 12Z Fri Oct 06 2023 ...There is a Moderate Risk of excessive rainfall over parts of the Southern Plains/Lower Mississippi Valley on Wednesday... ...There is a Slight Risk of severe thunderstorms over parts of the Southern Plains on Wednesday... ...Temperatures will be 15 to 25 degrees above average from the Great Lakes/Ohio Valley to the Northeast... A front extending from the Upper Mississippi Valley southward to the Southern High Plains will slowly move eastward to the Upper Great Lakes to the Southern Plains by Thursday. A secondary front moving southward from West-Central Canada will move southward and reinforce the lead front by Thursday evening. Tropical moisture streaming northward from the Western Gulf of Mexico will move northward over the Southern Plains/Lower Mississippi Valley, producing showers and thunderstorms with heavy rain over northeastern Texas, southeastern Oklahoma, and extreme southwestern Arkansas. Therefore, the WPC has issued a Moderate Risk of excessive rainfall over parts of the Southern Plains/Lower Mississippi Valley through Thursday morning. The associated heavy rain will create numerous areas of flash flooding. Furthermore, many streams may flood, potentially affecting larger rivers. Moreover, the boundary will create showers and severe thunderstorms over parts of Texas and Oklahoma. Therefore, the SPC has issued a Slight Risk of severe thunderstorms over parts of the Southern High Plains through Thursday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a few tornadoes. Further, the front will produce showers and thunderstorms from the Upper Great Lakes southward to the Southern Plains. Additionally, on Thursday, the threat of excessive rainfall will decrease to a Marginal Risk over the Southern Plains/Western Gulf Coast, as the severe thunderstorm threat ends with just showers and thunderstorms extending from the Great Lakes southwestward to the Southern Plains and Lower Mississippi Valley. Meanwhile, as the secondary front moves southward, mainly rain and a few scattered highest elevations snow showers will develop over parts of the Northern Rockies/Northern High Plains on late Wednesday night. On Thursday, the rain will move into parts of the Northern Plains/Mississippi Valley and the Upper Great Lakes by Thursday evening. Furthermore, the upper-level ridging extends from the Western/Central Gulf Coast to the Great Lakes/Northeast, allowing temperatures to be 15 to 25 degrees above normal over parts of the Upper Great Lakes/Ohio Valley, Lower Great Lakes, and the Northeast. Next, onshore flow off the Atlantic will aid in producing showers and thunderstorms over parts of Florida from Wednesday into Friday. Additionally, overnight Thursday, moisture from the Atlantic moves into parts of the Mid-Atlantic, producing scattered showers and thunderstorms near the coast. Ziegenfelder Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php