Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 352 AM EDT Thu Sep 02 2021 Valid 12Z Thu Sep 02 2021 - 12Z Sat Sep 04 2021 ...Post-Tropical Cyclone IDA is forecast to move northeastward into Canada... ...There is a Slight Risk of excessive rainfall over parts of the Upper Midwest into the Central Plains through Friday morning... ...There is a Slight Risk of severe thunderstorms over parts of Central Plains through Friday morning... Post-Tropical Cyclone IDA is forecast to be over New England on Thursday morning. The system has become extratropical on the Phase diagram and the flooding threat will slowly end. What was IDA will move off the Northeast Coast, also on Thursday morning, moving into the Canadian Maritime Provinces by Thursday evening. Meanwhile, a front extending from the Northern Plains westward to the Great Basin will move eastward into the Upper Mississippi Valley and dissipate by Friday morning. Moisture pooling along the front and upper-level energy will produce showers and thunderstorms over the Upper Midwest into the Southern High Plains. Therefore, the WPC has issued a Slight Risk of excessive rainfall with these thunderstorms. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, and small streams the most vulnerable through Friday morning. Furthermore, the SPC has issued a Slight Risk of severe thunderstorms over parts of the Central Plains through Friday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a few tornadoes. The excessive rainfall threat will continue on Friday into Saturday morning over parts of the Middle Mississippi Valley/Central Plains with a smaller area over parts of the Northern High Plains. Conversely, the severe thunderstorms threat will decrease slightly on Friday into Saturday. Elsewhere, moisture and upper-level energy will produce showers and thunderstorms over parts of the Southern Rockies and Southern High Plains during the late afternoon into the late evening on Thursday and Friday. The fire weather threat has subsided over the Western part of the country. However, Air Quality Alerts have also been published over parts of the Pacific Northwest and California and parts of Wyoming and Montana due to wildfire smoke. There are also Heat Advisories out for parts of the Southern Plains and the Lower Mississippi Valley. Ziegenfelder