Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 352 AM EDT Fri Aug 27 2021 Valid 12Z Fri Aug 27 2021 - 12Z Sun Aug 29 2021 ...There is a Slight Risk of severe thunderstorms over parts of the Northern High Plains/Northern Plains and over the Upper/Middle Mississippi Valley through Saturday morning... ...There is a Slight Risk of excessive rainfall over parts of the Upper/Middle Mississippi Valley/Upper Great Lakes and parts of the northern Mid-Atlantic through Saturday morning... ... Uncomfortable and potentially dangerous heat throughout much of the Southwest... ... Tropical Storm IDA is forecast to intensify moving toward the Central Gulf Coast, having amongst other hazards, there will be a Moderate Risk of excessive rainfall on Sunday... A front extending from the Northeast westward to the Northern High Plains will be quasi-stationary through Saturday. A wave of low pressure over the Northern High Plains moves to the Upper Mississippi Valley by Saturday evening and into South-Central Canada by Sunday morning. Showers and thunderstorms will develop along and near the boundary from the Northern High Plains to the Great Lakes. The SPC has issued two Slight Risk areas of severe thunderstorms along the front over parts of the Northern High Plains/Northern Plains and over the Upper/Middle Mississippi Valley through Saturday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a few tornadoes. The severe thunderstorm threat continues over the Upper Midwest on Saturday into Sunday morning. Furthermore, the WPC has issued a Slight Risk of excessive rainfall along the front, over parts of the Upper/Middle Mississippi Valley/Upper Great Lakes. Heavy rain associated with the thunderstorms will create mainly localized areas of flash flooding, with urban areas, roads, and small streams the most vulnerable through Saturday morning. The excessive rainfall threat decreases slightly on Saturday into Sunday. Farther east along the front over the Northeast/northern Mid-Atlantic, another region of showers and thunderstorms will develop as moisture pools along the boundary. The showers and thunderstorms will produce areas of heavy rain. 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 Saturday morning. The excessive rainfall threat decreases slightly over this area on Saturday into Sunday, too. Elsewhere, upper-level impulses and diurnal heating will produce showers and thunderstorms over parts of the Southwest into the Southern High Plains from the late afternoon into the late evening on Friday and Saturday. Meanwhile, tropical moisture and upper-level impulses will produce showers and thunderstorms along the Gulf Coast into the Southeast on Friday and Saturday. Additionally, heat will also produce hazards. Heat Advisories are posted over parts of New England and parts of the Middle Mississippi and Western Ohio Valleys, where high temperatures are forecast in the mid-to-upper 90s. Moreover, many areas from parts of the Northeast/Mid-Atlantic to the Midwest will have the possibility of record high minimum temperatures on Friday and Saturday morning. In the Southwest, highs in the 110s are expected on Friday, and an Excessive Heat Warning remains in effect for the area through Friday evening. The high temperatures will cool a little on Saturday but generally be in the upper 100s to lower 110s. Tropical Storm IDA, currently forecast to move northwestward across the Gulf of Mexico, heading toward the Central Gulf Coast by Sunday. Check with the NHCâ€s latest bulletin for the most up-to-date track and intensity of IDA. IDA will produce heavy rain over parts of the Central Gulf Coast on Sunday. Therefore, the WPC has issued a Moderate Risk of excessive rainfall for the heavy rain over the region lasting into Monday morning. The heavy rain will create numerous areas of flash flooding. Furthermore, many streams may flood, potentially affecting larger rivers from through Monday morning. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php