Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Mon Aug 26 2024 Valid 12Z Mon Aug 26 2024 - 12Z Wed Aug 28 2024 ...A couple of days of intense heat and humidity expected to impact the Midwest... ...Severe storms and isolated flash flooding possible across the Northern Plains/Upper Midwest today and the Great Lakes on Tuesday... ...Daily monsoonal thunderstorms shifting eastward into the southern Rockies/High Plains... A couple of days of intense heat and humidity are expected to impact the Midwest as deep southerly flow behind an intensifying upper-level high unleashes the heat from the southern Plains. Forecast highs in the mid-90s to near 100 combined with high humidity will send heat indices into the 105-115 degree range, with widespread heat-related advisories and warnings in place. Morning lows will also remain very warm, in the mid- to upper 70s, providing little relief from the heat overnight. Numerous record-tying/breaking highs will be possible both over the Midwest as well as into portions of the Southeast on Tuesday. Those without efficient air-conditioning or who must spend time or effort outdoors will be at a heightened risk of heat-related illness. Remember to drink plenty of water and seek out relief from the heat. An approaching cold front and increased storm coverage will help to bring relief to portions of the upper Midwest on Tuesday. While the southern Plains will see some relief from the record heat that has plagued the region, conditions will still be hot with highs generally in the mid to upper 90s. Meanwhile, as upper-level shortwaves eject out of the northern Rockies and interact with a low pressure wave tracking along a couple of fronts across the northern Plains, multiple rounds of showers and thunderstorms are expected to impact portions of the northern Plains into the upper Midwest. The hot temperatures and plentiful moisture ahead of the front will contribute to strong to extreme instability leading to the potential for rapid development of severe thunderstorms. The Storm Prediction Center is forecasting an enhanced risk of severe weather from eastern South Dakota through southern Minnesota into central Wisconsin today into tonight as the center of the low pressure wave tracks just to the south. Very large hail, widespread and potentially significant damaging winds with any organized lines of storms, and a few tornadoes will all be possible. A broader Slight Risk covers portions of the Upper Midwest and northern/central Plains for some more isolated instances of large hail and damaging winds. The upper-level shortwaves will help to erode the upper-high over the Great Lakes on Tuesday mainly across the Great Lakes. In addition to severe weather, the plentiful moisture and high instability will support areas of intense downpours which could organize into more widespread heavy rain coverage at times, leading to the risk of some isolated flash flooding each day. Monsoonal thunderstorm chances today are shifting a bit eastward into the southern Rockies and High Plains, with similar activities returning later on Tuesday. Some locally heavy downpours remain possible along with the threat of isolated flash flooding especially across terrain-sensitive areas along steeper hills/mountain ranges and over burn scars. Some post-frontal showers and storms are expected into the northern Rockies through this evening as well. Temperatures over portions of the West will remain well below average following a frontal passage and under the influence of an unseasonably strong upper-trough. Forecast highs in the 70s will be common over the northern/central Rockies and eastern Great Basin. More seasonably warm temperatures will return by Tuesday with highs back up into the 80s. However, a cold front moving into the Pacific Northwest will drop highs into the 60s and 70s along with the arrival of showers and embedded thunderstorms on Tuesday mainly over western Washington. Elsewhere, instability associated with an upper-level trough dipping into New England will bring shower and storm chances through this evening with some moderate to possibly locally heavy rainfall. Some severe storms will also be possible, with a Slight Risk over southern New England for the potential of some large hail and damaging winds. Plenty of clouds will help to keep temperatures cool here compared to elsewhere in the eastern U.S., with highs in the 70s and low 80s. Daily showers and storms are also expected over Florida and along the Gulf Coast into south Texas with a lingering frontal boundary in the region as an upper-level low tracks westward into southern Texas. Kong/Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php