Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 355 PM EDT Wed Aug 14 2024 Valid 00Z Thu Aug 15 2024 - 00Z Sat Aug 17 2024 ...Flash flooding and severe weather threat continues over the Midwest the next couple of days... ...Potentially dangerous heat anticipated across the southern Plains, lower Mississippi Valley, and Gulf Coast... A low pressure/frontal system traversing the center of the country continues to help trigger rounds of showers and thunderstorms leading to the threat of some flash flooding and severe weather. The system is forecast to lift northeastward through the Middle Missouri Valley this (Wednesday) evening. Increasing upper-level support with a strengthening wave as well as plentiful moisture should lead to some intense, heavy rain-producing thunderstorms, with a Slight Risk of Excessive Rainfall (level 2/4) for some scattered instances of flash flooding. In addition, the Storm Prediction Center has included a Slight Risk of severe weather (level 2/5) for the risk of some very large hail, damaging winds, and a few tornadoes with these storms. A similar scenario will play out on Thursday as the system moves eastward into the Middle Mississippi/Lower Ohio Valley and Great Lakes region with a broad warm sector supported by plentiful moisture, instability, and deep-layer shear. Storms should redevelop during the afternoon, increasing in coverage into the evening, with another Slight Risk of Excessive Rainfall given the threat for some heavy downpours and potential training convection leading to some flash flooding. A Slight Risk of severe weather similarly covers the chance for some instances of large hail and damaging winds. The system will push into the Lower Great Lakes and Upper Ohio/Tennessee Valleys by Friday, with storms likely and some chance of isolated flash flooding and severe weather. Heat will remain the major weather story throughout much of the south-central U.S. through the end of this week and likely beyond. Widespread highs into the upper 90s and triple digits are forecast to span from the Southwest to the central Gulf Coast. Elevated humidity levels will soar heat indices up to around 110 degrees in the southern Plains, lower Mississippi Valley, and central Gulf Coast. Low temperatures are anticipated to only drop into the upper 70s and 80s for many locations, which could break several daily records. This level of heat can affect anyone without effective cooling and/or adequate hydration. Therefore, it is imperative to follow proper heat safety and check on vulnerable individuals. Elsewhere, some showers and storms will continue over New England as a frontal boundary lingers in the region. This boundary is expected to weaken through the day Thursday, with storm chances subsequently tapering off. To the south, portions of central/south Florida will also see scattered storm chances the next couple of days as a cold front slowly pushes through. Some thunderstorms will be possible with a shortwave passing over portions of the northern Great Basin Thursday and into the northern Rockies by Thursday evening. Forecast high temperatures are expected to generally be around average along the East Coast with mid- to upper 80s expected. Areas of the Great Lakes/Upper Midwest behind the passing storm system will be cooler with highs in the 70s. More temperatures near or above average are expected over the northern/central Plains with highs in the 80s and 90s. Highs across the northern tier of the West will remain below average, with 70s for the Pacific Northwest and low 80s into the northern Great Basin, warming closer to average into the central Great Basin with mid-80s to low 90s. Putnam/Snell Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php