Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 240 AM EDT Thu Aug 15 2024 Valid 12Z Thu Aug 15 2024 - 12Z 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 low pressure center is forecast to gradually push eastward through the Upper Midwest today and reach the Great Lakes by the end of the week. A broad warm sector supported by plentiful moisture, instability, and deep-layer shear will allow for storms to potentially turn severe and contain heavy rainfall throughout Missouri, Illinois, and into the lower Ohio Valley. Storms should redevelop during the afternoon, increasing in coverage into the evening, with a Slight Risk (level 2/4) of Excessive Rainfall in effect given the threat for some intense downpours and potential training convection leading to instances of flash flooding. A Slight Risk (level 2/5) 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 Ohio/Tennessee Valleys by Friday and Saturday, with storms likely to spread as far east as the Appalachians and Mid-Atlantic. Some chances of isolated flash flooding and severe weather are forecast. Heat will remain the major weather story throughout much of the south-central U.S. into the beginning of this weekend 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 for areas outside of the Southwest and southern High Plains. However, actual high temperatures in these more arid regions will be higher and well into the triple digits for some locations. 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 an upper-level low churns over Nova Scotia. 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 also be possible with a shortwave passing over portions of the northern Great Basin today and into the northern Rockies by tonight. Monsoonal moisture and storm chances are set to return to the Southwest and central Great Basin by Saturday, where isolated flash flooding is the greatest concern. 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. Snell Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php