Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 339 AM EDT Thu Aug 15 2019 Valid 12Z Thu Aug 15 2019 - 12Z Sat Aug 17 2019 ...Numerous showers and thunderstorms along the Gulf Coast, the Southeast U.S, and into the Mid-Atlantic... ...Scattered strong to severe thunderstorms are expected to spread eastward across the Central Plains... ...Excessive heat expected to continue across the Desert Southwest... A ridge over the Southwest will keep temperatures above seasonal average across the western, southern and southeast portions of the country. Excessive heat warnings are in effect for the lower elevations of southern Arizona to central California; where daily max temperatures are forecast to be in the 105 to 115 degree range with overnight lows only in the middle 80s to near 90 degrees for the warmest locations. Portions of central, southern and coastal areas of California have heat advisories in effect. The northern-tier states will be a little cooler over the next couple thanks to couple of frontal boundaries that will sprawl across the central U.S. These boundaries will keep much of the hot and humid airmass from the Central Plains southward. Low pressure traveling across the Central Plains will generate widespread showers and thunderstorms. Several of these storms have the potential to be severe and produce intense rainfall. Both SPC and WPC have Slight Risks in effect for much of the Central Plains and Midwest region. With several inches of rain in store over the next couple of days, the threat for flash flooding will likely increase. Unsettled conditions will continue along the Eastern Seaboard through the end of the week as the two frontal boundaries slowly merge. Showers and thunderstorms are expected to span from the Gulf Coast to the southern Mid-Atlantic. Gradual improvement in the weather is expected for the Ohio and Tennessee Valleys behind the frontal boundaries. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php