Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 402 AM EDT Sat Jun 19 2021 Valid 12Z Sat Jun 19 2021 - 12Z Mon Jun 21 2021 ...There is a Slight Risk of severe thunderstorms over parts of the Central High Plains to the Ohio Valley, the Lower Great Lakes, and over parts of the Central Gulf Coast with Potential Tropical Cyclone THREE through Sunday morning... ...There is a Moderate Risk of excessive rainfall over parts of the Central Gulf Coast, Tennessee Valley, Southeast, and the Southern Appalachians with Potential Tropical Cyclone THREE through Sunday morning... ...Dangerous and record-breaking heat will continue across a large portion of the western U.S.... Heatwave continues. Excessive Heat Warnings and Heat Advisories remain in effect across much of California, Nevada, Arizona, and Utah. Temperatures are expected to once again reach record-breaking highs across much of the region, with several records likely to fall on Saturday. Additionally, Heat Advisories are also in effect for portions of California and Nevada on Saturday. Well-above normal temperatures are expected across the region, with record-breaking highs expected over parts of California, Nevada, and Arizona. While a front dropping into the region on Monday is expected to offer some relief, temperatures are forecast to remain well above average on Saturday. Severe thunderstorms will develop along and ahead of a front that extends from the Great Lakes roughly southwestward to the Central High Plains. The Storm Prediction Center has issued a Slight Risk of severe thunderstorms over parts of the Central High Plains to the Ohio Valley and the Lower Great Lakes through Sunday morning. The main hazards with these storms are frequent lightning, severe thunderstorm wind gust, large hail, and a few tornadoes. There is a 10% or greater probability of wind gust of 65 knots or greater over parts of the Central High Plains. Meanwhile, Potential Tropical Cyclone THREE will impact parts of the Central Gulf Coast, Tennessee Valley, Southeast, and the Southern Appalachians with heavy rain. Therefore, the WPC has issued a Moderate Risk of excessive rainfall over the region. The associated heavy rain will create numerous areas of flash flooding. Furthermore, many streams may flood, potentially affecting larger rivers through Sunday morning. The Storm Prediction Center has issued a Slight Risk of severe thunderstorms over parts of the Central Gulf Coast with Potential Tropical Cyclone THREE through Sunday morning. The main hazards with these storms are frequent lightning, severe thunderstorm wind gust, large hail, and a few tornadoes. Check the latest advisory from the National Hurricane Center for strength and track of Potential Tropical Cyclone THREE. A developing wave of low pressure over the Midwest will move northeastward to the Great Lakes with a trailing front by Sunday evening. Showers and thunderstorms will develop along and ahead of the boundary over parts of the Middle Mississippi Valley into parts of the Great Lakes. The Storm Prediction Center has issued a Slight Risk of severe thunderstorms over the area on Sunday into Monday morning. Additionally, Potential Tropical Cyclone THREE will continue to produce heavy rain over parts of the Southeast and Southern Appalachians on Sunday into Monday. The WPC has issued a Slight Risk of excessive rainfall with these downpours. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, and small streams are the most vulnerable on Sunday into Monday morning. Elsewhere, Red Flag Warnings have also been issued over parts of the Rockies and the Great Basin to highlight the fire danger associated with the ongoing heat and arid soils. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php