410 FXUS01 KWBC 150808 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 AM EDT Sat Aug 15 2026 Valid 12Z Sat Aug 15 2026 - 12Z Mon Aug 17 2026 ...Severe thunderstorm, heavy rainfall, and flash flooding threats continue along a corridor from the Midwest to the central Appalachians and across the central High Plains... ...Dangerous heat continues from the Central/Southern Plains to the Southeast through the weekend, spreading into the Carolinas by Monday... A locked-in weather pattern will continue to bring various weather hazards across the country through the weekend and into early next week. An upper-level high-pressure system will remain entrenched across the southern tier states east of the Rockies, sustaining the ongoing heatwave across this region. In fact, the heat is forecast to spread further east into the Carolinas by Monday as a warm front begins to lift across the region in response to a developing low-pressure wave passing through the Great Lakes. Meanwhile, a pronounced mid/upper-level trough over the western U.S. will slowly progress eastward, as embedded shortwave energy ejects from the Great Basin and Rockies into the central Plains and Midwest against the strong upper high. This pattern will continue to sustain repeated rounds of strong to severe thunderstorms, heavy rainfall, and flash flooding along a corridor from the Midwest to the central Appalachians and across the central High Plains to the north of a meandering front. With saturated soil from previous rainfall and ongoing flash flooding, a Moderate Risk (level 3/4) of Excessive Rainfall is maintained for parts of the Midwest to the Ohio Valley today and tonight. As a low pressure develops and moves eastward across the northern Plains today, drier and cooler air will spread into the northern Plains and the upper Midwest on Saturday, shifting the severe storms and flash flooding threats slightly southward on Sunday for the Ohio Valley with a Moderate Risk of excessive rainfall in West Virginia. A Slight Risk of excessive rainfall remains in the forecast for the central/southern High Plains on Sunday. Some strong to severe thunderstorms could slide could across the Appalachians to reach the Mid-Atlantic region on Sunday. Across the West, the southwesterly flow will bring monsoonal moisture into portions of the Interior West, the Four Corners, and central High Plains. With the combination of instability and sufficient moisture, showers and thunderstorms will develop across the area through the weekend, especially during the late-day to overnight hours. Some storms may produce periods of heavy rainfall, which can lead to flash flooding in vulnerable terrain, especially burn scars, slot canyons, and urbanized areas. The coverage of the showers and storms should gradually decrease from west to east over the next couple of days. The upper high/ridge will continue to bring dangerous heat across the southern tier states east of the Rockies through the weekend. Afternoon highs are expected to reach the upper 90s to mid-100s, while overnight lows will remain relatively warm, providing only minor relief. With the combination of high humidity, heat indices may reach up to 115 degrees, resulting in widespread Major to Extreme HeatRisk levels. Several consecutive days of high heat stress can lead to heat-related illness. Kong/Oudit Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$