Millions of people across parts of the South, Gulf Coast, and Texas are under a dangerous flood threat as storms are expected to bring heavy rain through Friday. The Big Bend and Hill Country regions of Texas are particularly vulnerable, with storms forecast to repeatedly track over the same areas.

This forecast includes areas along the Guadalupe River in Texas Hill Country, which experienced devastating flooding on July 4th of the previous year, resulting in 135 fatalities. The current week's flood concerns also follow a period of deadly flash flooding along the Black River in southeastern Missouri, which began on Friday and continued into the weekend.

During the recent Missouri flooding, a Flash Flood Emergency was issued for Iron and Reynolds counties, where some locations received between 9 and 12 inches of rain. A summer storm pattern is developing over Texas and the South as a cold front moves south and interacts with warm, humid air from the Gulf, creating conditions for sustained thunderstorms.

NOAA's Weather Prediction Center (WPC) has designated a Level 2 out of 4 risk for flash flooding on Monday, affecting areas from Western North Carolina to Texas's Big Bend. This region encompasses parts of southeastern Virginia, East Tennessee, South Carolina, Georgia, central and southern Alabama, central and southern Mississippi, much of Louisiana, eastern Oklahoma, and central and western Texas. Major cities within this risk zone include New Orleans, Houston, Austin, San Antonio, and portions of the Dallas metroplex.

Through Tuesday, widespread rainfall totals of 1 to 3 inches are anticipated along a broad area from the Gulf Coast into Central Texas. On Tuesday, the focus of the flood threat shifts primarily to the Texas Plains, impacting Austin and San Antonio, while storms persist in the Southeast, affecting Atlanta, Birmingham, Mobile, and New Orleans.

By mid-week, storms are expected to deliver between 5 and 8 inches of rain across West and Southwest Texas, including the Hill Country. Currently, a Level 3 flash flood risk is in effect for areas in the Big Bend region west and north of San Antonio. Flood watches are likely to be issued.

The current weather setup is influenced by a large heat dome over the northern United States, which is guiding a weaker storm system eastward and then westward into the southern Plains.

Visitors to Big Bend National Park this week are advised to closely monitor weather forecasts and local advisories.