Heavy downpours in South Texas washed out highways and stranded motorists Tuesday as forecasters warned that a threat of more severe weather could bring dangerous flooding to already drenched counties near the border with Mexico

Slow-moving storms could drop a summer’s worth of rain over parts of Texas this week, bringing a significant flash flood threat to the state.

Heavy downpours in South Texas washed out highways and stranded motorists Tuesday as forecasters warned that a threat of more severe weather could bring dangerous flooding to…