A highly active weather pattern is setting up across the southern and central United States this week. The biggest concern is a prolonged flooding threat from South Texas through Louisiana and into portions of the Lower Mississippi Valley, where repeated rounds of tropical downpours could produce significant flash flooding. Meanwhile, a powerful storm system will bring the risk of severe thunderstorms from the Midwest into the Great Lakes and Ohio Valley on Wednesday, with damaging winds, large hail, and a few tornadoes possible. While heat eases somewhat across the West, temperatures will remain above average in parts of the Pacific Northwest and California before additional cooling arrives later this week.