A storm system moving from the West is expected to bring severe thunderstorms, large hail, and strong winds to parts of the Plains and South starting Sunday, with flash flooding risks in northern New Mexico and Texas panhandle. As the system progresses, areas including east Texas, southern Arkansas, and northern Louisiana face heightened flash flood threats due to already saturated ground. Additionally, rainfall is anticipated across the Northeast, with potential heavy downpours and flash flooding in urban areas.