National Weather Service and Weather Prediction Center guidance highlight a warm front and strengthening upper-level jet driving widespread showers and thunderstorms across the Northeast and Midwest on September 13, with slight risks of excessive rainfall in the Mid-Atlantic, New York metro, and Missouri River Valley. Abundant moisture (precipitable water values 2.0–2.25 inches) and efficient warm-rain processes support locally heavy totals, while the Pacific Northwest sees soaking rains from an incoming system and the Southwest experiences typical monsoon activity. Model consensus favors these regions over the drier Southern Plains and Rockies, though exact placement of heaviest bands remains sensitive to short-term forecast updates and steering patterns.