National Weather Service and Weather Prediction Center outlooks indicate the primary driver for September 30 precipitation centers on tropical moisture streaming northward from Hurricane Polo, combined with a moderate risk of excessive rainfall across the Southwest, Southern Rockies, Central High Plains, and Southern Plains. These areas face the highest probabilities of showers and thunderstorms, while Florida and parts of the Southeast show 50-70% chances of storms amid humid southerly flow. Drier conditions prevail elsewhere, including much of the Northeast and Midwest following a weakening nor’easter. Model consensus supports these patterns, though exact boundaries and intensities remain sensitive to steering currents and diurnal heating; traders should monitor the next WPC excessive rainfall update and regional NWS forecast discussions for refinements before resolution.