Moisture from the remnants of Hurricane Polo combined with a plunging jet stream drove widespread heavy rainfall across the Desert Southwest and into the southern Plains on September 29, 2026, with rates up to 2–3 inches per hour reported by NOAA and NWS observations. This setup produced flood threats in Arizona, New Mexico, and Texas, contrasting with more localized showers from an upper-level disturbance over the northern Gulf that affected South Florida and lingering nor’easter bands that delivered additional totals in parts of the Northeast through early Tuesday. Official NWS climatological reports and WPC precipitation analyses confirm variable coverage, with dry conditions persisting in the Pacific Northwest and much of the northern Plains. Traders monitor these NWS station data and model verification for resolution thresholds on specific locations, as rapid shifts in steering patterns or moisture plumes can alter outcomes before final observations post.