CW3E Precipitation Outlook: 8 October 2026
October 8, 2026
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Widespread Rainfall Expected in the Southwestern US This Weekend Into Next Week
Tropical Storm Rachel is forecast to turn northeastward and interact with a deepening shortwave trough over the US West Coast this weekend, setting the stage for a multi-day rainfall event over the southwestern US.
Moderate-strength AR conditions (IVT≥500 kg m -1 s -1 ) are forecast to develop over Arizona as moisture from Rachel moves onshore and interacts with strengthening southerly flow downstream of the trough.
Ensemble guidance is showing the potential for climatologically extreme values of IVT over much of the Colorado River Basin on Sun 11 Oct.
After Rachel dissipates, the trough is forecast to develop into a cutoff low and help steer the remnants of Tropical Storm/Hurricane Simon northward, supporting another round of rainfall over the Four Corners Region.
The NWS Weather Prediction Center (WPC) is forecasting 2–5 inches of total precipitation in the higher terrain of central Arizona, southwestern Utah, and southwestern Colorado over the next 7 days.
A slight risk of rainfall exceeding flash flood guidance has been issued over southeastern California, southeastern Nevada, western and central Arizona, and southern Utah due to the potential for heavy rainfall Sun 11 Oct into early Mon 12 Oct.
Rainfall from these events may provide some drought relief to the Upper Colorado River Basin, where >60% of the area is experiencing severe-to-exceptional drought conditions.
Summary provided by C. Castellano, S. Roj, and J. Kalansky; 8 October 2026
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*Outlook products are considered experimental
For any unfamiliar terms, please refer to the American Meteorological Society Glossary.
Entry posted in: Drought, Extreme Events
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