A powerful atmospheric river (AR) is expected to bring significant rainfall to the West Coast, particularly affecting Washington and Oregon starting October 25, 2024, and continuing into early October 27. Following this, a second AR may impact the California-Mexico border and parts of the southwestern U.S. on October 28 – 29.
- The AR will transport moisture from the tropics, enhancing precipitation levels in coastal regions and extending inland into areas like Colorado and New Mexico.
- The first atmospheric river is expected to deliver 50 – 127 mm (2 – 5 inches) of rain in the Pacific Northwest, while lighter amounts of 12.7 – 38.1 mm (0.5 – 1.5 inches) are forecast for Northern California.
- The second atmospheric river event will bring additional precipitation to California’s southwest and extend into the Upper Colorado River Basin, southwestern Colorado, and northern New Mexico, with inland areas expecting 12.7 – 38.1 mm (0.5 – 1.5 inches) of rain.
A powerful atmospheric river (AR), a long, narrow zone in the atmosphere that transports water vapor from the tropics, is likely to bring significant rainfall to the West Coast, with moderate AR conditions starting today, October 25.
The CW3E’s AR landfall tool, powered by the Global Ensemble Forecast System (GEFS), shows a high probability (over 90%) of moderate AR conditions impacting Washington and Oregon during the first AR.
The first AR is expected to continue into early Sunday, October 27, delivering 50 – 127 mm (2 – 5 inches) of rain across the Olympic Peninsula, Oregon Coast Ranges, and the Washington/Oregon Cascades…