CW3E AR Update: 15 September 2022 Outlook

September 15, 2022

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Early-Season Atmospheric River to Bring Precipitation to California

  • An atmospheric river (AR) is forecasted to make landfall over California late Saturday night in association with a cutoff low
  • Forecast models show the potential for an AR 1/AR 2 (based on the Ralph et al. 2019 AR Scale) in coastal Northern and Central CA, but there is still some uncertainty in the magnitude and duration of AR conditions
  • The NWS Weather Prediction Center (WPC) is forecasting 1–2 inches of total precipitation over portions of the California Coast Ranges and Sierra Nevada over the next 7 days
  • As the cutoff low weakens and moves eastward, strengthening poleward moisture transport over the Four Corners Region may produce 1–3 inches of precipitation in the higher terrain of the Upper Colorado River Basin
  • Significant hydrologic impacts are not expected, but this precipitation will likely help fire management efforts to contain the Mosquito Fire, which has already burned about 64,000 acres

Click images to see loops of GFS IVT & IWV forecasts

Valid 0000 UTC 15 September – 0000 UTC 21 September 2022






Summary provided by C. Castellano, B. Kawzenuk, S. Roj, and F. M. Ralph; 15 September 2022

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