CW3E AR Update: 31 October 2017 Outlook

October 31, 2017

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Atmospheric River to potentially make landfall over California

  • A weak to moderate AR is predicted to make landfall over California during 3-8 November 2017
  • Current forecasts indicate the geometry of the AR conditions may not meet standard criteria to be considered and AR by AR conditions (IVT >250 kg m-1 s-1 and IWV >20 mm) are expected to impact the majority of CA
  • Precipitation amounts up to 5 inches are expected over the Sierra Nevada with the majority of CA receiving at least 0.25 inches of precipitation
  • Forecast certainty is currently low on timing and strength of AR conditions but confidence of at least weak AR conditions over central and southern CA is high

Click IVT or IWV image to see loop of 72-180 hour GFS forecast

Valid 1200 UTC 3 November – 0000 UTC 8 November 2017






Summary provided by B. Kawzenuk, J. Kalansky, C. Hecht, and F.M. Ralph; 3 PM PT Tuesday 31 October 2017

*Outlook products are considered experimental