CW3E AR Update: 3 January 2018 Outlook

January 3, 2018

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Two systems expected to produce precipitation over the U.S. West Coast in the next week

• AR conditions (IVT >250 kg m^-1 s^-1 and IWV >20 mm) are expected over most of the U.S. West Coast over the next two days
• While AR conditions are forecast for some locations of the USWC, this event is not necessarily an AR due to geometric and spatial structure, but could produce up to 5 inches of precipitation over the Sierra Nevada
• A second period of AR conditions is expected to make landfall over CA, OR, and WA on 9 January 2018
• Both periods of AR conditions are currently expected to have southerly oriented IVT which will result in less extreme precipitation

Click IVT or IWV image to see loop of 0-180 hour GFS forecast Valid 0600 UTC 3 January – 1800 UTC 10 January 2018

Summary provided by B. Kawzenuk, J. Kalansky, and F.M. Ralph; 3 PM PT Wednesday 3 January 2018

*Outlook products are considered experimental