CW3E AR Update: 16 January 2024 Outlook

January 16, 2024

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Active Weather Pattern to Bring Precipitation to US West Coast

An active weather pattern for the US West Coast is forecast to begin late Tue 16 Jan, when the first of three AR periods begins.
The first AR period begins late Tue 16 Jan and continues through Wed 17 Jan. The second AR follows close behind on Thu 18 Jan.
The first and second ARs are forecast to bring heavy precipitation to the PNW, including heavy snowfall (>12”) in the Northern Cascades and freezing rain in the Portland Metro area and regions along the WA/OR border through early Fri 19 Jan.
The third AR period begins late Sun 20 Jan as a large AR begins to make landfall across the USWC.
The third AR period is forecast to bring precipitation to the USWC, with the heaviest precipitation expected over the CA coast and in the Sierra Nevada, where heavy snowfall (>12”) is forecast through Tue 22 Jan.
The NWS Weather Prediction Center is forecasting > 6 inches of precipitation in the Cascades, Sierra Nevada and for regions along the WA, OR and CA coasts over the next 7 days.
Fresh snowpack and moist soils from previous events that impacted the USWC present the risk for rain-on-snow flooding.
The WPC Excessive Rainfall Outlook indicates a Marginal Risk (level 1 of 4, or at least 5% chance) for flooding in days 2 through 5 (24-hour periods ending 4 AM PT Thu 18 Jan through Sun 21 Jan).