(a) Multiple atmospheric rivers resulted in above-normal precipitation and flooding across California and the Pacific Northwest during mid to late December. 14-day precipitation, from December 18-31, averaged more than 200 percent of normal throughout California with southern parts of the state receiving more than 4 times their normal amount of precipitation during this two-week time period.

(b) An amplified 500-hPa ridge is forecast over the northeastern Pacific and near the West Coast from January 10-16.

(c) This strong mid-level ridge favors a much drier pattern for the West Coast and the week-2 outlook (valid January 10-16) indicates a 40 to 50 percent chance of below-normal precipitation for much of California and southeastern Oregon.

The drier mid-January pattern will end any flooding concerns for California. However, the lack of precipitation would maintain the low snowpack for the Cascades of Oregon and Washington where snow water equivalent is currently below 50 percent of normal. The mid-level ridge is likely to promote surface high pressure across the Great Basin which increases the chance of Santa Ana winds for southern California during mid-January.