Winter Outlook Part 4 - PDO

The Pacific Decadal Oscillation (PDO) can have a major impact on El Nino and La Nina. A negative PDO can enhance La Nina and a positive PDO can enhance El Nino. However, the opposite occurs if these are flipped - a positive PDO can greatly reduce the impacts of La Nina.

(NEGATIVE PDO)

Generally, we have been in a negative phase for the past few years, though last winter PDO was positive. This might have reduced the impact of last winter's moderate La Nina. Here is a month-by-month table of PDO for the past hundred years:

http://jisao.washington.edu/pdo/PDO.latest

Cold waters prevail over the Gulf of Alaska and farther south off the coast of Mexico, so it looks like this winter will feature a slightly negative PDO, which could possibly enhance the weak La Nina. However, there has been no evidence of this occurring within the current weather pattern...yet.

(SEA SURFACE TEMPERATURE ANOMALIES FOR THE PAST MONTH)

24 Hour Rain Totals

(SAN DIEGO COUNTY)

(CALIFORNIA)