Effects of PDO
| Table 1: summary of Pacific and North American climate anomalies associated with extreme phases of the PDO. |
| climate anomalies | Warm Phase PDO | Cool Phase PDO |
| Ocean surface temperatures in the northeastern and tropical Pacific | Above average | Below average |
| October-March northwestern North American air temperatures | Above average | Below average |
| October-March Southeastern US air temperatures | Below average | Above average |
| October-March southern US/Northern Mexico precipitation | Above average | Below average |
| October-March Northwestern North America and Great Lakes precipitation | Below average | Above average |
| Northwestern North American spring time snow pack and water year (October-September) stream flow | Below average | Above average |
| Winter and spring time flood risk in the Pacific Northwest | Below average | Above average |
Joe Bastardi, former Chief Long Range Meteorologist at Accuweather, has put up a message indicating that a +AMO/-PDO would help the potential for the theory of a major trough to hit the East/North US going into the last few days of November. You can see the differences between a warm PDO and negative PDO in the columns above, thanks to the University of Washington.
We are currently in a Cold PDO phase and a warm AMO phase. These indices change on a multidecadal basis- every couple decades. Since the mid 1990s, the AMO has been on a mainly positive streak. However, it is less positive than last year. During the warm phase of the AMO, temperatures across North America are above average, as shown by this map below thanks to Intellicast.
Since we are in a less positive phase than last year, it is possible that global temperatures may be slightly cooled from last year, in addition to low sunspots.
We will have more information on the trough as we come closer to the date.
