The latest SST forecast was issued this morning by CPC:

CPC 6-Month SST Forecast

The CPC outlook continues to show a robust La Nina in the eastern tropical Pacific during the Summer but it also indicates a continued cooling trend of the tropical Atlantic during August and September. The accuracy of the forecast is not as significant to me as is the continued trend toward a cooler tropical Atlantic by mid-Summer.

Looking at previous years where a weak El Nino switched to a La Nina ENSO event during the early Spring can also be helpful in developing an outlook for this season. Four representative years are noted, along with the storm totals for those seasons:

1954: 11/8/2
1964: 12/6/6
1970: 10/5/2
1988: 12/5/3

The best analog years from an ENSO viewpoint are 1964 and 1988. Both of these years had an average anomaly of +0.8C during the D/J/F timeframe - as does 2007.

If this cooling trend materializes during the Summer, the chances for late-season activity will decline. My new seasonal distribution is as follows:

M/J = 0; J = 2; A = 4; S = 4; O = 2; N = 1; D = 0

Although I've left the door open for a subtropical system in November, my revised seasonal forecast is 13/7/3 .
Cheers,
ED