Our latest calculation of the sea surface temperatures for the month of October stands at 1.0 degree Celsuis (2.0 deg Fahrenheit) above normal. This is up from the 0.7 degree C (1.4 F) above normal departure observed during September and the first half of October. This rise in the temperatures points to a building El Nino.

The Southern Oscillation Index (SOI) is likely the main factor behind the strengthening of the El Nino. This Pacific atmospheric index turned strongly negative during the middle of October and remains so now. This is supportive of El Nino. This support from the SOI had been lacking. and was the reason for the comments we made earlier that this would only be a weak to moderate El Nino. We really have no way of forecasting the direction of the SOI and can only go with the trends. The trends right now are telling us that El Nino is building.

Although there is no strong correlation between El Nino and Midwest weather, it may be possible that the turn to warmer and drier weather in the Midwest could be related to the bulding El Nino creating a milder Pacific flow across much of the U.S. This is initially a drier pattern due to more of a west to east flow shutting down Gulf moisture, before the transition into a stormier weather pattern coming in off the Pacific during late fall and winter.

Also, a strengthening El Nino would be favorable for corn and soybeans in central Argentina and southern Brazil as conditions are generally wetter than normal in these areas during an El Nino.

Mike