Development of Climatic Conditions in Fall 2006

Following the fall 2006 NOAA CPC advisory (NOAA 2006), which indicated El Niño conditions had developed in the tropical Pacific and were forecast to likely continue into early 2007, Anyamba et al. (2006) started examining global SST and OLR data sets and found that SSTs increased significantly in the EP during September (Fig. 1) and October 2006. In September (Fig. 1) and October 2006, positive OLR anomaly conditions, indicating suppressed convection and precipitation, were observed across all of Indonesia, Malaysia, and most of the Philippines, which are usually the first areas to experience ENSO-related impacts. This dryness continued for the remainder of 2006 into the early part of 2007. Negative OLR anomalies, indicating enhanced convection and precipitation, were observed eastwards between the date line and Papua New Guinea, and to the west in the equatorial WIO region extending into equatorial East Africa.

Using the SST anomalies for the 1997/98 period as a reference for the most significant ENSO event (Fig. 2) and the climate forecast for the next 3-9 months, Anyamba et al. (2006) concluded that there would be a high likelihood for drought conditions to prevail over southeast Asia, Mexico, northeast Brazil, and southern Africa, and above normal rainfall and flood conditions to occur over coastal Peru, southern California, the U.S. Gulf Coast and Florida, and eastern Africa.

SST Anomaly September 2006

SST Anomaly September 2006

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¡1.;- c s -< -i -i -1 o I ! I I i "Siis"1

OLR Anomaly Ssptsmber 2006

OLR Anomaly Ssptsmber 2006

Fig. 1 Sea surface temperature (SST) anomalies for September 2006 (top) and outgoing longwave radiation (OLR) anomalies for September 2006 (bottom). SSTs are shown in degrees Celsius and OLR is shown as watts per square meter. Positive (negative) SST anomalies in the western equatorial Indian Ocean are associated with negative (positive) OLR anomalies in East Africa. The opposite patterns occur over southeast Asia where the SSTs along the Indonesian Archipelago are cold (blue in color) and the OLR data depict very dry conditions (red in color)

Fig. 1 Sea surface temperature (SST) anomalies for September 2006 (top) and outgoing longwave radiation (OLR) anomalies for September 2006 (bottom). SSTs are shown in degrees Celsius and OLR is shown as watts per square meter. Positive (negative) SST anomalies in the western equatorial Indian Ocean are associated with negative (positive) OLR anomalies in East Africa. The opposite patterns occur over southeast Asia where the SSTs along the Indonesian Archipelago are cold (blue in color) and the OLR data depict very dry conditions (red in color)

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