Monthly Archive

Oceanic and atmospheric conditions over the last month remained generally consistent with a La Niña event (Figs. 1-2), but given the rapid decline of these conditions and the imminent seasonal transition, it is only a matter of time before ENSO-neutral conditions return. The current ENSO forecasts reflect this steady weakening, with most indicating a likely transition to ENSO-neutral conditions over the spring, and others having already declared an end to this La Niña event. On April 10, the Japanese Meteorological Agency (JMA) identified ongoing La Niña conditions but called for a 90-percent chance that this event will end in spring. On April 10, the Australian Bureau of Meteorology maintained their ENSO Outlook at “inactive,” stating “there is little sign of El Niño or La Niña developing in the coming months.” On April 12, the NOAA Climate Prediction Center (CPC) continued its La Niña advisory but expected a transition to ENSO-neutral conditions by May and forecast a greater-than-50-percent chance of ENSO-neutral lasting through summer. On April 19, the International Research Institute (IRI) issued its ENSO Quick Look, which still identified weak La Niña conditions present but called for a rapid transition to ENSO-neutral conditions over spring (Fig. 3). The North American Multi-Model Ensemble (NMME) is consistently indicative of a return to ENSO-neutral conditions, but with greater uncertainty over what the latter half of 2018 might hold (Fig. 4). (read more)