Here’s a brief summation of the first half of June both in terms of temperatures and precipitation.

Month-to-date temp anomalies:


Temp anomalies for the last 7 days:


14-day accumulated precip:


In a previous blog we discussed the slackening odds for a possible eventual +ENSO event to take hold this year. What may have initially seemed like a potential weak to perhaps moderate El Nino is beginning to shape up more like a top-end weak event or even ENSO-neutral (La Nada colloquially) conditions depending on the course of things over the coming weeks and months.

The tendency for guidance to falter with the ENSO outcome through the early part of the year is typical but that uncertainty is steadily clearing and we should hopefully be able to get a much better handle on things heading into the rest of summer and fall. This will play a pivotal role in winter forecasts later down the road.

For now this is the latest from both the IRI as promised in that earlier entry, along with the updated Nino 3.4 plume and SST profile from the most recent IMME package.

First off, the SST anomalies as of yesterday (June the 15th) to illustrate the current situation:


Summary of recent and current conditions from the IRI.

In mid-June 2017, the NINO3.4 SST anomaly hovered close to the borderline of a weak El Niño level. For May the SST anomaly was 0.46 C, near the borderline of weak El Niño, and for Mar-May it was 0.30 C, in the ENSO-neutral range. The IRI’s definition of El Niño, like NOAA/Climate Prediction Center’s, requires that the SST anomaly in the Nino3.4 region (5S-5N; 170W-120W) exceed 0.5 C.

The most recent weekly anomaly in the Nino3.4 region was 0.4, approaching the borderline of weak El Niño. The pertinent atmospheric variables, including the upper and lower level zonal wind anomalies, have been showing neutral patterns. The Southern Oscillation Index (SOI) had been somewhat below average, indicating an El Niño tendency, but recently has returned to near-average. Subsurface temperature anomalies across the eastern equatorial Pacific have been just slightly above average. Overall, given the SST and the atmospheric conditions, an ENSO-neutral diagnosis remains appropriate.

Mid-June ENSO probabilities into early 2018. The current indication is for a 45% chance of La Nada, 42% chance of El Nino and a scant 13% chance of repeating La Nina conditions in the DJF timeframe.


Mid-June ENSO plume from both the dynamical and statistical models.


Finally, the Nino 3.4 plume from the June run of the IMME (International multi-model ensemble) and associated members.


A graphical depiction of the model’s predicted SST outlook for OND 2017: