Today begins the hurricane season with a number of 12 storms, six hurricanes and 3 intense hurricanes according to data from the National Hurricane Center. It should be noted that hurricane season can be normal or out of normal all depending on the development of the El Niño phenomenon.
According to experts
ENSO-neutral persisted during April, with near-average sea surface temperatures (ssts) observed across the central equatorial Pacific and above-average ssts in the eastern Pacific [Fig. 1]. The latest child index values were + 0.5 ° C in the child-3 and child-3.4 regions, and + 0.3 and + 0.8 ° C in the child-4 and child-1 + 2 regions, respectively [Fig. 2]. The upper-ocean heat content anomaly was slightly positive during April [Fig. 3], reflecting the strengthening of above-average temperatures at depth around the date line [Fig. 4]. Atmospheric convection anomalies were weak over the central tropical Pacific and maritime continent [Fig. 5], while the lower-level and upper-level winds were near average over most of the tropical Pacific. Overall, the ocean and atmosphere system remains consistent with ENSO-neutral.
Most models predict the onset of El Niño (3-month average child-3.4 index at or greater than 0.5 ° C) during the northern hemisphere summer [fig. 6]. However, the NCEP CFSv2 and most of the statistical models are more conservative and indicate that while child-3.4 index may be near or greater than + 0.5 ° C for several months, the warmth may not last long enough to qualify as an El Niño episode (5 consecutive overlapping seasons) and/or may not significantly impact the atmospheric circulation. Relative to last month, the forecaster consensus reflects slightly lower chances of El Niño (~ 45%), in part due to the conflicting model guidance and lack of a clear shift towards El Niño in the observational data. In summary, while chances are slightly lower than 50%, ENSO-neutral and El Niño are nearly equally favoured during the northern hemisphere summer and Fall 2017 (click CPC/IRI consensus forecast for the chance of each outcome for each 3-month period).
HAVE A GOOD HURRICANE SEASON