The likelihood that La Niña will develop during the peak of the 2016 Atlantic and U.S. hurricane season is rising, with the U.S. NOAA now putting the probability that we’ll see La Niña conditions by September at 75%.
The U.S. NOAA has been warning for some time that conditions were becoming favourable for La Niña to develop within the next six months. It’s certainty on the pace of the transition from the recent El Niño phase into a La Niña phase has increased with every recent forecast, with the transition now looking increasingly likely.
In an update published yesterday, the U.S. NOAA’s Climate Prediction Center said; “La Niña is favored to develop during the Northern Hemisphere summer 2016, with about a 75% chance of La Nina during the fall and winter 2016-17.”
The update explains that sea surface temperature (SST) anomalies have decreased, with near-to-below average SSTs now observable. The latest set of Niño region indices show this decline and a clear trending toward ENSO-neutral, according to the NOAA.
However, there are still many atmospheric anomalies that are consistent with El Niño, the agency said, but it explained that these anomalies reflect a weakening El Niño and a definite trend toward ENSO-neutral conditions.
So the end of El Niño is forecast, with a brief period of ENSO-neutral during the summer and then the transition to La Niña conditions is expected.
But the NOAA warns that there is “clear uncertainty over the timing and intensity of a potential La Niña” the NOAA said, noting that forecasting the ENSO transition and onset is extremely difficult.
But, “Overall, La Niña is favored to develop during the Northern Hemisphere summer 2016, with about a 75% chance of La Nina during the fall and winter 2016-17,” and the forecast models do have a growing consensus on this probability.
As we wrote previously, the development of La Niña could mean an increase in insurance, reinsurance and insurance-linked securities (ILS) industry losses, with an expectation that it can raise the risk in the Atlantic tropics of the season being more active.
However, timing is everything and the real impacts of a La Niña phase to the insurance and reinsurance industry may not be felt until next year, as Andrew Siffert, Assistant Vice President and Senior Meteorologist of BMS Intermediaries Inc., told us recently “historical insurance industry losses suggest worldwide impacts, but likely these impacts won’t be fully felt until 2017 when the La Niña is fully developed.”
And timing could mean that we see La Niña conditions developing around the peak of this year’s Atlantic hurricane season, a season which is already forecast to be at or very slightly above the long-term average, as we wrote yesterday here.
Alongside the potential for a developing La Niña, some forecasters have also warned of warmer than normal sea surface temperatures in the Gulf of Mexico and near the U.S. eastern coast which could encourage development or intensification of any tropical storms or hurricanes that find their way towards these areas.
As a result and with the forecast probability for La Niña development rising and suggesting it could begin around the peak of the U.S. hurricane season, this year it looks especially important to keep one eye on the Atlantic tropics as the season develops.