Tropical Storms

Weak El Nino could bring above-average Atlantic hurricane season

26th May 2017

Author: Marianne Lehnis

A weak or non-existent El Nino could bring another above-normal hurricane season this year, potentially causing significant re/insurance payouts, as Forecasters at NOAA’s Climate Prediction Center say weather conditions point towards a hard-hitting Atlantic hurricane season.

The chances of an above-normal Atlantic hurricane season – the season running from June 1st through November 30th – is set by forecasters at 45%, while a near-normal season is only 35% likely, and a below-normal season has just a 20% chance of occurring.

Gerry Bell, Ph.D., lead seasonal hurricane forecaster with NOAA’s Climate Prediction Center, said; “The outlook reflects our expectation of a weak or non-existent El Nino, near- or above-average sea-surface temperatures across the tropical Atlantic Ocean and Caribbean Sea, and average or weaker-than-average vertical wind shear in that same region.”

The average season produces 12 named storms of which six become hurricanes, three of which are likely to be major hurricanes.

Forecasters predict a 70% chance of 11-17 named storms with winds at 39 mph or higher, of which 5 to 9 are expected to turn into hurricanes with winds at 74 mph or above, and 2 to 4 major hurricanes.

These numbers include Tropical Storm Arlene, a rare pre-season storm that formed over the eastern Atlantic in April.

Atlantic hurricanes are usually suppressed by strong El Ninos and wind shear, so a weak El Nino points towards an above-average active hurricane season.

In addition, warmer sea surface temperatures fan the flames of hurricanes – making them grow in intensity as they move across the ocean, and with the Gulf of Mexico at record-high temperatures, the conditions appear set for heavy duty hurricanes and storms, which could hit vulnerable states and translate into above average insurance and reinsurance catastrophe payouts.

However, NOAA forecasters said, that while this scenario is the most likely to occur, the comparable probabilities for an above and near-normal season still show considerable uncertainty.

So although a hard-hitting catastrophe season for U.S. re/insurers is possible, it’s not yet set in stone and the coming season could see a fluctuation of intensity of storms and hurricanes.


Categories: Tropical Storms

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