Early start to 2018 Atlantic Hurricane season?
- Published
How early or late the first storm of the season develops doesn't tell us much about how active a hurricane season is going to be.
Satellite image of Hurricane Irma moving across the Atlantic towards the Caribbean.
But after last year's devastatingly powerful and prolific season, many want to know if this year is going to be as bad. Early forecasts and the meteorological evidence suggest not.
There are differing opinions about the potential severity of the 2018 hurricane season. They range from Tropical Storm Risk's prediction of a less active than normal season, to North Carolina State University's forecast for an above-average season with up to 5 major hurricanes.
In 2017 there were 6. Colorado State University falls in between by expecting a slightly above average season to include 3 major hurricanes.
The meteorology underpinning these predictions centres on sea surface temperatures in the Atlantic and Caribbean where hurricanes form, and El Nino/La Nina conditions in the Pacific.
Tropical Storm Risk says anticipated cooler than average water in the tropical Atlantic and Caribbean is one of the reasons for its forecast. Tropical cyclones can only form over warm ocean water and the warmer the water, the more powerful they can become.
Atlantic Sea-Surface Temperature Anomaly.
Meanwhile, El Nino/La Nina sea surface temperature anomalies in the Pacific are now neutral and although El Nino may develop later this year which normally favours a less active hurricane season, this may happen too late to have much of an influence.
Typical influence of El Ni帽o on Pacific and Atlantic seasonal hurricane activity. Map by NOAA Climate.gov, based on originals by Gerry Bell.
Many of these early forecasts admit that these conditions are finely balanced and there is a high degree of uncertainty about how things will actually progress this year.
Both the UK Met Office and USA National Oceanic and Atmospheric Administration are yet to issue their forecasts for the 2018 season.
Of course these are just forecasts and although made with the best possible scientific analysis at the time, they sometimes get overtaken by real-world events. It's sobering to note that many of the early forecasts ahead of the 2017 hurricane season predicted it to be near average. Well we all know how that turned out.
Power line poles downed by the passing of Hurricane Maria lie on a street in San Juan, Puerto Rico.
Even during a below average season you can still get a major hurricane striking a heavily populated area. That's why people who live in this part of the world know that the forecasts they really need to heed are for storms that are about to or have already formed. That's when action has to be taken and potentially life or death decisions have to be made.