June 1st officially marks the beginning of 2018 Atlantic Hurricane Season which will run until November 30th . We cannot talk about this year’s season without taking a step back to remind ourselves of the record breaking season we had last year. The 2017 Atlantic Hurricane Season produced 17 named storms, 10 of which became hurricanes with 6 of these hurricanes being major hurricanes, that is with wind exceeding 111 mph. Additionally in the 2017 hurricane season we saw: the highest number of major hurricanes since 2005. All 10 of the season’s hurricanes occurred in a row; this was the greatest number of consecutive hurricanes in the satellite era and tied with the greatest number of consecutive hurricanes observed in the Atlantic basin since records began in 1851. It was also the costliest season on record in damages. (Irma and Maria in the Caribbean)
Based on long-term averages, in an average season there are about twelve (12) named storms out of which six (6) become hurricanes with three (3) being major hurricanes (with wind 111mph or higher). Many institutions and individuals have presented their predictions for the upcoming season which suggests a near normal to above normal activity. Institutions Named Storms Hurricanes Major Hurricanes University of Colorado (CSU) 14- 7- 3 Weather Channel 12 5 2 National Oceanic & Atmospheric Administration (NOAA) 10-16 5-9 1-4 Average 12- 6- 3
Let’s look at three (3) of the factors which contribute to hurricane activity across the Atlantic basin:
1. Atlantic Seas Surface Temperature (SST): A minimum SST of 26.5oC (80oF) is necessary to provide enough heat for the development of systems. Temperatures across the eastern and central Atlantic up till the beginning of May were cooler than average for this time of year. If these ocean waters remain in the cooler end of the scale this could suppress the development of cyclones.
2. El Nino/ La Nina Phenomenon When sea surface temperatures across the eastern Pacific are cooler than average, it is referred to as La Nina. Based on historical data, during these episodes the Atlantic basin experiences increased activity during its hurricane season. On the other hand, when sea surface temperatures are warmer than usual in the Pacific the term El Nino is used. In most years during an El Nino phase the Atlantic Basin experiences less storm activity. This year most models agree that during the peak of our hurricane season August to October El Nino conditions will develop across the eastern Pacific and continue through the first quarter of 2019.
3. The North Atlantic Oscillation (NAO) This is the fluctuation in the high-pressure system in the north Atlantic and the lowpressure system near Greenland. When the NAO is positive, both of these systems strengthen. The NAO has been positive for most of the year so far leading to stronger winds across the sub tropics and cooler sea surface temperatures. If the NAO remains in the positive phase this will decrease the chances for an active hurricane season.
The question is, how much of an impact will these factors either individually or collectively have on the formation of storms or hurricanes during the 2018 Atlantic Hurricane Season? Ultimately, these conditions will continue to change as we go through the season therefore monitoring is key. Sea surface temperatures can heat up within a month, the NAO could weaken and ofcourse, there is the uncertainty surrounding the onset and intensity of the El Nino phenomenon.
In the past there have been El Nino years that produced damaging hurricanes/storms. During the strong El Nino of 1997/98 Hurricane Georges ripped through the Leeward Island with 150mph winds, during the moderate El Nino of 2009/10 Hurricane Tomas devastated St. Lucia and during a weak El Nino of 2004/05 Ivan crushed Grenada.
It should be noted that the seasonal forecasts have little operational value. This means that no matter how many tropical cyclones are forecast to develop, there is no way to predict so many weeks or months in advance where a certain tropical cyclone is going to develop or what country will it make landfall.
Remember, that it takes only one major hurricane to make landfall on our island to make it an active season for us. We must also be conscious of the fact that, it doesn’t have to be a storm or a hurricane, an active tropical wave or just 2 to 3 hours of heavy rainfall can have devastating impacts on our lives. The geographical location of our islands make us vulnerable to these forms of natural disasters consequently being prepared and well informed is key.
As we begin yet another hurricane season let us learn from our past experience of hurricane Irma and do all in our power to prepare adequately and to seek credible information in other to make timely decisions that will protect life and property.
The Meteorological Department St. Maarten (MDS) will monitor the development of all tropical systems closely and will issue watches or warnings when it becomes necessary using various communication mediums; radio, newspaper, through our website and facebook.
Remember, the official source for weather information of St. Maarten is:
Meteorological Department St. Maarten. Tel. # 721-545 4226 Website: meteosxm.com Facebook: www.facebook.com/sxmweather.