The 2017 hurricane season was disastrous, with the likes of Harvey, Irma, and Maria creating havoc and causing deaths and untold billions of dollars in damage to the U.S. mainland and our territory, Puerto Rico. And it looks like the 2018 season is going to be a repeat of last year.
The Colorado State University Tropical Meteorology Project is forecasting a slightly above average season, with 14 named storms. Seven of those are expected to become hurricanes and three are expected to be major hurricanes. The 2018 forecast is a bit quieter than the 2017 season. There were 17 named storms, with 10 hurricanes and six that became major hurricanes.
This year’s prediction is just above the 30-year average of 12 named storms, six hurricanes, and two major hurricanes. A major hurricane is defined as a Category 3 or stronger on the Saffir-Simpson Hurricane Wind Scale. And although the Atlantic Basin hurricane season runs from June through November, remember, we can see storms outside those months – Like Tropical Storm Arlene that popped up in April 2017.
The team is led by Dr. Phil Klotzbach, a research scientist in the Department of Atmospheric Science at CSU. So far, the 2018 hurricane season is exhibiting characteristics similar to 1960, 1967, 1996, 2006 and 2011. “The years 1960, 1967 and 2006 had near-average Atlantic hurricane activity, while 1996 and 2011 were both above-normal hurricane seasons,” said Dr. Klotzbach, according to CNN News.
Critical factors in forecasting
The CSU meteorological project bases its forecasts on over 60 years of historical data that include Atlantic sea surface temperatures, sea level pressures, vertical wind shear levels (the change in wind direction and speed with height in the atmosphere), El Niño (warming of waters in the central and eastern tropical Pacific), and other factors.
DR. Klotzbach points out that “Last season had near-record warm sea surface temperatures in the tropical Atlantic.” The near-record warmth of the water was a contributing factor to the increased activity in the region. He also points out that the western tropical Atlantic is currently warmer than average, while other portions, including the eastern tropical Atlantic and the North Atlantic, are cooler than average.
Dr. Klotzbach said, “As of now, I don’t see anything in the immediate future that would cause sea surface temperatures to warm up dramatically. However, there is certainly still time for this to occur, which is one of the biggest challenges with issuing forecasts this early.”
We are currently in a weak La Nina cycle. However, the odds are increasingly in favor of the development of a neutral state of El Niño or a weak El Niño by the heart of the hurricane season. This means that average or slightly warmer than average water temperatures in the eastern Pacific are anticipated.
And while the prediction of a developing El Nino rises toward the end of the hurricane season, having a neutral La Nina is most likely during the peak of hurricane season, which occurs in September.
In fact, Dr. Klotzbach noted in the outlook that there is considerable uncertainty regarding the future state of El Niño. “The latest plume of ENSO (El Niño-Southern Oscillation) predictions from a large number of statistical and dynamical models shows a large spread by the peak of the Atlantic hurricane season in August-October.”
Needless to say, but the ENSO conditions will be closely monitored over the coming months. Keep in mind that it is the actual water temperatures that allow hurricanes to intensify. Water temperatures of 80 degrees or higher are generally supportive of tropical storm and hurricane formation and development.
The CSU team will issue forecast updates on May 31, July 2 and Aug. 2. The CSU forecast is intended to provide a best estimate of activity to be experienced during the upcoming season – not an exact measure.
