Forecasters Now See Below-Average Activity for Rest of Hurricane Season

Scientists at Colorado State University’s Tropical Meteorology Project have decreased their forecast and now believe that 2018 hurricane season will have below-average activity.

According to the forecasters, the tropical and subtropical Atlantic is currently much colder than normal, and the odds of a weak El Niño developing in the next several months have increased.

With the decrease in the forecast, the probability for major hurricanes making landfall along the United States coastline and in the Caribbean has decreased as well, report Philip J. Klotzbach and Michael M. Bell.

The Colorado team now estimates that the rest of 2018 will see additional 4 hurricanes (median is 6.5), 10 named storms (median is 12.0), 41.50 named storm days (median is 60.1), 15 hurricane days (median is 21.3), 1 major (Category 3-4-5) hurricane (median is 2.0) and 2 major hurricane days (median is 3.9).

The forecast cites a 22 percent probability of a direct hit to the eastern United States; the average is 31 percent.

This revised prediction is a decrease from the group’s prior seasonal forecasts issued in April and June and there remains some uncertainty with this forecast. This forecast is based on an extended-range early July statistical prediction scheme that was developed utilizing 36 years of past data.

In explaining the changed forecast, they note that the tropical Atlantic is much colder than normal. “A colder than normal tropical Atlantic provides less fuel for developing tropical cyclones but also tends to be associated with higher pressure and a more stable atmosphere,” the forecasters note. “These conditions tend to suppress Atlantic hurricane activity.”

Also, the odds of a weak El Niño for the peak of the Atlantic hurricane season in 2018 have increased somewhat. If El Niño were to develop, it would tend to lead to “more vertical wind shear in the Caribbean extending into the tropical Atlantic, tearing apart hurricanes as they are trying to develop and intensify.”

At the start of the hurricane season in June, National Oceanic and Atmospheric Administration estimated total of 10 to 16 named storms, tropical-strength or stronger, would likely affect the U.S., Mexico and the Caribbean. NOAA predicted that one to four of them might become major hurricanes.