Hurricane season is under way
National forecasters are anticipating anywhere from average activity to an above-normal season, depending on the source.
Dr. Philip Klotzbach and Dr. Michael M. Bell, who oversee the Tropical Meteorology Project at Colorado State University, expect that the 2017 Atlantic hurricane season will have activity near the median 1981-2010 season. It is an increase in the forecast from what was predicted in early April.
“We anticipate a near-average probability for major hurricanes making landfall along the United States coastline and in the Caribbean,” they wrote in the updated forecast, which was released Thursday.
There are 13 named storms predicted, with six reaching hurricane-level status – two of those are anticipated to become “major” hurricanes. A major storm is defined as a Category 3 or higher.
A Category 3 reaches a sustained low-level wind of at least 111 mph.
“The odds of a significant El Nino in 2017 have diminished somewhat, and portions of the tropical Atlantic have anomalously warmed over the past two months,” they wrote. “While the tropical Atlantic is warmer than normal, the far North Atlantic remains colder than normal, potentially indicative of a negative phase of the Atlantic Multi-Decadal Oscillation.”
“Negative phases of the AMO (Atlantic Multi-Decadal Oscillation) tend to be associated with overall less conducive conditions for Atlantic hurricane activity, due to higher tropical Atlantic surface pressures, drier middle levels of the atmosphere and increased levels of sinking motion,” they added.
The outlook covers the North Atlantic Ocean, Gulf of Mexico and Caribbean Sea.
The probabilities for at least one major hurricane landfall along: the U.S. coastline is 55 percent; East Coast, including Florida, is 33 percent; and Gulf Coast, from Panhandle west to Texas, is 32 percent.
The probability of a major hurricane tracking into the Caribbean is 44 percent.
In comparison, the National Oceanic and Atmospheric Administration’s Climate Prediction Center released its 2017 Atlantic hurricane season outlook May 25, predicting an above-normal season.
“Forecasters predict a 45 percent chance of an above-normal season, a 35 percent chance of a near-normal season and only a 20 percent chance of a below-normal season,” officials said via a statement.
Forecasters predicted a 70 percent chance of 11 to 17 named storms (winds of 39 mph or higher), five to nine hurricanes (winds of 74 mph or higher) and two to four major storms (Category 3 or higher).
“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,” Gerry Bell, lead seasonal hurricane forecaster with NOAA’s Climate Prediction Center, said in the statement.
Officials noted that strong El Ninos and wind shear typically suppress development of Atlantic hurricanes, so the prediction for weak conditions points to more hurricane activity for the year. Also, warmer sea surface temperatures tend to fuel hurricanes as the storms move across the ocean.
According to the NOAA’s Climate Prediction Center, the 2016 hurricane season was the most active since 2012. There were with 15 named storms, with seven hurricanes and four major hurricanes.
Hurricane season is recognized as June 1 through Nov. 30.