The 2013 hurricane season officially closes Saturday, allowing Louisiana to escape with little more than a few rain showers from Tropical Storm Karen, the one storm that even threatened the state.
Activity in the Atlantic Ocean was the reason storms this year failed to eclipse the strength of Category 1, which covers wind speeds of 74 to 95 mph.
“We had a giant buzz saw in the middle of the Atlantic,” state climatologist Barry Keim said.
That “buzz saw” was a large area of dry air coupled with a large amount of wind shear.
When a storm came off the African coast, it ran into the buzz saw. Wind shear lopped off the top of the storm and the dry air fed into it. Both factors hampered greater storm development.
A similar set of circumstances also took care of the one storm that threatened Louisiana this year. Karen formed in the Caribbean but fell apart in the Gulf south of Houma before ever making landfall in the United States.
Despite forecasts that the 2013 hurricane season would bring an above-normal number of storms to the Atlantic Ocean basin, only 13 named storms formed in the Atlantic and the Gulf of Mexico this year.
With only two Category 1 hurricanes, this was the quietest hurricane season on the Gulf Coast since 2009, when there were nine named storms.
Compare that with this year when, for the first time since 1994, no major hurricane formed during the entire season.
That was a relief from the past three years, which had well above-average seasons with 19 named storms each in 2010, 2011 and 2012, including Isaac last year.
Before the 2013 season began June 1, the National Oceanic and Atmospheric Administration’s Climate Prediction Center forecast there would be 13 to 20 named storms, with seven to 11 of them becoming hurricanes and with three to six of those developing into major hurricanes with winds of 111 mph or more.
The midseason forecast in August changed little, calling for 13 to 19 storms, with six to nine becoming hurricanes and three to five of those major hurricanes.
“The forecast for hurricanes and major hurricanes fell way short,” Keim said. “It was a much milder season than originally anticipated.”
The 30-year average for hurricane seasons is 12 named storms, six hurricanes and three major hurricanes.
The 2013 season started off quickly with two named storms in June, but things slowed, with just one named storm in July followed by two in August.
Activity quickened in September with four named storms, but they did not threaten Louisiana.
There were seven tropical storms and one tropical depression in 2013 before the first hurricane, Humberto, formed in early September, followed closely by the formation of Hurricane Ingrid.
But by Sept. 19, it was all over, and the rest of the season brought only four more tropical storms, one of which was Karen.
Although coastal parishes and state emergency managers prepared for what at one point was expected to become Hurricane Karen, the storm reached maximum wind speeds of only 65 mph before fizzling out offshore, bringing a little rain and above-average tides across the coast.