NOAA – Increased hurricane activity over the past three decades will see the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center (CPC) raise its meaning of the word ‘average’ when it comes to the Atlantic hurricane season.
Using 1991-2020 as the new 30-year period of record, the updated averages for the Atlantic hurricane season now would see 14 named storms and seven hurricanes. That compares with the previous average (based on a period from 1981 to 2010) of 12 named storms and six hurricanes. Major hurricanes (Category 3, 4 or 5) remained unchanged at three.
NOAA update to the set of statistics used to determine when hurricane seasons are above-, near-, or below-average relative to the climate record occurs once every decade.
“This update allows our meteorologists to make forecasts for the hurricane season with the most relevant climate statistics taken into consideration,” said Michael Farrar, director of NOAA’s National Centers for Environmental Prediction in a news release. “Our work illustrates the value of NOAA’s investments in next-generation technologies to capture the data that underpins our outlooks and other forecast products. These products are essential to providing the public and local emergency managers with advance information to prepare for storms, and achieving NOAA’s mission of protecting life and property.”
The increase in the averages may be attributed to the overall improvement in observing platforms, including NOAA’s fleet of next-generation environmental satellites and continued hurricane reconnaissance. It may also be due to the warming ocean and atmosphere which are influenced by climate change. The update also reflects a very busy period over the last 30 years, which includes many years of a positive Atlantic Multi-decadal Oscillation, which can increase Atlantic hurricane activity.
“These updated averages better reflect our collective experience of the past 10 years, which included some very active hurricane seasons,” said Matt Rosencrans, seasonal hurricane forecaster at NOAA’s Climate Prediction Center. “NOAA scientists have evaluated the impacts of climate change on tropical cyclones and determined that it can influence storm intensity. Further research is needed to better understand and attribute the impacts of anthropogenic forcings and natural variability on tropical storm activity.”
For the Eastern Pacific and Central Pacific basins the averages over the 1991 to 2020 period did not change. The Eastern Pacific basin will remain at 15 named storms, eight hurricanes, and four major hurricanes. The Central Pacific basin will maintain an average of four named storms, three hurricanes and two major hurricanes.
NOAA will issue its initial seasonal outlook for the 2021 hurricane season in late May. The Atlantic hurricane season officially runs from June 1 through Nov. 30.