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NOAA mulls moving start of Atlantic hurricane season up to May 15

Meteorologists have noticed storms forming earlier in the year

Tropical Storm Arthur during May 2020. (NOAA/NASA)
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Atlantic hurricane season doesn’t officially start until June 1, but that could soon change. A committee at the National Hurricane Center in Miami, part of the National Oceanic and Atmospheric Administration, is working to decide whether the start date of Atlantic hurricane season should be moved to May 15.

The change would reflect an increasing tendency for early-season storms to form ahead of the internationally agreed-upon June 1 conventional start date in an effort to respond to observed trends.

The National Hurricane Center has announced plans to begin issuing routine tropical weather outlooks starting on May 15.

Perspective: With increasing storms, Atlantic hurricane season needs to expand and begin on May 15

The 2020 Atlantic hurricane season sparked to life last year when Tropical Storm Arthur formed east of Florida shortly after noontime on May 16. It produced sustained winds of 39 mph at Alligator River Bridge on the Outer Banks of North Carolina. Before its formation, the waterlogged disturbance interacted with another atmospheric wave to drop 10 inches of rain on Marathon, Fla., 8 inches on Fort Lauderdale and 6 on Miami.

It was the sixth-consecutive season to feature a preseason storm that formed before the official June 1 start date. Tropical Storm Alberto in late May 2018 brought nearly a foot of rainfall near Lake Okeechobee in Florida, while also producing 65 mph winds over the Gulf of Mexico. A storm surge of roughly a meter was observed in the Florida Panhandle.

In 2015, Tropical Storm Ana scraped the East Coast in mid-May, with a gust to 62 mph and up to 6.7 inches of rainfall in North Carolina.

Also forming early in the past six seasons were a number of subtropical storms — hybrid systems that bear the characteristics of ordinary mid-latitude and tropical cyclones — which began receiving names in 2002.

Andrea in May 2019 was a small subtropical blob that dizzily meandered about the open Atlantic for a few days. Arlene in April 2017 started subtropical before becoming a tropical storm and tracing a loop in the middle of fish territory.

Since 2000, 11 storms have been named before the official start of hurricane season.

“Many of the May systems are short-lived, hybrid (subtropical) systems that are now being identified because of better monitoring and policy changes that now name subtropical storms,” wrote Dennis Feltgen, a meteorologist and public affairs specialist at the National Hurricane Center, in an email. “In 2020, NHC issued 36 ‘special’ Tropical Weather Outlooks prior to June 1st.”

These unscheduled outlooks, which aren’t otherwise issued until June 1, were issued in response to Tropical Storms Arthur and Bertha.

The record-shattering 2020 Atlantic hurricane season is over, but the scars it left remain

In their annual hurricane plan, the World Meteorological Organization announced the National Hurricane Center “will determine a quantitative threshold for adding or removing dates from the official Atlantic Hurricane Season,” and “will then examine the need for … potentially moving the beginning of hurricane season to May 15.”

There is research to support that warming Atlantic waters in response to the changing climate could become supportive of tropical storms and hurricanes earlier in the season than in years past, making the issue more topical.

The average date of a season’s first named storm has shifted upward by about a month since 1970. At first glance, it would be easy to attribute that to climate change — but better technology and satellites in today’s day and age mean meteorologists are able to track and name storms that otherwise may have been missed. Subsequently, the shifting date is probably a product of both better detection and warming oceans.

The preseason storm activity “seems to be, certainly, very attached to sea surface temperature,” Jim Kossin, an atmospheric scientist with NOAA, told the Capital Weather Gang last July. “There’s no question about that.”

There have been calls for years to revise the official start date of Atlantic hurricane season to May 15, matching the first day of hurricane season in the east Pacific. June 1 is an arbitrarily chosen date; some think it’s time to change the definition to reflect reality.

Others, including former Federal Emergency Management Agency director W. Craig Fugate, have expressed little interest in the semantics of when hurricane season starts, noting that a changed date would do little to spur public preparation. E&E News reported that only two preseason storms since 1954 have ever elicited a major disaster declaration from FEMA.

“I guess the question that I’ve asked before is … are we trying to define the Atlantic hurricane season or the Atlantic piece of junk season?” wrote Philip Klotzbach, a hurricane researcher at Colorado State University, in an email. “Since 1950, we’ve only had three hurricanes prior to 1 June. We had Able in May of 1951, Alma in May of 1970 and Alex in January of 2016.” (Some consider Alex as a hangover from 2015, rather than part of the 2016 hurricane season.)

Klotzbach, too, is unsure if the recent uptick of early-season storminess is a fluke or the start of a trend.

“The improved sensing technology was available in the 2000s, but we didn’t see much of an increase in pre-1 June named storms during that decade [until 2011],” he wrote. “Given that these storms are typically pretty weak, it’s hard to say for sure if this is a trend that will continue into the future.”

Despite the habitual messaging of both FEMA and the National Hurricane Center urging a state of vigilance throughout hurricane season, each landfalling storm still brings about a mad dash for food, water and supplies — making some question whether the advertised start date of a season has any real-world significance.

As it stands, less than 100 days remain until the official start of the Atlantic hurricane season this year, and after a record 30 named storms in 2020, this season could once again be active. A La Niña weather pattern, coupled with myriad other atmospheric factors, could load the dice toward another challenging season.