Lazaro Aleman
news@greenepublishing.com
As if the coronavirus pandemic weren't enough, weather experts are forecasting an unusually active 2020 Atlantic hurricane season, which officially begins June 1 and runs through Nov. 30.
Colorado State University (CSU) – nationally regarded as one of the premier seasonal hurricane forecasters – recently issued its 37th annual prediction, while recognizing the measure's inexactness.
"We issue these forecasts to satisfy the curiosity of the general public and to bring attention to the hurricane problem," a university representative is quoted saying in USA Today.
The National Oceanic and Atmospheric Administration (NOAA), meanwhile, won't issue its forecast until late May.
That said, the CSU outlook, which other early models echo, calls for a season that will see above-normal activity because of such factors as an unusually warm Atlantic Ocean and the absence of El Niño.
The CSU prediction also foretells an above-average probability of major hurricanes striking the continental United States. AccuWeather, another early forecaster, is more specific. It puts the number of hurricanes likely to strike the U.S. at two to four.
All the early outlooks, in fact, foresee between 14 to 16 named tropical storms, eight to nine of which will turn into hurricanes. And of the eight to nine, four are expected to become major hurricanes, characterized as categories 3, 4 or 5, with sustained winds of 111 mph or greater.
Consider Hurricane Michael, which devastated the Florida Panhandle in 2018. It was a Category 5 hurricane, packing winds of up to 162 mph.
The 30-year normalized average, according to meteorologists, is 13 tropical storms, of which seven become hurricanes and three become major hurricanes. Last year, for example, was also an above-average season. It saw 18 named storms, six of which turned into hurricanes, according to the experts. At one point, it is reported, 2019 saw six tropical storms whirling in the Atlantic Ocean simultaneously.
A tropical storm becomes a hurricane when its winds exceed 73 mph.
The experts note that hurricanes require a precise set of ingredients to come together in order for them to form.
One of those ingredients is the absence of El Niño in the Atlantic Ocean during the summer and fall, which experts expect will be the case this season. In general, El Niño, which is marked by warm ocean waters, suppresses hurricane formation by increasing the vertical wind shear, which destroys hurricanes.
Its counterpart, La Niña, is marked by cooler Atlantic waters, which increases the formation of hurricanes. It is the expectation of experts that a transition toward La Niña conditions will likely occur as the spring and summer progress.
Another of the cited ingredients is the warmth of the ocean waters. And climate models, the experts say, suggest that most of, if not the entire, Atlantic Basin will be warmer than average during the peak of the hurricane season.
A third factor is how much dry air rolls off the coast of Africa. Even if water temperatures are very warm and there is little wind shear, dry air can still disrupt developing tropical cyclones and even prohibit their birth, the experts say.
The Weather Channel, an IBM Business that also makes early forecasts, adds the caveat that there is no strong correlation between the number of predicted storms or hurricanes and U.S. landfalls in any given season. It notes that one or more of the 16 named storms predicted to develop this season could hit the U.S. or it could be that none hit. That's why residents of the coastal U.S. should prepare each year no matter the forecast, the Weather Channel warns.
It cites as examples the 1992 and 1983 seasons. In 1992, according to the Weather Channel, the season produced only six named storms and one subtropical storm. Yet one of the storms was Hurricane Andrew, which devastated South Florida as a Category 5 hurricane. In 1983, likewise, only four named storms formed, one of them Alicia. Alicia, however, became a hurricane that hit the Houston-Galveston area as a Category 3 storm, causing almost as many direct fatalities as Andrew in South Florida.
By contrast, the Weather Channel notes, the 2010 Atlantic season proved quite active, generating 19 named storms and 12 hurricanes. Out of the high number of storms in 2010, however, only one tropical storm made landfall in the U.S.
The rule of thumb, according to the Weather Channel, is that a season can deliver many storms and have little impact. Or conversely, it may deliver a few storms and have "one or more hitting the U.S. coast with major impact."
On average, according to NOAA statistics, the U.S. experiences one to two hurricane landfalls per season. Keep in mind, however, that even a weak tropical storm can cause major impacts, particularly if it moves slowly and triggers flooding rainfall, the experts warn.