By John Murphy, AccuWeather staff writer
& Meghan Mussoline, AccuWeather meteorologist
Updated May. 31, 2020 10:55 PM
Two tropical storms have already formed prior to the official start of the 2020 Atlantic hurricane season, which begins on June 1— and AccuWeather meteorologists say there are two factors behind the unusual occurrence. These weather factors could soon cause more storms to brew, but this time, forecasters are watching a new tropical hotspot of the basin.
Tropical Storm Arthur, the first storm of the season, was named by the National Hurricane Center (NHC) on May 16, the earliest-named tropical system to form in the Atlantic since Tropical Storm Arlene in April 2017. The system first developed into a tropical depression about 125 miles off Melbourne, Florida. As the disturbance gained strength and moved northward over warm waters in the western Atlantic, Arthur avoided landfall in North Carolina. But, the system still unleashed wind gusts of up to 49 mph in the state. Fortunately, no major impacts were reported, and Arthur went out to sea before it could directly strike land.
Less than two weeks later, Tropical Storm Bertha became the second-named storm of the season on May 27 in a similar area to where Arthur had developed. Bertha will also go down as the first-named storm to make landfall in the U.S. this year. Bertha struck about 20 miles south of Charleston, South Carolina, last Wednesday, and unleashed flooding rainfall across the Carolinas and portions of the mid-Atlantic. Before officially being named the system drenched South Florida with flooding rainfall, which pushed monthly rain totals to more than two times the normal amount for May in places like Miami.
The last time two named storms preceded the official start of hurricane season in the Atlantic was in 2016, when Hurricane Alex and Tropical Storm Bonnie both formed before June 1.
This GOES-16 satellite image taken Wednesday, May 27, 2020, at 11:40 UTC and provided by The National Oceanic and Atmospheric Administration (NOAA), shows Tropical Storm Bertha approaching the South Carolina coast. (NOAA via AP)
"You get early season development when you get an interaction between the jet stream and the tropics," AccuWeather Chief Broadcast Meteorologist Bernie Rayno said. "It's still early enough in the year that, at times, the jet stream can take pronounced dips into the south."
A southward plunge in the jet stream causes weather systems to interact with the warm water of the Atlantic, explained Rayno.
“The jet stream brings down frontal boundaries that stall, frontal boundaries are locations where showers and thunderstorms could form, and in time, if you can get that area to sit, you start to get lower pressure to form, and in time this could turn into a tropical system,” said Rayno.
Arthur and Bertha both formed from a similar set of weather factors, and a third-named tropical storm could form as early as next weekend, fueled by another big dive of the jet stream.
"On Monday, this dip in the jet stream [is] gonna push a frontal boundary into the northwest Caribbean. [On] Tuesday, showers and thunderstorms start to form and by mid- to- late-week, I think we are going to get an area of low pressure to form," said Rayno.
The Miami skyline is shrouded in clouds as a cyclist rides along Biscayne Bay at Matheson Hammock Park, Friday, May 15, 2020, in Miami. A trough of low pressure moved through the Florida Straits and organized over the northwest Bahamas to become Tropical Storm Arthur. (AP Photo/Lynne Sladky)
Rayno said that he believes there is a 50/50 chance that a named storm could be the result of this setup. The third name for the Atlantic season is Cristobal. For all of the names for this season and all tropical-weather-related information, visit the AccuWeather Atlantic hurricane center.
AccuWeather meteorologists say the tropical trouble in the Gulf of Mexico this week will result from the leftover circulation of Amanda, which made landfall in Central America as a tropical storm at the end of the weekend.
Even though Amanda has dissipated over the rugged terrain of Central America, AccuWeather Senior Meteorologist Dave Samuhel said that, "There will be abundant moisture associated with the system and when that moisture moves northward into the Gulf of Mexico, it could reform into a new tropical system." This means it would get a new name once it develops in the Atlantic.
The last three tropical cyclones to make landfall in the U.S. during the month of June were all Gulf of Mexico storms, similar to the hotspot currently being monitored. The most recent Gulf of Mexico storm to result in a June landfall was Tropical Storm Cindy, which came ashore in western Louisiana in 2017.
Samuhel advised that while the reformation of the storm would not happen until several days into June, the conditions could be favorable for development as water temperatures in the Gulf of Mexico are above normal and upper-level conditions in the atmosphere could remain favorable.
It has been a few years since the third-named storm of the season formed as early in the season as June and made landfall in the U.S., with the last occurrence being Tropical Storm Cindy in 2017 and then again in 2016 when Tropical Storm Colin developed and slammed into the Gulf Coast of Florida, north of Tampa.
Before that, it had been several decades since this happened with the last time prior to 2016 being back in 1968, when Tropical Storm Candy formed in late June.
Having three named storms this early in the season is a rare occurrence, and only twice in the last decade has a fourth-named storm formed in June with Tropical Storm Danielle in 2017 and Tropical Storm Debby in 2012.
Tommy and Dorothy McIntosh walk away from their daughters flooded home in Live Oak Fla., Wednesday, June 27, 2012. Dozens of homes and businesses were flooded by torrential rains from Tropical Storm Debby. (AP Photo/Dave Martin)
Landfalling hurricanes are even more rare during the month of June. Hurricane Bonnie in 1986 was the last hurricane to make landfall in the U.S. during the month. The Category 1 storm generated peak winds of 85 mph before rolling into High Island, Texas. Bonnie claimed five lives in the U.S. and it triggered more than a foot of rainfall in parts of Texas, including 13 inches in Ace, Texas.
"Only one major hurricane has made landfall in June anywhere in the U.S.," Samuhel said, adding that Hurricane Audrey dealt a devastating blow to southwestern Louisiana when it crashed onshore as a Category 3 storm, packing 125-mph winds, in 1957, and killed more than 400 in the U.S. According to the National Weather Service (NWS), Bonnie ranks as the seventh deadliest storm to make landfall in the U.S. and the third deadliest in Louisiana history.
Dan Kottlowski, AccuWeather's top hurricane expert, and his team of long-range meteorologists, have been hard at work analyzing weather patterns for the upcoming Atlantic hurricane season since late in winter. Kottlowski warned about early season risks in the Gulf of Mexico in his initial forecast for the season, which was released on March 25.
Kottlowski upped the numbers projected for the 2020 season in an early May forecast update. He expressed "growing concern" for an active season due to a La Niña pattern that is expected to develop during the season. La Niña is the cool phase and counterpoint to El Niño -- and it is characterized by three consecutive months of below-normal temperatures in the central and eastern Pacific, near the equator. The team is now predicting 14 to 20 tropical storms and seven to 11 hurricanes, since La Niña patterns can limit episodes of high winds that can disrupt tropical development in the Atlantic.
Four to six of the storms could strengthen into major hurricanes – Category 3 or higher. And Kottlowski warned that four to six named tropical systems could make direct impacts on the U.S mainland, Puerto Rico and the Virgin Islands.
The AccuWeather TV Network on Thursday night hosted its first-ever hurricane town hall. The exclusive one-hour event was moderated by AccuWeather Broadcast Meteorologist Brittany Boyer who led a roundtable discussion with several of the top minds in hurricane forecasting and weather preparedness.
Among those in discussion were National Hurricane Center Director Ken Graham, AccuWeather's own hurricane expert Dan Kottlowski and Trevor Riggen of the American Red Cross, along with several others. Chief among the topics discussed was the impact the coronavirus pandemic will have on preparing for hurricanes this season, which AccuWeather forecasters believe will be very active. If you missed Thursday night's broadcast, check AccuWeather.com for highlights and a recap.
Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier and Verizon Fios
