Fast Start in Tropical Atlantic

Fast Start in Tropical Atlantic

Early Formation of Two Systems in Eastern Atlantic Has Tropics Off and Running

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SOUTH PLAINFIELD, NJ – June is usually a quiet month in the Tropical Atlantic.  While the month signifies the beginning of the Atlantic Hurricane Season, June usually doesn’t kick off the Cape Verde Season.  The months of August and September are normally the peak times for the classic Cape Verde Storms coming off West Africa.  Nevertheless, the fast start in the Tropical Atlantic with two Eastern Atlantic tropical storms over the past week has things off and running, and the weather world talking.

Entering the final week of June 2023, the young season has already tallied three named storms.  Arlene formed back in the first few days of the season with only 40 mph winds.  More recently, Tropical Storm Bret formed and Cindy developed shortly afterward.  Bret nearly reached hurricane strength before passing through the Leeward Islands late this week.  Bret dissipated on Saturday, and Cindy has also shown signs of weakening in a hostile shear environment.  Cindy’s remnants may affect Bermuda later in the week.

Tropical Atlantic Ahead of Schedule

Nevertheless, the fast start in the Tropical Atlantic during the month of June is noteworthy. Three named storms in an Atlantic season’s first 30 days are very rare if not unprecedented.  Usually, the Atlantic doesn’t see its third named storm until the first week of August.  This year the Atlantic Tropics are six weeks ahead of schedule.  The question is will it last?  With a moderately strong El Niño forecasted to develop towards the end of the summer, conditions may not be as favorable by the true peak season.

Above Average Ocean Temperatures

The key factor in this tropical fast start has been the above-normal sea surface temperatures throughout the Atlantic Basin.  While ocean temperatures are quite cool along the mid-Atlantic, the waters from Cape Hatteras southward are very warm.  According to SST Analysis from NOAA, temperatures are running anywhere from just under 76 degrees to as high as nearly 85 degrees from off the coast of Northern Florida to the Outer Banks.  Much of that consists of the warm water current known as the Gulf Stream.

Reviewing data from the Gulf of Mexico, the Caribbean, and the Western Atlantic, you’ll find the water temperatures are even warmer.  Temperatures in those three portions of the Atlantic basin are running anywhere from near 80 degrees to as high as 90.  More importantly, the waters of the Eastern Atlantic are running between 79 and 86 degrees.  One of the factors in tropical cyclone formation is sea surface temperatures of at least 80 degrees.  

Deep Waters of Tropical Atlantic Already Open for Business

The deep waters of the Tropical Atlantic need to bake in the hot summer sun a bit to reach the point where they are just right for formation.  Consequently, the Cape Verde storms and the statistical peak of the season don’t arrive until August and September.  However, early on in the 2023 season, the ocean temperatures in these deep tropical waters are already running very high.  Waves are always coming off Africa throughout the season and the year.  Normally, the waves in June and July would strike cooler waters and fizzle out.  Not this year.

Forming on June 19th, Bret strengthened to nearly a minimal hurricane with 70 mph winds as it approached the Lesser Antilles on Thursday.  Bret continued to move westward across the Leeward Islands into the South Central Caribbean where it dissipated late Saturday afternoon.  Right on the heels of Bret, Cindy emerged on Thursday morning and peaked with 60-mile-per-hour winds on Saturday.  

Tropical Atlantic Conveyor Belt Churning

Taking a peek further eastward in the Atlantic, another vigorous wave with lots of convection has just moved off the African coast.  We will have to see how this new wave holds up in the coming days.  More tropical convection is moving westward along the Sub-Saharan portion of the African continent.  One storm complex, in particular, will be departing into the Eastern Atlantic over the next day or so.  Currently, it is producing showers and thunderstorms over Southwestern Mali, the Northern Ivory Coast, and Eastern Guinea. 

Earlier this year, several seasonal forecasts were issued.  Colorado State University’s forecast from Phil Klotzbach called for a slightly below-normal season in April.  Despite the emergence of a moderate El Niño by the season’s peak, the updated forecast from the beginning of June now calls for a near-normal season.  The Weather Company’s latest update is calling for above-average tropical activity in 2023.  Meanwhile, NOAA issued its forecast in late May and called for a near-normal season.

Complicated Seasonal Hurricane Forecast

The conflicting factors of extremely warm ocean temperatures and the emergence of an El Niño later this summer make the 2023 hurricane season forecast a challenge.  The conflict is already evident with the quick start in the Atlantic.  Last season turned out to be a roller coaster year in the Atlantic tropics.  Within the first 33 days of the season, three named storms emerged in the Atlantic a year ago as well.  Then, the basin went nearly two months without a named storm before the active cycle kicked in from September to November.

Seasonal forecasts are a way to get the public prepared.  Giving coastal residents an idea of what is to come each hurricane season is a means to get them ready.  It is roughly gauging how much activity there will be in the basin.  The forecasts are not written in stone.  In addition, a near-normal, below-average, or above-average season doesn’t tell whether or not there will be a landfalling major hurricane in the United States.  All it takes is one devastating and deadly storm to throw the numbers out the window.

Devastating Storms in Below-Average Years

There have been a number of below-average seasons that produced a significant landfalling storm in the United States.  Most recently in 1992, Hurricane Andrew became the first named storm of the season on August 14th.  Andrew went on to be one of the most destructive U.S. hurricanes of all time.  In 1935, the Labor Day Hurricane that roared through the Florida Keys developed during a below-average year.  Several years later, the Long Island Express of 1938 became another deadly and devastating storm in a below-average year.

The fast start in the Tropical Atlantic doesn’t necessarily mean an active finish.  Two named storms forming in the Eastern Atlantic this early is unusual.  When El Niño does begin to kick in, will it temper the tropical activity in the Atlantic?  Normally, it should, but with above-average sea surface temperatures in the Atlantic Basin, a moderate El Niño emergence may not be enough to slow the ongoing active cycle down.