Saturday marks the official start of the 2019 Atlantic Hurricane Season, and the second named storm of the year could already be developing. However, it poses no current threat to the United States.
Forecasters at the National Hurricane Center are watching a disturbance moving into the southern Bay of Campeche, labeling it as having a “medium chance” of developing into a tropical depression or storm by Monday. The system referred to by meteorologists as Invest 91, is expected to move to the west and bring heavy rain to portions of northeast Mexico over the weekend and into early next week. If Invest 91 becomes a tropical storm, it would acquire the name Barry.
Other than Invest 91, no other tropical developments are expected across the Atlantic Ocean, Caribbean Sea or Gulf of Mexico in the next five days. Upper-level winds are quite strong in most areas, which isn't unusual for this time of year and tends to prevent significant storm formation in the tropics. The first named storm of the season, Subtropical Storm Andrea, formed May 18 south of Bermuda, nearly two weeks before the official start to the season. However, it was weak and short-lived.
The more active months for tropical activity are August, September and October. Based on publicly available historical hurricane data, more than 90% of hurricanes form after July 15 and 92% of all major hurricane landfalls in the U.S. have occurred after August 15. The statistical peak of the season occurs during the second week of September.
Forecasters from NOAA, the parent agency of the National Weather Service, released their annual forecast on May 23, stating that a “near average” hurricane season is most likely this year.
This year's forecast has an important caveat: There is considerable uncertainty because of competing climate factors. An El Niño, which is a cyclical warming of the Pacific Ocean that typically suppresses Atlantic Basin hurricanes, is coinciding with a period of above average water temperatures in the western Atlantic Ocean, which tends to favor increased hurricane activity. For this reason, NOAA says there is a 40% chance of near-normal hurricane season, a 30% chance of an above-normal season, and a 30% chance of a below-normal season.
NOAA's forecast is in line with most other agencies, calling for a near-normal season. The seasonal forecasts do not take into account how many storms will steer into the coastline. For example, the active 2010 hurricane season produced 12 hurricanes, none of which made a direct hit on the United States mainland. The relatively quiet 1992 hurricane season had only 4 hurricanes, but Hurricane Andrew — one of the nation's most infamous natural disasters — devastated parts of south Florida that year. For this reason, experts say it's important to prepare for every hurricane season regardless of the seasonal forecast.