In early September Hurricane Dorian reached Category 5, becoming the second strongest hurricane on record before downgrading over the Atlantic off the Eastern Coast of the U.S. As the peak of the 2019 hurricane season passes, our analyses indicate that the 2019 season overall could end up the quietest season in 4 years, despite a forecasted near normal year with respect to total storm number, hurricanes, and major hurricanes.
Averages, Trends, Forecasts & Factors
The average historical annual hurricane activity is 11 named storms of which 6 are typically hurricanes and 2.5 are category 3 or higher. Our Refinitiv Weather team forecast for 2019, released in April, was for 13 named storms, 7 hurricanes, and 3 major hurricanes from June-November, 2019.
The most consecutive years with at least one Category 5 hurricane each is four, from 2016 to 2019.
Interestingly, the number of Category 4 and 5 hurricanes has doubled over the past 35 years. Major hurricanes are dependent upon warm sea surface temperatures (SSTs) in the Atlantic. There is a ~60-year climate oscillation of Atlantic SSTs called the Atlantic Multi-Decadal Oscillation (AMO). The AMO moves between warm and cool phases that each last about 30 years. Thus the 35-year trend toward more major hurricanes corresponds to a warm phase of the AMO, explaining a portion of the increase.
Lower Atlantic Hurricane Activity Than The Past 3 Years, After A Consensus For At Least A Near Normal Season
A statistical model and historical analog analysis showed a strong consensus for a near-normal 2019 season likely to avoid extremes, based on the Refinitiv Weather team’s forecast issued in April. Though the forecast numbers were all slightly above normal, the breakdown of the analogs suggested that an inactive season was more probable than a very active season. Since the forecast was issued, El Niño conditions have collapsed, which made an inactive season unlikely. Given current (Hurricane Humberto) and anticipated tropical cyclone activity through the next 1-2 weeks, 2019 is on track for a near normal to slightly active season.
Gulf of Mexico Interests Could Benefit From A Quiet 2019, With Higher Activity Focused Along The U.S. East Coast
After several consecutive years of high impact storms around North America, 2019 could offer a reprieve in some critical areas for oil/agricultural interests in particular.
The Gulf of Mexico showed a lower than normal risk for hurricane impacts, while a zone of elevated activity was likely from the Atlantic Main Development Region (MDR) through portions of the U.S. East Coast. If these risks continue to verify, oil interests should enjoy a quiet season with minimal hurricane interruptions, while natural gas/shipping interests along the eastern coastline may experience more adverse effects from the remaining peak hurricane season through October.
Updates can be monitored in the tropical section of the Weather App in Eikon.