Colorado State University has maintained its reduced forecast for a well below-average 2026 Atlantic hurricane season, continuing to call for nine named storms, four hurricanes and one major hurricane while putting the Caribbean’s probability of a major-hurricane landfall during the remainder of the season at 17 percent.
The August outlook is unchanged from CSU’s July forecast and substantially lower than where researchers began the season. In April, the team projected 13 named storms, six hurricanes and two major hurricanes. That was lowered in June to 11 named storms, five hurricanes and two major hurricanes, before falling in July to the current projection of nine, four and one, respectively.
Two named storms — Arthur and Bertha — had formed through August 4, but no hurricanes or major hurricanes had developed. CSU therefore expects seven additional named storms during the remainder of the season, including four hurricanes and one major hurricane.
The long-term seasonal averages are approximately 14 named storms, seven hurricanes and three major hurricanes.
Strong El Nino Expected to Suppress Storm Development
CSU researchers cited the high likelihood of a strong El Niño as the principal reason for maintaining the below-average outlook.
El Niño is characterized by warmer-than-normal waters in the eastern and central tropical Pacific. Those conditions tend to strengthen upper-level westerly winds across the Caribbean and tropical Atlantic, increasing vertical wind shear that can disrupt the formation and intensification of tropical cyclones.
Researchers said vertical wind shear across the Caribbean and tropical Atlantic was extremely high during July, providing an early indication that El Niño was already exerting a strong influence on tropical circulation.
Although uncertainty remains about precisely how strong the El Niño event will become, CSU said it is almost certain that a strong event will persist through the remainder of hurricane season.
At the same time, sea-surface temperatures in the tropical Atlantic and Caribbean have warmed modestly in recent months and are now slightly above normal. Those warm waters would ordinarily favor increased hurricane activity, but researchers expect the effects of El Niño to outweigh that influence.
CSU anticipates well-above-normal wind shear will significantly suppress Atlantic hurricane development and said the forecast team has considerable confidence in its below-normal seasonal projection.
2026 Activity Expected at About 40 Percent of Average
Researchers estimate that total Atlantic hurricane activity in 2026 will amount to approximately 40 percent of the 1991-2020 average.
By comparison, activity during the 2025 season reached approximately 105 percent of the historical average.
The most significant storm of that season was Hurricane Melissa, which struck Jamaica as a Category 5 hurricane. The storm caused approximately $12 billion in damage and was blamed for 93 deaths across the Caribbean.
CSU senior research scientist Phil Klotzbach said the current season resembles several previous years associated with suppressed Atlantic activity.
“So far, the 2026 hurricane season is exhibiting characteristics similar to the 1965, 1982, 1987, 1997, 2009 and 2015 seasons,” he said.
“Our analog seasons all had below-average Atlantic hurricane activity,” Klotzbach said. “The relative lack of activity in our analog seasons increases our confidence in a below-normal 2026 Atlantic hurricane season.”
Caribbean Major-Hurricane Probability at 17 Percent
For the remainder of the season, CSU places the probability of at least one major hurricane making landfall somewhere in the Caribbean at 17 percent. The historical full-season average from 1880 through 2020 is 47 percent.
The probability is 16 percent for the entire U.S. coastline, compared with a historical full-season average of 43 percent.
For the U.S. East Coast, including the Florida Peninsula, the remaining-season probability is 7 percent, compared with the historical average of 21 percent. Along the Gulf Coast from the Florida Panhandle westward to Brownsville, Texas, the probability is 9 percent, compared with a 27 percent historical average.
CSU also provides probabilities for named storms, hurricanes and major hurricanes tracking within 50 miles of individual counties or parishes along the Gulf and U.S. East coasts, along with hurricane-prone U.S. and Mexican states, Canadian provinces and countries in Central America and the Caribbean. Those probabilities are adjusted according to the current seasonal outlook.
Despite the comparatively low seasonal numbers, researchers cautioned against interpreting the forecast as a reason to relax hurricane preparations.
“It takes only one storm near you to make this an active season for you,” Michael Bell said.
Forecast Models Point in Same Direction
CSU uses several different approaches to build its seasonal forecast rather than relying on a single model.
The team uses two statistical models and four physics-based models designed to predict the large-scale atmospheric conditions used in its statistical forecast. Those physics-based models come from the European Centre for Medium-Range Weather Forecasts, the UK Met Office, the Japan Meteorological Agency and the Centro Euro-Mediterraneo sui Cambiamenti Climatici.
The statistical models use between 25 and 40 years of historical hurricane-season data and examine forecasts of vertical wind shear across the western Atlantic during August and September.
For the first time this year, CSU is also using a machine-learning model known as the Ai2 Climate Emulator, or ACE2. The model operates using predicted sea-surface temperatures from the ECMWF climate model.
All of the model guidance points toward below-average tropical cyclone activity and above-average vertical wind shear.
Less Storm Energy Expected in Western Atlantic
CSU is also forecasting Accumulated Cyclone Energy, or ACE, which measures tropical cyclone frequency, strength and duration.
Researchers pay particular attention to ACE generated west of 60 degrees west longitude because most hurricane-prone landmasses in the Atlantic are located in that portion of the basin. Storm energy west of that longitude therefore has a stronger relationship with Atlantic landfalls than basinwide ACE.
During El Niño years, a smaller share of total Atlantic ACE generally occurs west of 60 degrees than during La Niña years. With El Niño underway, CSU expects the percentage of basinwide storm energy generated west of 60 degrees to be somewhat below normal this season.
CSU’s August projection calls for an overall ACE of 50, compared with the 1991-2020 average of 123. Through August 4, an ACE of three had been recorded, leaving a forecast of 47 for the remainder of the season.
ACE west of 60 degrees is projected at 25 for the full season, compared with the historical average of 73.
43rd Year of CSU Hurricane Forecasts
This marks the 43rd year that Colorado State University has issued a seasonal Atlantic hurricane forecast.
The late Professor Emeritus Bill Gray began the forecasts in 1984 and continued authoring them until his death in 2016.
CSU emphasizes that its seasonal forecast represents a best estimate of overall Atlantic activity rather than an exact prediction of what will occur.
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