Eastern Pacific to churn out more tropical storms before Atlantic activity begins

Yahoo

10-06-2025

The eastern Pacific Ocean will remain active in the coming days and weeks with more chances for tropical storms, AccuWeather meteorologists say. Meanwhile, the Atlantic is likely to remain quiet through the end of June, despite some early hints at tropical formation.
The eastern Pacific hurricane season officially began on May 15, which was about two weeks ahead of the official start to the Atlantic hurricane season on June 1.
"This year was one of the latest starts to any tropical activity in the Northern Hemisphere, which not only includes the Atlantic and the eastern Pacific, but also the western Pacific," AccuWeather Meteorologist and Senior Content Editor Brian Lada said.
Eastern Pacific has turned things around, is moving swiftly along
Last year, the eastern Pacific got off to a record slow start with Tropical Storm Aletta not forming until July 4.
This year, Tropical Storm Alvin formed on May 28, or about two weeks after the start of the season, but about two weeks ahead of the historical average for the first tropical storm. Alvin only lasted a few days and peaked as a 60-mph tropical storm over the open waters. Moisture from Alvin caused localized flooding in parts of Central America and Mexico, and some rain even reached parts of the south-central United States.
•Have the app? Unlock AccuWeather Alerts™ with Premium+
Just days after Alvin's demise, two more tropical storms formed in the waters west of Central America and southwest of Mexico in the Pacific. Suddenly, the eastern Pacific jumped well ahead of the historical average pace and even set an early-season formation record. Barbara was named on June 4 and two days later, Cozme formed in roughly the same zone.
Barbara went on to become a hurricane on June 9. However,, that status only lasted a matter of hours before slipping back to tropical storm intensity.
"Barbara was the first hurricane or typhoon in the Northern Hemisphere this year," AccuWeather Meteorologist and Digital Producer Jesse Ferrell said, "Not since 1993 has the first hurricane-force storm been seen this late."
Despite that late start in the Northern Hemisphere, the flurry of named systems in the eastern Pacific has taken center stage.
The second named storm, Barbara, as a tropical storm and hurricane, is also ahead of schedule for the East Pacific basin. The second tropical storm typically forms around June 24 and the first hurricane about June 26.
Cosme, the third named storm of this season, is also way ahead of schedule and one of the earliest third-named storms on record, with the historical average formation date of July 6.
"The basin has seen plenty of storms form early, with 44 storms, including 19 hurricanes, forming in May in the historical record," Ferrell said.
Yet another tropical storm is likely be just days away from forming in the eastern Pacific. The next name on the list of tropical storms for the 2025 eastern Pacific hurricane season is Dalila.
It is possible that, toward the middle and latter part of the summer, downpours from an eastern Pacific tropical rainstorm may enhance the North American monsoon and could bring heavy rainfall to parts of the southwestern U.S.
Atlantic still waiting on first storm of 2025
For early-season development in the Atlantic to get a boost, meteorologists look for a front that dips down into the Gulf, Caribbean or Bahamas waters. Another way is for a large area of low pressure to form and slowly spin near Central America. This is known as a gyre.
Thus far, fronts dipping in have been unsuccessful at initiating tropical development, and the gyre has failed to fully develop.
"We still expect the Central American gyre to form later this month, and its formation could spur tropical development in waters in the western Caribbean or southwestern Gulf," AccuWeather Lead Hurricane Expert Alex DaSilva said.
Although the gyre has yet to develop, another critical weather pattern is delaying the start of the Atlantic season-a large area of high pressure over the central Atlantic, known as the Bermuda high.
A strong Bermuda high can force budding tropical storms to track close to North America, assuming the tropical storms can form in the first place. Early in the season, that can be a challenging task, especially with water temperatures well short of their peak for the season.
"The Bermuda high has been stronger than average this season and has helped to bring more dry air from northern Africa and dust (grains of sand) from the Sahara Desert westward across the Atlantic so far," DaSilva explained, "This, along with a significant amount of disruptive breezes, called wind shear, has greatly contributed to the slow start to the Atlantic hurricane season."
AccuWeather is expecting a near- to above-historical-average Atlantic tropical storm and hurricane season for 2025. Between three and six named tropical cyclones are forecast to directly impact the U.S.
Based on the historical average, the first tropical storm does not form in the Atlantic until June 20 and the first hurricane not until Aug. 11.
In 1992, for example, the first tropical storm did not form until Aug. 16. That storm would go on to become Category 5 Hurricane Andrew and would tear a swath of destruction across South Florida during the last week of August.
Want next-level safety, ad-free? Unlock advanced, hyperlocal severe weather alerts when you subscribe to Premium+ on the AccuWeather app. AccuWeather Alerts™ are prompted by our expert meteorologists who monitor and analyze dangerous weather risks 24/7 to keep you and your family safer.