First tropical storm of hurricane season may form prior to end of May
North America is waiting on the first tropical storm of the 2025 season, but one forming may be just days away on the eastern Pacific side.
AccuWeather’s Melissa Constanzer and Ariella Scalese monitor the eastern Pacific where a tropical rainstorm will likely develop into the first storm, Alvin, of the Pacific hurricane season.
There are no signs of tropical activity in the Atlantic basin over the next few days. However, a tropical rainstorm in the Pacific basin is on the verge of further organization and may be on its way to a tropical depression or tropical storm in the next one to three days, AccuWeather meteorologists say.
This image of the tropical eastern Pacific and Central America was captured on Wednesday, May 28, 2025. It reveals a budding tropical rainstorm off the west coast of Central America and south of Mexico. (AccuWeather Enhanced RealVue™ Satellite)
"This tropical rainstorm we are watching could wander close enough to part of the southwestern coast of Mexico to bring locally drenching rain," AccuWeather Meteorologist Alex DaSilva said.
There is a chance the current tropical rainstorm may wander far enough to the north along the west coast of Mexico to allow some moisture in the form of clouds and downpours to reach parts of Texas or New Mexico as early as this weekend.
What's ahead for the eastern Pacific hurricane season?
The eastern Pacific hurricane season began May 15 and runs through Nov. 30.
AccuWeather's meteorologists expect 14-18 tropical storms and seven to 10 hurricanes for the eastern Pacific in 2025. The historical average numbers are 15 and four, respectively.
The tropical rainstorm in the eastern Pacific could mark the first tropical system of the season in either basin bordering North America.
The first name on the eastern Pacific storm list for 2025 is Alvin.
The average date for the first tropical storm of the eastern Pacific season is June 10, according to the National Hurricane Center. If a storm forms soon, it would be well ahead of the historical pace — and much earlier than last year’s first storm. In 2024, Aletta didn’t form until July 4, marking the latest start to an eastern Pacific hurricane season in the satellite era.
The average first hurricane in the eastern Pacific typically forms by June 26.
2025 eastern Pacific hurricane season could bring US impacts
The eastern Pacific hurricane season could bring notable indirect impacts to the southwestern United States.
"While a repeat of the tactics of Hurricane Hilary from August 2023 is not anticipated, a heavy amount of tropical moisture could be pumped into the Southwest in addition to what is likely to be an active (drenching) North American monsoon season for New Mexico and Arizona," AccuWeather Lead Long-Range Meteorologist Paul Pastelok said.
Hilary peaked as a Category 4 major hurricane with maximum sustained winds of 160 mph over the warm waters of the eastern Pacific. After weakening, Hilary pushed inland over Southern California as a tropical rainstorm, unloading several inches of rain and triggering major flooding. Downtown Los Angeles picked up nearly 3 inches of rain from Hilary, where the month is typically bone dry. The deluge even turned Death Valley into a temporary lake.
Hilary was blamed for multiple fatalities, and total damage was estimated at $1 billion.
"With waters starting off cooler than historical average and likely to continue through the summer off of California, the circulation of any non-tropical storm offshore that forms could help pump moisture and generate heavy rainfall in not only New Mexico and Arizona, but perhaps Southern California and Nevada as well late in the summer season," Pastelok said. "It is a lot of ifs, but that is something we are looking at closely."
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