Plenty of Activity in the Eastern Pacific as Atlantic is Calm

The Eastern Pacific basin is brimming with tropical activity while the Atlantic Ocean continues to remain docile. Will this trend continue as the month of June progresses? Read on for all of the details.

Tale of Two Contrasting Situations in the Eastern Pacific and the Atlantic

Forecasters with the National Hurricane Center (NHC) are signaling that the fourth tropical event of the season will form in the Eastern Pacific before the Atlantic basin sees its first named feature. The Eastern Pacific hurricane season officially got underway on May 15, roughly two weeks ahead of the designated start day of June 1 in the Atlantic. The earlier start date in the Pacific compared to the Atlantic is in response to activity typically beginning earlier in this part of the world.

The 2024 season was exceptionally slow to get going in the Eastern Pacific. Tropical Storm Aletta did not form until July 4, making it one of the latest starts to the season in the Northern Hemisphere. It has been the opposite situation this year in the Eastern Pacific with three named storms already on the record books.

Tropical Storm Alvin came to life on May 28, just two weeks after the start of the season and two weeks ahead of the average date for tropical development in this part of the world's oceans. Alvin hung on for a few days as it churned through the waters, peaking with winds of 60 mph. The moisture associated with Alvin created localized flooding in parts of Central America and Mexico. Some of the leftover rain showers created by Alvin moved into the south-central portions of the U.S.

Two new tropical storms formed in the area west of Central America and southwest of Mexico in the days after Alvin dissipated. This production put the Eastern Pacific well over the historical average pace, setting a record for early-season activity.

Tropical Storm Barbara formed on June 8, becoming a hurricane the next day. Barbara only lasted a few hours as a hurricane before it came into prohibitive conditions that knocked it back to a tropical storm. Cosme became the third named storm of the season for the Eastern Pacific. Both Barbara and Cosme have devolved into remnant lows and are no longer being monitored.

For historical perspective, the second tropical storm in this part of the oceans typically happens around June 24 with the first hurricane forming on an average date of June 26. Cosme was also well ahead of the historical averages. The third named feature of the season typically forms on July 6.

The Eastern Pacific is no stranger to early-season development. Since recorded history, there have been 44 tropical storms, including 19 hurricanes, that have come together in the month of May.

The activity is not likely to ease anytime soon. Forecasters are predicting that the fourth tropical storm of the season is days away from springing to life in the Eastern Pacific. The next name up on this list is Dalila.

While these features in this part of the Pacific generally do not impact the U.S., the moisture coming along for the ride is likely to enhance the downpours that distinguish the Northern American monsoon season by the middle and latter part of the summer season. The monsoonal rains are most common this time of the year in the southwestern U.S.

What is Keeping Tropical Activity in the Atlantic Suppressed?

Meanwhile, interests in the Atlantic basin are still waiting for the first named storm of the year. Early season development in the Atlantic generally happens when fronts creep far enough to the south into the Gulf and the Caribbean. These storms can also pop up early in the season as a result of the presence of a Central American gyre.

However, a gyre has not yet come to fruition and any arriving fronts have failed at supporting tropical development. The latest long-range forecast models indicate that a Central American gyre is likely to come together later in June. This development could prime the area of the western Caribbean Sea or southwestern Gulf for tropical action.

While the anticipated gyre has yet to materialize, another element is also pushing back the start of the Atlantic. The large area of high pressure positioned over the central Atlantic, known as the Bermuda high, has been stronger than normal thus far this year. This strength has sucked in more dry and dusty air from northern Africa and the Sahara Desert. The mass of dust has worked to mitigate the threat of tropical weather.

Additionally, ocean water temperatures are trending below their peak readings. Lastly, significant amounts of wind shear are also putting a lid on tropical weather development in the Atlantic.

Forecasters are still in agreement that the Atlantic basin is in store for a slightly higher number of tropical features this year. The first tropical storm in the Atlantic typically happens around June 20. The first hurricane of the season generally does not make an appearance until early to mid-August. So while the lack of action is a bit curious so far, it is still well within normal ranges.

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