Atlantic hurricane season off to a slow start as El Niño strengthens
While activity has ramped up in the Pacific Ocean over the last month, the Atlantic activity levels have been on the quieter side. Find out what factors could lead to an uptick in activity as the month goes on.
Cruise lines do everything they can to avoid canceling a cruise, but that could mean significant changes to your itinerary if you’re sailing during hurricane season.
As summer heats up, so too does the water across the Atlantic and Pacific oceans, a key ingredient for tropical storms during hurricane season. However, more than warm water is needed to spin up a storm, including one of the biggest players in global weather patterns.
Atlantic basin: Warm water isn't the whole story
The Atlantic basin remains quiet for now, while the Pacific Ocean has already produced several powerful storms this season.
The contrast between the two oceans largely reflects the current global weather pattern, with strengthening El Niño conditions favoring more tropical activity in the Pacific than the Atlantic. Often, El Niño leads to reduced activity over the Atlantic waters due to more frequent periods of disruptive winds, known as wind shear.
Wind shear, or changes in wind speed and direction with height in the atmosphere, plays a critical role in tropical development. Strong wind shear can disrupt a storm's structure and prevent it from strengthening. In contrast, weaker wind shear allows storms to organize and intensify, provided other favorable conditions are also in place.
That is exactly the pattern unfolding across the Atlantic, where wind shear and dry Saharan air have kept the basin largely quiet despite otherwise favorable ocean conditions.
At this point in the season, it is not entirely unusual to have a lull in tropical activity across the Atlantic waters. On average, the second named storm of the Atlantic season forms by July 17.
The second half of the month may be more active than recent weeks, however.
One ingredient the Atlantic is not lacking is warm water. Sea surface temperatures across the basin remain above the historical average, providing ample fuel for tropical systems.
AccuWeather Lead Hurricane Forecaster Alex DaSilva highlights, "Very warm Atlantic sea surface temperatures, especially along the United States, can allow tropical storms and hurricanes to develop and rapidly intensify much closer to the U.S. coastline."
"As a result, residents may have significantly less time to prepare than they would if storms formed near Africa and tracked across the Atlantic," warns DaSilva.
He added, "It will be especially important to closely monitor every tropical wave this season. Some tropical waves may remain disorganized while crossing the Atlantic, only to develop and intensify once they reach the exceptionally warm waters near the United States."
Eastern Pacific basin
AccuWeather hurricane experts have highlighted two zones off the coast of Mexico in the eastern Pacific Ocean. One zone has a high risk of tropical development and the other has a medium risk.
A third area of potential tropical development has been highlighted south of Hawaii for mid-July, carrying a medium risk of development. A fourth area has also been identified south of Hawaii, though it currently has only a low risk of development.
If development does occur in any of these areas, forecasters expect limited, if any, direct impacts to land.
Sea surface temperatures are plenty warm enough to support development in the East Pacific basin, and wind shear levels are expected to decrease into mid-July.
Western Pacific basin
Over the last week, two potent storms developed over the western Pacific waters, one of which is still leaving a path of destruction.
Typhoon Bavi peaked with 10-minute sustained winds of 127 mph and gusts to 178 mph as it approached Guam and Saipan, equivalent to a high-end Category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. As it crossed Guam and made a direct impact, more than 1 foot of rainfall has been observed so far with hurricane-force wind gusts.
Bavi will continue tracking toward the northwest over the coming days before approaching Taiwan and China.
A separate storm, Maysak, was originally known as Iow/Henry around the Philippines late last week before moving across the South China Sea into China with rain and wind.
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