Halfway through an Atlantic hurricane season that forecasters expected would be one of the most active on record, there has been a considerable interlude in storms during what is typically the busiest portion of the season, leaving observers to wonder if the forecast was a bust — or if the worst may be yet to come.
Often, at this time of the year, it isn’t uncommon to see two, three or even four named storms occurring simultaneously. But on Wednesday there were no current storms, and there hasn’t been one since Hurricane Ernesto formed, beginning as a tropical storm, on Aug. 12. A quiet spell this significant has not been seen during this part of the season since 1968, according to Phil Klotzbach, a researcher of hurricane activity at Colorado State University.
Dr. Klotzbach — whose team predicted in April that there would be 23 named storms this year — joked that when the season ends in November, he may be eating crow for dinner. He won’t be alone at the table: More than two dozen private, academic and government metrological institutions, including the National Oceanic and Atmospheric Administration, also predicted a hyperactive season.
At the beginning of last month, all signs still pointed to a thriving, above-average season after a strong start with four other named storms before Ernesto. In late June and early July, Hurricane Beryl had broken records as a Category 5 storm as it spun across the Caribbean Sea, thrashing islands with wind and rain.
The first weeks of August had consistent storms, including Debby, which brought a deluge of rain to Florida and the Carolinas. Then, activity halted. And while on Wednesday there were four areas of concern across the sea from North America to Africa — areas that may or may not develop into named storms — the forecast will most likely remain below average for the next two weeks.
Despite the reprieve in recent weeks, though, “it is too early to dismiss the seasonal hurricane outlook as a bust,” said Dan Harnos, a meteorologist at the NOAA Climate Prediction Center. “The typical peak of the season is not until Sept. 10, while more hurricane activity historically occurs following the peak than prior to it.”
In early August, NOAA — which in May had predicted between 17 and 25 named storms — issued a midseason update in which it continued to predict the season could rank among the busiest on record, with as many as 24 named storms. (A tropical storm gets a name when its sustained wind speeds reach 39 miles per hour, and it becomes a hurricane when they reach 74 m.p.h.)
The last time Dr. Klotzbach was nervous about his forecast was during a shorter lull last year — right before everything took off for the season. After a nearly one-month break from late July to late August, no storms formed. Then, within days, Emily, Franklin, Gert, Harold and Idalia formed, and the season ended with 20 named storms. Dr. Klotzbach thinks this season may yet pick up during the second half.
He pointed out that a La Niña weather pattern (a cooling change to ocean temperature in the Pacific that reduces a wind pattern that enables hurricane development in the Atlantic) is forecast to form, which, when combined with warm Caribbean Ocean temperatures, will most likely enhance storm activity late in the season.
Here’s what would have to change to see more hurricanes.
In the record-breaking 2020 season, 13 named storms formed after the official midway point on Sept. 10. That year, nine of them grew strong enough to become hurricanes, and six of those hurricanes reached major strength, meaning they were Category 3 or higher.
For that to happen this year, one of the main factors sequestering the season right now will have to change: The storm track across Africa has to shift.
Storms have been incredibly active there, creating heavy rains across the continent, which is usually a harbinger of a busy hurricane season for the Atlantic. However, over the last several weeks, that line of storm systems in Africa has moved farther north, and each storm has moved off the continent and over a much cooler part of the Atlantic Ocean, off the coast of northern Mauritania, that isn’t as conducive for hurricanes to grow. If the line of storms shifts only slightly south over Senegal, and storms move west over the excessively warm ocean temperatures, that could indicate that activity may ramp up again.
Another suppressing factor is that the air is too warm above the region where hurricanes typically form. This warmer air aloft could be stabilizing the rest of the air closer to the surface, and instead of letting the warmer, moist air near the ocean surface bubble up into thunderstorms, it is putting a lid on their growth. This warmer air will begin to cool as the autumn season takes hold.
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