Tropical Storm Erin Churns Far Out in the Atlantic

New York Times

a day ago

This year's Atlantic hurricane season has been relatively quiet so far, with just four storms becoming strong enough to merit names, and none strong enough to be hurricanes. But that may be about to change.
Experts at the National Oceanic and Atmospheric Administration released an update on Thursday to their seasonal hurricane forecast, with a very slight adjustment down from their initial estimates in May. They said that the forecast remains on track for an above-average season, and that they still expect to see between five and nine hurricanes before the season ends on Nov. 30.
'Many of the factors we identified ahead of the season are still at play, and conditions are largely tracking along with our May predictions,' said Matt Rosencrans, the lead hurricane season forecaster with NOAA.
The announcement comes as the weather pattern suddenly indicates an increase in storm activity across the Atlantic. Phil Klotzbach, a hurricane expert at Colorado State University, warned that 'over the next two weeks, we could be entering a very active period.'
NOAA's new forecast predicts as many as 18 named storms for the season, which runs from June 1 to Nov. 30. That's just one fewer than the agency predicted before the season started. A storm gets a name when wind speeds reach 39 miles per hour, and it becomes a Category 1 hurricane if those winds reach 74 m.p.h.
The number of named storms includes the four tropical storms that have already formed in the Atlantic this season. Four storms had formed by this time last year, too, before Ernesto, the fifth named storm of 2024, formed on Aug. 12.
On average, the fourth named storm of the year forms by Aug. 15; the first hurricane by Aug. 11. But last year, Hurricane Beryl, the earliest Category 5 Atlantic hurricane on record, was supercharged by excessively warm ocean temperatures that gave the season a violent start.
This season's early storms have not been as intense. But the remnants of Tropical Storm Barry enhanced the rainfall on July 4, which led to devastating flash floods in Central Texas, and then Tropical Storm Chantal flooded the Carolinas days later.
Of the five to nine hurricanes expected this year, NOAA experts predict that two to five could become major hurricanes, defined as a Category 3 or higher. This is similar to the May forecast, when experts said they expected six to 10 hurricanes, and three to five major ones.
This is the time of year when these strong storms tend to be more threatening to land, and forecasters urged people to be ready.
'We are still anticipating a slightly above average probability for major hurricanes making landfall,' Dr. Klotzbach said.
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Homes in Durham, N.C., flooded after heavy rains brought by Tropical Strom Chantal in July.
Credit...
Cornell Watson for The New York Times
Weather patterns have kept Atlantic storms at bay.
The activity in the Atlantic this week comes after a few weather events in July made some hurricane forecasters question their earlier predictions.
The ocean temperatures in the Atlantic this summer have been warmer than usual, which can promote hurricane growth. Still, nothing has been 'too wildly out of line for this time of the year,' said Brian McNoldy, a senior research associate at the Rosenstiel School of Marine, Atmospheric, and Earth Science at the University of Miami. These temperatures, while warm, are still cooler than those of the last two seasons, when the thermal energy from the Atlantic Ocean was at a record high.
In July, another factor in hurricane formation, wind shear — the changing of wind speed and direction — was extremely high across the Caribbean. Picture trying to build a tower of playing cards while industrial fans blow from every direction at varying speeds and heights.
That shear over the Caribbean in July 'typically correlates with a quiet season,' Dr. Klotzbach said, because it keeps storms from organizing into hurricanes.
That shear has weakened, and Dr. Klotzbach said that forecast models indicate it will continue to weaken through August. That is what has allowed this potential burst of activity.
The water temperatures are now warm enough to support hurricanes, Dr. McNoldy said. 'Warm anomalies on top of that do make rapid intensification more likely for storms that develop.'
The Pacific has had an active summer.
The Eastern Pacific has been off to a much faster start this season, with nine storms so far, including Tropical Storm Ivo, which formed on Wednesday and could bring heavy rain to the coast of Mexico.
Pacific storms tend to generate less attention, as storms that form in either ocean generally move west. This means that in the Atlantic, they pose a threat to Eastern North America, but in the Pacific, they more often churn through the open sea. But the activity in the two oceans is connected.
The reason for the activity in the eastern Pacific is a large-scale weather pattern consisting of clouds, rainfall, winds and pressure that slowly circles the globe near the Equator, called the Madden-Julian Oscillation. Typically, this equates to half the world having active thunderstorms across the Earth's midsection, while the other half is calm. Depending on where it is and how long it lasts, the oscillation can enhance hurricane activity. It is now moving into a phase that could enhance activity in the Atlantic.