Four tropical or subtropical storms have formed this season — an unnamed oddball in January that was first missed by the National Hurricane Center, then Arlene, Bret and Cindy. The latter two already hold records as the farthest eastward-forming June storms observed in modern times.
Hurricane season usually peaks in late August and September, but it doesn’t officially end until November. 30. It is likely that in the next month or two there will be an increase in activity, and some experts are already expecting an increased possibility of a major storm to hit. in the United States.
“The probability of major hurricane landfall in the US is estimated to be above the long-term average,” Philip Klotzbach, a hurricane researcher at Colorado State University, wrote in an updated hurricane outlook release. Thursday.
Colorado State’s revised vision
The Colorado State University team, which initially predicted a quieter-than-normal season, upped their predictions Thursday, suggesting the following:
- 18 called typhoon, including the four that have already happened. The 1991-2020 average is 14.4.
- Nine storms. At the start of the season, the team only predicted six. The long-term average is 7.2 per season.
- Four great storms, or double what they originally expected. A season has 3.2 major hurricanes on average. Major hurricanes are Category 3 or greater hurricanes with winds of 111 mph or greater.
- A 50 percent chance of a major hurricane hitting the United States. The full-time probabilities averaged from 1880 to 2020 are 43 percent for a period.
- A 25 percent chance of a major East Coast hit, and a 32 percent chance in a big storm hit the US Gulf Coast.
Klotzbach, the lead author of the report, Tweet that “anomalous warmth” in the Atlantic prompted a more aggressive forecast.
Colorado State joined the British Met Office and a team at the University of Pennsylvania in predicting a busy season. Many other forecasts, including the National Oceanic and Atmospheric Administration’s outlook, call for near-average activity, but that’s done in May when ocean waters aren’t as warm as they are now.
Clarification of revised forecasts
Early weather forecasts focused heavily on the expected arrival of El Niño, a climate pattern that begins to warm the equatorial waters of the eastern tropical Pacific and changes to shuffle the setting in important parts of the world. That warming of the Pacific waters increases the upwelling of air there, which in turn drives subsidence, or sinking, over the Atlantic. That often stops tropical activity. El Niño also strengthens the high level of Atlantic air that interferes with thunderstorm development, another negative factor.
Despite the emergence of El Niño, however, forecasters only think that the warmer waters of the Atlantic Ocean, running 1 to 2 degrees above average, will win.
“Sea surface temperatures in the eastern and central tropical Atlantic are already at record levels, so despite the high potential for El Niño, the effects of the tropical Atlantic/Caribbean vertical wind shear may not be as strong. in the generally experienced because of extreme heat. Atlantic,” Klotzbach wrote in the report.
Four tropical-storm-strength systems have occurred in the Atlantic so far in 2023:
- Unnamed subtropical storm. On January 16, the National Hurricane Center issued a special tropical weather outlook, highlighting a suspicious part of the open Atlantic but indicating that it will not develop. It was a pinched-off pocket of thunderstorms at the core of a large sprawling mid-latitude low-pressure system — both prompting wind warnings in Nova Scotia and dumping 3.5 inches of snow on Boston . That convection, or thunderstorm activity, takes on a life of its own. It separated from the fronts, and satellites showed it had tropical-storm-force winds, which the National Hurricane Center discovered in post-analysis.
- Arlene. In late May, a disturbance in the Bahamas began west of the Florida Straits. It strengthened and investigated the plane, which received the name Arlene on June 2 while in the southeastern part of the Gulf of Mexico. But it didn’t last long; harsh winds and dry air caused its disappearance.
- Bret formed over the Atlantic’s Main Upwelling Region, or the strip of warm water between the Lesser Antilles and west Africa, about a month ahead of schedule; that part of the ocean doesn’t usually produce hurricanes until around August. Bret’s formation on June 19 about 1,295 miles east of the Windward Islands marked the farthest southeast-forming storm observed so early in the season. It hovered near hurricane strength before passing north of Barbados and St. Vincent on June 22-23. Winds gusted to 69 mph at Hewanorra International Airport in Saint Lucia.
- Cindy formed from a tropical wave following Bret. It was named on June 23 and developed into a 60 mph storm over the open Atlantic before moving into a remnant low during the evening of June 25.
The combination of Bret and Cindy marked the first time on record that two hurricanes formed in the Atlantic Ocean east of the Caribbean in June.
Right now, the Atlantic is very warm. That’s because of a nudge from climate change, and also a series of dominoes toppled by meteorological coincidences.
In June, the Bermuda High – a semi-stagnant ridge of high pressure extending from Bermuda to the Azores – weakened significantly. The weakening of the high decreases in the easterly trade winds over the tropical belt of the Atlantic. That air leakage means less vertical mixing of ocean waters; there is not enough breeze to blow the cooler water from below, and so the surface waters of the sea are able to cook.
Weaker winds may also have reduced the transport of sun-blocking Saharan plumes, which may have slowed ocean warming.
Abnormally warm waters will help fuel any disturbance that moves across the Atlantic in the coming weeks. But so far, the Hurricane Center has not identified any disturbances that may occur in the next seven days.
