High chance subtropical storm could be first named system of 2021
By
Alex Sosnowski, AccuWeather senior meteorologist
Published May 19, 2021 2:32 PM EST
|
Updated May 22, 2021 12:25 AM EST
Satellite showed clouds becoming more organized around the center of low pressure east of Bermuda Friday morning, indicating the development of tropical characteristics. (RAMMB/CIRA)
The official start to the 2021 Atlantic hurricane season, June 1, is about a week and a half away, but AccuWeather forecasters have already been busy monitoring the basin for early tropical development. Since early this week, meteorologists have been tracking one particular area closely, and they say that there's a high chance for a subtropical system, which could be the season's first named storm, to form in the days ahead.
As of Friday, the area of low pressure being watched is still dubbed Invest 90L by the National Hurricane Center. A second area with the potential for further tropical development, known as Invest 91L, also surfaced by early Friday morning in the western Gulf of Mexico, challenging Invest 90L to become the first named tropical system of the 2021 Atlantic Hurricane season.
This is not likely to come as welcome news given the intense season that many Americans weathered in 2020. Last year, the hyperactive hurricane season began early with two systems developing before June 1. Tropical Storm Arthur formed southeast of Florida on May 16, and Tropical Storm Bertha was named after a non-tropical system rapidly strengthened over the western Atlantic, off the Georgia coast, on May 27. The tropical storm crashed ashore near Isle of Palms, South Carolina, a few hours after forming. Bertha unleashed locally flooding rainfall and dangerous rip currents and surf along the coast.
The 2020 season went on to become the busiest on record with 30 named systems. There were so many storms that the Greek alphabet was tapped to name nine different systems once the pre-designated list of names for the season had been exhausted -- a naming convention that will no longer be used by the National Hurricane Center (NHC). A record 11 tropical systems made landfall in the United States in 2020.
The developing feature over the middle of the Atlantic this week is currently non-tropical in nature and is associated with a pocket of cool air high up in the atmosphere. However, occasionally, over time, features such as this can acquire tropical characteristics, provided water temperatures are warm enough to allow such a transition. When this happens, subtropical depressions or storms can be named by the NHC.
"The biggest hurdle this system faces in terms of tropical development is relatively cool water temperatures, which currently range from the middle 60s to near 70 F," AccuWeather Senior Meteorologist Adam Douty said.
"For tropical development we would like to see water temperatures upwards of the middle 70s and preferably near 80 or higher," Douty added.
The feature is forecast to drift slowly to the southwest into the first part of this weekend encountering gradually warmer water.
It will then begin a more northward turn later this weekend. However, this path would put the system fairly close to Bermuda over the weekend.
The most likely time frame for the system to develop enough tropical characteristics to be named would span Friday night to Saturday night.
AccuWeather meteorologists do not expect this storm to develop into anything stronger than a subtropical or tropical depression or storm. However, as it brushes Bermuda, breezy conditions with showers are likely to impact the island nation. "Heavier rain and stronger winds would likely stay to the northeast of the islands," Douty explained.
The first name on the list of tropical and subtropical storms for the Atlantic basin in 2021 is Ana. The last time the name Ana was used to name an Atlantic storm, it was given to another pre-season storm that developed in the basin. In 2015, a subtropical storm formed from a non-tropical system -- in a manner similar to the current feature being watched -- north of the Bahamas. The system went on to strengthen into a tropical storm while over the warm waters of the Gulf Stream on May 9 about 130 miles southeast of Myrtle Beach. It made landfall near North Myrtle Beach in South Carolina the next day.
Should Invest 91L in the Gulf of Mexico also get named, the next name after Ana will be Bill.
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In any event, direct impact on the U.S. is not expected with this system.
Regardless of development, the feature being monitored is expected to be pulled northward and absorbed by a non-tropical system that is forecast to emerge from the southeastern coast of Canada early next week.
Many may wonder whether the early signs of development could signal a busy season ahead, since a similar trend occurred in 2020, and AccuWeather forecasters say there may be some echoes and similar trends to last year, albeit with less non-stop action.
"We are expecting another very busy Atlantic hurricane season for 2021," Kottlowski said.
"There is the potential for more than 20 named storms this season in the Atlantic with three to five impacts anticipated in the U.S," Kottlowski said.
Several tropical systems may continue to churn over the basin from mid-October through November, which is a time when tropical conditions typically diminish. How active the season gets or remains may depend on the return of La Niña.
La Niña is part of a cycle of water temperatures in the tropical Pacific that oscillates between warm and cool patterns. When waters are cooler than average over the tropical Pacific, known as La Niña, the Atlantic is often more active than average in terms of tropical activity. On the other hand, when waters are warmer than average over the tropical Pacific, known as El Niño, the Atlantic is often less active than average.
Currently, water temperatures are relatively close to average over the tropical Pacific, with a neutral phase present. Conditions are expected to remain in this state well into the summer season before a La Niña pattern may develop again. The timing of that transition will be key to just how active the season becomes.
Back in late March of this year, AccuWeather’s team of tropical weather experts, led by Kottlowski, released its annual forecast for the 2021 Atlantic hurricane season. The team predicted 16-20 named storms, including seven to 10 hurricanes. Of the storms projected to reach hurricane strength, three to five are expected to become major hurricanes -- Category 3 or higher storms that have maximum sustained winds of 111 mph or greater.
Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, FuboTV, Philo, and Verizon Fios.
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News / Hurricane
High chance subtropical storm could be first named system of 2021
By Alex Sosnowski, AccuWeather senior meteorologist
Published May 19, 2021 2:32 PM EST | Updated May 22, 2021 12:25 AM EST
Satellite showed clouds becoming more organized around the center of low pressure east of Bermuda Friday morning, indicating the development of tropical characteristics. (RAMMB/CIRA)
The official start to the 2021 Atlantic hurricane season, June 1, is about a week and a half away, but AccuWeather forecasters have already been busy monitoring the basin for early tropical development. Since early this week, meteorologists have been tracking one particular area closely, and they say that there's a high chance for a subtropical system, which could be the season's first named storm, to form in the days ahead.
As of Friday, the area of low pressure being watched is still dubbed Invest 90L by the National Hurricane Center. A second area with the potential for further tropical development, known as Invest 91L, also surfaced by early Friday morning in the western Gulf of Mexico, challenging Invest 90L to become the first named tropical system of the 2021 Atlantic Hurricane season.
This is not likely to come as welcome news given the intense season that many Americans weathered in 2020. Last year, the hyperactive hurricane season began early with two systems developing before June 1. Tropical Storm Arthur formed southeast of Florida on May 16, and Tropical Storm Bertha was named after a non-tropical system rapidly strengthened over the western Atlantic, off the Georgia coast, on May 27. The tropical storm crashed ashore near Isle of Palms, South Carolina, a few hours after forming. Bertha unleashed locally flooding rainfall and dangerous rip currents and surf along the coast.
The 2020 season went on to become the busiest on record with 30 named systems. There were so many storms that the Greek alphabet was tapped to name nine different systems once the pre-designated list of names for the season had been exhausted -- a naming convention that will no longer be used by the National Hurricane Center (NHC). A record 11 tropical systems made landfall in the United States in 2020.
The developing feature over the middle of the Atlantic this week is currently non-tropical in nature and is associated with a pocket of cool air high up in the atmosphere. However, occasionally, over time, features such as this can acquire tropical characteristics, provided water temperatures are warm enough to allow such a transition. When this happens, subtropical depressions or storms can be named by the NHC.
"The biggest hurdle this system faces in terms of tropical development is relatively cool water temperatures, which currently range from the middle 60s to near 70 F," AccuWeather Senior Meteorologist Adam Douty said.
"For tropical development we would like to see water temperatures upwards of the middle 70s and preferably near 80 or higher," Douty added.
The feature is forecast to drift slowly to the southwest into the first part of this weekend encountering gradually warmer water.
It will then begin a more northward turn later this weekend. However, this path would put the system fairly close to Bermuda over the weekend.
The most likely time frame for the system to develop enough tropical characteristics to be named would span Friday night to Saturday night.
AccuWeather meteorologists do not expect this storm to develop into anything stronger than a subtropical or tropical depression or storm. However, as it brushes Bermuda, breezy conditions with showers are likely to impact the island nation. "Heavier rain and stronger winds would likely stay to the northeast of the islands," Douty explained.
The first name on the list of tropical and subtropical storms for the Atlantic basin in 2021 is Ana. The last time the name Ana was used to name an Atlantic storm, it was given to another pre-season storm that developed in the basin. In 2015, a subtropical storm formed from a non-tropical system -- in a manner similar to the current feature being watched -- north of the Bahamas. The system went on to strengthen into a tropical storm while over the warm waters of the Gulf Stream on May 9 about 130 miles southeast of Myrtle Beach. It made landfall near North Myrtle Beach in South Carolina the next day.
Should Invest 91L in the Gulf of Mexico also get named, the next name after Ana will be Bill.
CLICK HERE FOR THE FREE ACCUWEATHER APP
In any event, direct impact on the U.S. is not expected with this system.
Regardless of development, the feature being monitored is expected to be pulled northward and absorbed by a non-tropical system that is forecast to emerge from the southeastern coast of Canada early next week.
Many may wonder whether the early signs of development could signal a busy season ahead, since a similar trend occurred in 2020, and AccuWeather forecasters say there may be some echoes and similar trends to last year, albeit with less non-stop action.
"We are expecting another very busy Atlantic hurricane season for 2021," Kottlowski said.
"There is the potential for more than 20 named storms this season in the Atlantic with three to five impacts anticipated in the U.S," Kottlowski said.
Several tropical systems may continue to churn over the basin from mid-October through November, which is a time when tropical conditions typically diminish. How active the season gets or remains may depend on the return of La Niña.
La Niña is part of a cycle of water temperatures in the tropical Pacific that oscillates between warm and cool patterns. When waters are cooler than average over the tropical Pacific, known as La Niña, the Atlantic is often more active than average in terms of tropical activity. On the other hand, when waters are warmer than average over the tropical Pacific, known as El Niño, the Atlantic is often less active than average.
Currently, water temperatures are relatively close to average over the tropical Pacific, with a neutral phase present. Conditions are expected to remain in this state well into the summer season before a La Niña pattern may develop again. The timing of that transition will be key to just how active the season becomes.
Back in late March of this year, AccuWeather’s team of tropical weather experts, led by Kottlowski, released its annual forecast for the 2021 Atlantic hurricane season. The team predicted 16-20 named storms, including seven to 10 hurricanes. Of the storms projected to reach hurricane strength, three to five are expected to become major hurricanes -- Category 3 or higher storms that have maximum sustained winds of 111 mph or greater.
Related:
Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, FuboTV, Philo, and Verizon Fios.
Report a Typo