El Niño and extreme Atlantic Ocean heat are about to clash
Published: Monday, June 5, 2023 |
JAMAICA GLEANER
NOAA via AP
This GOES-East GeoColor satellite image taken Friday, June 2 at 1:21 p.m. EDT., and provided by NOAA, shows Tropical Storm Arlene, the first named storm of the Atlantic hurricane season, in the Gulf of Mexico off the west coast of Florida.
The Atlantic hurricane season started on June 1, and forecasters are keeping a close eye on rising ocean temperatures, and not just in the Atlantic.
Globally, warm sea surface temperatures that can fuel hurricanes have been off the charts in the spring of 2023, but what really matters for Atlantic hurricanes are the ocean temperatures in two locations: the North Atlantic basin, where hurricanes are born and intensify, and the eastern-central tropical Pacific Ocean, where El Niño forms.
This year, the two are in conflict – and likely to exert counteracting influences on the crucial conditions that can make or break an Atlantic hurricane season. The result could be good news for the Caribbean and Atlantic coasts: a near-average hurricane season. But forecasters are warning that that hurricane forecast hinges on El Niño panning out.
NOAA via AP
This GOES-East GeoColor satellite image taken Friday, June 2 at 1:21 p.m. EDT., and provided by NOAA, shows Tropical Storm Arlene, the first named storm of the Atlantic hurricane season, in the Gulf of Mexico off the west coast of Florida.
The Atlantic hurricane season started on June 1, and forecasters are keeping a close eye on rising ocean temperatures, and not just in the Atlantic.
Globally, warm sea surface temperatures that can fuel hurricanes have been off the charts in the spring of 2023, but what really matters for Atlantic hurricanes are the ocean temperatures in two locations: the North Atlantic basin, where hurricanes are born and intensify, and the eastern-central tropical Pacific Ocean, where El Niño forms.
This year, the two are in conflict – and likely to exert counteracting influences on the crucial conditions that can make or break an Atlantic hurricane season. The result could be good news for the Caribbean and Atlantic coasts: a near-average hurricane season. But forecasters are warning that that hurricane forecast hinges on El Niño panning out.
INGREDIENTS OF A HURRICANE
In general, hurricanes are more likely to form and intensify when a tropical low-pressure system encounters an environment with warm upper-ocean temperatures, moisture in the atmosphere, instability, and weak vertical wind shear.
Warm ocean temperatures provide energy for a hurricane to develop. Vertical wind shear, or the difference in the strength and direction of winds between the lower and upper regions of a tropical storm, disrupts the organisation of convection – the thunderstorms – and brings dry air into the storm, inhibiting its growth.
THE ATLANTIC OCEAN’S ROLE
The Atlantic Ocean’s role is pretty straightforward. Hurricanes draw energy from warm ocean water beneath them. The warmer the ocean temperatures, the better for hurricanes, all else being equal.
Tropical Atlantic Ocean temperatures were unusually warm during the most active Atlantic hurricane seasons on recent record. The 2020 Atlantic hurricane season produced a record 30 named tropical cyclones, while the 2005 Atlantic hurricane season produced 28 named storms, a record 15 of which became hurricanes, including Katrina.
HOW THE PACIFIC OCEAN GETS INVOLVED
The tropical Pacific Ocean’s role in Atlantic hurricane formation is more complicated.
You may be wondering, how can ocean temperatures on the other side of the Americas influence Atlantic hurricanes? The answer lies in teleconnections. A teleconnection is a chain of processes in which a change in the ocean or atmosphere in one region leads to large-scale changes in atmospheric circulation and temperature that can influence the weather elsewhere.
When the tropical eastern-central Pacific Ocean is unusually warm, El Niño can form. During El Niño events, the warm upper-ocean temperatures change the vertical and east-west atmospheric circulation in the tropics. That initiates a teleconnection by affecting the east-west winds in the upper atmosphere throughout the tropics, ultimately resulting in stronger vertical wind shear in the Atlantic basin. That wind shear can tamp down hurricanes.
That’s what forecasters are expecting to happen this summer. The latest forecasts show a 90 per cent likelihood that El Niño will develop by August and stay strong through the fall peak of the hurricane season.
A TUG OF WAR
My research and work by other atmospheric scientists has shown that a warm Atlantic and a warm tropical Pacific tend to counteract each other, leading to near-average Atlantic hurricane seasons.
Both observations and climate model simulations have shown that outcome. The National Oceanic and Atmospheric Administration’s 2023 forecast calls for a near-average 12 to 17 named storms, five to nine hurricanes, and one to four major hurricanes. An earlier outlook from Colorado State University forecasters anticipates a slightly below-average season, with 13 named storms, compared with a climatological average of 14.4.
THE WILD CARDS TO WATCH
Although tropical Atlantic and Pacific Ocean temperatures often inform skilful seasonal hurricane forecasts, there are other factors to consider and monitor.
First, will the forecasted El Niño and Atlantic warming pan out? If one or the other does not, that could tip the balance in the tug of war between the influences.
The Atlantic Coast should be rooting for El Niño to develop as forecast, since such events often reduce hurricane impacts there. If this year’s expected Atlantic Ocean warming were instead paired with La Niña – El Niño’s opposite, characterised by cool tropical Pacific waters – that could have led to a record-breaking active season instead.
Two other factors are also important. The Madden-Julian Oscillation, a pattern of clouds and rainfall that travels eastward through the tropics on a time scale of 30 to 90 days, can either encourage or suppress tropical storm formation. And dust storms from the Saharan air layer, which contains warm, dry and dusty air from Africa, can suppress tropical cyclones.
Christina Patricola is assistant professor of Atmospheric Sciences, Iowa State University. This article is republished from The Conversation under a Creative Commons licence. Read the original article here: https://theconversation.com/atlantic-hurricane-season-2023-el-nino-and-e...
The 2023 Atlantic hurricane season is under way – Here’s what to know
Published:Monday | June 5, 2023 | 1:01 AM
AP
Mike Brennan, director of the National Hurricane Center, speaks during a news conference on May 31.
MIAMI (AP):
It’s time for residents along the southeastern US coastlines to make sure their storm plans are in place as the 2023 Atlantic hurricane season got under way last Thursday.
Forecasters are predicting a “near-normal” season, but Mike Brennan, the new director at the National Hurricane Center in Miami, stressed during a Wednesday news conference that there’s really nothing normal when it comes to hurricanes.
“A normal season might sound good in comparison to some of the hurricane seasons in the past few years,” he said. “But there’s nothing good about a near-normal hurricane season in terms of activity.”
WILL THE 2023 ATLANTIC HURRICANE SEASON BE BUSY?
Uncertainty is the key word, Brennan said.
The National Oceanic and Atmospheric Administration predicted in late May a 40 per cent chance of 2023 being a near-normal hurricane season; a 30 per cent chance of an above-average season, which has more storms than usual; and a 30 per cent chance of a below-normal season, which has fewer.
“So we’re expecting a busy season with 12 to 17 named storms,” Brennan said, adding that five to nine of those storms could become hurricanes, with one to four growing into major hurricanes.
“It only takes one storm affecting your area to make it a busy season for you,” he said.
Already, the first named storm of the season formed on Friday in the Gulf of Mexico.
WHAT’S NEW THIS SEASON?
This year, the hurricane centre is rolling out a new storm surge model that, Brennan said, “helps push real-time storm surge prediction out to 72 hours in advance of the storm”, in hopes of getting life-saving information to emergency managers regarding evacuation orders.
In addition, tropical weather outlooks have been extended from five days out to seven days, providing “an additional heads-up” for residents to make decisions about whether to evacuate in advance of a storm, Brennan said.
WHAT IS EL NINO? HOW WILL IT AFFECT THE 2023 SEASON?
El Niño is a natural temporary warming of the Pacific Ocean that occurs every few years, changing weather patterns worldwide.
Generally, the Atlantic is quieter and has fewer storms during El Niño years. That’s because the warmer waters of El Niño make warmer air over the Pacific reach higher into the atmosphere and affect wind shear that could head off storms.
Brennan noted there are other factors that add to the uncertainty of the effects of El Niño, such as very warm sea surface temperatures, weaker low-level easterly flows and a more active African monsoon season.
“So these forces are going to kind of fight it out over the course of this hurricane season,” Brennan said. “We don’t know how this season’s going to play out.”
WHAT IS THE FEDERAL EMERGENCY MANAGEMENT AGENCY’S ROLE?
FEMA Director Deanne Criswell said her agency is working to protect residents in hurricane zones by getting them the “critical information that they need” and making it easier for people to apply for help.
She said the summer doesn’t just bring the start of hurricane season, but it’s also the beginning of wildfire season.
“So we are in the summer season of severe weather events, but I think, as many of you know, it’s not just a summer season of severe weather any more,” she said, noting weather-related events take place throughout the year.
WHY DO HURRICANES HAVE NAMES? WHEN ARE THEY RETIRED?
Hurricanes are named primarily to eliminate confusion if there are two or more storm systems occurring at the same time.
The United States began using female names for storms in 1953, and began alternating male and female names in 1978.
There is a rotating list of Atlantic hurricane season names every six years. The list can then be repeated, with names being eliminated if they are retired from the rotation, according to the National Hurricane Center’s website.
The 2023 hurricane names are: Arlene, Bret, Cindy, Don, Emily, Franklin, Gert, Harold, Idalia, Jose, Katia, Lee, Margot, Nigel, Ophelia, Philippe, Rina, Sean, Tammy, Vince and Whitney.
Hurricane names are routinely retired if a storm was so deadly or caused so much destruction that using the name again would be inappropriate. It’s not up to the National Hurricane Center to retire a name, however. That practice is left to an international committee of the World Meteorological Organization, which selects another name to replace the retired one.
The most recent names to be retired include Ian, which struck southwest Florida as a Category 5 hurricane in September 2022 with ferocious winds and storm surge as high as 15 feet (four metres). Ian killed more than 156 people in the US, the vast majority in Florida, according to a comprehensive National Oceanic and Atmospheric Administration report on the hurricane.
Other retired names include Katrina, Harvey, Charley, Wilma, Matthew, Michael and Irma.
WHAT HAVE BEEN SOME OF THE WORST HURRICANES TO HIT THE UNITED STATES?
In August 1992, powerful Hurricane Andrew struck south of Miami, crossing Florida and making a second landfall in Louisiana. For years, it was the costliest and most damaging hurricane to ever hit the US coastline, resulting in around 65 reported deaths and causing more than $27.3 billion in damages at the time. The Category 5 storm destroyed more than 65,000 houses.
Hurricane Katrina, which struck Louisiana as a Category 3 storm in August 2005, still ranks as one of the most devastating hurricanes to hit the United States. Katrina caused about 1,400 deaths and produced catastrophic damage along the Gulf Coast.
Hurricane Harvey struck Louisiana after slamming into Houston in 2017, causing severe flooding. Harvey killed more than 80 people, including 50 in the Houston area.
According to the National Oceanic and Atmospheric Administration, Katrina and Harvey are listed as the two costliest US hurricanes on record, with total costs of over $160 billion and $125 billion, respectively.
Published:Monday | June 5, 2023 | 1:01 AM
AP
Mike Brennan, director of the National Hurricane Center, speaks during a news conference on May 31.
MIAMI (AP):
It’s time for residents along the southeastern US coastlines to make sure their storm plans are in place as the 2023 Atlantic hurricane season got under way last Thursday.
Forecasters are predicting a “near-normal” season, but Mike Brennan, the new director at the National Hurricane Center in Miami, stressed during a Wednesday news conference that there’s really nothing normal when it comes to hurricanes.
“A normal season might sound good in comparison to some of the hurricane seasons in the past few years,” he said. “But there’s nothing good about a near-normal hurricane season in terms of activity.”
WILL THE 2023 ATLANTIC HURRICANE SEASON BE BUSY?
Uncertainty is the key word, Brennan said.
The National Oceanic and Atmospheric Administration predicted in late May a 40 per cent chance of 2023 being a near-normal hurricane season; a 30 per cent chance of an above-average season, which has more storms than usual; and a 30 per cent chance of a below-normal season, which has fewer.
“So we’re expecting a busy season with 12 to 17 named storms,” Brennan said, adding that five to nine of those storms could become hurricanes, with one to four growing into major hurricanes.
“It only takes one storm affecting your area to make it a busy season for you,” he said.
Already, the first named storm of the season formed on Friday in the Gulf of Mexico.
WHAT’S NEW THIS SEASON?
This year, the hurricane centre is rolling out a new storm surge model that, Brennan said, “helps push real-time storm surge prediction out to 72 hours in advance of the storm”, in hopes of getting life-saving information to emergency managers regarding evacuation orders.
In addition, tropical weather outlooks have been extended from five days out to seven days, providing “an additional heads-up” for residents to make decisions about whether to evacuate in advance of a storm, Brennan said.
WHAT IS EL NINO? HOW WILL IT AFFECT THE 2023 SEASON?
El Niño is a natural temporary warming of the Pacific Ocean that occurs every few years, changing weather patterns worldwide.
Generally, the Atlantic is quieter and has fewer storms during El Niño years. That’s because the warmer waters of El Niño make warmer air over the Pacific reach higher into the atmosphere and affect wind shear that could head off storms.
Brennan noted there are other factors that add to the uncertainty of the effects of El Niño, such as very warm sea surface temperatures, weaker low-level easterly flows and a more active African monsoon season.
“So these forces are going to kind of fight it out over the course of this hurricane season,” Brennan said. “We don’t know how this season’s going to play out.”
WHAT IS THE FEDERAL EMERGENCY MANAGEMENT AGENCY’S ROLE?
FEMA Director Deanne Criswell said her agency is working to protect residents in hurricane zones by getting them the “critical information that they need” and making it easier for people to apply for help.
She said the summer doesn’t just bring the start of hurricane season, but it’s also the beginning of wildfire season.
“So we are in the summer season of severe weather events, but I think, as many of you know, it’s not just a summer season of severe weather any more,” she said, noting weather-related events take place throughout the year.
WHY DO HURRICANES HAVE NAMES? WHEN ARE THEY RETIRED?
Hurricanes are named primarily to eliminate confusion if there are two or more storm systems occurring at the same time.
The United States began using female names for storms in 1953, and began alternating male and female names in 1978.
There is a rotating list of Atlantic hurricane season names every six years. The list can then be repeated, with names being eliminated if they are retired from the rotation, according to the National Hurricane Center’s website.
The 2023 hurricane names are: Arlene, Bret, Cindy, Don, Emily, Franklin, Gert, Harold, Idalia, Jose, Katia, Lee, Margot, Nigel, Ophelia, Philippe, Rina, Sean, Tammy, Vince and Whitney.
Hurricane names are routinely retired if a storm was so deadly or caused so much destruction that using the name again would be inappropriate. It’s not up to the National Hurricane Center to retire a name, however. That practice is left to an international committee of the World Meteorological Organization, which selects another name to replace the retired one.
The most recent names to be retired include Ian, which struck southwest Florida as a Category 5 hurricane in September 2022 with ferocious winds and storm surge as high as 15 feet (four metres). Ian killed more than 156 people in the US, the vast majority in Florida, according to a comprehensive National Oceanic and Atmospheric Administration report on the hurricane.
Other retired names include Katrina, Harvey, Charley, Wilma, Matthew, Michael and Irma.
WHAT HAVE BEEN SOME OF THE WORST HURRICANES TO HIT THE UNITED STATES?
In August 1992, powerful Hurricane Andrew struck south of Miami, crossing Florida and making a second landfall in Louisiana. For years, it was the costliest and most damaging hurricane to ever hit the US coastline, resulting in around 65 reported deaths and causing more than $27.3 billion in damages at the time. The Category 5 storm destroyed more than 65,000 houses.
Hurricane Katrina, which struck Louisiana as a Category 3 storm in August 2005, still ranks as one of the most devastating hurricanes to hit the United States. Katrina caused about 1,400 deaths and produced catastrophic damage along the Gulf Coast.
Hurricane Harvey struck Louisiana after slamming into Houston in 2017, causing severe flooding. Harvey killed more than 80 people, including 50 in the Houston area.
According to the National Oceanic and Atmospheric Administration, Katrina and Harvey are listed as the two costliest US hurricanes on record, with total costs of over $160 billion and $125 billion, respectively.
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