The following essay is reprinted with permission 
The Conversation is an online publication covering the latest research.
The Atlantic hurricane season begins on June 1, and forecasters are watching warming waters, not just in the Atlantic.
Globally, warm sea surface temperatures that can trigger hurricanes are an anomaly in the spring of 2023, but what really matters for hurricanes in the Atlantic is the North Atlantic Basin, where hurricanes form and intensify, and hurricane are seawater temperatures at two locations in the North Atlantic Basin where The eastern to central tropical Pacific Ocean where El Niño occurs.
The two are at odds this year and are likely to have conflicting effects on key conditions that determine the success or failure of the Atlantic hurricane season. The results could be good news for the Caribbean and Atlantic coasts, which are facing near-normal hurricane seasons. But forecasters warn that hurricane forecasts depend on El Niño events.
hurricane ingredients
In general, hurricanes are more likely to form and intensify when tropical cyclones encounter an environment of warm upper ocean temperatures, atmospheric moisture, instability, and weak vertical wind shear.
Warm ocean temperatures provide the energy for hurricane development. Vertical wind shear, the difference in wind strength and direction below and above a tropical cyclone, disrupts the organization of convection, thunderstorms, and brings dry air into the storm, impeding its growth.
Role of the Atlantic Ocean
The role of the Atlantic Ocean is very simple. Hurricanes draw energy from the warm ocean waters beneath them. All else being equal, warmer ocean temperatures favor hurricanes.
During the most active Atlantic hurricane season on recent record, temperatures in the tropical Atlantic were unusually warm. The 2020 Atlantic Hurricane Season produced a record 30 named tropical cyclones, and the 2005 Atlantic Hurricane Season produced 28 named storms, 15 of which were hurricanes, including Katrina. I had a record.
How the Pacific Engages
The role of the tropical Pacific in forming Atlantic hurricanes is more complex.
You may be wondering how ocean temperatures on the other side of the Americas affect Atlantic hurricanes. The answer lies in teleconnections. Teleconnection is a series of processes in which oceanic and atmospheric changes in one region cause large-scale changes in atmospheric circulation and temperature, affecting the weather in other regions.
One of the recurring patterns of climate change in the tropical Pacific that initiates teleconnections is the El Niño Southern Oscillation.
El Niño can occur when the tropical eastern to central Pacific is unusually warm. During El Niño events, warmer upper-ocean temperatures alter the vertical and east-west circulation of the atmosphere in the tropics. This initiates teleconnection by influencing zonal winds in the upper atmosphere across the tropics, ultimately resulting in stronger vertical wind shear in the Atlantic Basin. Its wind shear can stomp a hurricane.
That’s what we expect to happen this summer. The latest forecasts show a 90% chance that an El Niño event will develop by August and remain strong until the fall peak of the hurricane season.
Tug of war between Atlantic and Pacific influences
My research and that of other atmospheric scientists have found that the warm Atlantic and warm tropical Pacific tend to influence each other, leading to near-average Atlantic hurricane seasons.
Both observations and climate model simulations show the results. His 2023 forecast for the National Oceanic and Atmospheric Administration sees roughly an average of 12 to 17 named storms, 5 to 9 hurricanes, and 1 to 4 major hurricanes. Earlier forecasts by Colorado State University forecasters predicted a slightly below-average season with 13 named storms, compared to the climatological average of 14.4.
Notable Wildcards
Temperatures in the tropical Atlantic and Pacific Oceans are often useful predictors of seasonal hurricanes, but there are other factors to consider and monitor.
First, will the projected El Niño and Atlantic warming do the trick? If one does not, the tug of war between influences can be unbalanced.
On the Atlantic coast, El Niño events often mitigate the effects of hurricanes, so they should support the predicted development of El Niño events. If this year’s projected Atlantic warming had coincided with a La Niña event, which is the opposite of an El Niño and features cold tropical Pacific waters, we might instead have a record-breaking season. .
Two other factors are also important. The Madden-Julian Oscillation is a pattern of clouds and rainfall that moves eastward over the tropics on a 30- to 90-day timescale and can either promote or suppress tropical cyclone formation. And dust storms from the Saharan atmosphere, which contains warm, dry, dusty air from Africa, can keep tropical cyclones in check.
This article originally appeared in The Conversation. Please read the original article.
