Forecasters at Colorado State say another busy hurricane season is ahead in 2022.Slower winds in the Atlantic may allow for more storms.But warmer water in the Pacific could lead to a quieter Atlantic.
We could be in for yet another active hurricane season next year, according to scientists at Colorado State University.
, produced by a team led by , says that there is about a 65% chance of above-average activity.
While it is much too early to forecast the number of tropical storms and hurricanes, scientists are able to look at some of the slow-motion drivers that may assist or hinder hurricane activity next summer and autumn.
The status of the El Niño-Southern Oscillation (ENSO) and water temperatures in the northern Atlantic are the two key factors Klotzbach and his team use to determine how active next season will be at this early stage.
Here's how each may play a part.
We entered another La Niña at the end of summer. This cooling of the equatorial Pacific waters is a key driver in many weather phenomena, including an active hurricane season.
La Niña typically allows for more favorable atmospheric conditions in the Atlantic while its counterpart pattern, El Niño, typically allows fewer tropical storms and hurricanes to form.
As for what's to come in 2022, there is still a lot of uncertainty.
Most models suggest La Niña will weaken, and that the Pacific will gradually warm into the first half of hurricane season.
This could mean that one of the favorable factors that led to the active hurricane season this year may not be in play in the upcoming hurricane season, potentially lowering the number of storms.
By the time hurricane season ramps up in July, August and September (denoted JAS at the right of the graph below), water temperatures are anticipated to be warm enough to be considered at least neutral – neither La Niña nor El Niño.
Model forecasts of El Niño or La Niña (or neutral) from mid-November 2021 into summer 2022.
(IRI/CPC, annotated by Colorado State University)
The CSU outlook said an El Niño is "relatively unlikely" by next summer, which would require faster warming of the Pacific than currently forecast.
For the last quarter-century, water temperatures have been running above average at the height of a cycle called the .
The AMO can greatly impact the amount of activity in an Atlantic hurricane season. To put it into perspective, "A positive phase of the AMO typically leads to 3-5 times more major Atlantic Basin hurricane activity than does a negative phase," says the team at CSU.
"The typical period of the AMO is about 60 years, with the period length varying between as short as 40-50 years and as long as 70-80 years. This means that we typically have 25-35 years of above-average Atlantic Basin major TC activity and similar length periods with considerably reduced amounts of major TC activity," according to CSU.
Given the last six active seasons in a row, CSU believes AMO will remain positive. Additionally, both the North Atlantic and tropical Atlantic are warmer than normal, indicating an enhanced AMO.
An enhanced AMO can also slow down the Bermuda high.
The Bermuda high, typically located between Bermuda and the Azores during hurricane season, is greatly responsible for steering (or shoving) tropical waves, tropical storms and hurricanes westward from Africa toward the Caribbean and United States.
The slower the Bermuda high rotates, the slower tropical systems move westward and the more likely they are to develop and intensify.
A stronger Bermuda high acts to bring cooler air and water into the Atlantic Basin. Cooler waters in the area diminish hurricane development. Additionally, stronger Bermuda highs can increase shear in the area, which could greatly inhibit hurricane formation and intensification.
The ENSO and the AMO are only two of the mechanisms that can change how many storms we will see.
Both of these are climate-related. Typically, in a given hurricane season, we will see around 14 named tropical storms, seven of which become hurricanes.
These two features either elevate or decrease the favorability of conditions that may lead to more or fewer named storms and hurricanes.
That's where weather comes in.
It won't be until April that we can start to talk about the weather conditions that may lead to more or fewer storms.
This is why CSU does not issue a forecast with numbers just yet.
As this report says, we're still figuring out the slower-moving climate signals for next year.
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