The oceans where hurricanes roam are unaware that hurricane season is months away. The North Atlantic is seeing historically warm ocean temperatures, increasing the risk of a strong hurricane season, possibly fueled by a developing La Niña.
“This season should be full speed ahead, as there are no factors going against an active season,” University of Miami senior research scientist Brian McNoldy told CNN. “An anomalously warm ocean and neutral or La Niña conditions are likely during peak hurricane season, which is not ideal for reducing Atlantic storms.”
Stronger too. Warm water fuels storms and strengthens them.
This month, North Atlantic Ocean sea surface temperatures hit an unprecedented 1 degree Celsius above normal, more like June than February. West Africa to Central America, where most Atlantic hurricanes form, had July-like temperatures.
Global ocean heat has been rising steadily since March, driven by a severe El Niño and human-caused climate change, according to McNoldy.
“(The heat) was so far above anything ever observed that it seemed impossible,” McNoldy added.
But it did. Ocean temperatures this year, notably in the Atlantic, are warmer than last year, which might lead to a disastrous hurricane season.
In February, much can change. If not, it may be a busy season, said Colorado State University research scientist Phil Klotzbach.
North Atlantic temperatures rise from here, peaking in early autumn during hurricane season. McNoldy said they will “almost certainly” be warmer-than-normal into summer.
A La Niña, an ocean and meteorological phenomenon in the tropical Pacific, increases the possibility of a stronger Atlantic hurricane season, making the prognosis even more ominous.
Tropical systems arise from various meteorological conditions, but minimal wind shear—upper level winds that can tear storms apart or prevent them from forming—is crucial. La Niña reduces wind shear in the Atlantic, facilitating storm formation, strengthening, and potential land impacts.
According to Klotzbach, the timing of La Niña is crucial as it will cause gradual changes in the atmosphere.
It takes time for La Niña’s impact to reach the Atlantic. Early arrival of La Niña means earlier impact on storm season.
To avoid an active hurricane season, McNoldy suggests delaying the start of La Niña.
NOAA’s Climate Prediction Centre predicts La Niña could occur by summer, but more likely by fall.
Klotzbach questioned the potential impact of near-record ocean warmth and La Niña, as no prior hurricane season has experienced such severe temperatures.
Katrina, Rita, and Irene hit between the 2010 and 2005 seasons, two of the most active. Both experienced neutral or La Niña conditions, although Klotzbach cautioned that similar outcomes are not certain due to warmer anomalies than in recent years.
It was hard to compare last year’s busy season. El Niño was expected to reduce storm activity, but the record-warm Atlantic partially offset that. Twenty storms formed, fourth-most ever.
