hurricanes1234 wrote:It's amazing how much the La Niña this year did absolutely nothing to promote late-season activity. The basin has behaved like an El Niño since early October. Also, the season only surpassed 140 ACE because of Sam, without Sam, I don't even know if we would've crossed 100.
I think that climate change may be altering the large-scale atmospheric patterns and resulting in unusual outcomes. Even with La Niña in place, the Pacific and Indian basins are larger and thus tend to absorb more heat in a warmer climate than the tropical Atlantic, so in absolute terms they exert more influence on Earth’s weather. I cannot recall the exact source, but elsewhere some sources have blamed a warming Pacific basin for the recent dearth of active tornado seasons, especially on the Great Plains, since 2013. Combined with a warmer subtropical Atlantic, the warming Pacific and Indian basins may, along with an expanded Hadley cell, contribute to greater stability and TUTT intrusions over the tropical Atlantic, on balance, in a warming climate, so Niñas may at time behave more like Niños. At the very least, these factors might tend to result in fewer and/or shorter-lived major hurricanes (à la 2005 and 2020 vs. a year like 2004 or 2017) and thus less ACE, even in active seasons, especially over the MDR. Studies have suggested that climate change would decrease the number of tropical storms and perhaps even hurricanes in the Atlantic basin, but result in a slight increase in maximum potential intensity insofar as the strongest storms are concerned.