Climate Depot:
Meteorologist Paul Dorian: “Tropical cyclone activity across the Northern Hemisphere has been below-normal in 2021 in much the same way as it was last year. Specifically, while the Atlantic Basin featured above-normal tropical activity in this year and last, the Pacific Ocean experienced below-normal conditions in both years leading the way to below-normal levels across the hemisphere as a whole. In terms of tornadoes, it has been another below-normal season in the US with no EF-5’s recorded.”
The accumulated cyclone energy (ACE) is the best measure of overall tropical activity and it is below-normal for the 2021 season across the Northern Hemisphere. Data courtesy Colorado State University, NOAA.
Tropical cyclone activity across the Northern Hemisphere has been below-normal in 2021 in much the same way as it was last year. Specifically, while the Atlantic Basin featured above-normal tropical activity in this year and last, the Pacific Ocean experienced below-normal conditions in both years leading the way to below-normal levels across the hemisphere as a whole. In terms of tornadoes, it has been another below-normal season in the US with no EF-5’s recorded. There was, however, tornadic activity in some unusual places in 2021 including the Mid-Atlantic and New England.
Colder-than-normal sea surface temperatures continue to dominate the scene in the equatorial part of the Pacific Ocean. These “La Nina” conditions likely played an important role in the above-normal tropical activity across the Atlantic Basin in 2021 and the below-normal activity in the Pacific Ocean. Map courtesy NOAA, tropicaltidbits.com
There is no tropical activity right now in either the Atlantic or Pacific Ocean and none is expected in the near term. In fact, the tropical activity in both of these large bodies of water may very well be done for the 2021 season and there has been a rather dramatic drop off of activity in recent weeks.
In fact, the quiet period in terms of tropical activity began in October and it turned out to be rather unusual in that there were no “major” hurricanes (Category 3 or above) anywhere across the globe. According to Dr. Philip Klotzbach of Colorado State University, this is the first time since 1977 that there were no “major” hurricanes during the month of October anywhere across the globe. Furthermore, in the period from mid-October to mid-November, the accumulated cyclone energy (defined below) across the globe was the lowest in the satellite era (since 1966).
The number of named storms in the 2021 Atlantic Basin was above-normal, but the INTENSITY has been low giving an over all low cyclone energy ranking.
