#842 Postby aspen » Mon Aug 09, 2021 5:38 pm
The quality of storms this season so far can be compared to over recent seasons by looking at the average ACE and ICE (my intensity metric) per storm up until this point in each year. I chose 2017, 2018, 2019, and 2020 for comparison, each being four very different seasons: a cool neutral ENSO, an El Niño year with record-breaking ACE, a weak Niño with a generally favored Atlantic, and a La Niña with a heavily favored Atlantic.
So far, 2021 has produced 11 named storms, with an average ICE of 16.56 units per system. Felicia dominates the season’s total of 182.21 units so far.
As of August 9th, 2017, the EPac was up to TD-11E (tropical depressions still count towards the ICE total unless they have winds of 25 kt and/or a pressure of 1015 mbar). The average ICE per storm was 24.13 units, and the season ended with 461.66 units, about 1.19x the 1977-2017 Atlantic mean. It was a respectable season but nothing crazy.
As of August 9th, 2018, several storms were active or had just dissipated. The basin was also up to its K storm and was at 34.21 ICE/storm. This is the highest of the seasons I picked, but I’m surprised it was that low due to all the hurricanes by this point (Aletta, Bud, Fabio, and Hector). 2018 went on to have the highest ACE of any EPac system due to an insane number of long-tracking Cat 4/5s, and finished with a huge ICE total of 1,337.94 units.
As of August 9th, 2019, the basin was only up to Gil. Both ACE and ICE were dominated by borderline Cat 5 Barbara and Cat 4 Erick, with lots of weak development. Both storms, especially Barbara, helped get the season’s ICE/storm by this point to 30.66 units. The season ended as a similarly “eh” year like 2017 with a total of 464.41 units of ICE.
As of August 9th, 2020, TS Elida was currently active, but since it had not reached peak intensity yet, it is not counted in my calculations. The ACE per storm at this point was only 11.47 units; it was ridiculous how many depressions were failing to even become named storms, and how pathetic most storms were. The average ICE/storm by 8/9/20 was entirely carried by Cat 4 Douglas, which was responsible for >85% of the ICE. We all know how unimpressive 2020 was. It ended with 339.32 units of ICE, only 88% the 1977-2017 Atlantic mean.
In summary: 2021 is essentially just a slightly less garbage version of 2020, with both seasons being carried by a single Cat 4 and having most of their storms struggle with shear and stability brought on by a developing La Niña.
The ICE formula is:
([1015-pressure] x [winds-25])/72.5
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Irene '11 Sandy '12 Hermine '16 5/15/2018 Derecho Fay '20 Isaias '20 Elsa '21 Henri '21 Ida '21
I am only a meteorology enthusiast who knows a decent amount about tropical cyclones. Look to the professional mets, the NHC, or your local weather office for the best information.