Weather Dude wrote:My early thoughts are that 2021 will be active, but it won't "feel" active since we are coming off a 30 named storm season. 15-16 NS seems like a solid guess at this point. It's kind of weird to think that 2021 could end up with half of the storms that 2020 had, yet still potentially be above average...
It will be interesting to see whether 2021 ends up featuring much lower numbers than 2020 yet ends up with similar or even higher seasonal ACE. A number of hyperactive seasons have come in pairs or even triplets: 1886–7, 1932–3, 1995–6, 1998–9, and 2003–5 come to mind. On the other hand, there have also been many “isolated” hyperactive years, including 1878, 1893, 1906, 1926, 1950, 1955, 1961, 1964, 1969, 2010, and 2017. Obviously, 2020 was heavily weighted toward “quantity” vs. “quality,” whereas 2017, like 1996 and 1999, was
vice versa. Given that we have seen a lot of unusual oceanic-atmospheric patterns recently—including the ongoing, robust surface La Niña coupled with +PDO and lacklustre subsurface—I would surmise that we may see yet another odd combination of factors in ‘21. SSTs may be closer to neutral or even warm neutral ENSO but we might end up with a -PDO, for instance. Maybe the tropical Atlantic will be a bit cooler and the African monsoon less active, yet we may still end up with a more intense season in the MDR than we saw in 2020. 2018–19 were not particularly impressive in terms of ACE and/or long-lived major hurricanes; 2020 produced numerous intense storms, yet these were mainly short-lived. Perhaps ‘21 will feature more long-trackers despite featuring cooler SSTs and a weaker African monsoon, given that there may be more room for smaller, more discrete circulations to “spin up,” so to speak. Possibly an Edouard ‘96 or Floyd/Gert ‘99 (or two) might find sufficient conditions under which to develop.