cycloneye wrote:ABSTRACT
Information obtained through July indicates that the 2023 Atlantic hurricane
season will have activity above the 1991–2020 average. We estimate that 2023 will have
a total of 18 named storms (average is 14.4), 90 named storm days (average is 69.4), 9
hurricanes (average is 7.2), 35 hurricane days (average is 27.0), 4 major (Category 3-4-5)
hurricanes (average is 3.2) and 9 major hurricane days (average is 7.4). These numbers
include the five storms that have formed already this year (January subtropical storm,
Arlene, Bret, Cindy and Don). The probability of U.S. major hurricane landfall is
estimated to be above the long-period average. We predict Atlantic basin Accumulated
Cyclone Energy (ACE) and Net Tropical Cyclone (NTC) activity in 2023 to be
approximately 130 percent of their 1991–2020 average. We are forecasting the same
seasonal numbers with our August forecast that we predicted in early July.
This forecast is based on two early August statistical models that were developed
using ~40 years of past data. Analog predictors are also utilized. We are also including
statistical/dynamical models based on ~25–40 years of past data from the European
Centre for Medium Range Weather Forecasts, the UK Met Office, the Japan
Meteorological Agency and the Centro Euro-Mediterraneo sui Cambiamenti Climatici
model. The statistical/dynamical models unanimously agrees that the 2023 Atlantic
hurricane season should be hyperactive, while statistical model guidance is calling for
an above-average remainder of the Atlantic hurricane season. We stress that there is
considerable uncertainty with this season’s outlook given the large spread in model
guidance, as well as uncertainty with exactly how El Niño will interact with the
extremely warm Atlantic.
The tropical Pacific is currently characterized by El Niño conditions. The
intensity of the El Niño for the remainder of the hurricane season remains unclear,
although a moderate to strong event seems relatively likely. El Niño typically reduces
Atlantic hurricane activity through increases in vertical wind shear.
Sea surface temperatures across most of the tropical and subtropical Atlantic
remain at record levels, so despite the potential for a moderate/strong El Niño, the
impacts on tropical Atlantic/Caribbean vertical wind shear are likely to not be as strong
as is typically experienced given the extremely warm Atlantic.
The average of all their schemes is 184 ACE
