Tropical Storm Risk (TSR) has issued its 2022 hurricane and typhoon season forecast review, which found that:

  • The North Atlantic hurricane season was less active than forecast
  • The TSR hurricane forecast was the most accurate
  • The TSR North West Pacific typhoon forecast was ‘near perfect’

The north Atlantic hurricane season has seen near average activity in terms of storm and hurricane numbers but around 22% below average for the Accumulated Cyclone Energy (ACE) index relative to the recent 1991-2020 30-year climatology. The NW Pacific basin has seen activity well below average at around 45% below the 30-year 1991-2020 climatology.

Tropical Storm Risk (TSR) over-predicted Atlantic hurricane activity but was the most accurate compared to Colorado State University, NOAA and the Met Office in early August. The TSR forecasts for NW Pacific typhoon activity correctly predicted a well below average season with the early August forecast for ACE near perfect.

The TSR forecasts predicted above-normal activity at all lead times from early December. The reasoning behind the forecasts was the expectation of weak to moderate La Nina conditions during the summer, which were expected to persist through autumn and historically tend to enhance late season activity, and for warmer than normal sea surface temperatures in the tropical Atlantic.

The expectation of above-average activity was further enhanced by development of a tropical storm in the Caribbean Sea during July. Historically, formation of a tropical storm in the tropics prior to 1st August is indicative of at least an active season to follow. In early August, it was established that the July trade wind anomalies were stronger than normal, which is indicative of below-average activity, and so the August forecast update predicted a less active season than in early July, but still above-normal. After near average activity in June, August saw no named storms form in the Atlantic, which has only happened twice since 1950 (1997 and 1961).

Activity from September onward was slightly above average but with the absence of activity in August, the seasonal activity in terms of the ACE index finished about 22% below the 1991-2020 climatology. Hurricane and intense (MSW > 95 kts) hurricane numbers were also overpredicted with the TSR forecasts predicting 8 hurricanes and 3-4 intense hurricanes, which compares to the observed values of 7 and 2.

For the NW Pacific, the expectation of La Nina conditions through summer and autumn resulted in TSR predicted well below average typhoon activity which verified well. Forecast activity steadily declined from the early May to early August lead times and the ACE index forecast of 166 is very close to the observed ACE index of 162. Forecasts for typhoon and intense typhoon numbers were 14 and 6 which compares well with the observed values of 12 and 5.

For more information please email nick.wood@eurotempest.com.