London-based forecaster Tropical Storm Risk predicts the 2021 storm season will see 18 named storms, nine hurricanes and four major hurricanes, defined as Category 3 or worse, according to a report released Friday by Aon PLC's Impact Forecasting. The forecast represents a slight increase from TSR's initial forecasts for 2021 tropical activity, which were released in December and April. The estimated activity is expected to be approximately 30% to 35% above the long-distance norm since 1950 and slightly above the most recent ten-year norm 2011-2020, according to TSR, which is part of UCL University College.
In December, the TSR predicted 16 named storms, seven hurricanes and three major hurricanes, which in April had risen to 1
Last week, the National Oceanic and Atmospheric Administration's Climate Forecasting Center predicts an abnormal Atlantic hurricane season with a likely range of 13 to 20 named storms with winds of 39 mph or higher, of which six to 10 could be hurricanes with winds of 74 mph or higher, including three to five major hurricanes, categories 3, 4 or 5, with winds of 111 mph or higher.
NOAA said it gives these intervals 70% confidence. The agency predicted a 60% chance for a season that is above normal, a 30% chance for an almost normal season and a 10% chance for one during normal season.
The hurricane season in the Atlantic extends from 1 June to Nov. 30.