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Q3 2021

Atlantic name windstorm season forecast

Tropical blue cyclone

The chart below plots the latest 2021 Atlantic Basin tropical storm forecasts from Tropical Storm Risk (TSR), the National Oceanic and Atmospheric Administration (NOAA), and Colorado State University (CSU), as well as the 71-year and 10-year averages.

Both TSR and CSU have slightly reduced their August forecast for the season’s storm numbers. However, all forecasters are still predicting an above-average Atlantic hurricane season in 2021, citing anomalously warm tropical Atlantic waters and vertical wind shear across the tropical Atlantic and Caribbean in July as major factors. Warmer than normal water across the tropical Atlantic provides more fuel for tropical cyclones. Lower vertical wind shear allows hurricanes to better vertically couple and also inhibits entrainment of dry air into the circulation. Vertical wind shear in July typically has strong persistence, so if vertical wind shear is high in July it is likely to remain elevated during the peak of the season.

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