Significant Increase in Projected North Atlantic Basin 2023 Seasonal Hurricane Forecast

Forecast summary: Due to a delayed atmospheric El Nino and record warm North Atlantic, the North Atlantic basin seasonal forecast is revised. The updated forecast projects 20 tropical storms, 9 hurricanes, and 4 intense hurricanes. Previously, only 3 seasons have produced 20 (or more) tropical cyclones. If 2023 observes 20 tropical cyclones, 3 of the past 4 years will have managed that achievement. Causal of this potential scenario is the very warm North Atlantic basin and the expected westerly shear aloft caused by El Nino is likely delayed. The accumulated cyclone energy (ACE) index is raised to 171. Colorado State University raised their seasonal totals to similar levels late last week. Tropical Storm Risk/U.K. also raised their seasonal forecast levels significantly in an early July update. The very (anomalous) warm Gulf of Mexico and most recently waters off the U.S. East Coast increase the risk of stronger storms approaching and making landfall.

Table 1: The 2023 updated North Atlantic basin seasonal tropical cyclone activity forecast compared to various climatology and previous outlook.

Table 2: The updated 2023 North Atlantic basin seasonal tropical cyclone activity forecast by all leading providers compared to the 30-year normal.