The evolution of hurricanes can be followed on Ventusky
A hurricane is a tropical cyclone in the Atlantic and northeastern tropical Pacific. It is a rapidly rotating storm system characterised by a low-pressure centre, a closed low-level circulation, strong winds, and a spiralling arrangement of storms that produce heavy rainfall. Tropical cyclones may also develop tornadoes. The first major hurricane of the 2025 Atlantic hurricane season was Erin.
Ventusky provides current geostationary satellite imagery (see map). Fig. 1 shows Hurricane Erin east of the Greater Antilles on August 16. Erin formed west of the Cape Verde Islands on August 11 from a tropical wave. Subsequently, Tropical Storm Erin moved westward in the tropical Atlantic. On August 15, the tropical storm strengthened into a hurricane near the Lesser Antilles. Very favourable conditions allowed Erin to undergo rapid intensification on August 16, when it peaked at Category 5 with one-minute maximum sustained winds of 260 km/h. The modelled wind gusts are shown in Fig. 2 (see map).
Hurricane Erin became remarkable primarily due to its rapid intensification, strengthening from Category 1 to Category 5 in just 24 hours. This rapid 24-hour intensification of Hurricane Erin was the most significant recorded Atlantic hurricane based on the drop in central pressure before September 1. During hurricane intensification, the central air pressure decreases. The lower the central pressure, the more intense the storm becomes, as this creates a stronger horizontal pressure gradient between the cyclone’s centre and its surroundings, which is balanced by the wind. In the case of Hurricane Erin, the central pressure dropped by 70 hPa within 24 hours, from Friday to Saturday morning. The pressure difference between the storm’s centre and its surroundings is clearly visible in Fig. 3 (see map).
A warm core mainly causes the decrease in air pressure at the centre of a cyclone. Hurricanes have a warm core primarily due to the release of latent heat during the condensation of water vapour. As moist air rises from warm ocean surfaces, it cools and the water vapour condenses, releasing heat into the storm's centre. This warming lightens the air, increasing upward motion, lowering central pressure, and strengthening the wind field. This self-reinforcing process maintains the intensity of a hurricane and is a key factor in developing its warm core. The warm core in the centre of the cyclone at a pressure level of 700 hPa (approximately 3 km altitude) is clearly visible in Fig. 4 (see map).
Hurricane Erin illustrates the dynamic nature of tropical cyclones and the critical role of oceanic and atmospheric conditions in their rapid development. The storm’s record-breaking intensification highlights how quickly hurricanes can evolve, emphasising the importance of continuous monitoring using satellite imagery and forecasting models like those provided by Ventusky. Understanding the mechanisms behind such storms, including the formation of a warm core and the associated drop in central pressure, is essential for improving prediction, preparedness, and response to future hurricanes.
