The
eye is a region of mostly calm weather at the center of strong
tropical cyclones. The eye of a storm is a roughly circular area, typically 30–65 km (20–40 miles) in diameter. It is surrounded by the
eyewall, a ring of towering
thunderstorms where the most severe weather occurs. The cyclone's lowest
barometric pressure occurs in the eye and can be as much as 15 percent lower than the pressure outside the storm.