The Atlantic hurricane season, which begins June 1 and typically ends November 30, is almost upon us. Here’s an introduction to three of the terms you’re likely to hear during this potentially stormy period.
The eye, along with the eye wall and the rainbands are the most notable features of a hurricane.
The eye, or center, or a hurricane is a relatively calm area typically 20 to 40 miles in diameter. Eyes may be clear or cloudy, but they are usually clear during periods of rapid storm intensification (storms with eyes usually have wind speeds higher than 85 knots). Cloudy eyes are often indicative that a storm is past its peak intensity.
The eye wall
The eye wall is a dense wall of thunderstorms surrounding the eye and is the most intense part of a hurricane in terms of wind and rain. Changes in the structure of the eye and eyewall can cause changes in the wind speed, which is an indicator of the storm's intensity.
A storm's outer rainbands—which consist of dense bands of thunderstorms—can extend hundreds of miles from the center. Typically, they range from 50 to 300 miles long. According to forecasters, the curvature of the rainbands provides a clue to a storm’s intensity. In general, the more curved the rainbands, the more intense the storm. Finally, although the size of a hurricane can vary widely, it is important to note that a storm’s size is not an indication of its intensity.
NOAA released its 2017 Atlantic Hurricane Season Outlook today, May 25, 2017. In brief, forecasters predict a 70 percent likelihood of 11 to 17 named storms (winds of 39 mph or higher). Of those named storms, 5 to 9 could become hurricanes (winds of 74 mph or higher), including 2 to 4 major hurricanes (category 3, 4, or 5; winds of 111 mph or higher). You can read the full 2017 Atlantic Hurricane Season Outlook on the NOAA.gov website.