ASK THE METEOROLOGIST
“How do hurricanes form?”
St. Mary’s 6th graders — Mrs. Schultz’s class
Hurricanes form from thunderstorms that develop over oceans! You will never see a hurricane develop over land. In order for these storms to form we need unstable air. Another way of thinking of this is rising air. When temperatures are very warm, a lot of air rises. This rising air will cool and form a cloud. If there is enough rising air, these clouds will start growing vertically in cumulonimbus clouds ..also known as thunderstorms. This process of rising air and cloud development is referred to as convection.
Once the thunderstorm clouds develop, they must continue to maintain their strength. These clouds grow to tremendous heights, bringing moisture as far up as 15,000!’ What we don’t want for thunderstorm development is shearing winds. When winds shear, it means their direction is changing with height. Too much off this wind direction changing can prevent a hurricane from forming.
One of the biggest contributors to tropical storms is ocean temperatures. Hurricanes only form over water, and warm water at that. Temperatures need to be in the mid 80′s at least for a tropical system to maintain it’s energy or strengthen. Once all of these thunderstorms start developing, and ocean temperatures are warm enough …the group of storms will begin to organize. They then will form a circulation. The strength of the wind circulation is what determines just how strong the system is. If winds are less than 39mph, it’s considered a tropical depression. If winds are between 39-74mph it’s a tropical storm. If winds are greater than 74mph it is then a hurricane!
Meteorologist Alyssa Caroprese