TechNotes Tips - Weather Archive

TechNotes provided by SyngentaThe Stages of Hurricane Development:
The Tropical Storm Season is not to be taken lightly. Hurricanes start with thunderstorms over a body of tropical water. Once a group of thunderstorms come together under the right atmospheric conditions, and constant winds near the center of the thunderstorms reach between 23-39 mph, a tropical depression has formed. As the tropical depression intensifies and winds become constant with speeds of 39-73 mph, a tropical storm has formed. Tropical storms begin to take on the circular shape of hurricanes. The speed in which a storm develops from a tropical depression to a tropical storm can range from 1/2 a day to two days. Once a tropical storm forms, it is given a name. As the winds intensify to constant speeds of 74 mph, the tropical storm is changed to a hurricane. The time it takes for a tropical storm to go to a hurricane can be as short as 1/2 to two days.

The danger and potential damage threat of a hurricane is described in categories. Below are the 5 categories hurricanes are classified as.
Category Winds (mph) Pressure (inches) Storm Surge (feet)
1 74-95 >28.94 4-5
2 96-110 28.5-28.91 6-8
3 111-130 27.91-28.47 9-12
4 131-155 27.17-27.88 13-18
5 >155 27.16 >118