A tropical wave or easterly wave defined as a cluster of clouds and thunderstorms moving through the tropics.
When the tropical wave develops a rotary, cyclonic circulation with sustained winds to 38 miles per hour.
Once winds within a tropical system reach 39 miles per hour and the distinct low-pressure area is well defined by a rotating circulation, the system is considered a tropical storm and is given a name.
A hurricane has sustained winds exceeding 74 miles per hour or greater, dangerously high water and rough seas. Hurricanes are categorized by severity using the Saffir-Simpson Hurricane Wind Scale:
Watches & Warnings
When a tropical storm or hurricane threatens, the National Hurricane Center will issue advisories based on the projected time until landfall of the storm.
A tropical storm or hurricane watch means that tropical storm or hurricane conditions pose a possible threat in a specified region within 36 hours. You should begin preliminary preparations. Stay tuned to local news or the weather channel for updates.
A tropical storm or hurricane warning means that tropical storm or hurricane conditions are expected in a specified region within 24 hours. All preparations should be completed. Stay tuned to local news or the weather channel for evacuation orders and additional instructions.