tropical cyclone – From tropical waves to hurricane categories, this guide breaks down the storm language used in forecasts—so you can understand what’s coming and act faster when warnings are issued.
TALLAHASSEE, Fla. — It only takes one storm to change someone’s life.
As the hurricane season ramps up, the WCTV Weather Team is walking people through the words that matter when a forecast shifts from “monitoring” to real threat. The goal is simple: when weather language shows up in alerts, you know what it means for your home and your family.
A tropical cyclone is the umbrella term for hurricanes, tropical storms and tropical depressions.
The life cycle often starts as a tropical wave in the open Atlantic waters. A tropical wave is an easterly cyclonic disturbance in the tropics. Over open warm waters, it can mature—especially when ocean temperatures are 80 degrees or warmer. Winds also matter: for efficient organization, winds need to be light from the surface to the upper air.
When the wave becomes a clear closed circulation, it becomes a tropical depression. Winds with a depression are 38 mph or less. If 80-degree waters remain and low wind shear holds, the tropical depression can organize further.
Once winds reach 39 mph, the system is given a name and becomes a tropical storm. Tropical storm winds can climb as high as 73 mph, bringing damaging winds, flooding and isolated tornadoes.
The jump to hurricane strength happens at 74 mph. Then, the definition tightens again: a hurricane becomes a major hurricane once winds hit 111 mph, which is Category 3 strength.
What makes these storms so dangerous is how quickly they can change. Storms can go from a low-end hurricane to a major hurricane in 24 hours in 80-degree waters that run deep into the ocean. The deeper the heat content, the more likely rapid strengthening—or rapid intensification—is.
But conditions can also cut them down. Tropical cyclones weaken gradually once they move into an atmosphere with high wind shear. water temperatures below 80 degrees. or after they make landfall. At that point. the storm essentially runs out of steam—it can’t keep drawing energy from warm ocean waters the way it needs to.
Tropical watches and warnings
When officials issue alerts, the thresholds aren’t random. Here’s the breakdown used by the National Weather Service and National Hurricane Center:
Tropical Storm Watch: winds between 39 and 73 mph are possible within 36 hours. Tropical Storm Warning: winds between 39 and 73 mph are expected within 36 hours. Hurricane Watch: winds between 39 and 73 mph are possible within 36 hours. Hurricane Warning: winds between 39 and 73 mph are expected within 36 hours.
Storm surge: the danger near the waterline
One term that can sound abstract until you picture the coastline is storm surge.
Storm surge is when sea level rises due to strong onshore winds in a tropical storm or hurricane. It can produce life-threatening wave heights and flooding near the coast. The forecast for the surge is the peak height that waves would reach during high tide.
And for people trying to read maps when landfall is near, there’s another phrase that shows up: the “dirty side” of the storm.
The dirty side of the storm
Meteorologists and hurricane specialists often refer to a hurricane in quadrants—four separate sections. One of those quadrants is known as the “dirty side.” It’s the northeast part of the hurricane or tropical storms, where winds are often the strongest and the tornado threat is often the highest.
If a storm is making landfall to your west, you may find yourself on the dirty side. That means being positioned for some of the worst impacts.
The WCTV Weather Team points to the 2017 landfall of Hurricane Michael, when much of the area was on the nasty side of the storm. That exposure helped lead to extensive damage in Mexico Beach.
Saffir-Simpson scale: what the categories actually mean
Winds aren’t the only threat from tropical storms and hurricanes, but they define the storm’s category.
Major hurricanes are Category 3 storms or stronger.
The Saffir-Simpson scale used in the guide breaks down as follows:
Category 1: 74 to 95 mph.
Category 2: 96 to 110 mph.
Category 3: 111 to 129 mph.
Category 4: 130 to 156 mph.
Category 5: 157+ mph.
The guide also lists Tropical Storm: 39 to 73 mph.
Notable Big Bend storms: what people here have already faced
In the Big Bend region, the language of hurricanes isn’t just textbook material. The team highlights a string of storms that map those categories onto real outcomes.
Hurricane Helene (2024): Helene made landfall 10 miles southwest of Perry, Florida as a Category 4. Winds were significant with Helene from Florida and Georgia to the Carolinas, and it also brought devastating flooding to parts of the southeast.
Hurricane Idalia (2023): Similar to Michael, Idalia underwent rapid intensification. The major hurricane was the first storm of this magnitude to hit the Apalachee Bay region in history, making landfall as a Category 3.
Hurricane Michael (2018): Michael made landfall as a Category 5 hurricane. The guide notes it was the first Category 5 to make landfall in the contiguous U.S. since Andrew.
Hurricane Dennis (2005): Dennis made landfall as a Category 3 hurricane in 2018. Although landfall was over 150 miles from the area, Apalachee Bay still experienced 6 to 9 feet of storm surge.
Hurricane Kate (1985): Kate made landfall as a Category 2 in 1985. The storm was one of the most direct hits that the Big Bend has dealt with, with landfall just west of Apalachicola.
How to stay updated
To keep up with forecasts as conditions change, WCTV First Alert Weather tells viewers to follow WCTV First Alert Weather on Facebook and X (Twitter). The team also points people to push alerts and the free WCTV First Alert Weather app for watching forecasts anytime.
For those who want to get involved, the guide invites people to join the team as a WCTV First Alert Weather Watcher.
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hurricane season tropical cyclone tropical wave tropical depression tropical storm hurricane major hurricane rapid intensification tropical storm watch tropical storm warning hurricane watch hurricane warning storm surge dirty side Saffir-Simpson scale Big Bend storms