Track of Hurricane Charley, August 9-15, 2004
Courtesy of USGS based on data from the National Weather Service
How do we know which way a hurricane will go? Forecasters track hurricane movements and predict where the storms will travel as well as when and where they will reach land. While each storm will make its own path, the movement of every hurricane is affected by a combination of the factors described below.
Hurricanes are steered by global winds. These winds, called trade winds, blow from east to west in the tropics. They carry hurricanes and other tropical storms from east to west. In the Atlantic, storms are carried by the trade winds from the coast of Africa where they typically form westward to the Caribbean and North American coasts. When the trade winds are strong it is easier to predict where the storm will travel. When they are weak it's more difficult.
After a hurricane crosses an ocean and reaches a continent, the trade winds weaken. This means that the Coriolis Effect has more of an impact on where the storm goes. In the Northern Hemisphere the Coriolis Effect can cause a tropical storm to curve northward.
When a storm starts to move northward, it leaves the trade winds and moves into the westerlies, the west to east global wind found at mid-latitudes. Because the westerlies move in the opposite direction from trade winds, the hurricane can reverse direction and move east as it travels north.
High pressure systems can also affect the path of storms. In the Atlantic Ocean, the Bermuda High affects the path of hurricanes. When the storms are carried west by the trade winds, they are pushed north around the edge of the high pressure area.
Although these factors add up to a typical hurricane path that travels west and then bends poleward, there are other factors that affect a hurricane's path and complex hurricane tracks are common too. Forecasters use computer models to predict the path that a hurricane will follow but there is always some uncertainty. They can project where a hurricane will be a day in the future with much more certainty that they can project a week in the future. Predicting where a hurricane will make landfall is currently an area of active research.
Last modified March 31, 2009 by Lisa Gardiner.
Shop Windows to the Universe Science Store!Cool It!
is the new card game from the Union of Concerned Scientists that teaches kids about the choices we have when it comes to climate change—and how policy and technology decisions made today will matter. Cool It! is available in our online store
You might also be interested in:
What types of instructional experiences help K-8 students learn science with understanding? What do science educators teachers, teacher leaders, science specialists, professional development staff, curriculum designers, school administrators need to know to create and support such experiences?...more
Earth's ocean covers more than 70% of our planet's surface. There are five major ocean basins. The Pacific Ocean is the largest. It’s so large that it covers a third of the Earth's surface. The Atlantic...more
Why do the 53rd Weather Reconnaissance Squadron and the Hurricane Research Division use different airplanes? Actually, they only use two main types. The top two airplanes in the graphic, the WC-130H Hercules...more
The official "Hurricane Hunters" are the Air Force Reserve's 53rd Weather Reconnaissance Squadron. The squadron consists of ten WC-130 Hercules aircraft which are regularly flown through the eyes of hurricanes....more
The hurricane season in the North Atlantic is particularly strong this year. And scientists predict that the storms will be getting stronger because of global warming. Follow the links below to find out...more
Rain, wind, tornadoes, and storm surge related to hurricanes cause change to natural environments, damage to the human-built environment, and even loss of life. When a hurricane is over the ocean and far...more
A cyclone is an area of low pressure with winds blowing counter-clockwise around it in the Northern Hemisphere and clockwise around it in the Southern Hemisphere. A tropical cyclone is a cyclone which...more
Different places in the world call tropical cyclones by different names. If you click on the image at left you will see which areas use "cyclone", which use "hurricane", and which use "typhoon" when refering...more