In the U.S., the National Weather Service Tropical Prediction Center is responsible for hurricane forecasting, tracking and warning the general public. The Tropical Prediction Center (TPC) consists of the National Hurricane Center (NHC), the Tropical Analysis and Forecast Branch (TAFB) and the Technical Support Branch (TSB).
In addition to the national offices, the local National Weather Service Forecast Offices (WFOs) take part in hurricane forecasting when their areas are in danger. They are also responsible for issuing weather updates to their communities.
According to the National Hurricane Center, “In an average 3-year period, roughly five hurricanes strike the US coastline, killing approximately 50 to 100 people anywhere from Texas to Maine. Of these, two are typically "major" or "intense" hurricanes (a category 3 or higher storm on the Saffir-Simpson Hurricane Scale).”
There are several resources used by the National Weather Service (NWS) for detecting and forecasting hurricane activity.
Weather Satellites
The earliest sign of potential hurricanes is detected by satellite. The Geostationary Operational Environmental Satellites (GOES) measure wind direction, atmospheric temperature, potential rainfall, sea surface temperature, cloud depth and movement.
Weather Buoys
Weather buoys are scattered across the ocean and they contain measuring devices, which transmit data to the National Weather Service. They give an accurate reading of wave height, along with wind speed and temperature of the water and air. Most ships have weather gauges and will broadcast data if they are in the path of a storm.
Buoys and satellites provide early warning to the weather stations on land. When the storm gets closer to shore, additional resources are implemented.
Reconnaissance Aircraft
Aircraft owned by the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Air Force Reserve fly into the hurricane and take measurements. When the aircraft reach the center of the storm, they calculate wind speed, humidity, barometric pressure, plus the exact location of the eye of the hurricane.
The scientists on board the reconnaissance aircraft release a capsule called a dropsonde. It contains instruments to measure air pressure, humidity and temperature. The capsule also contains a radio transmitter and a small parachute to slow down the fall. Data is transmitted to computers located at the weather offices on land.
Weather Balloons
As the hurricane approaches, scientists on land launch an instrument capsule called a radiosonde. It is attached to a weather balloon that takes it up into the atmosphere. It measures barometric pressure, humidity and air temperature. The data is sent to computers at the weather offices.
Radar
When the hurricane is within 200 miles of the coast, weather forecasters and scientists are able to track the storm activity by using radar. Warnings and watches have already been issued long before the storm has reached the range of the radar but more specific data can be derived.
The National Weather Service Prediction Center works with the National Weather Service offices by updating the public with warnings and working with governments on carrying out evacuation orders.
Surface Observation
Once the hurricane makes landfall, a network of land-based weather stations called Automated Surface Observation System (ASOS), continues to monitor weather conditions. The stations transmit data to the weather offices in order to evaluate the severity of the effects of the storm and to warn areas that are in its path.
In addition, HAM radio operators provide real-time weather observations to the National Hurricane Center. This method is useful if there is a failure in the transmission of data in the land-based weather stations.
With the reliance on technology and the development of more sophisticated weather detection equipment, people who are in the path of a hurricane can be better prepared for the storm.
Sources
Hurricane Preparedness. National Oceanic Atmospheric Administration (NOAA). National Hurricane Center. Accessed March 24, 2011.
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