Models: Helping to Forecast Severe Storms
National Hurricane Center in Miami, Florida, is a component of the
NOAA National Centers for Environmental
Prediction and the NOAA National
Weather Service. NHCs mission is to track tropical cyclones
and predict their future position and intensity over the north Atlantic
Ocean, Caribbean Sea, Gulf of Mexico and eastern North Pacific Ocean.
This monitoring begins in a tropical cyclones infancy as tropical
depression through its maturity as a hurricane.
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To forecast the track and intensity of tropical cyclones, NHC uses mathematical
models run on the IBM R/S 6000 SP System super computer. These models
represent the future motion and intensity of a tropical cyclone and its
environment in a simplified manner. Hurricane forecasters then interpret
model results to arrive at a final track and intensity forecast, distributing
it to the public in the form of advisories.
NHC uses three types of mathematical models: Statistical, Dynamical or
a combination (Statistical-Dynamical). Statistical Models forecast the
future by using current information about a tropical cyclone and comparing
it to the historical behavior of similar storms. The historical record
for storms in the north Atlantic begins in 1871, while the record for
storms for the east Pacific extends back to 1945.
Dynamical Models use the results of global atmospheric data to forecast
tropical cyclone motion and intensity. Global models take current wind,
temperature, pressure and humidity observations and make forecasts of
the actual atmosphere in which the cyclone exists.
Statistical Models are defined by their simplicity; while Dynamical Models
are hampered by incomplete data sets and lack of computer horse
power. Predictions from both computer models are only approximate.
Statistical Models dont directly include current atmospheric conditions,
and Dynamical Models omit the historical behavior of storms.
Because of their simplicity, Statistical Models were designed first in
the late 1960s for tropical cyclone forecasting. In the early 1970s, Combination
Models were developed as global models and began making forecasts in tropical
regions. As computers became more powerful, pure Dynamic Models began
dominating the accuracy race. This is particularly true when tropical
cyclones approach data-rich regions close to the continents, where the
state of the atmospheric environment is adequately observed and well known.
For more information contact NOAA National
Hurricane Center public affairs at (305) 229-4404 or visit the NOAA
Tropical Cyclone Track and Intensity Guidance Models Web site.
Updated May 2005