To forecast the track and intensity of
tropical cyclones, the NHC uses several different mathematical computer
models that represent the tropical cyclone and its environment in a
greatly simplified manner. Each of the models has particular strengths
and weaknesses, and researchers are constantly working to improve them.
If you read the hurricane discussions
(described in the products subsection), you will see forecasters
referring to different models and giving their reasons why they think
particular models are doing a better job of representing current and
future conditions. Acronyms for models commonly discussed are GFDL,
CLIPER, AVN, LBAR, BAM, NOGAPS (the U.S. Navy's model), and UKMET (the
model run by the United Kingdom's Meteorological Service). These are
all track models. Intensity model acronyms include SHIFOR, SHIPS, and
GFDL.
It is important to know that these models
are only run a few times a day and cannot, therefore, take into account
all of the short-term changes the atmosphere is constantly undergoing.
Models cannot produce forecasts more frequently because they require
huge amounts of data and long computational times.
Hurricane forecasters must look at all of
the models' results, which frequently give widely different pictures of
the future. When the models do disagree, hurricane forecasters must use
their experience and judgment to decide which model is performing the
best under the current conditions. Unfortunately, we are not at a point
in this science where one model can reliably be used for forecasts in
all the different situations that can occur given the complexity of our
atmosphere.
A good forecaster has an extensive
education in the science of meteorology and considerable experience in
tropical forecasting. Nonetheless, many times the different data
sources are too conflicting for forecasters to have a high degree of
confidence in their predictions. Even when they are more sure,
forecasters
still recognize that conditions can change quickly. This is why
forecasts talk about "probabilities" and "margin of error". This is
also why emergency managers consider planning for a hurricane one
category higher than is currently forecast and why they prepare in
advance to take action in case the track shifts suddenly or the storm
speeds up as was the case with Hurricane Opal, 1995.
All information intended for
informational purposes only!
For Emergency situations and/or decisions, please refer to your local
Emergency Management Office.
