Of all the major advances in weather technology over the last 50 years, computer technology has arguably had the greatest impact on the science of forecasting the weather, and in particular forecasting tropical weather.
Meteorology is a science of numbers. Lots of numbers. From air temp, humidity, and wind speed to helicity, vorticity, and advection, massive amounts of data go into making a forecast. The same applies to forecasting where a tropical storm will go.
Before the computer revolution, forecasters relied primarily on ground observations and satellite imagery to forecast the tracks that hurricanes might take. Collecting and organizing all this data by hand was a tedious and time consuming task, with only marginal results.
Computers allowed forecasters to enter much, much larger amounts of information into the various weather equations that help decipher how storms will evolve over time. As computer have continued to get more and more powerful, forecasters have been able to input more and more data.
In the present day, dozens of computer models iinterpret massive amounts of data up to 4 times every day. The output of these programs has greatly increased the accuracy of track forecasting of tropical systems. In the 10 years from 1999 to 2009 the average error has gone from about 400 nautical miles to 200 nautical miles when it comes to 3 to 5 day forecasts.
These great results allowed the National Hurricane Center to upgrade the 3 day track forecast to a 5 day forecast in 2003. Two extra days to prepare for a potentially devastating hurricane can go a long way towards saving more lives and property. With computer technology still rapidly growing, tropical storm track forecasts will likely continue to get better and better in the years to come.