Yes they are not the most exciting graphic images published by us (technically published by the National Hurricane Center 2015 Forecast Verification Report) but it does show an interesting trend with hurricane forecasting. The charts track the errors from 1990 to 2015 broken down to track errors (in miles) and intensity errors (in knots).
Both show that the forecasts are improving but not at the same rate. Track forecasts have become much more accurate with all the time periods analyzed showing the distance error pretty much cut in half over the 25 year period. Intensity forecasts however show very little improvement compared to the tracks. So why is it harder to predict a storms intensity as compared to a storms location?
A hurricane is like a car driving along a path. In recent years improvements in satellite technology, computer power, and GPS data from new and improved hurricane hunter aircraft have made it easier to determine that path the car is traveling on. This is why track forecasts have been able to improve consistently year to year during the study period. Not only is the date received more accurate than years past, but there is a lot more of it. Computers are able to handle that data better and process this into actual forecast models specific to the storm and it’s surroundings.
While the path our hurricane car has become more visible, the actual engine driving that car has not. This would represent the intensity of the storm and without knowing or even understanding the processes inside the storm, it makes it more difficult to determine how the storm will change over time. Initial errors can grow drastically over time with computer forecasting so not getting the most accurate information inside a complex tropical cyclone can make an intensity forecast extremely difficult compared to the track. The forecasts have improved and will continue to do so, just maybe not as rapidly.
So even though intensity forecasts may not be as reliable as the track forecast, they are still good and getting better. Pay close attention to the forecast and the instructions since the errors may have little significance on the damage caused by the storm. The average errors in the report were less than 50 miles for the track and 10 knots for the intensity. That would make little to no noticeable difference when your talking about a major hurricane.