With Tropical Storm Isaac moving northwest possibly toward Florida in coming days and a potential Joyce behind that, I thought it would be interesting to see how hurricane forecast accuracy has improved over the years. First of all let’s just look at the 5-year average official forecast errors from the National Hurricane Center for the Atlantic Basin for the period 2007 to 2011.
12 24 36 48 120
Track Error (nautical miles) 30 48 66 83 213
Intensity Error (knots) 7 11 13 15 18
As you probably would have guessed, there is a much large track error when looking out 5 days versus just forecasting ahead 12 hours. The intensity error increase doesn’t seem to be as noticeably with time.
When you compare the track error trends from 1970 to that of 2011 their has been remarkable improvement. The 24 hour average forecast error has dropped from 150 nautical miles in the 1970 to 50 miles in 2011. The 48 hour error has fallen from 300 n. miles to 80. Furthermore, the 72 hour forecast error has been reduced from 450 n. miles in 1970 to 100 n. miles in 2011. I really like those trends and should this improvement continue for another few decades, this is going to become a really precise business.
You can learn much more about errors and trends for hurricane models as well as data for the Eastern Pacific from the following National Hurricane Center link. http://www.nhc.noaa.gov/verification/verify4.shtml