(Cont)
The cone size is set so that 66% of the previous 5 year errors in storm center point positions falls within that area at each forecast point.
2023 cone represents 5yr average error(in miles) of:
12hr: 30
24hr: 45
36hr: 61
48hr: 77
60hr: 93
72hr: 114
96hr: 167
120hr: 236
(Cont)
(Cont)
Are forecast storm positions from NHC improving? Cone getting smaller if they are?
Yes!
That improvement rate is slowing though. Improving the science of Hurricanes will help.
7-day cone? One day! NHC is testing in house now but error at that range still too great to publish.