Verification of tracks made on Gordon using GEFS mean fields
I made 20 tracks about Tropical Storm Gordon. Additionally, within 384
hours of cyclogenesis, there were 23 instances, when I missed
cyclogenesis entirely. Originally, I often projected Gordon to form in eastern tropical Atlantic, the tropical cyclone and/or its precursor wave sometimes stalling, or even moving east. Then, I missed the system altogether for many days. In the end, there were a few instances, where I projected Gordon to form in Gulf of Mexico, way later than the actual time of cyclogenesis. Intensity forecast was variable, and position accuracy constantly very poor.
As of this analysis, best track positions are available September 1, 12Z thru September 8, 00Z, and as such, position comparisons are possible only for this timespan.
Since I give only SSHS categories in my tracks, I don't calculate intensity errors in units of speed, but in categories. For this purpose, I define tropical or subtropical storms as "Category 0", tropical or subtropical depressions as "Category -1" and non-existence of a tropical or subtropical cyclone as "Category -2".
In the 20 tracks, formation times ranged between August 24, 00Z and September 8, 18Z. Average was August 29, 11Z and median was August 28, 18Z.
In the 43 cases (20 tracks and 23 complete misses), peak intensity ranged between Category -2 and Category 5. Average was Category -0.37 and median was Category -2.
In the 20 tracks, dissipation times ranged between August 28, 00Z and September 23, 12Z. Average was September 6, 01Z and median was September 4, 15Z.
As of this analysis, best track positions are available September 1, 12Z thru September 8, 00Z, and as such, position comparisons are possible only for this timespan.
Since I give only SSHS categories in my tracks, I don't calculate intensity errors in units of speed, but in categories. For this purpose, I define tropical or subtropical storms as "Category 0", tropical or subtropical depressions as "Category -1" and non-existence of a tropical or subtropical cyclone as "Category -2".
In the 20 tracks, formation times ranged between August 24, 00Z and September 8, 18Z. Average was August 29, 11Z and median was August 28, 18Z.
In the 43 cases (20 tracks and 23 complete misses), peak intensity ranged between Category -2 and Category 5. Average was Category -0.37 and median was Category -2.
In the 20 tracks, dissipation times ranged between August 28, 00Z and September 23, 12Z. Average was September 6, 01Z and median was September 4, 15Z.
At the lead time of 1 day (24 hours), there were 0 hits, 0 false detections and 1 misses. No available position comparisons.
At the lead time of 2 days (48 hours), there were 0 hits, 0 false detections and 2 misses. No available position comparisons.
At the lead time of 3 days (72 hours), there were 0 hits, 0 false detections and 3 misses. No available position comparisons.
At the lead time of 4 days (96 hours), there were 0 hits, 0 false detections and 3 misses. No available position comparisons.
At the lead time of 5 days (120 hours), there were 0 hits, 0 false detections and 4 misses. No available position comparisons.
At the lead time of 6 days (144 hours), there were 0 hits, 1 false detections and 4 misses. No available position comparisons.
At the lead time of 7 days (168 hours), there were 0 hits, 1 false detections and 6 misses. No available position comparisons.
At the lead time of 8 days (192 hours), there were 0 hits, 2 false detections and 7 misses. No available position comparisons.
At the lead time of 9 days (216 hours), there were 0 hits, 5 false detections and 7 misses. 1 available position comparison produces an average error of 488 nautical miles.
At the lead time of 10 days (240 hours), there were 0 hits, 11 false detections and 6 misses. 1 available position comparison produces an average error of 2151 nautical miles.
At the lead time of 11 days (264 hours), there were 0 hits, 14 false detections and 6 misses. 1 available position comparison produces an average error of 2121 nautical miles.
At the lead time of 12 days (288 hours), there were 1 hits, 14 false detections and 7 misses. 1 available position comparison produces an average error of 2146 nautical miles.
At the lead time of 13 days (312 hours), there were 0 hits, 13 false detections and 9 misses. 2 available position comparisons produce an average error of 1963 nautical miles.
At the lead time of 14 days (336 hours), there were 1 hits, 10 false detections and 8 misses. 5 available position comparisons produce an average error of 2251 nautical miles.
At the lead time of 15 days (360 hours), there were 1 hits, 9 false detections and 8 misses. 4 available position comparisons produce an average error of 2443 nautical miles.
At the lead time of 16 days (384 hours), there were 3 hits, 6 false detections and 6 misses. 5 available position comparisons produce an average error of 2071 nautical miles.
Here are the tracks once again.
August 13, 18Z run:
August 13, 18Z run:
August 23, 06Z run:
The complete misses were from the following GEFS runs:
August 20, 06Z
August 20, 18Z
August 21, 06Z
August 21, 18Z
August 22, 06Z
August 22, 12Z
August 22, 18Z
August 23, 12Z
August 23, 18Z
August 24, 06Z
August 24, 18Z
August 25, 06Z
August 25, 12Z
August 26, 12Z
August 26, 18Z
August 27, 06Z
August 27, 12Z
August 27, 18Z
August 29, 12Z
August 30, 12Z
August 31, 18Z
September 1, 12Z
September 2, 12Z
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