Verification of tracks made on Florence using GEFS mean fields
I made 30 tracks about Hurricane Florence. Additionally, within 384
hours of cyclogenesis, there were 7 instances, when I missed
cyclogenesis entirely. Intensity forecast was very variable. Earliest tracks were generally either depicting a short-lived system in East Tropical Atlantic, or a Caribbean hurricane. Later, solution shifted to show early movement to subtropics, followed by dissipation well east of Bermuda. Only one track had Florence being mostly in the subtropics and hitting U.S. East Coast. Timing of cyclogenesis was excellent, while dissipation was mostly too early.
As of this analysis, best track positions are available August 29, 06Z thru September 18, 12Z, 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 30 tracks, formation times ranged between August 30, 00Z and September 4, 06Z. Average was August 31, 17Z and median was August 31, 15Z.
In the 37 cases (30 tracks and 7 complete misses), peak intensity ranged between Category -2 and Category 5. Average was Category 0.86 and median was Category 0.
In the 30 tracks, dissipation times ranged between September 1, 18Z and October 1, 06Z. Average was September 10, 06Z and median was September 9, 00Z.
At the lead time of 1 day (24 hours), there were 0 hits, 1 false detections and 0 misses. 1 available position comparison produces an average error of 53 nautical miles.
At the lead time of 2 days (48 hours), there were 1 hits, 2 false detections and 0 misses. 3 available position comparisons produce an average error of 73 nautical miles.
At the lead time of 3 days (72 hours), there were 3 hits, 0 false detections and 0 misses. 3 available position comparisons produce an average error of 70 nautical miles.
At the lead time of 4 days (96 hours), there were 5 hits, 2 false detections and 0 misses. 7 available position comparisons produce an average error of 96 nautical miles.
At the lead time of 5 days (120 hours), there were 7 hits, 0 false detections and 1 misses. 7 available position comparisons produce an average error of 126 nautical miles.
At the lead time of 6 days (144 hours), there were 9 hits, 2 false detections and 0 misses. 11 available position comparisons produce an average error of 176 nautical miles.
At the lead time of 7 days (168 hours), there were 11 hits, 1 false detections and 1 misses. 12 available position comparisons produce an average error of 173 nautical miles.
At the lead time of 8 days (192 hours), there were 12 hits, 0 false detections and 2 misses. 12 available position comparisons produce an average error of 229 nautical miles.
At the lead time of 9 days (216 hours), there were 12 hits, 2 false detections and 5 misses. 14 available position comparisons produce an average error of 330 nautical miles.
At the lead time of 10 days (240 hours), there were 15 hits, 3 false detections and 5 misses. 19 available position comparisons produce an average error of 371 nautical miles.
At the lead time of 11 days (264 hours), there were 16 hits, 0 false detections and 7 misses. 18 available position comparisons produce an average error of 438 nautical miles.
At the lead time of 12 days (288 hours), there were 18 hits, 1 false detections and 8 misses. 20 available position comparisons produce an average error of 506 nautical miles.
At the lead time of 13 days (312 hours), there were 19 hits, 0 false detections and 10 misses. 20 available position comparisons produce an average error of 531 nautical miles.
At the lead time of 14 days (336 hours), there were 17 hits, 0 false detections and 14 misses. 17 available position comparisons produce an average error of 563 nautical miles.
At the lead time of 15 days (360 hours), there were 18 hits, 0 false detections and 15 misses. 18 available position comparisons produce an average error of 518 nautical miles.
At the lead time of 16 days (384 hours), there were 15 hits, 0 false detections and 22 misses. 15 available position comparisons produce an average error of 589 nautical miles.
Here are the tracks once again.
August 17, 06Z run:
August 18, 06Z run:
August 18, 18Z run:
August 19, 06Z run:
August 19, 12Z run:
August 19, 18Z run:
August 20, 06Z run:
August 20, 12Z run:
August 20, 18Z run:
August 21, 06Z run:
August 21, 12Z run:
August 21, 18Z run:
August 22, 06Z run:
August 22, 12Z run:
August 22, 18Z run:
Beginning with August 23, 12Z, run, coloration scheme changed to the following, and this legend ceased to be included in every track.
August 23, 12Z run:
August 23, 18Z run:
August 24, 06Z run:
August 24, 18Z run:
August 25, 06Z run:
August 25, 12Z run:
August 26, 12Z run:
August 26, 18Z run:
August 27, 06Z run:
August 27, 12Z run:
August 27, 18Z run:
August 28, 06Z run:
August 28, 18Z run:
August 29, 12Z run:
August 29, 18Z run:
The complete misses were from following runs:
August 15, 18Z
August 16, 00Z
August 16, 06Z
August 16, 12Z
August 16, 18Z
August 18, 12Z
August 23, 06Z
As of this analysis, best track positions are available August 29, 06Z thru September 18, 12Z, 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 30 tracks, formation times ranged between August 30, 00Z and September 4, 06Z. Average was August 31, 17Z and median was August 31, 15Z.
In the 37 cases (30 tracks and 7 complete misses), peak intensity ranged between Category -2 and Category 5. Average was Category 0.86 and median was Category 0.
In the 30 tracks, dissipation times ranged between September 1, 18Z and October 1, 06Z. Average was September 10, 06Z and median was September 9, 00Z.
At the lead time of 1 day (24 hours), there were 0 hits, 1 false detections and 0 misses. 1 available position comparison produces an average error of 53 nautical miles.
At the lead time of 2 days (48 hours), there were 1 hits, 2 false detections and 0 misses. 3 available position comparisons produce an average error of 73 nautical miles.
At the lead time of 3 days (72 hours), there were 3 hits, 0 false detections and 0 misses. 3 available position comparisons produce an average error of 70 nautical miles.
At the lead time of 4 days (96 hours), there were 5 hits, 2 false detections and 0 misses. 7 available position comparisons produce an average error of 96 nautical miles.
At the lead time of 5 days (120 hours), there were 7 hits, 0 false detections and 1 misses. 7 available position comparisons produce an average error of 126 nautical miles.
At the lead time of 6 days (144 hours), there were 9 hits, 2 false detections and 0 misses. 11 available position comparisons produce an average error of 176 nautical miles.
At the lead time of 7 days (168 hours), there were 11 hits, 1 false detections and 1 misses. 12 available position comparisons produce an average error of 173 nautical miles.
At the lead time of 8 days (192 hours), there were 12 hits, 0 false detections and 2 misses. 12 available position comparisons produce an average error of 229 nautical miles.
At the lead time of 9 days (216 hours), there were 12 hits, 2 false detections and 5 misses. 14 available position comparisons produce an average error of 330 nautical miles.
At the lead time of 10 days (240 hours), there were 15 hits, 3 false detections and 5 misses. 19 available position comparisons produce an average error of 371 nautical miles.
At the lead time of 11 days (264 hours), there were 16 hits, 0 false detections and 7 misses. 18 available position comparisons produce an average error of 438 nautical miles.
At the lead time of 12 days (288 hours), there were 18 hits, 1 false detections and 8 misses. 20 available position comparisons produce an average error of 506 nautical miles.
At the lead time of 13 days (312 hours), there were 19 hits, 0 false detections and 10 misses. 20 available position comparisons produce an average error of 531 nautical miles.
At the lead time of 14 days (336 hours), there were 17 hits, 0 false detections and 14 misses. 17 available position comparisons produce an average error of 563 nautical miles.
At the lead time of 15 days (360 hours), there were 18 hits, 0 false detections and 15 misses. 18 available position comparisons produce an average error of 518 nautical miles.
At the lead time of 16 days (384 hours), there were 15 hits, 0 false detections and 22 misses. 15 available position comparisons produce an average error of 589 nautical miles.
Here are the tracks once again.
August 17, 06Z run:
August 23, 12Z run:
August 23, 18Z run:
August 15, 18Z
August 16, 00Z
August 16, 06Z
August 16, 12Z
August 16, 18Z
August 18, 12Z
August 23, 06Z
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