Verification of tracks made of TD 21E using GEFS mean fields

December 10, 2019

I made six tracks of Tropical Depression Twenty-One-E. Additionally, within 384 hours of cyclogenesis, there were twelve instances, when I missed cyclogenesis entirely. Formation time was often late, while dissipation time was even more late.

As of this analysis, best track positions are available November 14, 12Z thru November 18, 18Z, 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 six tracks, formation times ranged between November 15, 06Z and November 24, 06Z. Average was November 19, 09Z and median was November 18, 12Z.

In the eighteen cases (6 tracks and 12 complete misses), peak intensity ranged between Category -2 and Category 3. Average was Category -0.94 and median was Category -2.

In the six tracks, dissipation times ranged between November 22, 00Z and December 2, 00Z. Average was November 25, 15Z and median was November 23, 18Z.

At the lead time of 1 day (24 hours), there were 1 hit, 1 false detection and 0 misses. 2 available position comparisons produce an average error of 89 nautical miles.

At the lead time of 2 days (48 hours), there were 2 hits, 0 false detections and 0 misses. 2 available position comparisons produce an average error of 112 nautical miles.

At the lead time of 3 days (72 hours), there were 2 hits, 0 false detections and 1 miss. 2 available position comparisons produce an average error of 163 nautical miles.

At the lead time of 4 days (96 hours), there were 1 hit, 0 false detections and 3 misses. 1 available position comparison produces an average error of 182 nautical miles.

At the lead time of 5 days (120 hours), there were 0 hits, 2 false detections and 3 misses. No available position comparisons.

At the lead time of 6 days (144 hours), there were 0 hits, 2 false detections and 3 misses. No available position comparisons.

At the lead time of 7 days (168 hours), there were 0 hits, 1 false detection and 3 misses. No available position comparisons.

At the lead time of 8 days (192 hours), there were 0 hits, 1 false detection and 3 misses. No available position comparisons.

At the lead time of 9 days (216 hours), there were 0 hits, 1 false detection and 3 misses. No available position comparisons.

At the lead time of 10 days (240 hours), there were 0 hits, 0 false detections and 3 misses. No available position comparisons.

At the lead time of 11 days (264 hours), there were 0 hits, 0 false detections and 4 misses. No available position comparisons.

At the lead time of 12 days (288 hours), there were 0 hits, 0 false detections and 4 misses. No available position comparisons.

At the lead time of 13 days (312 hours), there were 0 hit, 2 false detections and 4 misses. 1 available position comparison produces an average error of 438 nautical miles.

At the lead time of 14 days (336 hours), there were 0 hits, 2 false detections and 4 misses. No available position comparisons.

At the lead time of 15 days (360 hours), there were 0 hits, 3 false detections and 4 misses. No available position comparisons.

At the lead time of 16 days (384 hours), there were 0 hits, 4 false detections and 3 misses. No available position comparisons.

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