Verification of tracks made of TD 3 using GEFS mean fields

July 30, 2019

I made five tracks of Tropical Depression Three. Additionally, within 384 hours of cyclogenesis, there were seven instances, when I missed cyclogenesis entirely. All of the tracks were made long before cyclogenesis. Predicted cyclogenesis was too early, too far east, and mostly consistent with extratropical origins. Longevity and intensity were overestimated.

As of this analysis, best track positions are available July 20, 00Z thru July 23, 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 five tracks, formation times ranged between July 14, 12Z and July 22, 12Z. Average was July 18, 06Z and median was July 16, 18Z.

In the twelve cases (5 tracks and 7 complete misses), peak intensity ranged between Category -2 and Category 5. Average was Category 0.17 and median was Category -2.

In the five tracks, dissipation times ranged between July 26, 18Z and July 31, 18Z. Average was July 30, 08Z and median was July 31, 00Z.

At the lead time of 1 day (24 hours), there were 0 hits, 0 false detections and 1 miss. No available position comparisons.

At the lead time of 2 days (48 hours), there were 0 hits, 0 false detections and 0 misses. No available position comparisons.

At the lead time of 3 days (72 hours), there were 0 hits, 0 false detections and 1 miss. No available position comparisons.

At the lead time of 4 days (96 hours), there were 0 hits, 0 false detections and 1 miss. No available position comparisons.

At the lead time of 5 days (120 hours), there were 0 hits, 0 false detections and 1 miss. No available position comparisons.

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

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

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

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

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

At the lead time of 11 days (264 hours), there were 0 hits, 1 false detection and 0 misses. No available position comparisons.

At the lead time of 12 days (288 hours), there were 0 hits, 2 false detections and 0 misses. No available position comparisons.

At the lead time of 13 days (312 hours), there were 0 hits, 3 false detections and 0 misses. No available position comparisons.

At the lead time of 14 days (336 hours), there were 1 hit, 2 false detections and 0 misses. 1 available position comparison produces an average error of 1043 nautical miles.

At the lead time of 15 days (360 hours), there were 0 hits, 5 false detections and 1 miss. 2 available position comparisons produce an average error of 506 nautical miles.

At the lead time of 16 days (384 hours), there were 1 hit, 4 false detections and 0 misses. 2 available position comparisons produce an average error of 604 nautical miles.

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