Verification of tracks made of Lowell

January 04, 2021

I made one track of Tropical Storm Lowell, before it was assessed as a tropical cyclone. I made three more tracks after that point. Additionally, within 480 hours of cyclogenesis, there were three instances, when I missed cyclogenesis entirely.

As of this analysis, tropical cyclone report or best track positions are available September 19, 06Z thru September 28, 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 one track (made before operationally recognized cyclogenesis), range, average and median of formation times was September 24, 06Z.

In the five cases (2 tracks, before the tracks and data agreed, that tropical storm would remain the peak intensity, and 3 complete misses), peak intensity ranged between Category -2 and Category 1. Average was Category -1.00 and median was Category -2.

In the four tracks (made before operationally recognized degeneration into remnant low), dissipation times ranged between September 25, 12Z and September 29, 06Z. Average was September 27, 13Z and median was September 27, 18Z.

At the lead time of 1 day (24 hours), there were 2 hits, 0 false detections and 1 miss. 3 available position comparisons produce an average error of 32 nautical miles.

At the lead time of 2 days (48 hours), there were 2 hits, 0 false detections and 1 miss. 2 available position comparisons produce an average error of 63 nautical miles.

At the lead time of 3 days (72 hours), there were 1 hit, 1 false detection and 0 misses. 2 available position comparisons produce an average error of 106 nautical miles.

At the lead time of 4 days (96 hours), there were 1 hit, 0 false detections and 0 misses. 1 available position comparison produces an average error of 184 nautical miles.

At the lead time of 5 days (120 hours), there were 0 hits, 1 false detection and 1 miss. 1 available position comparison produces an average error of 295 nautical miles.

At the lead time of 6 days (144 hours), there were 0 hits, 1 false detection and 1 miss. 1 available position comparison produces an average error of 405 nautical miles.

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

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

At the lead time of 9 days (216 hours), there were 0 hits, 0 false detections and 2 misses. No available position comparisons.

At the lead time of 10 days (240 hours), there were 0 hits, 0 false detections and 1 miss. No available position comparisons.

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

At the lead time of 12 days (288 hours), there were 0 hits, 0 false detections and 1 miss. No available position comparisons.

At the lead time of 13 days (312 hours), there were 0 hits, 0 false detections and 1 miss. No available position comparisons.

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

At the lead time of 15 days (360 hours), there were 0 hits, 0 false detections and 1 miss. No available position comparisons.

At the lead time of 16 days (384 hours), there were 0 hits, 0 false detections and 1 miss. No available position comparisons.

At the lead time of 17 days (408 hours), there were 0 hits, 0 false detections and 1 miss. No available position comparisons.

At the lead time of 18 days (432 hours), there were 1 hit, 0 false detections and 1 miss. 1 available position comparison produces an average error of 468 nautical miles.

At the lead time of 19 days (456 hours), there were 1 hit, 0 false detections and 1 miss. 1 available position comparison produces an average error of 514 nautical miles.

At the lead time of 20 days (480 hours), there were 0 hits, 1 false detection and 1 miss. 1 available position comparison produces an average error of 436 nautical miles.

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