Verification of tracks made of Flossie using GEFS mean fields

August 23, 2019

I made seven tracks of Hurricane Flossie. Additionally, within 384 hours of cyclogenesis, there were two instances, when I missed cyclogenesis entirely. Timing of cyclogenesis was great, and location errors were pretty small. Intensity and longevity were mostly overestimated.

As of this analysis, best track positions are available July 25, 12Z thru August 6, 00Z, and as such, position comparisons are possible only for this timespan.

Getting out of the frame of East Pacific tracking map is considered equal to dissipation for the purpose of this verification.

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 seven tracks, formation times ranged between July 27, 06Z and July 28, 18Z. Average was July 27, 23Z and median was July 27, 18Z.

In the nine cases (7 tracks and 2 complete misses), peak intensity ranged between Category -2 and Category 5. Average was Category 2.67 and median was Category 3.

In the seven tracks, dissipation times ranged between August 6, 00Z and August 13, 00Z. Average was August 9, 06Z and median was August 8, 12Z.

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

At the lead time of 4 days (96 hours), there were 0 hits, 1 false detection and 1 miss. 1 available position comparison produces an average error of 185 nautical miles.

At the lead time of 5 days (120 hours), there were 0 hits, 1 false detection and 2 misses. 1 available position comparisons produce an average error of 279 nautical miles.

At the lead time of 6 days (144 hours), there were 1 hit, 1 false detection and 2 misses. 2 available position comparisons produce an average error of 220 nautical miles.

At the lead time of 7 days (168 hours), there were 3 hits, 0 false detections and 2 miss. 3 available position comparisons produce an average error of 269 nautical miles.

At the lead time of 8 days (192 hours), there were 3 hits, 1 false detection and 2 misses. 4 available position comparisons produce an average error of 287 nautical miles.

At the lead time of 9 days (216 hours), there were 4 hits, 0 false detections and 2 misses. 4 available position comparisons produce an average error of 367 nautical miles.

At the lead time of 10 days (240 hours), there were 5 hits, 0 false detections and 2 misses. 5 available position comparisons produce an average error of 421 nautical miles.

At the lead time of 11 days (264 hours), there were 7 hits, 0 false detections and 2 misses. 7 available position comparisons produce an average error of 443 nautical miles.

At the lead time of 12 days (288 hours), there were 7 hits, 0 false detections and 1 miss. 7 available position comparisons produce an average error of 497 nautical miles.

At the lead time of 13 days (312 hours), there were 7 hits, 0 false detections and 0 misses. 7 available position comparisons produce an average error of 535 nautical miles.

At the lead time of 14 days (336 hours), there were 6 hits, 1 false detection and 0 misses. 6 available position comparisons produce an average error of 575 nautical miles.

At the lead time of 15 days (360 hours), there were 5 hits, 2 false detections and 0 misses. 5 available position comparisons produce an average error of 589 nautical miles.

At the lead time of 16 days (384 hours), there were 4 hits, 3 false detections and 0 misses. 4 available position comparisons produce an average error of 618 nautical miles.

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