Verification of tracks made of Dalila using GEFS mean fields

August 21, 2019

I made nine tracks of Tropical Storm Dalila. Additionally, within 384 hours of cyclogenesis, there were five instances, when I missed cyclogenesis entirely. Most of the tracks were made at least 16 days before actual cyclogenesis ; in those tracks, projected cyclogenesis was way too east, way too early.

As of this analysis, best track positions are available July 14, 12Z thru July 25, 12Z, 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 nine tracks, formation times ranged between July 14, 18Z and July 22, 12Z. Average was July 17, 20Z and median was July 16, 06Z.

In the fourteen cases (9 tracks and 5 complete misses), peak intensity ranged between Category -2 and Category 4. Average was Category 1.00 and median was Category 2.

In the nine tracks, dissipation times ranged between July 23, 18Z and July 27, 12Z. Average was July 26, 10Z and median was July 26, 18Z.

At the lead time of 1 day (24 hours), there were 1 hit, 0 false detections and 0 misses. 1 available position comparison produces an average error of 43 nautical miles.

At the lead time of 2 days (48 hours), there were 1 hit, 1 false detection and 1 miss. 2 available position comparisons produce an average error of 33 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 90 nautical miles.

At the lead time of 4 days (96 hours), there were 2 hits, 1 false detection and 1 miss. 3 available position comparisons produce an average error of 110 nautical miles.

At the lead time of 5 days (120 hours), there were 2 hits, 0 false detections and 2 misses. 2 available position comparisons produce an average error of 126 nautical miles.

At the lead time of 6 days (144 hours), there were 1 hit, 1 false detection and 2 misses. 1 available position comparison produces an average error of 99 nautical miles.

At the lead time of 7 days (168 hours), there were 0 hits, 1 false detection and 2 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, 3 false detections and 0 misses. 3 available position comparisons produce an average error of 739 nautical miles.

At the lead time of 12 days (288 hours), there were 0 hits, 3 false detections and 0 misses. 3 available position comparisons produce an average error of 736 nautical miles.

At the lead time of 13 days (312 hours), there were 0 hits, 5 false detections and 1 miss. 5 available position comparisons produce an average error of 779 nautical miles.

At the lead time of 14 days (336 hours), there were 0 hits, 5 false detections and 2 misses. 5 available position comparisons produce an average error of 728 nautical miles.

At the lead time of 15 days (360 hours), there were 0 hits, 6 false detections and 3 misses. 6 available position comparisons produce an average error of 764 nautical miles.

At the lead time of 16 days (384 hours), there were 1 hit, 5 false detections and 3 misses. 6 available position comparisons produce an average error of 759 nautical miles.

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