Verification of tracks made of Nana

December 03, 2020

I made five tracks of Hurricane Nana, from four analyses, before it was assessed as a tropical cyclone. (The two tracks from a single analysis didn't overlap in time, and will hereafter be considered a single track.) I made one more track after that point. Additionally, within 480 hours of cyclogenesis, there were five instances, when I missed cyclogenesis entirely.

As of this analysis, best track positions are available August 29, 18Z thru September 4, 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 four tracks (made before operationally recognized cyclogenesis), formation times ranged between September 2, 00Z and September 4, 06Z. Average was September 3, 11Z and median was September 3, 18Z.

In the nine cases (4 tracks, before the tracks and data agreed, that Category 1 would remain the peak intensity, and 5 complete misses), peak intensity ranged between Category -2 and Category 1. Average was Category -1.11 and median was Category -2.

In the five tracks (made before operationally recognized dissipation), dissipation times ranged between September 3, 00Z and September 7, 12Z. Average was September 4, 22Z and median was September 4, 18Z.

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 1 hit, 0 false detections and 1 miss. 1 available position comparison produces an average error of 111 nautical miles.

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

At the lead time of 4 days (96 hours), there were 0 hits, 0 false detections and 2 misses. No available position comparisons.

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

At the lead time of 6 days (144 hours), there were 0 hits, 0 false detections and 1 miss. No available position comparisons.

At the lead time of 7 days (168 hours), there were 0 hits, 0 false detections 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 1 miss. 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, 1 false detection and 0 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 2 misses. No available position comparisons.

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

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

At the lead time of 17 days (408 hours), there were 0 hits, 2 false detections and 1 miss. No available position comparisons.

At the lead time of 18 days (432 hours), there were 0 hits, 1 false detection and 1 miss. No available position comparisons.

At the lead time of 19 days (456 hours), there were 0 hits, 0 false detections and 1 miss. No available position comparisons.

At the lead time of 20 days (480 hours), there were 0 hits, 0 false detections and 1 miss. No available position comparisons.

Circle coloration scheme