Verification of tracks made of Arthur

I made 20 tracks of Tropical Storm Arthur, before it was assessed as a tropical cyclone. I made eight more tracks after that point. Additionally, within 480 hours of cyclogenesis, there were 37 instances, when I missed cyclogenesis entirely. At long lead times, non-detection was consistent, while at short lead times, detection was consistent, mostly with good timing of cyclogenesis. After detections began, assessment of peak intensity was very good. Position accuracy was also good.

As of this analysis, best track positions are available May 13, 18Z thru May 19, 18Z, 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 20 tracks (made before operationally recognized cyclogenesis), formation times ranged between May 16, 00Z and May 19, 06Z. Average was May 17, 05Z and median was May 17, 06Z.

In the 58 cases (21 tracks, before the tracks and data agreed, that tropical storm would remain the peak intensity, and 37 complete misses), peak intensity ranged between Category -2 and  Category 1. Average was Category -1.22 and median was Category -2.

In the 28 tracks (made before operationally recognized degeneration into remnant low), dissipation times ranged between May 19, 12Z and May 21, 06Z. Average was May 20, 08Z and median was May 20, 09Z.

At the lead time of 1 day (24 hours), there were 9 hits, 4 false detections and 0 misses. 14 available position comparisons produce an average error of 46 nautical miles.

At the lead time of 2 days (48 hours), there were 8 hits, 5 false detections and 0 misses. 11 available position comparisons produce an average error of 61 nautical miles.

At the lead time of 3 days (72 hours), there were 6 hits, 4 false detections and 2 misses. 10 available position comparisons produce an average error of 101 nautical miles.

At the lead time of 4 days (96 hours), there were 7 hits, 1 false detection and 1 miss. 8 available position comparisons produce an average error of 128 nautical miles.

At the lead time of 5 days (120 hours), there were 7 hits, 2 false detections and 1 miss. 9 available position comparisons produce an average error of 203 nautical miles.

At the lead time of 6 days (144 hours), there were 4 hits, 2 false detections and 4 misses. 6 available position comparisons produce an average error of 227 nautical miles.

At the lead time of 7 days (168 hours), there were 5 hits, 2 false detections and 3 misses. 7 available position comparisons produce an average error of 262 nautical miles.

At the lead time of 8 days (192 hours), there were 3 hits, 3 false detections and 5 misses. 5 available position comparisons produce an average error of 209 nautical miles.

At the lead time of 9 days (216 hours), there were 1 hit, 3 false detections and 7 misses. 3 available position comparisons produce an average error of 123 nautical miles.

At the lead time of 10 days (240 hours), there were 0 hits, 1 false detection and 8 misses. No available position comparisons.

At the lead time of 11 days (264 hours), there were 0 hits, 0 false detections and 8 misses. No available position comparisons.

At the lead time of 12 days (288 hours), there were 0 hits, 0 false detections and 8 misses. No available position comparisons.

At the lead time of 13 days (312 hours), there were 0 hits, 0 false detections and 7 misses. No available position comparisons.

At the lead time of 14 days (336 hours), there were 0 hits, 0 false detections and 7 misses. No available position comparisons.

At the lead time of 15 days (360 hours), there were 0 hits, 0 false detections and 7 misses. No available position comparisons.

At the lead time of 16 days (384 hours), there were 0 hits, 0 false detections and 7 misses. No available position comparisons.

At the lead time of 17 days (408 hours), there were 0 hits, 0 false detections and 6 misses. No available position comparisons.

At the lead time of 18 days (432 hours), there were 0 hits, 0 false detections and 6 misses. No available position comparisons.

At the lead time of 19 days (456 hours), there were 0 hits, 0 false detections and 8 misses. No available position comparisons.

At the lead time of 20 days (480 hours), there were 0 hits, 0 false detections and 8 misses. No available position comparisons.

Circle coloration scheme

Here are the tracks once again.
May 10, 06Z:

May 10, 12Z:

May 10, 18Z:

May 11, 06Z:

May 11, 12Z:

May 11, 18Z:

May 12, 06Z:

May 12, 12Z:

May 12, 18Z:

May 13, 06Z:

May 13, 12Z:

May 13, 18Z:

May 14, 06Z:

May 14, 12Z:

May 14, 18Z:

May 15, 06Z:

May 15, 12Z:

May 15, 18Z:

May 16, 06Z:

May 16, 12Z:

May 16, 18Z:

May 17, 06Z:

May 17, 12Z:

May 17, 18Z:

May 18, 06Z:

May 18, 12Z:

May 18, 18Z:

May 19, 06Z:

The complete misses were from the following model cycles:


April 26, 18Z
April 27, 06Z
April 27, 12Z
April 27, 18Z
April 28, 06Z


April 28, 12Z
April 28, 18Z
April 29, 06Z
April 29, 12Z
April 29, 18Z

April 30, 06Z
May 1, 06Z
May 1, 12Z
May 1, 18Z
May 2, 06Z

May 2, 12Z
May 2, 18Z
May 3, 06Z
May 3, 12Z
May 3, 18Z

May 4, 12Z
May 4, 18Z
May 5, 06Z
May 5, 12Z
May 5, 18Z

May 6, 06Z
May 6, 12Z
May 6, 18Z
May 7, 06Z
May 7, 12Z

May 7, 18Z
May 8, 06Z
May 8, 12Z
May 8, 18Z
May 9, 06Z

May 9, 12Z
May 9, 18Z