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Showing posts from July, 2019

Verification of tracks made of Cosme using GEFS mean fields

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I made eight tracks of Tropical Storm Cosme. Additionally, within 384 hours of cyclogenesis, there were 15 instances, when I missed cyclogenesis entirely. All the tracks were made relatively close to cyclogenesis. In those tracks, longevity and intensity were overestimated. As actual cyclogenesis got very close, the precursor disturbance of Cosme had two competing spins, and my technique produced tracks from the wrong one, resulting in relatively huge position errors at shortest lead times. As of this analysis, best track positions are available July 3, 06Z thru July 8, 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"

Verification of tracks made of TD 3 using GEFS mean fields

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I made five tracks of Tropical Depression Three. Additionally, within 384 hours of cyclogenesis, there were seven instances, when I missed cyclogenesis entirely. All of the tracks were made long before cyclogenesis. Predicted cyclogenesis was too early, too far east, and mostly consistent with extratropical origins. Longevity and intensity were overestimated. As of this analysis, best track positions are available July 20, 00Z thru July 23, 12Z, 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 five tracks, formation times ranged between July 14, 12Z and July 22, 12Z. Average was July 18, 06Z an

Verification of tracks made of Barry using GEFS mean fields

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I made six tracks of Hurricane Barry. Additionally, within 384 hours of cyclogenesis, there were 11 instances, when I missed cyclogenesis entirely. As of this analysis, best track positions are available July 7, 12Z thru July 14, 18Z, and as such, position comparisons are possible only for this timespan. In the absence of best track for the rest of Barry's existence, dissipation is assumed to be at July 16, 00Z. 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 six tracks, formation times ranged between July 10, 06Z and July 12, 00Z. Average was July 11, 03Z and median was July 11, 09Z. In the 17 cases (6 tracks and 11 complete misses), peak intensity ranged

Verification of a track made of Andrea using GEFS mean fields

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I made one track of Subtropical Storm Andrea. Additionally, within 384 hours of cyclogenesis, there were 46 instances, when I missed cyclogenesis entirely. The lone track didn't have concurrent duration as a tropical cyclone with actual Andrea. As of this analysis, best track positions are available May 18, 18Z thru May 21, 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 track, range, average and median of formation time was May 24, 18Z. In the 47 cases (1 track and 46 complete misses), peak intensity ranged between Category -2 and Category 0. Average was Category -1.96

Verification of tracks made of Barbara using GEFS mean fields

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I made 13 tracks of Hurricane Barbara. Additionally, within 384 hours of cyclogenesis, there were 19 instances, when I missed cyclogenesis entirely. There were two major gaps, when no cyclogenesis was expected. With the exception of the last track, the progression of precursor wave was estimated wrong, cyclogenesis was expected to happen too far east, and a sharp north turn was projected. As a result, position errors became huge at most lead times. As of this analysis, best track positions are available June 28, 06Z thru July 8, 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

Verification of Atlantic ghost storm tracks of January-May 2019

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I falsely detected (sub)tropical cyclogenesis in Atlantic (north of equator and west of Greenwich) 134 times in January thru May of 2019. Additionally, false East Pacific cyclogeneses led to crossover into the basin 10 times, and false Gulf of Guinea cyclogeneses led to crossover into the basin 4 times. Tracks were made of 28 systems. In the calculations, crossover into East Pacific as a tropical cyclone is considered equal to dissipation, and crossover from East Pacific or Gulf of Guinea as a tropical cyclone is considered equal to formation or regeneration. At the lead time of 1 day ( 24 hours), there were 0 false detections. At the lead time of 2 days ( 48 hours), there were 1 false detections. At the lead time of 3 days ( 72 hours), there were 1 false detections. At the lead time of 4 days ( 96 hours), there were 7 false detections. At the lead time of 5 days ( 120 hours), there were 18 false detections. At the lead time of 6 days ( 144 hours), there were