"Vortical" Hot Towers/Overshooting Tops in Pre-Genesis Tropical Cyclones
Sarah Monette     Research Advisors: Wayne Feltz & Chris Velden     OT Algorithm Developer: Kristopher Bedka

Current image of the Atlantic Ocean with areas of potential tropical cyclogenesis (invests) in white. Yellow dots represent the location of overshooting tops (OTs).

•  7.76,-8.55
•  6.01,-16.52
•  5.76,-16.25
•  8.11,-12.59
•  5.58,-14.10
•  5.07,-16.40
•  5.64,-15.10
•  9.24,-11.47
•  2.66,-9.59
•  5.70,-16.54
•  1.88,-11.11
•  6.04,-17.08
•  3.54,-11.38
•  3.12,-7.13
•  3.92,-11.19
•  4.94,-18.15
•  5.62,-16.25
•  2.89,-11.31
•  3.15,-9.18
•  3.10,-9.05
•  2.53,-11.56
•  5.45,-9.22
•  4.06,-9.86
•  3.54,-11.71
•  2.99,-8.85
•  2.85,-8.71
•  2.42,-12.62
•  1.46,-24.41
•  3.13,-19.04
•  3.73,-9.22
•  1.46,-24.22
•  3.10,-9.96
•  9.26,-10.69
•  9.29,-24.43
•  3.02,-18.74
•  3.10,-9.82
•  2.31,-12.09
•  2.61,-20.10
•  6.04,-27.66
•  3.87,-37.09
•  11.09,-12.50
•  5.34,-27.58
•  3.43,-11.13
•  6.07,-13.17
•  5.45,-16.36
•  8.01,-26.02
•  6.30,-78.01
•  5.42,-72.21
•  2.69,-72.24
•  6.63,-78.33
•  2.58,-72.41
•  6.19,-71.81
•  7.84,-76.88
•  3.77,-43.23
•  2.98,-71.52
•  5.56,-78.38
•  1.43,-90.43
•  3.27,-78.72
•  2.72,-72.86
•  4.51,-79.54
•  1.39,-93.16
•  2.92,-90.47
•  2.32,-41.15

Recent research has indicated that the presence of "vortical" hot towers in pre-genesis tropical cyclones increases a concentrated vertical component of vorticity and therefore increases the likelihood of tropical cyclone development. "Vortical" hot towers are defined as updrafts extending to at least the tropopause (A Vortical Hot Tower Route to Tropical Cyclogenesis, Montgomery et al, 2006). This research looks to employ an objective satellite-based overshooting top detection algorithm to average the number of overshooting tops experienced by an area of potential tropical cyclogenesis. However, instead of using a 6-hour tropopause forecasts, a greater temperature difference between the potential OT and surrounding anvil was used, with potential OTs being colder than 215K. Using this method, potential areas of topical cyclogenesis from 2010 are currently being analyzed and compared to results from 2009, evaluating the average number of overshooting tops per day with the vertical component of vorticity at 40W. Results can be seen at the bottom of the page.

The average number of overshooting tops experienced per day can be compared to the UKMet (or ECMWF) 700 hPa vertical component of vorticity at a temporal resolution of 6 hours. Therefore the invest vertical component of vorticity was linearly extrapolated for each satellite scan between the forecast times. Results from 2010 can be seen below.

In addition, results from 2009, where both position and vertical component of vorticity were linearly extrapolated have a corrlation of 0.792 does not include Hurricane Bill, since Hurricane Bill was a hurricane when crossing 40W whereas the other invests (Hurricane Fred and TD 8) were not (both lost strength before 40W). When including Hurricane Bill, the correlation drops to 0.628. Combining invests from 2009 and 2010 leads to a correlation of 0.75.

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DISCLAIMER: THESE PRODUCTS ARE GENERATED ON AN EXPERIMENTAL BASIS. ACCURACY AND TIMELINESS ARE NOT GUARANTEED.

Last updated at Mon Apr 25 17:03:20 UTC 2011