Hurricane Harvey (2017) spawned from a westward propagating tropical wave in the Atlantic and then tracked across the southern Caribbean
Sea, the Yucatán Peninsula, and lastly over the Gulf of Mexico, where it quickly intensified into a category 4 (on the Saffir-Simpson Scale)
tropical cyclone. As a mature hurricane, Harvey underwent an eyewall replacement cycle which led to structural and intensity changes hours
before making landfall over the Texas central coast. This study investigates the structure and frequency of secondary eyewalls in 20 forecast
simulations of Tropical Cyclone Harvey (2017) as produced by the 2017 operational Hurricane Weather Research and Forecast (HWRF) System. To
understand the predictability of secondary eyewalls, the secondary eyewall-producing simulations must be distinguished from the non-secondary
eyewall-producing simulations. Thus, a diagnostic method of subjectively detecting secondary eyewalls in forecast data is developed. The
diagnostic method identifies specific secondary eyewall traits that have been studied and documented in literature. The results show that most
of the simulations (~80%) produce a secondary eyewall. While the all secondary eyewall-producing simulations are initialized over the ocean, the
unsuccessful simulations, on the other hand, are initialized over or just west of the Yucatán Peninsula. To study the relationship between
land-storm interaction and secondary eyewall simulation, a comparison is made between the successful simulations initialized over the Caribbean
Sea (which tracked over the Yucatán Peninsula) and the unsuccessful runs. For both sets of simulations, the effect of land-storm interaction led
to temporary storm weakening while over the Yucatán Peninsula. However, this interaction has respectively a greater negative effect on vortex
spin-up and organization on those simulations initialized over land. A comparison between the over land evolution of a non-SE producing and
aSE-producing simulation is made. The results show that both storms maintain a similar dynamic structure as they move west over the Yucatán
Peninsula. However, the SE-producing simulation is in a more favorable thermodynamic environment with higher RH values above the storms and more
convective activity near its center when compared to the non-SE producing simulation. Based on these results, it is speculated that deep moist
convective feedback processes enhanced by a thermodynamically favorable conditions within and near the Caribbean Sea initialized storms act as
an additional intensification mechanism which lacks in the over land initialized storms. The relatively drier air mass and less convective
activity associated with the land simulations produces a less favorable environment and limits the intensification rate of these storms over
once over water. It is speculated that slower intensification rates inhibit these storms from reaching an adequate TC intensity and structure
conducive for SEF before making landfall over Texas/Mexico and weakening. / A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of the
requirements for the degree of Master of Science. / Summer Semester 2018. / July 5, 2018. / 2017, Harvey, Hurricane, HWRF, Secondary, Structure / Includes bibliographical references. / Jeffrey Chagnon, Professor Directing Thesis; Robert E. Hart, Committee Member; Philip Sura, Committee
Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_661131 |
| Contributors | Di Catarina, Federico (author), Chagnon, Jeffrey M. (professor directing thesis), Hart, Robert E., 1972- (committee member), Sura, Philip (committee member), Florida State University (degree granting institution), College of Arts and Sciences (degree granting college), Department of Earth, Ocean and Atmospheric Science (degree granting departmentdgg) |
| Publisher | Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text, master thesis |
| Format | 1 online resource (76 pages), computer, application/pdf |
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