Extended Abstract (180K)9C.2
Baroclinic Tropical Cyclogenesis: Developing and Non-developing Cases
Christipher A. Davis, NCAR, Boulder, CO; and L. F. Bosart
Within a two week period during October 2000, two low-latitude baroclinic cyclones developed to the east of Florida. One transitioned into Hurricane Michael, a minimal hurricane at low-latitudes which strengthened further as it underwent extratropical transformation. The other, following Michael by about 1 week, formed in a similar location and exhibited a a similar track but did not become a warm core tropical cyclone at any time during its life. The purpose of this talk is to contrast these two cases, and compare the development of Michael with the development of Hurricane Diana (1984), another noted case of baroclinic tropical cyclogenesis. Preliminary investigation suggests that a key similarity held by Diana and Michael is that the baroclinity decreased throughout the troposphere after the incipient cyclone formed. In the non-developing case, the PV anomaly on the dynamic tropopause never separated from the stratospheric reservoir of high PV, consistent with the observed, prolonged deep-tropospheric vertical wind shear and the separation of deep convection from the storm center. At the conference, we will present diagnostics to further clarify the essential dynamics of warm-core, tropical transformation.
Session 9C, Tropical Cyclogenesis II (Parallel with Sessions 9A, 9B, and 9D)
Wednesday, 1 May 2002, 11:00 AM-12:30 PM
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