• Anthes, R. A., 1990: Advances in the understanding and prediction of cyclone development with limited-area fine-mesh models. Extratropical Cyclones, The Erik Palmen Memorial Volume, C. W. Newton and E. O. Holopainen, Eds., Amer. Meteor. Soc., 221–253.

  • Bennetts, D. A., and B. J. Hoskins, 1979: Conditional symmetric instability—A possible explanation for frontal rainbands. Quart. J. Roy. Meteor. Soc.,105, 945–962.

  • Bosart, L. F., and G. M. Lackmann, 1995: Postlandfall tropical cyclone reintensification in a weakly baroclinic environment: A case study of hurricane David (September 1979). Mon. Wea. Rev.,123, 3268–3291.

  • Browning, K. A., 1990: Organization of clouds and precipitation in extratropical cyclones. Extratropical Cyclones, The Erik Palmen Memorial Volume, C. W. Newton and E. O. Holopainen, Eds., Amer. Meteor. Soc., 129–153.

  • ——, S. P. Ballard, and C. S. A. Davitt, 1997: High-resolution analysis of frontal fracture. Mon. Wea. Rev.,125, 1212–1230.

  • ——, G. Vaughan, and P. Panagi, 1998: Analysis of an ex-tropical cyclone after its reintensification as a warm-core extratropical cyclone. Quart. J. Roy. Meteor. Soc.,124, 2329–2356.

  • Davies, H. C., C. Schar, and H. Wernli, 1991: The palette of fronts and cyclones within a baroclinic wave development. J. Atmos. Sci.,48, 1666–1689.

  • Davies-Jones, R., 1985: Comments on “A kinematic analysis of frontogenesis associated with a nondivergent vortex.” J. Atmos. Sci.,42, 2073–2075.

  • DiMego, G. J., and L. F. Bosart, 1982a: The transformation of tropical storm Agnes into an extratropical cyclone. Part I: The observed fields and vertical motion computations. Mon. Wea. Rev.,110, 385–411.

  • ——, and ——, 1982b: The transformation of tropical storm Agnes into an extratropical cyclone. Part II: Moisture, vorticity and kinetic energy budgets. Mon. Wea. Rev.,110, 412–433.

  • Doswell, C. A., III, 1984: A kinematic analysis of frontogenesis associated with a nondivergent vortex. J. Atmos. Sci.,41, 1242–1248.

  • ——, 1985: Reply. J. Atmos. Sci.,42, 2076–2079.

  • Emanuel, K. A., 1983: The Lagrangian parcel dynamics of moist symmetric instability. J. Atmos. Sci.,39, 2152–2158.

  • Evans, M. S., D. Keyser, L. F. Bosart, and G. M. Lackmann, 1994: A satellite-derived classification scheme for rapid maritime cyclogenesis. Mon. Wea. Rev.,122, 1381–1416.

  • Gronas, S., 1995: The seclusion intensification of the New Year’s day storm 1992. Tellus,47A, 733–746.

  • Harr, P. A., R. L. Elsberry, and T. F. Hogan, 2000: Extratropical transition of tropical cyclones over the western North Pacific. Part II: The impact of midlatitude circulation characteristics. Mon. Wea. Rev.,128, 2634–2653.

  • Hogan, T. F., and T. E. Rosmond, 1991: The description of the Navy Operational Global Atmospheric Prediction System’s spectral forecast model. Mon. Wea. Rev.,119, 1786–1815.

  • Keyser, D., M. J. Reeder, and R. J. Reed, 1988: A generalization of Petterssen’s frontogenesis function and its relation to the forcing of vertical motion. Mon. Wea. Rev.,116, 762–780.

  • ——, B. D. Schmidt, and D. G. Duffy, 1992: Quasigeostrophic vertical motions diagnosed from along- and cross-isentrope components of the Q vector. Mon. Wea. Rev.,120, 731–741.

  • Klein, P. M., P. A. Harr, and R. L. Elsberry, 2000: Extratropical transition of western North Pacific tropical cyclones: An overview and conceptual model of the transformation stage. Wea. Forecasting,15, 373–395.

  • Liu, G., and J. A. Curry, 1992: Retrieval of precipitation from satellite microwave measurements using both emission and scattering. J. Geophys. Res.,97, 9959–9974.

  • Neiman, P. J., and M. A. Shapiro, 1993: The life cyclone of an extratropical marine cyclone. Part I: Frontal-cyclone evolution and thermodynamic air–sea interaction. Mon. Wea. Rev.,121, 2153–2176.

  • ——, ——, and L. S. Fedor, 1993: The life cycle of an extratropical marine cyclone. Part II: Mesoscale structure and diagnostics. Mon. Wea. Rev.,121, 2177–2199.

  • Palmen, E., 1958: Vertical circulation and release of kinetic energy during the development of Hurricane Hazel into an extratropical storm. Tellus,10, 1–23.

  • Petersen, R. A., and L. W. Uccellini, 1979: The computation of isentropic trajectories using a “discrete model” formulation. Mon. Wea. Rev.,107, 566–574.

  • Petterssen, S., 1956: Weather Analysis and Forecasting. Vol. 1, Motion and Motion Systems, 2d ed., McGraw-Hill, 428 pp.

  • Schultz, D. M., and C. A. Doswell III, 1999: Conceptual models of upper-level frontogenesis in southwesterly and northwesterly flow. Quart. J. Roy. Meteor. Soc.,125, 2535–2562.

  • ——, and P. N. Schumacher, 1999: The use and misuse of conditional symmetric instability. Mon. Wea. Rev.,127, 2709–2732.

  • ——, D. Keyser, and L. F. Bosart, 1998: The effect of large-scale flow on low-level frontal structure and evolution in midlatitude cyclones. Mon. Wea. Rev.,126, 1767–1791.

  • Shapiro, M. A., and D. Keyser, 1990: Fronts, jet streams and the tropopause. Extratropical Cyclones, The Erik Palmen Memorial Volume, C. W. Newton and E. O. Holopainen, Eds., Amer. Meteor. Soc., 167–191.

  • Shimazu, Y., 1998: Classification of precipitation systems in mature and early weakening stages of typhoons around Japan. J. Meteor. Soc. Japan,76, 437–445.

  • Sinclair, M. R., 1993: Synoptic-scale diagnosis of the extratropical transition of a southwest Pacific tropical cyclone. Mon. Wea. Rev.,121, 941–960.

  • ——, and M. J. Revell, 2000: Classification and composite diagnosis of extratropical cyclogenesis events in the southwest Pacific. Mon. Wea. Rev.,128, 1089–1105.

  • Thorncroft, C. D., B. J. Hoskins, and M. E. McIntyre, 1993: Two paradigms of baroclinic-wave life-cycle behavior. Quart. J. Roy. Meteor. Soc.,119, 17–55.

  • Velden, C. S., C. M. Hayden, S. J. Nieman, W. P. Menzel, S. Wanzong, and J. S. Goerss, 1997: Upper-tropospheric winds derived from geostationary satellite water vapor observations. Bull. Amer. Meteor. Soc.,78, 173–195.

  • Xu, Q., 1986; Conditional symmetric instability and mesoscale rainbands. Quart. J. Roy. Meteor. Soc.,112, 315–334.

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Extratropical Transition of Tropical Cyclones over the Western North Pacific. Part I: Evolution of Structural Characteristics during the Transition Process

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  • 1 Department of Meteorology, Naval Postgraduate School, Monterey, California
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Abstract

The development of extratropical cyclone structural characteristics that resulted from the extratropical transition of Typhoon (TY) David (1997) and TY Opal (1997) over the western North Pacific is examined. David moved poleward ahead of a midlatitude trough that was moving eastward as the dominant midlatitude circulation feature over the western North Pacific. During the transition, David coupled with the midlatitude trough, which led to the evolution of an intense cyclone that became the primary circulation over the North Pacific. Although Opal also moved poleward ahead of a midlatitude trough, the principal midlatitude feature over the western North Pacific was a preexisting stationary cyclone over the Kamchatka peninsula. During transition, Opal weakened and became a secondary cyclone to the preexisting primary North Pacific cyclone.

The structural characteristics of the evolving extratropical cyclone with respect to each case are examined in the context of the interaction between a vortex and a baroclinic zone using vector-frontogenesis diagnostics for the Lagrangian rate of change of the magnitude and direction of the horizontal gradient of potential temperature. In this framework, total frontogenesis is divided into components that define the magnitude and rotation of the potential temperature gradient. The initial evolution of extratropical cyclone features for both cases was dominated by warm frontogenesis due to the large amount of warm advection on the east side of the decaying tropical cyclone and the deformation field defined by the poleward movement of the tropical cyclone. However, large differences between the components of rotational frontogenesis for David and Opal are observed that are related to the subsequent reintensification of David and weakening of Opal. The differences are attributed to the different midlatitude circulation characteristics into which each tropical cyclone moved. The pattern of rotational frontogenesis associated with TY David reinforced the dynamical support for the coupling of David with the midlatitude trough, which resulted in the development of an intense extratropical cyclone. During the transition of Opal, maximum rotational frontogenesis occurred over the region where Opal interacted with the preexisting midlatitude cyclone. This weakened the coupling between Opal and the midlatitude trough and prevented the development of a separate extratropical cyclone.

One of the unresolved aspects of forecasting extratropical transition is to define when transition has occurred. Although the final extratropical cyclone characteristics may vary greatly from case to case, increased warm frontogenesis seems to be consistent during the initial change from tropical to extratropical characteristics. Therefore, evolution of a frontogenesis parameter is calculated for each case from before transition, through transition, and after transition. In both cases, the rate of increase in frontogenesis peaks at a time that may be defined as the transition time.

Corresponding author address: Patrick A. Harr, Code MR/Hp, Department of Meteorology, Root Hall, 589 Dyer Rd., Monterey, CA 93943-5114.

Email: paharr@nps.navy.mil

Abstract

The development of extratropical cyclone structural characteristics that resulted from the extratropical transition of Typhoon (TY) David (1997) and TY Opal (1997) over the western North Pacific is examined. David moved poleward ahead of a midlatitude trough that was moving eastward as the dominant midlatitude circulation feature over the western North Pacific. During the transition, David coupled with the midlatitude trough, which led to the evolution of an intense cyclone that became the primary circulation over the North Pacific. Although Opal also moved poleward ahead of a midlatitude trough, the principal midlatitude feature over the western North Pacific was a preexisting stationary cyclone over the Kamchatka peninsula. During transition, Opal weakened and became a secondary cyclone to the preexisting primary North Pacific cyclone.

The structural characteristics of the evolving extratropical cyclone with respect to each case are examined in the context of the interaction between a vortex and a baroclinic zone using vector-frontogenesis diagnostics for the Lagrangian rate of change of the magnitude and direction of the horizontal gradient of potential temperature. In this framework, total frontogenesis is divided into components that define the magnitude and rotation of the potential temperature gradient. The initial evolution of extratropical cyclone features for both cases was dominated by warm frontogenesis due to the large amount of warm advection on the east side of the decaying tropical cyclone and the deformation field defined by the poleward movement of the tropical cyclone. However, large differences between the components of rotational frontogenesis for David and Opal are observed that are related to the subsequent reintensification of David and weakening of Opal. The differences are attributed to the different midlatitude circulation characteristics into which each tropical cyclone moved. The pattern of rotational frontogenesis associated with TY David reinforced the dynamical support for the coupling of David with the midlatitude trough, which resulted in the development of an intense extratropical cyclone. During the transition of Opal, maximum rotational frontogenesis occurred over the region where Opal interacted with the preexisting midlatitude cyclone. This weakened the coupling between Opal and the midlatitude trough and prevented the development of a separate extratropical cyclone.

One of the unresolved aspects of forecasting extratropical transition is to define when transition has occurred. Although the final extratropical cyclone characteristics may vary greatly from case to case, increased warm frontogenesis seems to be consistent during the initial change from tropical to extratropical characteristics. Therefore, evolution of a frontogenesis parameter is calculated for each case from before transition, through transition, and after transition. In both cases, the rate of increase in frontogenesis peaks at a time that may be defined as the transition time.

Corresponding author address: Patrick A. Harr, Code MR/Hp, Department of Meteorology, Root Hall, 589 Dyer Rd., Monterey, CA 93943-5114.

Email: paharr@nps.navy.mil

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