Extratropical Transition of Western North Pacific Tropical Cyclones: An Overview and Conceptual Model of the Transformation Stage

Abstract Extratropical transition (ET) in the western North Pacific is defined here in terms of two stages: transformation, in which the tropical cyclone evolves into a baroclinic storm; and reintensification, where the transformed storm then deepens as an extratropical cyclone. In this study, 30 ET cases occurring during 1 June–31 October 1994–98 are reviewed using Navy Operational Global Atmospheric Prediction System analyses; hourly geostationary visible, infrared, and water vapor imagery; and microwave imagery. A brief climatology based on these cases is presented for the transformation stage and the subsequent cyclone characteristics of the reintensification stage. A three-dimensional conceptual model of the transformation stage of ET in the western North Pacific Ocean is proposed that describes how virtually all 30 cases evolved into an incipient, baroclinic low. The three-step evolution of the transformation of Typhoon (TY) David (September 1997) is described as a prototypical example. Four importa...

[1]  M. Sekioka,et al.  Some Aspects of Extratropical Transformation of A Tropical Cyclone , 1971 .

[2]  Intensity of Recurved Typhoons , 1972 .

[3]  S. Brand,et al.  Extratropical Storm Evolution from Tropical Cyclones in the Western North Pacific Ocean , 1978 .

[4]  Lance F. Bosart,et al.  The Transformation of Tropical Storm Agnes into an Extratropical Cyclone. Part I: The Observed Fields and Vertical Motion Computations , 1982 .

[5]  Toby N. Carlson,et al.  Mid-Latitude Weather Systems , 1991 .

[6]  M. Sinclair.  Synoptic-scale diagnosis of the extratropical transition of a southwest Pacific tropical cyclone , 1993 .

[7]  B. Hanstrum,et al.  The Capture of Tropical Cyclones by Cold Fronts off the West Coast of Australia , 1994 .

[8]  L. Bosart,et al.  Postlandfall Tropical Cyclone Reintensification in a Weakly Baroclinic Environment: A Case Study of Hurricane David (September 1979) , 1995 .

[9]  A. J. Waters,et al.  Images in Weather Forecasting a Practical Guide for Interpreting Satellite and Radar Imagery , 1995 .

[10]  Mark DeMaria,et al.  The Effect of Vertical Shear on Tropical Cyclone Intensity Change , 1996 .

[11]  R. Elsberry,et al.  Extratropical transition of western North Pacific tropical cyclones: Midlatitude and tropical cyclone contributions to reintensification , 1997 .

[12]  Y. Shimazu.  Classification of precipitation systems in mature and early weakening stages of typhoons around Japan , 1998 .

[13]  Analysis of an ex‐tropical cyclone after its reintensification as a warm‐core extratropical cyclone , 1998 .

[14]  E. Ritchie,et al.  Effects of Environmental Flow upon Tropical Cyclone Structure , 1999 .

[15]  Russell L. Elsberry,et al.  Extratropical transition of tropical cyclones over the Western North pacific. Part II: The impact of midlatitude circulation characteristics , 2000 .

[16]  Russell L. Elsberry,et al.  Extratropical Transition of Tropical Cyclones over the Western North Pacific. Part I: Evolution of Structural Characteristics during the Transition Process , 2000 .