Prediction and Diagnosis of Tropical Cyclone Formation in an NWP System. Part III: Diagnosis of Developing and Nondeveloping Storms

Abstract This is the third of a three-part investigation into tropical cyclone (TC) genesis in the Australian Bureau of Meteorology’s Tropical Cyclone Limited Area Prediction System (TC-LAPS), an operational numerical weather prediction (NWP) forecast model. In Parts I and II, a primary and two secondary vortex enhancement mechanisms were illustrated, and shown to be responsible for TC genesis in a simulation of TC Chris. In this paper, five more TC-LAPS simulations are investigated: three developing and two nondeveloping. In each developing simulation the pathway to genesis was essentially the same as that reported in Part II. Potential vorticity (PV) cores developed through low- to middle-tropospheric vortex enhancement in model-resolved updraft cores (primary mechanism) and interacted to form larger cores through diabatic upscale vortex cascade (secondary mechanism). On the system scale, vortex intensification resulted from the large-scale mass redistribution forced by the upward mass flux, driven by d...

[1]  C. Gautier,et al.  Mesoscale Events within a GATE Tropical Depression , 1978 .

[2]  Brian E. Mapes,et al.  An integrated view of the 1987 Australian monsoon and its mesoscale convective systems. I: horizontal structure , 1993 .

[3]  M. Montgomery,et al.  Tropical Cyclogenesis via Convectively Forced Vortex Rossby Waves in a Three-Dimensional Quasigeostrophic Model , 1998 .

[4]  M. Montgomery,et al.  Prediction and diagnosis of tropical cyclone formation in an NWP system. Part I: The critical role of vortex enhancement in deep convection , 2006 .

[5]  Lucio López Cavazos,et al.  Case‐studies of developing east Pacific easterly waves , 1998 .

[6]  Brian E. Mapes,et al.  Diabatic Divergence Profiles in Western Pacific Mesoscale Convective Systems , 1995 .

[7]  R. Houze.  Stratiform precipitation in regions of convection : A meteorological paradox ? , 1997 .

[8]  Kerry A. Emanuel,et al.  The Genesis of Hurricane Guillermo: TEXMEX Analyses and a Modeling Study , 1997 .

[9]  Melville E. Nicholls,et al.  A Vortical Hot Tower Route to Tropical Cyclogenesis. , 2006 .

[10]  J. Chan,et al.  Transformation of a Large Monsoon Depression to a Tropical Storm during TCM-93 , 1996 .

[11]  S. Jones.  The evolution of vortices in vertical shear. I: Initially barotropic vortices , 1995 .

[12]  W. M. Gray,et al.  The formation of tropical cyclones , 1998 .

[13]  D. Raymond,et al.  A Theory for Long-Lived Mesoscale Convective Systems , 1990 .

[14]  Raymond M. Zehr.  Tropical cyclogenesis in the western North Pacific , 1992 .

[15]  K. Emanuel,et al.  An Air–Sea Interaction Theory for Tropical Cyclones. Part II: Evolutionary Study Using a Nonhydrostatic Axisymmetric Numerical Model , 1987 .

[16]  Elizabeth A. Ritchie,et al.  Mesoscale Interactions in Tropical Cyclone Genesis , 1997 .

[17]  J. Holton.  An introduction to dynamic meteorology , 2004 .

[18]  J. Kain,et al.  Warm Core Vortex Amplification over Land , 1994 .

[19]  Christopher A. Davis,et al.  The Role of “Vortical” Hot Towers in the Formation of Tropical Cyclone Diana (1984) , 2004 .

[20]  M. Tiedtke.  A Comprehensive Mass Flux Scheme for Cumulus Parameterization in Large-Scale Models , 1989 .

[21]  N. Davidson,et al.  Influence of Environmental Vertical Wind Shear on the Intensity of Hurricane-Strength Tropical Cyclones in the Australian Region , 2005 .

[22]  Kerry Emanuel,et al.  An Air-Sea Interaction Theory for Tropical Cyclones. Part I: Steady-State Maintenance , 1986 .

[23]  Stephen B. Fels,et al.  The Simplified Exchange Approximation: A New Method for Radiative Transfer Calculations , 1975 .

[24]  M. Montgomery,et al.  A New Look at the Problem of Tropical Cyclones in Vertical Shear Flow: Vortex Resiliency , 2004 .

[25]  Peter H. Haynes,et al.  On the Evolution of Vorticity and Potential Vorticity in the Presence of Diabatic Heating and Frictional or Other Forces , 1987 .

[26]  A Numerical Simulation Study on the Genesis of a Tropical Storm , 1981 .

[27]  Elizabeth A. Ritchie,et al.  Scale interactions during the formation of typhoon irving , 1997 .

[28]  R. P. Pearce,et al.  A three‐dimensional primitive equation model of cumulonimbus convection , 1974 .

[29]  M. Montgomery,et al.  Prediction and Diagnosis of Tropical Cyclone Formation in an NWP System. Part II: A Diagnosis of Tropical Cyclone Chris Formation , 2006 .

[30]  Shuyi S. Chen.  A numerical study of the genesis of extratropical convective mesovortices , 1993 .

[31]  Richard H. Johnson,et al.  Circulations Associated with a Mature-to-Decaying Midlatitude Mesoscale Convective System. Part I: Surface Features—Heat Bursts and Mesolow Development , 1989 .

[32]  I. Troen,et al.  A simple model of the atmospheric boundary layer; sensitivity to surface evaporation , 1986 .