Editorial Type:
Article
Article Type:
Research Article

Synoptic Composites of the Extratropical Transition Life Cycle of North Atlantic Tropical Cyclones: Factors Determining Posttransition Evolution

Robert E. Hart Department of Meteorology, The Florida State University, Tallahasee, Florida

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Jenni L. Evans Department of Meteorology, The Pennsylvania State University, University Park, Pennsylvania

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Clark Evans Department of Meteorology, The Florida State University, Tallahasee, Florida

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Print Publication:
01 Feb 2006
DOI:
https://doi.org/10.1175/MWR3082.1
Page(s):
553–578
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Abstract

A 34-member ensemble-mean trajectory through the cyclone phase space (CPS) is calculated using Navy Operational Global Atmospheric Prediction System (NOGAPS) analyses for North Atlantic tropical cyclones (TCs) undergoing extratropical transition (ET). Synoptic composites at four ET milestones are examined: 24 h prior to the beginning of ET (TB − 24), the beginning of ET (TB), the end of ET (TE), and 24 h after the end of ET (TE + 24). While the extratropically transitioning TC structure is tightly constrained in its tropical phase, it has a variety of evolutions after TE. Partitioning the ensemble based upon post-ET intensity change or structure discriminates among statistically significant ET precursor conditions. Compositing the various post-ET intensity regimes provides insight into the important environmental factors governing post-ET development.

A TC that intensifies (weakens) after TE begins transition (t = TB) with a negatively (positively) tilted trough 1000 km (1500 km) upstream. The negative tilt permits a contraction and intensification of the eddy potential vorticity (PV) flux, while the positive trough tilt prevents contraction and intensification of the forcing. In 6 of the 34 cases, the posttropical cold-core cyclone develops a warm-seclusion structure, rather than remaining cold core. Anticipation of this warm-seclusion evolution is critical since it represents a dramatically increased risk of middle- to high-latitude wind and wave damage. The warm-seclusion evolution is most favored when the scale of the interacting trough closely matches the scale of the transitioned TC, focusing the eddy PV flux in the outflow layer of the transitioning TC. The sensitivity of structural evolution prior to and after TE illustrated here gives insight into the degradation of global model midlatitude forecast accuracy during a pending ET event.

Eliassen–Palm flux cross sections suggest that ET is primarily driven by the eddy angular momentum flux of the trough, rather than the eddy heat flux associated with the trough. The response of the transitioning TC to the eddy angular momentum forcing is to produce adiabatic ascent and cooling radially inward and beneath the region of the forcing to restore thermal wind balance. In the case of ET, the forcing is maximized lower in the atmosphere, and spread over much greater depth, than in the case of trough-induced TC intensification. Only after TE is the eddy heat flux forcing as significant as the eddy angular momentum forcing, further supporting a physical foundation for the CPS description of cyclone evolution.

Corresponding author address: Robert Hart, Dept. of Meteorology, The Florida State University, 404 Love Building, Tallahassee, FL 32306-4520. Email: rhart@met.fsu.edu

Abstract

A 34-member ensemble-mean trajectory through the cyclone phase space (CPS) is calculated using Navy Operational Global Atmospheric Prediction System (NOGAPS) analyses for North Atlantic tropical cyclones (TCs) undergoing extratropical transition (ET). Synoptic composites at four ET milestones are examined: 24 h prior to the beginning of ET (TB − 24), the beginning of ET (TB), the end of ET (TE), and 24 h after the end of ET (TE + 24). While the extratropically transitioning TC structure is tightly constrained in its tropical phase, it has a variety of evolutions after TE. Partitioning the ensemble based upon post-ET intensity change or structure discriminates among statistically significant ET precursor conditions. Compositing the various post-ET intensity regimes provides insight into the important environmental factors governing post-ET development.

A TC that intensifies (weakens) after TE begins transition (t = TB) with a negatively (positively) tilted trough 1000 km (1500 km) upstream. The negative tilt permits a contraction and intensification of the eddy potential vorticity (PV) flux, while the positive trough tilt prevents contraction and intensification of the forcing. In 6 of the 34 cases, the posttropical cold-core cyclone develops a warm-seclusion structure, rather than remaining cold core. Anticipation of this warm-seclusion evolution is critical since it represents a dramatically increased risk of middle- to high-latitude wind and wave damage. The warm-seclusion evolution is most favored when the scale of the interacting trough closely matches the scale of the transitioned TC, focusing the eddy PV flux in the outflow layer of the transitioning TC. The sensitivity of structural evolution prior to and after TE illustrated here gives insight into the degradation of global model midlatitude forecast accuracy during a pending ET event.

Eliassen–Palm flux cross sections suggest that ET is primarily driven by the eddy angular momentum flux of the trough, rather than the eddy heat flux associated with the trough. The response of the transitioning TC to the eddy angular momentum forcing is to produce adiabatic ascent and cooling radially inward and beneath the region of the forcing to restore thermal wind balance. In the case of ET, the forcing is maximized lower in the atmosphere, and spread over much greater depth, than in the case of trough-induced TC intensification. Only after TE is the eddy heat flux forcing as significant as the eddy angular momentum forcing, further supporting a physical foundation for the CPS description of cyclone evolution.

Corresponding author address: Robert Hart, Dept. of Meteorology, The Florida State University, 404 Love Building, Tallahassee, FL 32306-4520. Email: rhart@met.fsu.edu

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  • Agusti-Panareda, A., C. D. Thorncroft, G. C. Craig, and S. L. Gray, 2004: The extratropical transition of Hurricane Irene (1999): A potential vorticity perspective. Quart. J. Roy. Meteor. Soc, 130 , 1047–1074.

    • Search Google Scholar
    • Export Citation

  • Arnott, J. M., J. L. Evans, and F. Chiaromonte, 2004: Characterization of ET using cluster analysis. Mon. Wea. Rev, 132 , 2916–2937.

  • Bluestein, H. B., 1992: : Kinematics and Dynamics. Vol. I, Synoptic-Dynamic Meteorology in the Mid-Latitudes, Oxford University Press, 431 pp.

  • Bluestein, H. B., 1993: Observations and Theory of Weather Systems. Vol. II, Synoptic-Dynamic Meteorology in the Mid-Latitudes, Oxford University Press, 594 pp.

    • Search Google Scholar
    • Export Citation

  • Bosart, L. F., E. H. Atallah, and J. E. Molinari, 2001: The quantitative precipitation forecast problem associated with landfalling and transitioning tropical cyclones. Preprints, Symp. on Precipitation Extremes, Albuquerque, NM, Amer. Meteor. Soc., 359–362.

  • Bowyer, P. J., 2000: Phenomenal waves with a transitioning tropical cyclone (Luis, the Queen, and the buoys). Preprints, 24th Conf. on Hurricanes and Tropical Meteorology, Fort Lauderdale, FL, Amer. Meteor. Soc., 294–295.

  • Bowyer, P. J., and C. Fogarty, 2003: Hurricane Juan: A forecasting perspective. Proc. Second Int. Workshop on ET, Halifax, NS, Canada.

  • Brand, S., and C. P. Guard, 1978: Extratropical storm evolution from tropical cyclones in the western North Pacific Ocean. Naval Environmental Prediction Tech. Rep. TR78-02, 20 pp.

  • Caplan, P., J. Derber, W. Gemmill, S-Y. Hong, H-L. Pan, and D. Parrish, 1997: Changes to the 1995 NCEP Operational Medium-Range Forecast Model Analysis–Forecast System. Wea. Forecasting, 12 , 581–594.

    • Search Google Scholar
    • Export Citation

  • Charney, J. G., 1947: The dynamics of long waves in a baroclinic westerly current. J. Meteor, 4 , 135–162.

  • Eady, E. T., 1949: Long waves and cyclone waves. Tellus, 1 , 33–52.

  • Elsberry, R. L., Ed. 1995: Global perspectives on tropical cyclones. WMO Rep. TD-No. 693, Geneva, Switzerland, 289 pp.

  • Evans, A. C., and R. E. Hart, 2005: Towards a better understanding of and ability to forecast the wind field expansion during the extratropical transition process. Preprints, 21st Conf. on Weather Analysis and Forecasting, Washington, DC, Amer. Meteor. Soc., CD-ROM, P1.17.

  • Evans, J. L., and R. E. Hart, 2003: Objective indicators of the onset and completion of ET for Atlantic tropical cyclones. Mon. Wea. Rev, 131 , 909–925.

    • Search Google Scholar
    • Export Citation

  • Evans, J. L., and J. M. Arnott, 2004: Analysis of operational model forecast trends in ET storm structure. Preprints, 26th Tropical Meteorology and Tropical Cyclones Conf., Miami Beach, FL, Amer. Meteor. Soc., CD-ROM, 2C.5a.

  • Evans, J. L., and B. Prater-Mayes, 2004: Factors affecting the posttransition intensification of Hurricane Irene (1999). Mon. Wea. Rev, 132 , 1355–1368.

    • Search Google Scholar
    • Export Citation

  • Foley, G. R., and B. N. Hanstrum, 1994: The capture of tropical cyclones by cold fronts off the west coast of Australia. Wea. Forecasting, 9 , 577–592.

    • Search Google Scholar
    • Export Citation

  • Goerss, J. S., and R. A. Jeffries, 1994: Assimilation of synthetic tropical cyclone observations into the Navy Operational Global Atmospheric Prediction System. Wea. Forecasting, 9 , 557–576.

    • Search Google Scholar
    • Export Citation

  • Gyakum, J. R., 1983a: On the evolution of the QE II storm. Part I: Synoptic aspects. Mon. Wea. Rev, 111 , 1137–1155.

  • Gyakum, J. R., 1983b: On the evolution of the QE II storm. Part II: Dynamic and thermodynamic structure. Mon. Wea. Rev, 111 , 1156–1173.

    • Search Google Scholar
    • Export Citation

  • Hanley, D., J. Molinari, and D. Keyser, 2001: A composite study of the interactions between tropical cyclones and upper-tropospheric troughs. Mon. Wea. Rev, 129 , 2570–2584.

    • Search Google Scholar
    • Export Citation

  • Harr, P., and R. L. Elsberry, 2000: ET of tropical cyclones over the western North Pacific. Part I: Evolution of structural characteristics during the transition process. Mon. Wea. Rev, 128 , 2613–2633.

    • Search Google Scholar
    • Export Citation

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

    • Search Google Scholar
    • Export Citation

  • Hart, R. E., 2003: A cyclone phase space derived from thermal wind and thermal asymmetry. Mon. Wea. Rev, 131 , 585–616.

  • Hart, R. E., and J. L. Evans, 2001: A climatology of the extratropical transition of Atlantic tropical cyclones. J. Climate, 14 , 546–564.

    • Search Google Scholar
    • Export Citation

  • Hart, R. E., and J. L. Evans, 2003: Analyzing and forecasting cyclone structural transition using cyclone phase diagrams. Proc. Second Int. Workshop on ET, Halifax, NS, Canada.

  • 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.

    • Search Google Scholar
    • Export Citation

  • Jones, S. C., and Coauthors, 2003a: The ET of tropical cyclones: Forecast challenges, current understanding, and future directions. Wea. Forecasting, 18 , 1052–1092.

    • Search Google Scholar
    • Export Citation

  • Jones, S., C. Velden, S. Aberson, J. Abraham, and P. Harr, 2003b: ET, Thorpex, and the North Atlantic TrEC. Proc. Second Int. Workshop on ET, Halifax, NS, Canada.

    • Search Google Scholar
    • Export Citation

  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc, 77 , 437–471.

  • Kanamitsu, M., 1989: Description of the NMC global data assimilation and forecast system. Wea. Forecasting, 4 , 335–342.

  • Klein, P., P. Harr, and R. L. Elsberry, 2000: ET of western North Pacific tropical cyclones: An overview and conceptual model of the transformation stage. Wea. Forecasting, 15 , 373–396.

    • Search Google Scholar
    • Export Citation

  • Klein, P., P. Harr, and R. L. Elsberry, 2002: Extratropical transition of western North Pacific tropical cyclones: Midlatitude and tropical cyclone contributions to reintensification. Mon. Wea. Rev, 130 , 2240–2259.

    • Search Google Scholar
    • Export Citation

  • Kurihara, Y., R. E. Tuleya, and M. A. Bender, 1998: The GFDL Hurricane Prediction System and Its Performance in the 1995 Hurricane Season. Mon. Wea. Rev, 126 , 1306–1322.

    • Search Google Scholar
    • Export Citation

  • Liu, Q., T. Marchok, H-L. Pan, M. Bender, and S. Lord, 2000: Improvements in hurricane initialization and forecasting at NCEP with global and regional (GFDL) models. Technical Procedures Bulletin 472 NOAA/NWS, 7 pp. [Available online at http:www.nws.noaa.gov/om/tpb/472.htm, or from NOAA/NWS, 1325 East-West Highway, Silver Spring, MD 20910.].

  • Ma, S., H. Ritchie, J. Gyakum, J. Abraham, C. Fogarty, and R. McTaggart-Cowan, 2003: A study of the extratropical reintensification of former Hurricane Earl using Canadian Meteorological Centre regional analyses and ensemble forecasts. Mon. Wea. Rev, 131 , 1342–1359.

    • Search Google Scholar
    • Export Citation

  • Maue, R., and R. Hart, 2005: Warm-seclusion extratropical cyclone development: Sensitivity to the nature of the incipient vortex. Preprints, 21st Conf. on Weather Analysis and Forecasting, Washington, DC, Amer. Meteor. Soc., CD-ROM, P1.16.

  • McTaggart-Cowan, R., J. R. Gyakum, and M. K. Yau, 2001: Sensitivity testing of ETs using potential vorticity inversions to modify initial conditions: Hurricane Earl case study. Mon. Wea. Rev, 129 , 1617–1636.

    • Search Google Scholar
    • Export Citation

  • McTaggart-Cowan, R., J. R. Gyakum, and M. K. Yau, 2003: The influence of the downstream state on ET: Hurricane Earl (1998) case study. Mon. Wea. Rev, 131 , 1910–1929.

    • Search Google Scholar
    • Export Citation

  • McTaggart-Cowan, R., J. R. Gyakum, and M. K. Yau, 2004: The impact of tropical remnants on extratropical cyclogenesis: Case study of Hurricanes Danielle and Earl (1998). Mon. Wea. Rev, 132 , 1933–1951.

    • Search Google Scholar
    • Export Citation

  • Molinari, J., S. Skubis, and D. Vollaro, 1995: External influences on hurricane intensity. Part III: Potential vorticity structure. J. Atmos. Sci, 52 , 3593–3606.

    • Search Google Scholar
    • Export Citation

  • Ritchie, E. A., and R. L. Elsberry, 2001: Simulations of the transformation stage of the extratropical transition of tropical cyclones. Mon. Wea. Rev, 129 , 1462–1480.

    • Search Google Scholar
    • Export Citation

  • Ritchie, E. A., and R. L. Elsberry, 2003: Simulations of the extratropical transition of tropical cyclones: Contributions by midlatitude upper-level trough to reintensification. Mon. Wea. Rev, 131 , 2112–2128.

    • Search Google Scholar
    • Export Citation

  • Sekioka, M., 1957: A hypothesis on complex of tropical and extratropical cyclones for typhoon in the middle latitudes. III. Examples of typhoon not accompanied by extratropical cyclone in the middle latitudes. J. Meteor. Soc. Japan, 35 , 170–173.

    • Search Google Scholar
    • Export Citation

  • Shapiro, L. J., 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.

    • Search Google Scholar
    • Export Citation

  • Thorncroft, C., and S. C. Jones, 2000: The ET of Hurricanes Felix and Iris in 1995. Mon. Wea. Rev, 128 , 947–972.

  • Velden, C. S., T. Olander, and S. Wanzong, 1998: The impact of multispectral GOES-8 wind information on Atlantic tropical cyclone track forecasts in 1995. Part I: Dataset methodology, description, and case analysis. Mon. Wea. Rev, 126 , 1202–1218.

    • Search Google Scholar
    • Export Citation
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