Extratropical Transition of Southwest Pacific Tropical Cyclones. Part II: Midlatitude Circulation Characteristics

Sinclair, Mark R.
September 2004
Monthly Weather Review;Sep2004, Vol. 132 Issue 9, p2145
Academic Journal
This second of two papers on extratropical transition (ET) over the southwest Pacific Ocean focuses on the variability of ET. A climatology of ET onset based on a previously described objective technique shows that ET commences 15° of latitude nearer the equator on average than similar cases from the Northern Hemisphere. Characteristic midlatitude circulation patterns accompanying ET near 30°S are identified by means of empirical orthogonal function (EOF) analysis of 50 storms. The first eigenvector pattern, explaining nearly half the circulation variability, expresses relaxed and enhanced pressure gradients south of the storm that define composites similar to “cradled” and “captured” classifications previously described for the southeast Indian Ocean. The second EOF distinguishes redeveloping from weakening storms. Reintensifying storms were located beneath strong cyclonic vorticity advection (CVA) near the equatorward entrance region of an upper jet whereas the upper jet was well to the west of weakening storms. A survey of factors responsible for modulating central sea level pressure change during ET was conducted for the 50 storms. The quantity most strongly correlated with surface development was found to be CVA at the jet level. Extratropical reintensification occurred when the surface cyclone was located beneath the equatorward entrance region of an upper jet for storms between 28° and 34°S, and beneath the poleward exit jet region for storms farther south. Strongest examples of redevelopment each occurred beneath a potent double jet signature aloft, with maximum storm-relative upper-level CVA located directly above the surface low and net vorticity fluxes reflecting amplification of the upper wave. Weakening storms featured a weakening upper trough directly above the storm, with CVA to the east.


Related Articles

  • An Improved Statistical Scheme for the Prediction of Tropical Cyclones Making Landfall in South China. Zung-Ching Goh, Andy; Chan, Johnny C. L. // Weather & Forecasting;Apr2010, Vol. 25 Issue 2, p587 

    This study describes an improved statistical scheme for predicting the annual number of tropical cyclones (TCs) making landfall along the coast of south China using data from 1965 to 2005. Based on the factors affecting TC behavior inside the South China Sea (SCS), those responsible for TCs...

  • TROPICAL CYCLONE DESTRUCTIVE POTENTIAL BY INTEGRATED KINETIC ENERGY. Powell, Mark D.; Reinhold, Timothy A. // Bulletin of the American Meteorological Society;Apr2007, Vol. 88 Issue 4, p513 

    Tropical cyclone damage potential, as currently defined by the Saffir-Simpson scale and the maximum sustained surface wind speed in the storm, fails to consider the area impact of winds likely to force surge and waves or cause particular levels of damage. Integrated kinetic energy represents a...

  • THE INTERNATIONAL BEST TRACK ARCHIVE FOR CLIMATE STEWARDSHIP (IBTrACS). Knapp, Kenneth R.; Kruk, Michael C.; Levinson, David H.; Diamond, Howard J.; Neumann, Charles J. // Bulletin of the American Meteorological Society;Mar2010, Vol. 91 Issue 3, p363 

    The article focuses on the International Best Track Archive for Climate Stewardship (IBTraCS), a tropical cyclone data consisting of storm position and intensity estimates with an interval of six hours. It cites the sources for IBTraCS including Hong Kong Observatory (HKO), Meteorological...

  • A Preliminary Survey of Rear-Flank Descending Reflectivity Cores in Supercell Storms. Rasmussen, Erik N.; Straka, Jerry M.; Gilmore, Matthew S.; Davies-Jones, Robert // Weather & Forecasting;Dec2006, Vol. 21 Issue 6, p923 

    This paper develops a definition of a supercell reflectivity feature called the descending reflectivity core (DRC). This is a reflectivity maximum pendant from the rear side of an echo overhang above a supercell weak-echo region. Examples of supercells with and without DRCs are presented from...

  • Climatology: Tempests in time. Elsner, James B. // Nature;6/7/2007, Vol. 447 Issue 7145, p647 

    The article discusses the characteristics of palaeotempestology in assessing the factors that contribute to hurricane activity. It is the study of prehistoric storms from geological and biological evidence and has been applied to hurricanes in the North Atlantic. It is also a valuable tool for...

  • It is Not Just about Wind When It Comes to Typhoon Risk in China. Sousounis, Peter // Asia Insurance Review;Jun2008, p71 

    The article examines the devastating storms that hit China each year. According to the author, out of the 11 storms that affect the country each year, about half of them actually landfall at only tropical storm strength. In addition, only 45% of the storms that struck the country is in the level...

  • Storm Track Predictability on Seasonal and Decadal Scales. Compo, Gilbert P.; Sardeshmukh, Prashant D. // Journal of Climate;Oct2004, Vol. 17 Issue 19, p3701 

    This paper is concerned with estimating the predictable variation of extratropical daily weather statistics (“storm tracks”) associated with global sea surface temperature (SST) changes on interannual to interdecadal scales, and its magnitude relative to the unpredictable noise. The...

  • Improved Detection Using Negative Elevation Angles for Mountaintop WSR-88Ds. Part III: Simulations of Shallow Convective Activity over and around Lake Ontario. Brown, Rodger A.; Niziol, Thomas A.; Donaldson, Norman R.; Joe, Paul I.; Wood, Vincent T. // Weather & Forecasting;Aug2007, Vol. 22 Issue 4, p839 

    During the winter, lake-effect snowstorms that form over Lake Ontario represent a significant weather hazard for the populace around the lake. These storms, which typically are only 2 km deep, frequently can produce narrow swaths (20–50 km wide) of heavy snowfall (2–5 cm h-1 or...

  • The Impact of Moist Singular Vectors and Horizontal Resolution on Short-Range Limited-Area Ensemble Forecasts for Two European Winter Storms. Walser, André; Arpagaus, Marco; Appenzeller, Christof; Leutbecher, Martin // Monthly Weather Review;Oct2006, Vol. 134 Issue 10, p2877 

    This paper studies the impact of different initial condition perturbation methods and horizontal resolutions on short-range limited-area ensemble predictions for two severe winter storms. The methodology consists of 51-member ensembles generated with the global ensemble prediction system (EPS)...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics