A Synoptic Climatology of the Subtropical Kona Storm

Otkin, Jason A.; Martin, Jonathan B.
June 2004
Monthly Weather Review;Jun2004, Vol. 132 Issue 6, p1502
Academic Journal
Ten years of surface and upper-air analyses from the ECMWF Tropical Ocean Global Atmosphere (TOGA) dataset were used to construct a synoptic climatology of kona storms in the subtropical central and eastern Pacific Ocean. Within a sample of 115 cyclones that predominantly occurred during the Northern Hemisphere cool season, three distinct types of kona storms were identified: cold-frontal cyclogenesis (CFC) cyclones, cold-frontal cyclogenesis/trade wind easterlies (CT) cyclones, and trade wind easterlies (TWE) cyclones. Of the three types, CFC cyclones were found to be the most common type of kona storm, while CT and TWE cyclones occur much less frequently. The geographical distribution, propagation characteristics, and the monthly and interannual variability in the number of kona storms are presented. Kona storms initially develop across a large portion of the subtropical Pacific, with the greatest concentration of kona storms found within a southwest-to-northeast-oriented band from west of Hawaii to 40°N, 140°W. A distinct latitudinal stratification was evident for each type of kona storm, with CFC, CT, and TWE cyclones each more likely to initially develop at successively lower latitudes. The analysis reveals that kona storms can propagate in any direction but exhibit a clear preference to propagate toward the northeast. Use of the multivariate ENSO index indicates that the number of kona storms that develop during each cool season is not correlated to the phase of ENSO. An analysis of the composite structure and evolution of each type of kona storm revealed some common and some unique characteristics. Development of the surface cyclone in all types results from the intrusion of an upper-level disturbance of extratropical origin into the subtropics, although differences in the initial structure and subsequent evolution of the 300-hPa trough were noted for each type of kona storm. The analysis also revealed that relatively weak 300-hPa winds are present throughout the evolution of each type of kona storm and that the composite kona storm tends to be nestled along the southern boundary of a region of higher surface pressure during the mature stage of its evolution. The development of robust ridges in the 300-hPa geopotential and 1000–500-hPa thickness fields downstream of the composite surface cyclone were noteworthy features that characterized the evolution of all kona storms, the latter feature strongly suggesting that these disturbances are fundamentally baroclinic in nature.


Related Articles

  • Large-Scale Environmental Parameters Associated with Tropical Cyclone Formations in the Western North Pacific. Cheung, Kevin K.W. // Journal of Climate;Feb2004, Vol. 17 Issue 3, p466 

    The local environmental conditions associated with 405 tropical cyclone (TC) formations in the western North Pacific during 1990–2001 are examined in this study. Six large-scale parameters are obtained and computed from the NCEP reanalyses with 2.5° latitude resolution. These include...

  • Cold-air cyclogenesis along the Gulf-Stream front: investigation of diabatic impacts on cyclone development, frontal structure, and track. Businger, S.; Graziano, T.M.; Kaplan, M.L.; Rozumalski, R.A. // Meteorology & Atmospheric Physics;Jan2005, Vol. 88 Issue 1/2, p65 

    On 24-25 February 1989 a storm brought high winds and moderate to heavy snow to the U.S. East Coast. The storm is noteworthy for its rapid mesoscale development within a polar air mass at relatively low latitudes and for the difficulty experienced by operational NWP models and forecasters in...

  • An Investigation of Extratropical Cyclone Development Using a Scale-Separation Technique. Parsons, Kenneth E.; Smith, Philip J. // Monthly Weather Review;Apr2004, Vol. 132 Issue 4, p956 

    The explosive development phase of an extratropical cyclone (ETC) is examined using output generated by the fifth-generation PSU–NCAR Mesoscale Model (MM5). A full-physics run of MM5 with 60-km grid spacing was used to simulate the intensive observation period (IOP)-4 storm of 4–5...

  • Statistical Tropical Cyclone Wind Radii Prediction Using Climatology and Persistence. Knaff, John A.; Sampson, Charles R.; DeMaria, Mark; Marchok, Timothy P.; Gross, James M.; McAdie, Colin J. // Weather & Forecasting;Aug2007, Vol. 22 Issue 4, p781 

    An operational model used to predict tropical cyclone wind structure in terms of significant wind radii (i.e., 34-, 50-, and 64-kt wind radii, where 1 kt = 0.52 m s-1) at the National Oceanic and Atmospheric Administration/National Hurricane Center (NHC) and the Department of Defense/Joint...

  • Hurricane forecasters see active 2009 season. Hofmann, Mark A. // Business Insurance;12/15/2008, Vol. 42 Issue 50, p3 

    The article reports that forecasters predict that the 2009 Atlantic hurricane season will have above-average activity. According to the Tropical Meteorology Project at Colorado State University in Fort Collins, Colorado, seven of the fourteen storms in 2009 will likely become hurricanes....

  • Validation Schemes for Tropical Cyclone Quantitative Precipitation Forecasts: Evaluation of Operational Models for U.S. Landfalling Cases. Marchok, Timothy; Rogers, Robert; Tuleya, Robert // Weather & Forecasting;Aug2007, Vol. 22 Issue 4, p726 

    A scheme for validating quantitative precipitation forecasts (QPFs) for landfalling tropical cyclones is developed and presented here. This scheme takes advantage of the unique characteristics of tropical cyclone rainfall by evaluating the skill of rainfall forecasts in three attributes: the...

  • Probabilistic Prediction of Tropical Cyclones. Part I: Position. Weber, Harry C. // Monthly Weather Review;Jul2005, Vol. 133 Issue 7, p1840 

    A new objective aid for operational prediction of the positions of tropical cyclones is presented. Its method is based on a simple analysis of the performance of all operationally available numerical models during a training period. In a subsequent forecast period, the results of this analysis...

  • Extratropical Cyclones with Multiple Warm-Front-Like Baroclinic Zones and Their Relationship to Severe Convective Storms. Metz, Nicholas D.; Schultz, David M.; Johns, Robert H. // Weather & Forecasting;Oct2004, Vol. 19 Issue 5, p907 

    Extratropical cyclones over the central United States and southern Canada from the years 1982 and 1989 were examined for the presence of two or more (multiple) warm-front-like baroclinic zones, hereafter called MWFL baroclinic zones. Of the 108 cyclones identified during this period, 42% were...

  • Vorticity-Based Detection of Tropical Cyclogenesis. Gierach, Michelle M.; Bourassa, Mark A.; Cunningham, Philip; O’Brien, James J.; Reasor, Paul D. // Journal of Applied Meteorology & Climatology;Aug2007, Vol. 46 Issue 8, p1214 

    Ocean wind vectors from the SeaWinds scatterometer aboard the Quick Scatterometer (QuikSCAT) satellite and Geostationary Operational Environmental Satellite (GOES) imagery are used to develop an objective technique that can detect and monitor tropical disturbances associated with the early...


Read the Article


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

Try another library?
Sign out of this library

Other Topics