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- Author or Editor: Stephen J. Hodanish x
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Abstract
Anticyclonic left-moving supercells are observed each year in the United States, emanating both discretely and from storm splitting processes. Such thunderstorms often produce severe hail and wind gusts and, on rare occasion, tornadoes. The body of documentary literature on this subset of supercells is relatively scant compared with right-moving storms, and this is especially true regarding visual characteristics and conceptual models. Here a characteristic example of the anticyclonic supercell is presented using an intense and well-defined specimen that passed over Aroya, Colorado, on 15 June 2002. Photographic and radar documentation is provided in original and mirrored forms, for aid in conceptualizing the left-moving supercell and associated structures and processes. A summary overview is presented of the environment, development, evolution, and effects of this remotely located but noteworthy event.
Abstract
Anticyclonic left-moving supercells are observed each year in the United States, emanating both discretely and from storm splitting processes. Such thunderstorms often produce severe hail and wind gusts and, on rare occasion, tornadoes. The body of documentary literature on this subset of supercells is relatively scant compared with right-moving storms, and this is especially true regarding visual characteristics and conceptual models. Here a characteristic example of the anticyclonic supercell is presented using an intense and well-defined specimen that passed over Aroya, Colorado, on 15 June 2002. Photographic and radar documentation is provided in original and mirrored forms, for aid in conceptualizing the left-moving supercell and associated structures and processes. A summary overview is presented of the environment, development, evolution, and effects of this remotely located but noteworthy event.
Abstract
For the state of Colorado, 10 years (2003–12) of 1 April–31 October cloud-to-ground (CG) lightning stroke data are mapped at 500-m spatial resolution over a 10-m spatial resolution U.S. Geological Survey (USGS) digital elevation model (DEM). Spatially, the 12.5 million strokes that are analyzed represent ground contacts, but translate to density values that are about twice the number of ground contacts. Visual interpretation of the mapped data reveals the general lightning climatology of the state, while geospatial analyses that quantify lightning activity by elevation identify certain topographic influences of Colorado’s physical landscape. Elevations lower than 1829 m (6000 ft) and above 3200 m (10 500 ft) show a positive relationship between lightning activity and elevation, while the variegated topography that lies between these two elevations is characterized by a fluctuating relationship. Though many topographic controls are elucidated through the mappings and analyses, the major finding of this paper is the sharp increase in stroke density observed above 3200 m (10 500 ft). Topography’s role in this rapid surge in stroke density, which peaks in the highest mountain summits, is not well known, and until now, was not well documented in the refereed literature at such high resolution from a long-duration dataset.
Abstract
For the state of Colorado, 10 years (2003–12) of 1 April–31 October cloud-to-ground (CG) lightning stroke data are mapped at 500-m spatial resolution over a 10-m spatial resolution U.S. Geological Survey (USGS) digital elevation model (DEM). Spatially, the 12.5 million strokes that are analyzed represent ground contacts, but translate to density values that are about twice the number of ground contacts. Visual interpretation of the mapped data reveals the general lightning climatology of the state, while geospatial analyses that quantify lightning activity by elevation identify certain topographic influences of Colorado’s physical landscape. Elevations lower than 1829 m (6000 ft) and above 3200 m (10 500 ft) show a positive relationship between lightning activity and elevation, while the variegated topography that lies between these two elevations is characterized by a fluctuating relationship. Though many topographic controls are elucidated through the mappings and analyses, the major finding of this paper is the sharp increase in stroke density observed above 3200 m (10 500 ft). Topography’s role in this rapid surge in stroke density, which peaks in the highest mountain summits, is not well known, and until now, was not well documented in the refereed literature at such high resolution from a long-duration dataset.
Abstract
The visual, radar, and lightning characteristics of a severe thunderstorm that spawned a large F3 tornado near Almena, Kansas, on 3 June 1999 are documented. The storm is interesting in that it made a transition from a low-precipitation to classic supercell then back to low-precipitation supercell again prior to dissipation after sunset. The storm remarkably produced only 17 cloud-to-ground lightning flashes during its 4.5-h lifetime, despite vertically integrated liquid (VIL) values reaching 95 kg m−2, reflectivities of 50 dBZ or greater at altitudes of 14 km, and baseball-size hail at the surface. In contrast, total lightning rates inferred from a portable lightning detector during the large tornado were very high, approximately 100 per minute, as expected for a storm of this size and intensity.
Abstract
The visual, radar, and lightning characteristics of a severe thunderstorm that spawned a large F3 tornado near Almena, Kansas, on 3 June 1999 are documented. The storm is interesting in that it made a transition from a low-precipitation to classic supercell then back to low-precipitation supercell again prior to dissipation after sunset. The storm remarkably produced only 17 cloud-to-ground lightning flashes during its 4.5-h lifetime, despite vertically integrated liquid (VIL) values reaching 95 kg m−2, reflectivities of 50 dBZ or greater at altitudes of 14 km, and baseball-size hail at the surface. In contrast, total lightning rates inferred from a portable lightning detector during the large tornado were very high, approximately 100 per minute, as expected for a storm of this size and intensity.
