Search Results
Rotunno 1983 ; Rotunno and Klemp 1985 ( RK85 ); Wicker and Wilhelmson 1995 ( WW95 ); Adlerman et al. 1999 ; Markowski et al. 2003 ], and theoretical studies (e.g., Davies-Jones and Brooks 1993 ; Davies-Jones et al. 2001 ) of tornadic and nontornadic supercells have advanced our knowledge of the processes necessary for tornadogenesis. But, the manner by which the finescale details of these processes and their interconnectivity instigate tornadogenesis is not well understood (see review papers
Rotunno 1983 ; Rotunno and Klemp 1985 ( RK85 ); Wicker and Wilhelmson 1995 ( WW95 ); Adlerman et al. 1999 ; Markowski et al. 2003 ], and theoretical studies (e.g., Davies-Jones and Brooks 1993 ; Davies-Jones et al. 2001 ) of tornadic and nontornadic supercells have advanced our knowledge of the processes necessary for tornadogenesis. But, the manner by which the finescale details of these processes and their interconnectivity instigate tornadogenesis is not well understood (see review papers
produced datasets that are able to resolve supercell structure in greater detail than was previously possible and also has raised a number of new questions concerning the processes that lead to tornadogenesis (e.g., Wakimoto et al. 1998 ; Trapp 1999 ; Wakimoto and Cai 2000 ; Dowell and Bluestein 2002a , b ). Wakimoto and Liu (1998) and Trapp (1999) examined the Garden City, Kansas, mesocyclone during the Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX; Rasmussen et al
produced datasets that are able to resolve supercell structure in greater detail than was previously possible and also has raised a number of new questions concerning the processes that lead to tornadogenesis (e.g., Wakimoto et al. 1998 ; Trapp 1999 ; Wakimoto and Cai 2000 ; Dowell and Bluestein 2002a , b ). Wakimoto and Liu (1998) and Trapp (1999) examined the Garden City, Kansas, mesocyclone during the Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX; Rasmussen et al
VOLUME 120 MONTHLY WEATHER REVIEW APRIL 1992Observations of a Colorado Tornado. Part I: Mesoscale Environment and Tornadogenesis J. M. WILCZAK,* T. W. CHRISTIAN,t D. E. WOLFE,* R. J. ZAMORA,* AND B. STANKOV* *NOAA/ERL/Wave Propagation Laboratory, Boulder, Colorado~'Cooperative Institute for Research in the Environmental Sciences (CIRES), University of Colorado/NOAA, Boulder, Colorado
VOLUME 120 MONTHLY WEATHER REVIEW APRIL 1992Observations of a Colorado Tornado. Part I: Mesoscale Environment and Tornadogenesis J. M. WILCZAK,* T. W. CHRISTIAN,t D. E. WOLFE,* R. J. ZAMORA,* AND B. STANKOV* *NOAA/ERL/Wave Propagation Laboratory, Boulder, Colorado~'Cooperative Institute for Research in the Environmental Sciences (CIRES), University of Colorado/NOAA, Boulder, Colorado
topography and vegetation, posing questions on how the lowest several hundred meters of the atmosphere, that is, the surface layer to lower boundary layer are influenced by horizontal gradients in the land surface roughness and how the tornadogenesis process may be affected. Figure 1. Tornado-track density for all EF0–EF5 tornadoes that occurred across counties intersecting the ARMOR coverage area from 1950 to 2014. This map reveals two areas with high frequencies of tornado occurrences for a given area
topography and vegetation, posing questions on how the lowest several hundred meters of the atmosphere, that is, the surface layer to lower boundary layer are influenced by horizontal gradients in the land surface roughness and how the tornadogenesis process may be affected. Figure 1. Tornado-track density for all EF0–EF5 tornadoes that occurred across counties intersecting the ARMOR coverage area from 1950 to 2014. This map reveals two areas with high frequencies of tornado occurrences for a given area
. Tornadogenesis relies on horizontal convergence within the boundary layer to amplify vertical vorticity to magnitudes characteristic of tornadoes ( Ward 1972 ; Lewellen 1993 ). In some cases, thunderstorms concentrate vertical vorticity already present in the storm environment ( Wilson 1986 ; Brady and Szoke 1989 ; Wakimoto and Wilson 1989 ). In contrast, supercell thunderstorms appear to act upon low-level vertical vorticity produced by the storm itself ( Barnes 1970 ; Brandes 1984b ; Rotunno and Klemp
. Tornadogenesis relies on horizontal convergence within the boundary layer to amplify vertical vorticity to magnitudes characteristic of tornadoes ( Ward 1972 ; Lewellen 1993 ). In some cases, thunderstorms concentrate vertical vorticity already present in the storm environment ( Wilson 1986 ; Brady and Szoke 1989 ; Wakimoto and Wilson 1989 ). In contrast, supercell thunderstorms appear to act upon low-level vertical vorticity produced by the storm itself ( Barnes 1970 ; Brandes 1984b ; Rotunno and Klemp
1. Introduction Tornado research has focused primarily on tornadogenesis within supercell thunderstorms owing to the fact that supercells produce a disproportionate number of significant tornadoes. 1 Tornadogenesis within supercells can be conceptualized as a three-step process (e.g., Davies-Jones 2015 ). First, midlevel rotation develops from the tilting of environmental horizontal vorticity ( Rotunno 1981 ). Second, vertical vorticity develops close to the surface (the tornado “seed,” e
1. Introduction Tornado research has focused primarily on tornadogenesis within supercell thunderstorms owing to the fact that supercells produce a disproportionate number of significant tornadoes. 1 Tornadogenesis within supercells can be conceptualized as a three-step process (e.g., Davies-Jones 2015 ). First, midlevel rotation develops from the tilting of environmental horizontal vorticity ( Rotunno 1981 ). Second, vertical vorticity develops close to the surface (the tornado “seed,” e
1. Introduction Operational forecasters face a number of challenges in attempts to skillfully “nowcast” (i.e., 0–1-h forecasts) the tornado life cycle. Here, we break up the life cycle simply into tornadogenesis, tornado intensification, and tornado dissipation. Difficulty in understanding and prediction in any of these stages derives from the small spatiotemporal scales over which relevant processes are thought to occur, which makes them difficult to observe. Most research efforts have focused
1. Introduction Operational forecasters face a number of challenges in attempts to skillfully “nowcast” (i.e., 0–1-h forecasts) the tornado life cycle. Here, we break up the life cycle simply into tornadogenesis, tornado intensification, and tornado dissipation. Difficulty in understanding and prediction in any of these stages derives from the small spatiotemporal scales over which relevant processes are thought to occur, which makes them difficult to observe. Most research efforts have focused
. As noted by Dunn (1990) the addition of Doppler radar to an NWS office makes it possible to observe the development of both supercell ( Browning 1964 ; Lemon and Doswell 1979 ; Klemp et al. 1981 ; Klemp and Rotunno 1983 ; Davies-Jones 1986 ) and nonsupercell ( Wakimoto and Wilson 1989 ; Brady and Szoke 1989 ; Collins et al. 2000 ) tornadoes in real-time operations. Tornadogenesis has received considerable interest from the research community for many years and although much has been
. As noted by Dunn (1990) the addition of Doppler radar to an NWS office makes it possible to observe the development of both supercell ( Browning 1964 ; Lemon and Doswell 1979 ; Klemp et al. 1981 ; Klemp and Rotunno 1983 ; Davies-Jones 1986 ) and nonsupercell ( Wakimoto and Wilson 1989 ; Brady and Szoke 1989 ; Collins et al. 2000 ) tornadoes in real-time operations. Tornadogenesis has received considerable interest from the research community for many years and although much has been
low-level shear, LCL, and supercell tornadogenesis are not fully understood, some straightforward hypotheses have been proposed. In terms of shear, stronger low-level shear is often associated with larger storm-relative helicity, implying greater potential for updraft rotation through the tilting and stretching of environmental streamwise vorticity within the supercell updraft, which is responsible for the generation of the midlevel mesocyclone ( Davies-Jones 1984 ). In turn, as rotation aloft
low-level shear, LCL, and supercell tornadogenesis are not fully understood, some straightforward hypotheses have been proposed. In terms of shear, stronger low-level shear is often associated with larger storm-relative helicity, implying greater potential for updraft rotation through the tilting and stretching of environmental streamwise vorticity within the supercell updraft, which is responsible for the generation of the midlevel mesocyclone ( Davies-Jones 1984 ). In turn, as rotation aloft
JuLY 1978 E D W A R D A. B R A N D E S 995Mesocyclone Evolution and Tornadogenesis: Some Observations EDWARD A. BRANDESNational Severe Storms Laboratory, NOAA, Norman, OK 73069(Manuscript received 15 September 1977, in final form 3 April 1978) ABSTRACT Updraft mesocyclones in tornado-producing thunderstorms form along convergent and cyclonicallysheared boundaries that
JuLY 1978 E D W A R D A. B R A N D E S 995Mesocyclone Evolution and Tornadogenesis: Some Observations EDWARD A. BRANDESNational Severe Storms Laboratory, NOAA, Norman, OK 73069(Manuscript received 15 September 1977, in final form 3 April 1978) ABSTRACT Updraft mesocyclones in tornado-producing thunderstorms form along convergent and cyclonicallysheared boundaries that
