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Robert Davies-Jones

1. Introduction Understanding of atmospheric vortices, such as tornadoes [see reviews by Davies-Jones et al. (2001) and Davies-Jones (2015) ], lee vortices ( Smolarkiewicz and Rotunno 1989 ; Davies-Jones 2000 ), and larger-scale cyclones ( Lackmann 2011 , 101–102) often involves determining the mechanisms by which air parcels obtain large vorticities. One approach to investigating tornadogenesis is to use a “bare-bones computer model” that forms a tornado ( Davies-Jones 2008 ). The results

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Robert Davies-Jones

Introduction to Fluid Dynamics. Cam bridge University Press, 615 pp.Davies-Jones, R. P., 1982: Observational and theoretical aspects of tornado-genesis. Intense Atmospheric Vortices, L. Bengtsson and J. Lighthill, Eds., Springer-Vefiag, 175-189.Doswell, C. A., III, 1984: A kinematic analysis of frontogenesis as sociated with a nondivergent vortex. J. Atmos. Sci., 41, 1242 1248.Petterssen, S., 1956: Weather Analysis and Forecasting. Vol. I: Motion and Motion Systems, 2nd ed., McGraw-Hill, 428 pp.

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Robert B. Seigel
and
Susan C. van den Heever

) upper-level neutral stratification from ~700 to ~500 hPa. These three environmental layers are synonymous with the environment simulated in this experiment ( Fig. 1 ). Additionally, supercell tornadogenesis is often observed to occur within environments that contain CINH and high CAPE ( Davies 2004 ). Ziegler et al. (2010) investigated the role that stable layers atop neutrally stratified boundary layers play in supercell tornadogenesis. They modeled a tornadic supercell that propagated within a

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Edwin J. Adlerman
,
Kelvin K. Droegemeier
, and
Robert Davies-Jones

-type supercells in certain environments. Early explanations of this phenomenon included the presence of multiple tornadoes rotating around a single mesocyclone ( Snow and Agee 1975 ; Agee et al. 1976 ), thereby producing the familiar cycloidal damage paths associated with tornado families (e.g., Forbes 1975 ). Lemon and Doswell (1979) used radar, aircraft, and visual observations to develop a conceptual model of mesocyclone/updraft evolution. They suggested that cyclic tornadogenesis results from the

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Brian J. Gaudet
,
William R. Cotton
, and
Michael T. Montgomery

tornadoes/mesocyclones, we would like to point out some qualitative features that we feel are relevant. First, extremely close-range observations of a tornado by Bluestein et al. (2003a) revealed an elliptical structure to the eye, but one that did not appear to rotate. They speculated that deformation was the likely reason for these observations. Bluestein et al. (2003b) found that tornadogenesis was associated with the arrival of a jet of convergence to a cold pool boundary that possessed vortices

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Andrew R. Wade
and
Matthew D. Parker

ground. In a subsequent article, we will address the origins of vorticity and processes linked to tornadogenesis in these storms. b. Parcels with large vertical velocities Time series for groups of parcels that, at a single subjectively chosen “peak time” targeting a strong updraft in each run, all exceed 30 m s −1 upward velocity (50 m s −1 for the high-CAPE case) are shown in Fig. 14 . In environments with reduced CAPE, parcel buoyancy can be expected to contribute less to updraft speeds, as in

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Andrew J. Muehr
,
James H. Ruppert
,
Matthew D. Flournoy
, and
John M. Peters

processes ( Coffer et al. 2017 ; Flournoy et al. 2020 ; Markowski 2020 ; Lyza et al. 2022 ). Two different thermodynamic profiles and five different hodographs resulted in a suite of 10 simulations driven from unique initial model profiles, the output of which is analyzed in the following section. Individual members are referred to by their hodograph (e.g., H2) and midlevel RH value (e.g., “dry” or “moist”). Many previous supercell modeling studies have focused on tornadogenesis in environments

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Masayuki Kawashima

, a = 2 km, and b = 1 km. Unlike the high-resolution simulations of nonsupercell tornadogenesis by LW97a , lobe and cleft instabilities, which in their simulations were important for triggering HSIs, do not occur along the leading edge in any of the present simulations. This is because the leading edge lacks a marked nose structure due to the use of a relatively weak surface friction and a relatively coarse horizontal model resolution. 1) Stably stratified cases Figure 7 shows the horizontal

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Wen-Chau Lee
and
Joshua Wurman

Bassett, Nebraska, on 5 June 1999. Part I: Tornadogenesis. Mon. Wea. Rev. , 131 , 2954 – 2967 . Brandes , E A. , 1978 : Mesocyclone evolution and tornadogenesis: Some observations. Mon. Wea. Rev. , 106 , 995 – 1011 . Brandes , E A. , 1981 : Finestructure of the Del City–Edmond tornado mesocirculation. Mon. Wea. Rev. , 109 , 635 – 647 . Brown , R A. , L R. Lemon , and D W. Burgess , 1978 : Tornado detection by pulsed Doppler radar. Mon. Wea. Rev. , 106 , 29 – 38

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Martin A. Satrio
,
David J. Bodine
,
Anthony E. Reinhart
,
Takashi Maruyama
, and
Franklin T. Lombardo

; Katona et al. 2016 ) or damage surveys (e.g., Fujita 1989 ; Karstens et al. 2013 ). Several case studies have examined how terrain may lead to more favorable conditions for the intensification of the supercell and mesocyclone. Schneider (2009) analyzed three separate tornado events that occurred over the Great Tennessee Valley and noted multiple effects from surface terrain that led to a higher likelihood of tornadogenesis, including increased low-level convergence, upslope flow resulting in a

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