An Observational Examination of Long-Lived Supercells. Part I: Characteristics, Evolution, and Demise

Bunkers, Matthew J.; Hjelmfelt, Mark R.; Smith, Paul L.

doi:10.1175/waf949.1

Cited by 63 publications

(60 citation statements)

References 54 publications

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“…The 700-hPa temperatures for the boundary significant tornado composite were cooler than those indicated for the null composite. These results were consistent with Bunkers et al (2010), who found that for the Great Plains, 700-hPa temperatures associated with significant tornadoes were cooler than those associated with significant hail. The 700-hPa temperatures found at the tornadogenesis location also were consistent with values found by G12 and associated with northern plains summertime tornadoes.…”

Section: B Synoptic Environmentsupporting

confidence: 91%

“…7f). The 700-hPa temperatures for the significant tornado composite were similar to findings from Bunkers et al (2010) and also were consistent for spring southern …”

Section: B Synoptic Environmentsupporting

confidence: 74%

“…The radar data were analyzed using Gibson Ridge GR2 Analyst software to determine if the parent thunderstorm producing the significant tornado or large hail was a supercell. For the purposes of this study, a thunderstorm was required to maintain $10 m s 21 of rotational velocity across a distance of ,10 km on two adjacent elevation angles for at least three consecutive volume scans to be classified as a supercell, similar to the criteria in Bunkers et al (2006). Events with improperly dealiased radar data were not used.…”

Section: Methodsmentioning

confidence: 99%

“…The kinematic parameters of 0-1-and 0-3-km SRH using the internal dynamics storm motion (Bunkers et al 2000); 0-1-, 0-3-, and 0-6-km bulk wind difference (BWD); and storm-relative winds (SRWs) from 0-1, 0-3, 5, 8, and 7-10 km were calculated. Consistent with previous studies indicating higher SRH is often observed with greater tornado potential (Thompson et al 2012; T03, CB04, RB98), the 0-1-and 0-3-km SRH Wind barbs are in meters per second (half barb is equal to 2.5 m s 21 and a full barb is 5 m s 21 ).…”

Section: Convective Environmentmentioning

confidence: 99%

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Discriminating Environmental Conditions for Significant Warm Sector and Boundary Tornadoes in Parts of the Great Plains

Boustead¹,

Mayes²,

Gargan³

et al. 2013

Weather and Forecasting

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Using system-relative composites, based on a dataset of significant tornadoes and null supercell events, environmental conditions associated with occurrences of significant tornadoes near discernible surface boundaries were compared to nontornadic boundary supercells, and warm sector significant tornadoes to nontornadic warm sector supercells, for a portion of the Great Plains. Results indicated that significant boundary tornadoes were associated with the exit region of a 300-hPa jet maximum, while null boundary events were in closer proximity to the 300-hPa jet entrance region. The differences at 300 hPa led to significant differences at the surface, as the null composite indicated deformation and confluence into the surface boundary and enhanced frontogenesis, while this was not present in the boundary significant tornado composite. Significant synoptic differences also were noted between the warm sector tornadoes and the warm sector null events. The warm sector significant tornadoes were associated with a much stronger, negatively tilted synoptic storm system, with the composite tornado in the 300-hPa jet exit region and downstream of increasing values of absolute vorticity. Additional thermodynamic and kinematic parameters pertaining to low-level moisture and environmental winds appeared to be important in distinguishing boundary and warm sector significant tornadoes from nontornadic supercell events. Statistical comparisons between boundary and warm sector significant tornado events showed significant differences in the climatology of their length, width, and date and time of occurrence.

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Section: B Synoptic Environmentsupporting

confidence: 91%

“…7f). The 700-hPa temperatures for the significant tornado composite were similar to findings from Bunkers et al (2010) and also were consistent for spring southern …”

Section: B Synoptic Environmentsupporting

confidence: 74%

Section: Methodsmentioning

confidence: 99%

Section: Convective Environmentmentioning

confidence: 99%

See 2 more Smart Citations

Discriminating Environmental Conditions for Significant Warm Sector and Boundary Tornadoes in Parts of the Great Plains

Boustead¹,

Mayes²,

Gargan³

et al. 2013

Weather and Forecasting

View full text Add to dashboard Cite

show abstract

“…Storms may experience variable lifetimes after entering inversion regions, presumably in relation to the magnitude of the stratification although for reasons that have not been revealed by previous research. The demise of a majority of the isolated, observed supercells analyzed by Bunkers et al (2006a) occurred either by weakening sufficiently to become nonsupercellular or by decaying entirely. Graziano and Carlson (1987) showed that the likelihood of strong storms decreases with increasing magnitude of the stratification of the cool surface and BL temperatures beneath a warm, dry, and elevated residual layer (ERL) in ''proximity'' soundings containing high values of CIN and lid strength index (LSI).…”

Section: Introductionmentioning

confidence: 99%

The Impact of Spatial Variations of Low-Level Stability on the Life Cycle of a Simulated Supercell Storm

Ziegler

Mansell

Straka

et al. 2010

Monthly Weather Review

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This study reports on the dynamical evolution of simulated, long-lived right-moving supercell storms in a high-CAPE, strongly sheared mesoscale environment, which initiate in a weakly capped region and subsequently move into a cold boundary layer (BL) and inversion region before dissipating. The storm simulations realistically approximate the main morphological features and evolution of the 22 May 1981 Binger, Oklahoma, supercell storm by employing time-varying inflow lateral boundary conditions for the storm-relative moving grid, which in turn are prescribed from a parent, fixed steady-state mesoscale analysis to approximate the observed inversion region to the east of the dryline on that day. A series of full life cycle storm simulations have been performed in which the magnitude of boundary layer coldness and the convective inhibition are varied to examine the ability of the storm to regenerate and sustain its main updraft as it moves into environments with increasing convective stability. The analysis of the simulations employs an empirical expression for the theoretical speed of the rightforward-flank outflow boundary relative to the ambient, low-level storm inflow that is consistent with simulated cold-pool boundary movement. The theoretical outflow boundary speed in the direction opposite to the ambient flow increases with an increasing cold-pool temperature deficit relative to the ambient BL temperature, and it decreases as ambient wind speed increases. The right-moving, classic (CL) phase of the simulated supercells is supported by increasing precipitation content and a stronger cold pool, which increases the right-moving coldpool boundary speed against the constant ambient BL winds. The subsequent decrease of the ambient BL temperature with eastward storm movement decreases the cold-pool temperature deficit and reduces the outflow boundary speed against the ambient winds, progressing through a state of stagnation to an ultimate retrogression of the outflow boundary in the direction of the ambient flow. Onset of a transient, left-moving lowprecipitation (LP) phase is initiated as the storm redevelops on the retrograding outflow boundary. The leftmoving LP storm induces compensating downward motions in the inversion layer that desiccates the inflow, elevates the cloudy updraft parcel level of free convection (LFC), and leads to the final storm decay. The results demonstrate that inversion-region simulations support isolated, long-lived supercells. Both the degree of stratification and the coldness of the ambient BL regulate the cold-pool intensity and the strength and capacity of the outflow boundary to lift BL air through the LFC and thus regenerate convection, resulting in variation of supercell duration in the inversion region of approximately 1-2 h. In contrast, horizontally homogeneous conditions lacking an inversion region result in the development of secondary convection from the initial isolated supercell, followed by rapid upscale growth after 3 h to form a long-lived mesoscale convective system.

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An overview of the 29 May 2012 Kingfisher supercell during DC3

et al. 2016

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On 29–30 May 2012, the Deep Convective Clouds and Chemistry experiment observed a supercell thunderstorm on the southern end of a broken line of severe storms in Oklahoma. This study focuses on an approximately 70 min period during which three mobile Doppler radars operated and a balloon‐borne electric field meter, radiosonde, and particle imager flew through the storm. An overview of the relationships among flash rates, very high frequency (VHF) source densities, and Doppler‐radar‐derived storm parameters is presented. Furthermore, the evolution of the flash distribution relative to the midlevel storm's kinematics and microphysics is examined at two times during a period of rapid storm intensification. The timing of increases in VHF counts in the 8–10 km above ground level (agl) layer, which contained the largest VHF source counts, is similar to the timing of increases in updraft mass flux, in updraft volume, and in graupel volume at approximately 5–9 km agl. Although some increases in VHF source counts had little or no corresponding increase in one or more of the other storm parameters, at least one other parameter had an increase near the time of every VHF increase, a pattern which suggests a common dependence on updraft pulses, as expected from the noninductive graupel‐ice electrification mechanism. A classic bounded weak lightning region was observed initially during storm intensification, but late in the period it appeared to be due to a wake in the flow around the updraft, rather than due to a precipitation cascade around the updraft core as is usually observed.

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An Observational Examination of Long-Lived Supercells. Part I: Characteristics, Evolution, and Demise

Cited by 63 publications

References 54 publications

Discriminating Environmental Conditions for Significant Warm Sector and Boundary Tornadoes in Parts of the Great Plains

Discriminating Environmental Conditions for Significant Warm Sector and Boundary Tornadoes in Parts of the Great Plains

The Impact of Spatial Variations of Low-Level Stability on the Life Cycle of a Simulated Supercell Storm

An overview of the 29 May 2012 Kingfisher supercell during DC3

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