Environmental factors influential to the duration and intensity of tornadoes in simulated supercells

Naylor, Jason; Gilmore, Matthew S.

doi:10.1029/2012gl053041

Cited by 10 publications

(14 citation statements)

References 48 publications

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“…Convection was initiated using the updraft nudging technique described by Naylor and Gilmore (2012a). Nudging was applied over a 10 km 3 10 km 3 3 km spheroid placed in the center of the domain for the first 900 s of simulation.…”

Section: Methodsmentioning

confidence: 99%

“…Updraft nudging was used because the traditional ''warm bubble'' technique is much less effective for realistic soundings with capping inversions [also see Naylor and Gilmore (2012a)]. …”

Section: Methodsmentioning

confidence: 99%

“…Following Naylor and Gilmore (2012b), a tornado was said to be present in the simulation at the first instance that the following three criteria are met: 3 (i) the pressure drop from the center of the vortex to the radius of maximum winds was 24.5 hPa or less, (ii) the horizontal wind speed at the radius of max winds was at least 30 m s 21 , and (iii) vertical vorticity z in the center of the vortex was at least 0.1 s 21 . For more information, refer to Naylor and Gilmore (2012b).…”

Section: B Automated Surface Mesocyclone and Tornado Detectionmentioning

confidence: 99%

“…At 100-m grid spacing, simulations were flagged for further analysis if UH 2-5 . 900 m 2 s 22 (extrapolated from coarser gridspacing results of Naylor et al 2012b). Cases were excluded from further analysis if they did not meet the criteria continually for at least 1 h. For those cases that passed the thresholds, supercell existence was confirmed subjectively every 5 min using a manual procedure previously used in radar observations of supercells (defined and described in Naylor et al 2012b).…”

Section: A Automated and Manual Supercell Identificationmentioning

confidence: 99%

“…Simulated supercells were identified objectively at 1-km grid spacing by the presence of 2-5-km integrated updraft helicity (UH 2-5 ) greater than 180 m 2 s 22 following Naylor et al (2012b). At 100-m grid spacing, simulations were flagged for further analysis if UH 2-5 .…”

Section: A Automated and Manual Supercell Identificationmentioning

confidence: 99%

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Vorticity Evolution Leading to Tornadogenesis and Tornadogenesis Failure in Simulated Supercells

Naylor

Gilmore

2014

Journal of the Atmospheric Sciences

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A three-dimensional idealized cloud model was used to study the storm-scale differences between simulated supercells that produce tornado-like vortices and those that do not. Each simulation was initialized with a different Rapid Update Cycle, version 2 (RUC-2), sounding that was associated with tornadic and nontornadic supercells in nature. The focus is an analysis of vorticity along backward-integrated trajectories leading up to tornadogenesis (19 simulations) and tornadogenesis failure (14 simulations). In so doing, the differences between the nontornadic and tornadic cases can be explored in relation to their associated environmental sounding.Backward-integrated trajectories seeded in the near-surface circulation indicate that the largest differences in vertical vorticity production between the tornadic and nontornadic simulations occur in parcels that descend to the surface from aloft (i.e., descending). Thus, the results from this study support the hypothesis that descending air in the rear of the storm is crucial to tornadogenesis. In the tornadic simulations, the descending parcels experience more negative vertical vorticity production during descent and larger tilting of horizontal vorticity into positive vertical vorticity after reaching the surface, owing to stronger horizontal gradients of vertical velocity. The larger vertical velocities experienced by the trajectories just prior to tornadogenesis in the tornadic simulations are associated with environmental soundings of larger CAPE, smaller convective inhibition (CIN), and larger 0-1-km storm-relative environmental helicity. Furthermore, in contrast with what might be expected from previous works, trajectories entering the incipient tornadic circulations are more negatively buoyant than those entering the nontornadic circulations.

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Section: Methodsmentioning

confidence: 99%

“…Updraft nudging was used because the traditional ''warm bubble'' technique is much less effective for realistic soundings with capping inversions [also see Naylor and Gilmore (2012a)]. …”

Section: Methodsmentioning

confidence: 99%

Section: B Automated Surface Mesocyclone and Tornado Detectionmentioning

confidence: 99%

Section: A Automated and Manual Supercell Identificationmentioning

confidence: 99%

Section: A Automated and Manual Supercell Identificationmentioning

confidence: 99%

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Vorticity Evolution Leading to Tornadogenesis and Tornadogenesis Failure in Simulated Supercells

Naylor

Gilmore

2014

Journal of the Atmospheric Sciences

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On the link between cold fronts and hail in Switzerland

Schemm

Nisi

Martinov

et al. 2016

Atmospheric Science Letters

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Hail is the costliest atmospheric hazard in Switzerland, causing substantial damage to agriculture, cars and buildings every year. In this study, a 12-year statistic of objectively identified cold fronts and a radar-based hail statistic are combined to investigate the co-occurrence of cold fronts and hail in Switzerland. In a first step, an automated front identification scheme, which has previously been designed for and applied to global reanalysis data, is modified for a high-resolution regional analysis data set. This front detection method is then adapted, tested and applied to the Consortium for Small Scale Modelling (COSMO) analysis data for the extended hail season (May to September) in the years 2002-2013. The resulting cold front statistic is presented and discussed. In a second step, the frequency of cold fronts is linked to a high-resolution radar-based hail statistic to determine the relative fraction of hail initiation events in pre-frontal environments. Up to 45% of all detected hail events in north-eastern and southern Switzerland form in pre-frontal zones. Similar fractions are identified upstream of the Jura and the Black Forest mountains. The percentage of front-related hail formation is highest in regions where hail is statistically less frequent, with the exception of southern Switzerland. Furthermore, it is shown that fronts create wind-sheared environments, which are favourable for hail cells.

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A tornado daily impacts simulator for the central and southern United States

Hatzis

Koch

Brooks

2020

Meteorological Applications

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In an average year (1979–2016), the United States experiences nearly 1,100 tornadoes, which cause a total of 68 fatalities. Annual fatality rates have decreased since the peak in the 1920s, but there is a concern that they could start to rise again with increases in vulnerable populations and the impacts of climate change. It is possible to assess the risk of tornado fatalities using the historical record. However, the rarity of tornadoes and the short period of record may not capture the true risk. One way around this problem is to simulate thousands of years’ worth of tornadoes to obtain a broader picture of risk. Previous tornado risk models have distributed tornadoes randomly or used climatology to generate realistic tornado patterns on an annual (or longer) time scale. From an operational standpoint, it would be useful to have a model that distributes tornadoes on a daily time step to enable the forecasting of potential tornado impacts on a given day. The present study introduces one such model that distributes tornadoes using information about the favourability of the atmospheric environment for tornado development: The Tornado Daily Impacts Simulator (TorDIS). The paper demonstrates model utility through 1,000 year simulations over several metropolitan areas and with a comparison between modelled and observed impacts for several high‐impact tornado days. Forecasting potential tornado impacts on a daily time step could allow emergency managers to plan ahead for high‐risk days to prioritize their resources and save lives.

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Environmental factors influential to the duration and intensity of tornadoes in simulated supercells

Cited by 10 publications

References 48 publications

Vorticity Evolution Leading to Tornadogenesis and Tornadogenesis Failure in Simulated Supercells

Vorticity Evolution Leading to Tornadogenesis and Tornadogenesis Failure in Simulated Supercells

On the link between cold fronts and hail in Switzerland

A tornado daily impacts simulator for the central and southern United States

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