Processes Preventing the Development of a Significant Tornado in a Colorado Supercell on 26 May 2010

Murdzek, Shawn S.; Markowski, Paul; Richardson, Yvette; Tanamachi, Robin L.

doi:10.1175/mwr-d-19-0288.1

Cited by 8 publications

(2 citation statements)

References 61 publications

(84 reference statements)

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Section: Resultssupporting

confidence: 67%

“…In contrast, S_ON and QC CAPE are aligned with U.S. midwest environments. AB CAPE is comparable to Dupilka and Reuter (2006a) as well as Colorado case studies (e.g., Murdzek et al, 2020). Rasmussen (2003) suggested that CAPE between 0 and 3 km may be important for enhancing low level updrafts and vertical stretching in U.S. tornadic supercells.…”

Section: Thermodynamic Parameterssupporting

confidence: 62%

See 1 more Smart Citation

ERA5‐Based Significant Tornado Environments in Canada Between 1980 and 2020

Hanesiak,

Taszarek,

Walker

et al. 2024

JGR Atmospheres

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This study uses ERA5 close‐proximity soundings and associated convective parameters to characterize significant tornadic storm (F/EF2+) environments between 1980 and 2020 in parts of Canada. It is shown that ERA5 convective parameters are suitable to represent observed parameters, based on radiosonde comparisons. Results indicate that the eastern Canadian Prairies have nearly double the lifted condensation level with higher level of free convection compared to eastern Canada (southern Ontario/Quebec). Eastern Canada has more a humid boundary layer and free troposphere that can lead to warmer cold pools, favoring tornadogenesis. Central Canada (Manitoba) has the largest mixed‐layer (ML) convective available potential energy (CAPE) mainly due to a combination of regional differences in low level moisture and steeper mid‐level lapse rates in western Canada. Central continental U.S. and Canadian regions appear to have the highest (most negative) convective inhibition, leading to more explosive initiation. Mean bulk wind shear and storm relative helicity (SRH) increases from west to east, with eastern regions being significantly larger. The supercell composite and significant tornado parameters are generally less than U.S. magnitudes, particularly in western Canada, and would require recalibration for more practical use in Canada. Overall, western Canada significant tornadic storms are associated with more low‐level looping hodographs and dominated by thermodynamic influences compared to larger wind influences in eastern regions. This is likely due to more spring, late summer, and autumn events that typically have well‐developed synoptic systems (stronger wind shear) with overall less buoyant energy in eastern regions.

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Section: Resultssupporting

confidence: 67%

Section: Thermodynamic Parameterssupporting

confidence: 62%

ERA5‐Based Significant Tornado Environments in Canada Between 1980 and 2020

Hanesiak,

Taszarek,

Walker

et al. 2024

JGR Atmospheres

View full text Add to dashboard Cite

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Infrasound signals in simulated nontornadic and pre-tornadic supercells

Coffer

Parker

2022

The Journal of the Acoustical Society of America

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There has been increased interest in improving severe weather detection by supplementing the conventional operational radar network with an infrasound observation network, which may be able to detect distinct sub-audible signatures from tornadic supercells. While there is evidence that tornadic thunderstorms exhibit observable infrasound signals, what is not well-understood is whether these infrasound signals are unique to tornadic supercells (compared to nontornadic supercells) or whether there is useful signal prior to tornadogenesis, which would be most relevant to forecasters. Using simulations of supercells, tailored to represent acoustic waves with frequencies from 0.1 to 2 Hz, spectral analysis reveals that both nontornadic and pre-tornadic supercells produce strikingly similar sound pressure levels at the surface, even in close spatial proximity to the storms (less than 20 km). Sensitivity tests employing varying microphysics schemes also show similar acoustic emissions between supercells. Riming of supercooled water droplets in the upper-troposphere is the sole mechanism generating high-frequency pressure waves in supercells prior to tornadogenesis or during tornadogenesis-failure; however, riming occurs continuously in mature nontornadic and tornadic supercells. Our simulations found no clear evidence that infrasound produced by supercells prior to tornado formation (compared to nontornadic supercells) is sufficiently distinct to improve lead-time of tornado warnings.

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Low-level Updraft Intensification in Response to Environmental Wind Profiles

Goldacker

Parker

2021

Journal of the Atmospheric Sciences

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Supercell storms can develop a “dynamical response” whereby upward accelerations in the lower troposphere amplify as a result of rotationally induced pressure falls aloft. These upward accelerations likely modulate a supercell’s ability to stretch near-surface vertical vorticity to achieve tornadogenesis. This study quantifies such a dynamical response as a function of environmental wind profiles commonly found near supercells. Self-organizing maps (SOMs) were used to identify recurring low-level wind profile patterns from 20,194 model-analyzed, near-supercell soundings. The SOM nodes with larger 0–500 m storm-relative helicity (SRH) and streamwise vorticity (ωs) corresponded to higher observed tornado probabilities. The distilled wind profiles from the SOMs were used to initialize idealized numerical simulations of updrafts. In environments with large 0–500 m SRH and large ωs, a rotationally induced pressure deficit, increased dynamic lifting, and a strengthened updraft resulted. The resulting upward-directed accelerations were an order of magnitude stronger than typical buoyant accelerations. At 500 m AGL, this dynamical response increased the vertical velocity by up to 25 m s–1, vertical vorticity by up to 0.2 s–1, and pressure deficit by up to 5 hPa. This response specifically augments the near-ground updraft (the midlevel updraft properties are almost identical across the simulations). However, dynamical responses only occurred in environments where 0–500 m SRH and ωs exceeded 110 m2 s–2 and 0.015 s–1, respectively. The presence vs. absence of this dynamical response may explain why environments with higher 0–500 m SRH and ωs correspond to greater tornado probabilities.

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Processes Preventing the Development of a Significant Tornado in a Colorado Supercell on 26 May 2010

Cited by 8 publications

References 61 publications

ERA5‐Based Significant Tornado Environments in Canada Between 1980 and 2020

ERA5‐Based Significant Tornado Environments in Canada Between 1980 and 2020

Infrasound signals in simulated nontornadic and pre-tornadic supercells

Low-level Updraft Intensification in Response to Environmental Wind Profiles

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