Buoyancy and Shear Characteristics of Hurricane-Tornado Environments

McCaul, Eugene W.

doi:10.1175/1520-0493(1991)119<1954:bascoh>2.0.co;2

Cited by 155 publications

(185 citation statements)

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“…1), but should be small enough to capture the regional characteristics of environmental parameters in Miyazaki. The relative geographical location of the key and target areas in this study is also consistent with that of the tropical cyclones and associated tornadoes shown by McCaul (1991). Within the target area, there are 48 (204) grid points for the 1st (2nd) period.…”

Section: Methodology and Datasupporting

confidence: 82%

“…Moreover, the deep shear zone extends up to the upper troposphere (to 6 km). The shape of the hodograph in 0 6 km layer for the Nobeoka-Tor event is also larger than that for environments with hurricane-spawned tornadoes shown by McCaul (1991), which indicates that the shear parameters for the Nobeoka-Tor event are much larger than those derived from the hodograph of McCaul (1991). Figure 4 also shows that the upstream of the southerly is connected to the strong westerly jet in the southwestern flank of the typhoon on 500 hPa.…”

Section: Discussionmentioning

confidence: 71%

“…A one-sided Student's t-test shows that the mean value of the Nobeoka-Tor event is signifi- cantly larger than the other two groups at the 95% confidence level (Table 1). It is also noticeable that the mean of mlCAPE for the Nobeoka-Tor event (399 J kg 1 ) is much smaller than that for significant tornadic (F2 or greater damage) supercells in the U.S. (2303 J kg 1 ) (Thompson et al 2003), but comparable to that with hurricane-spawned tornadoes (253 J kg 1 ) (McCaul 1991). By examing other thermodynamic parameters as shown in Supplement 2, we found that some parameters discriminate the Nobeoka-Tor event from the other two groups as well as mlCAPE (e.g., lifted index and lapse rate in the lowest 3 km AGL).…”

Section: Environmental and Composite Parametersmentioning

confidence: 93%

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Characteristics of the Meso-scale Environments of Storms Associated with Typhoon-spawned Tornadoes in Miyazaki, Japan

Sakurai

Mukougawa

2009

SOLA

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In order to elucidate meso-scale environmental characteristics contributing the generation of a typhoonspawned significant tornado (F2) occurred in Nobeoka of Miyazaki prefecture, Japan in 2006, environmental and composite parameters in Miyazaki are examined in comparison with typhoon-spawned 3 tornadic events in Miyazaki and 16 nontornadic events using the forecast dataset of the operational nonhydrostatic mesoscale model of the Japan Meteorological Agency (JMA).It is found that the significant tornado in Nobeoka is accompanied by enhanced convectively unstable environment with large vertical wind shear, which is represented by a relatively large convective available potential energy based on mean parcel in the lowest 500 m layer above ground level (AGL) (mlCAPE) and significantly large shear parameters (e.g., storm relative helicity; SRH) compared with other tornadic and nontornadic events. We also discuss synoptic condition producing these characteristic environments along with the comparison of the environment for the tornadic supercells and hurricane-spawned tornadoes in the U.S. IntroductionFor the mitigate of disastrous damages due to tornadoes, it is important to improve the potential predictability for the outbreak of tornadoes. Although there are several statistical studies to characterize environmental parameters for the occurrence of tornadoes in the U.S. (Rasmussen 2003;Thompson et al. 2003), only few studies have been conducted in the similar approach for the outbreaks of tornadoes in Japan (e.g., Sakurai and Kawamura 2008). In particular, the distinct characteristics of environments associated with tornadic storms in Japan have not been elucidated in comparison with those of nontornadic events.On the other hand, Niino et al. (1997) indicated that tornadoes in Japan took place in various synoptic conditions such as extratropical cyclone, typhoon (or tropical cyclone), cold front, winter monsoon and stationary front, and also in various geographical locations. It is also well known that the environmental parameters such as CAPE in Japan critically depend on the locations and seasons as well as synoptic conditions (Chuda and Niino 2005). Thus, it is very hard to extract common characteristics of environmental parameters for the genesis of tornadoes using all tornadic events in Japan. Here, we focus instead on tornadoes in a specific location and synoptic condition in Japan, and try to reveal their environmental characteristics.On 17 Sep. 2006, a significant tornado associated with typhoon T0613 took place in Nobeoka of Miyazaki prefecture in Japan (hereafter, Nobeoka-Tor event, Fig. 1) and caused serious damages (F2 scale) (Miyazaki District Meteorological Observatory 2006). This typhoon caused also two other F1-scale tornadoes in Hyuga and Nichinan of Miyazaki on the same day. Mashiko (2007) shows horizontal distribution of environmental parameters associated with the Nobeoka-Tor by a simulation with a high-resolution nonhydrostatic model of the JMA. Hence, by focusing on typhoonspawned tor...

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Section: Methodology and Datasupporting

confidence: 82%

Section: Discussionmentioning

confidence: 71%

Section: Environmental and Composite Parametersmentioning

confidence: 93%

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Characteristics of the Meso-scale Environments of Storms Associated with Typhoon-spawned Tornadoes in Miyazaki, Japan

Sakurai

Mukougawa

2009

SOLA

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“…Previous studies have revealed that tornado occurrences tend to be concentrated in the northeast quadrant of TCs [Hill et al, 1966;Orton, 1970;Novlan and Gray, 1974] or the right front quadrant with respect to the moving direction of TCs [Smith, 1965;Fujita et al, 1972;McCaul, 1991] in the Northern Hemisphere. Using a number of rawinsonde observations, McCaul [1991] found that the spatial distribution of tornadoes relative to the TC centers correlated strongly with that of the storm-relative environmental helicity (SREH), a measure of the potential of environmental horizontal vorticity to produce rotating updrafts of supercells through tilting [Davies-Jones et al, 1990]. In addition, Novlan and Gray [1974] noted that the vertical shear near the surface for tornadic hurricanes was larger than that for nontornadic hurricanes.…”

Section: Introductionmentioning

confidence: 98%

Toward better assessment of tornado potential in typhoons: Significance of considering entrainment effects for CAPE

Sueki

Niino

2016

Geophysical Research Letters

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The characteristics of typhoons that spawned tornadoes (tornadic typhoons: TTs) in Japan from 1991 to 2013 were investigated by composite analysis using the Japanese 55 year Reanalysis and compared with those of typhoons that did not spawn tornadoes (nontornadic typhoons: NTs). We found that convective available potential energy (CAPE), which considers the effects of entrainment (entraining CAPE: E‐CAPE), and storm‐relative environmental helicity (SREH) are significantly large in the northeast quadrant of TTs where tornadoes frequently occur and that E‐CAPE and SREH in that quadrant for TTs are larger than those for NTs. On the other hand, ordinary CAPE without entrainment does not account for the spatial distribution of tornado occurrences nor does it distinguish TTs from NTs. E‐CAPE is sensitive to humidity in the midtroposphere; thus, it is effective for detecting a conditionally unstable layer up to about 550 hPa, which is distinctive of TTs.

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“…28) and the total number of tornado observations in this study). There are significant differences in the relative magnitudes of moisture, instability, shear and lift in conditions preceding TC tornadoes 29 . The smaller-scale boundaries associated with TC tornadoes are distinctly different from those of large-scale extratropical cyclones in spring and late autumn 30 .…”

Section: Discussionmentioning

confidence: 99%