On the Environments of Tornadic and Nontornadic Mesocyclones

Brooks, Harold E.; Doswell, Charles A.; Cooper, Justine

doi:10.1175/1520-0434(1994)009<0606:oteota>2.0.co;2

Cited by 241 publications

(118 citation statements)

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“…The 2004 UTC sounding appears to be especially influenced by deep convection, as attested by the moist layer between 80 and 55 kPa, and winds that differ appreciably from earlier (1200 and 1730 UTC) soundings. The large difference between the two adjacent soundings suggests that convectively induced shear exceeds the ambient shear, such that the environment is ill defined (Brooks et al 1994). We believe that the 1730 sounding better represents the undisturbed atmospheric profiles.…”

Section: The Environmentmentioning

confidence: 94%

Analysis of a Small, Vigorous Mesoscale Convective System in a Low-Shear Environment. Part I: Formation, Radar Echo Structure, and Lightning Behavior

1998

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The evolution of a small, vigorous mesoscale convective system (MCS) over northern Alabama is described using Doppler radar, GOES satellite, surface mesonet, lightning, and sounding data. The MCS formed near noon in a relatively unstable environment having weak synoptic forcing and weak shear. The initiation of separate lines and clusters of deep convection occurred in regions exhibiting cumulus cloud streets, horizontal variations in stratocumulus cloud cover, and variations in inferred soil moisture. MCS growth via merger of storms within clusters and lines, and among the clusters, was accomplished largely through intersection of storm-scale and mesoscale outflow boundaries. The MCS maximum anvil area (ϳ60 000 km 2 at 220 K) and lifetime (8 h) were about 50% that of the typical Great Plains mesoscale convective complex (MCC).Despite its smaller size, this MCS displayed many aspects that typify the mostly nocturnal Great Plains MCS. The precipitation output was highly variable due to the transient nature of the intense convective elements, many of which produced microbursts. The radar measurements documented the formation of a stratiform region along the trailing side of an intense convective line. This stratiform region formed as decaying convective cores coalesced, rather than through advection of precipitation particles directly from the convective region. Combined GOES IR imagery and radar reflectivity analyses within the stratiform region show a sinking anvil cloud top in the presence of increases in the vertical radar reflectivity gradient within the cloud during the maturation of the stratiform region.During its intense developing stages, the MCS generated a peak cloud-to-ground (CG) flash rate of 2400 h Ϫ1 , comparable to rates produced by larger MCCs. Early on, positive CG flashes were most prevalent around intense convective core regions exhibiting strong divergence at anvil level. During the latter stages, the emergence of positive CG was coincident with the formation of a prominent radar bright band within the stratiform region. Thus, a bipole was established, but its length was quite short at approximately 50 km, 25%-50% of the distance documented in other MCSs.

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Section: The Environmentmentioning

confidence: 94%

Analysis of a Small, Vigorous Mesoscale Convective System in a Low-Shear Environment. Part I: Formation, Radar Echo Structure, and Lightning Behavior

1998

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“…Rawinsonde proximity soundings have been extensively used both overseas (Brooks et al 1994;Rasmussen and Blanchard 1998;Rasmussen 2003) and in Australia (Ryan 1992;Davis and Walsh 2008) to provide relationships between large-scale environmental conditions and thunderstorm occurrence. A problem with this type of approach is the sparse spatial distribution of rawinsonde stations relative to the location of recorded severe thunderstorms.…”

Section: Introductionmentioning

confidence: 99%

“…A problem with this type of approach is the sparse spatial distribution of rawinsonde stations relative to the location of recorded severe thunderstorms. Upperair soundings taken more than 200 kilometres away from a thunderstorm may not be representative of that storm's environment (Ryan 1992;Brooks et al 1994;Potvin et al 2010). The Australian rawinsonde network exceeds spatial distances of 200 km between sites in most cases (Ryan 1992).…”

Section: Introductionmentioning

confidence: 99%

A severe thunderstorm climatology for Australia and associated thunderstorm environments

Allen¹,

Karoly²,

Mills³

2011

AMOJ

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“…The local character of storms is the main obstacle in any meteorological study of the convective activity in a particular area. Thunderstorms develop within environments that exhibit high spatial and temporal variability (Brooks et al, 1994) and convective cells with lightning are meteorological phenomena with a limited spatial and temporal resolution. Predicting the occurrence of convective storms, which often occur with lightning, is one of the most complicated tasks in weather forecasting.…”

Section: Introductionmentioning

confidence: 99%

Synoptic patterns associated with wildfires caused by lightning in Castile and Leon, Spain

García‐Ortega¹,

Trobajo²,

López³

et al. 2011

Nat. Hazards Earth Syst. Sci.

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Abstract. The Iberian Peninsula presents the highest number of wildfires in Europe. In the NW of Spain in particular, wildfires are the natural risk with the greatest economic impact in this region. Wildfires caused by lightning are closely related to the triggering of convective phenomena. The prediction of thunderstorms is a very complex task because these weather events have a local character and are highly dependent on mesoscale atmospheric conditions. The development of convective storms is directly linked to the existence of a synoptic environment favoring convection. The aim of this study is to classify the atmospheric patterns that provide favorable environments for the occurrence of wildfires caused by lightning in the region of Castile and Leon, Spain. The database used for the study contains 376 wildfire days from the period 1987-2006. NCEP data reanalysis has been used. The atmospheric fields used to characterise each day were: geopotential heights and temperatures at 500 hPa and 850 hPa, relative humidity and the horizontal wind at 850 hPa. A Principal Component Analysis in T-mode followed by a Cluster Analysis resulted in a classification of wildfire days into five clusters. The characteristics of these clusters were analysed and described, focusing particularly on the study of those wildfire days in which more than one wildfire was detected. In these cases the main feature observed was the intensification of the disturbance typical of the cluster to which the wildfire belongs.

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On the Environments of Tornadic and Nontornadic Mesocyclones

Cited by 241 publications

References 0 publications

Analysis of a Small, Vigorous Mesoscale Convective System in a Low-Shear Environment. Part I: Formation, Radar Echo Structure, and Lightning Behavior

Analysis of a Small, Vigorous Mesoscale Convective System in a Low-Shear Environment. Part I: Formation, Radar Echo Structure, and Lightning Behavior

A severe thunderstorm climatology for Australia and associated thunderstorm environments

Synoptic patterns associated with wildfires caused by lightning in Castile and Leon, Spain

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