AMPLIATIVE REASONING TO VIEW THE PREVALENCE OF SEVERE THUNDERSTORMS

Abstract An algorithm that provides an early indication of impending severe weather from observed trends in thunderstorm total lightning flash rates has been developed. The algorithm framework has been tested on 20 thunderstorms, including 1 nonsevere storm, which occurred over the course of six separate days during the spring months of 2002 and 2003. The identified surges in lightning rate (or jumps) are compared against 110 documented severe weather events produced by these thunderstorms as they moved across portions of northern Alabama and southern Tennessee. Lightning jumps precede 90% of these severe weather events, with as much as a 27-min advance notification of impending severe weather on the ground. However, 37% of lightning jumps are not followed by severe weather reports. Various configurations of the algorithm are tested, and the highest critical success index attained is 0.49. Results suggest that this lightning jump algorithm may be a useful operational diagnostic tool for severe thunderstorm potential.

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Analysis of Severe Elevated Thunderstorms over Frontal Surfaces Using DCIN and DCAPE

Atmosphere ◽

10.3390/atmos10080449 ◽

2019 ◽

Vol 10 (8) ◽

pp. 449

Author(s):

Patrick Market ◽

Kevin Grempler ◽

Paula Sumrall ◽

Chasity Henson

Keyword(s):

Weather Prediction ◽

Convective Available Potential Energy ◽

Numerical Weather Prediction Model ◽

Surface Boundary ◽

Storm Events ◽

Cold Side ◽

Severe Thunderstorms ◽

Stable Surface Layer ◽

Different Populations ◽

Convective Inhibition

A 10-year study of elevated severe thunderstorms was performed using The National Centers for Environmental Information Storm Events Database. A total of 80 elevated thunderstorm cases were identified, verified, and divided into “Prolific” and “Marginal” classes. These severe cases occurred at least 80 km away from, and on the cold side of, a surface boundary. The downdraft convective available potential energy (DCAPE), downdraft convective inhibition (DCIN), and their ratio are tools to help estimate the potential for a downdraft to penetrate through the depth of a stable surface layer. The hypothesis is that as the DCIN/DCAPE ratio decreases, there exists enhanced possibility of severe surface winds. Using the initial fields from the Rapid Refresh numerical weather prediction model, datasets of DCIN, DCAPE, and their ratio were created. Mann-Whitney U tests on the Prolific versus Marginal case sets were undertaken to determine if the DCAPE and DCIN values come from different populations for the two different case sets. Results show that the Prolific cases have values of DCIN closer to zero, suggesting the downdraft is able to penetrate to the surface causing severe winds. Thus, comparing DCIN and DCAPE is a viable tool in determining if downdrafts will reach the surface from elevated thunderstorms.

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Atmosphere-Space Interactions Monitor (ASIM): State of the Art

Acta Polytechnica CTU Proceedings ◽

10.14311/app.2014.01.0303 ◽

2014 ◽

Vol 1 (1) ◽

pp. 303-306

Author(s):

Pere Blay ◽

Lola Sabau-Graziati ◽

Víctor Reglero ◽

Paul H. Connell ◽

Juana M. Rodrigo ◽

...

Keyword(s):

International Space Station ◽

Gamma Ray ◽

State Of The Art ◽

Space Station ◽

Upper Atmosphere ◽

International Space ◽

Severe Thunderstorms

Atmosphere-Space Interactions Monitor (ASIM) mission is an ESA pay load which will be installed in the Columbus module of the International Space Station (ISS). ASIM is optimized to the observation and monitoring of luminescent phenomena in the upper atmosphere, the so called Transient Luminous Event (TLEs) and Terrestrial Gamma Ray Flashes(TGFs). Both TLEs and TGFs have been discovered recently (past two decades) and opened a new field of research in high energetic phenomena in the atmosphere. We will review the capabilities of ASIM and how it will help researchers to gain deeper knowledge of TGFs, TLEs, their inter-relationship and how they are linked to severe thunderstorms and the phenomena of lightning.

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Simulation of Severe Thunderstorms in Conjugation of Westerly and Easterly on 31 March 2019 in Bangladesh

Journal of Engineering Science ◽

10.3329/jes.v12i3.57477 ◽

2022 ◽

Vol 12 (3) ◽

pp. 29-43

Author(s):

Samarendra Karmakar ◽

Mohan Kumar Das ◽

Md Quamrul Hassam ◽

Md Abdul Mannan

Keyword(s):

South Asian ◽

Wrf Model ◽

Horizontal Resolution ◽

Weather Research And Forecasting ◽

Atmospheric Conditions ◽

Microphysics Scheme ◽

Severe Thunderstorms ◽

Synoptic Conditions ◽

Pbl Scheme ◽

Single Moment

The diagnostic and prognostic studies of thunderstorms/squalls are very important to save live and loss of properties. The present study aims at diagnose the different tropospheric parameters, instability and synoptic conditions associated the severe thunderstorms with squalls, which occurred at different places in Bangladesh on 31 March 2019. For prognostic purposes, the severe thunderstorms occurred on 31 March 2019 have been numerically simulated. In this regard, the Weather Research and Forecasting (WRF) model is used to predict different atmospheric conditions associated with the severe storms. The study domain is selected for 9 km horizontal resolution, which almost covers the south Asian region. Numerical experiments have been conducted with the combination of WRF single-moment 6 class (WSM6) microphysics scheme with Yonsei University (YSU) PBL scheme in simulation of the squall events. Model simulated results are compared with the available observations. The observed values of CAPE at Kolkata both at 0000 and 1200 UTC were 2680.4 and 3039.9 J kg-1 respectively on 31 March 2019 and are found to be comparable with the simulated values. The area averaged actual rainfall for 24 hrs is found is 22.4 mm, which complies with the simulated rainfall of 20-25 mm for 24 hrs. Journal of Engineering Science 12(3), 2021, 29-43

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The Impact of the Storm Prediction Center's Convective Outlooks and Watches on Emergency Management Operational Planning

Journal of Operational Meteorology ◽

10.15191/nwajom.2021.0903 ◽

2021 ◽

pp. 36-46

Author(s):

Heather A. Cross ◽

Dennis Cavanaugh ◽

Christopher C. Buonanno ◽

Amy Hyman

Keyword(s):

Emergency Management ◽

Severe Weather ◽

Emergency Operations ◽

Risk Levels ◽

Severe Thunderstorms ◽

Emergency Managers ◽

Weather Events ◽

Storm Prediction ◽

Near Term ◽

The Impact

For many emergency managers (EMs) and National Weather Service (NWS) forecasters, Convective Outlooks issued by the Storm Prediction Center (SPC) influence the preparation for near-term severe weather events. However, research into how and when EMs utilize that information, and how it influences their emergency operations plan, is limited. Therefore, to better understand how SPC Convective Outlooks are used for severe weather planning, a survey was conducted of NWS core partners in the emergency management sector. The results show EMs prefer to wait until an Enhanced Risk for severe thunderstorms is issued to prepare for severe weather. In addition, the Day 2 Convective Outlook serves as the threshold for higher, value-based decision making. The survey was also used to analyze how the issuance of different risk levels in SPC Convective Outlooks impact emergency management preparedness compared to preparations conducted when a Convective Watch is issued.

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CHAOTIC GRAPH THEORY APPROACH FOR IDENTIFICATION OF CONVECTIVE AVAILABLE POTENTIAL ENERGY (CAPE) PATTERNS REQUIRED FOR THE GENESIS OF SEVERE THUNDERSTORMS

Advances in Complex Systems ◽

10.1142/s0219525907001215 ◽

2007 ◽

Vol 10 (03) ◽

pp. 413-422 ◽

Cited By ~ 8

Author(s):

SUTAPA CHAUDHURI

Keyword(s):

Graph Theory ◽

Potential Energy ◽

Deep Convection ◽

Convective Available Potential Energy ◽

Pressure Level ◽

Theory Approach ◽

Severe Thunderstorm ◽

Available Potential Energy ◽

Severe Thunderstorms ◽

Conditional Instability

Severe thunderstorms are a manifestation of deep convection. Conditional instability is known to be the mechanism by which thunderstorms are formed. The energy that drives conditional instability is convective available potential energy (CAPE), which is computed with radio sonde data at each pressure level. The purpose of the present paper is to identify the pattern or shape of CAPE required for the genesis of severe thunderstorms over Kolkata (22°32′N, 88°20′E) confined within the northeastern part (20°N to 24°N latitude, 85°E to 93°E longitude) of India. The method of chaotic graph theory is adopted for this purpose. Chaotic graphs of pressure levels and CAPE are formed for thunderstorm and non-thunderstorm days. Ranks of the adjacency matrices constituted with the union of chaotic graphs of pressure levels and CAPE are computed for thunderstorm and non-thunderstorm days. The results reveal that the rank of the adjacency matrix is maximum for non-thunderstorm days and a column with all zeros occurs very quickly on severe thunderstorms days. This indicates that CAPE loses connectivity with pressure levels very early on severe thunderstorm days, showing that for the genesis of severe thunderstorms over Kolkata short, and therefore broad, CAPE is preferred.

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On the Origin of Rotation Derived from Super Rapid Scan Satellite Imagery at the Cloud-Tops of Severe Deep Convection

Monthly Weather Review ◽

10.1175/mwr-d-20-0209.1 ◽

2021 ◽

Author(s):

Jason M. Apke ◽

John R. Mecikalski

Keyword(s):

Quality Control ◽

Numerical Model ◽

Flow Field ◽

Optical Flow ◽

Case Studies ◽

Model Simulation ◽

Deep Convection ◽

Vertical Wind Shear ◽

Future Research ◽

Severe Thunderstorms

AbstractSevere thunderstorms routinely exhibit adjacent maxima and minima in cloud-top vertical vorticity (CTV) downstream of overshooting tops within flow fields retrieved using sequences of fine-temporal resolution (1-min) geostationary operational environmental satellite (GOES)-R series imagery. Little is known about the origin of this so-called “CTV couplet” signature, and whether the signature is the result of flow field derivational artifacts. Thus, the CTV signature’s relevance to research and operations is currently ambiguous. Within this study, we explore the origin of near-cloud-top rotation using an idealized supercell numerical model simulation. Employing an advanced dense optical flow algorithm, image stereoscopy, and numerical model background wind approximations, the artifacts common with cloud-top flow field derivation are removed from two supercell case studies sampled by GOES-R imagers. It is demonstrated that the CTV couplet originates from tilted and converged horizontal vorticity that is baroclinically generated in the upper levels (above 10 km) immediately downstream of the overshooting top. This baroclinic generation would not be possible without a strong and sustained updraft, implying an indirect relationship to rotationally-maintained supercells. Furthermore, it is demonstrated that CTV couplets derived with optical flow algorithms originate from actual rotation within the storm anvils in the case studies explored here, though supercells with opaque above anvil cirrus plumes and strong anvil-level negative vertical wind shear may produce rotation signals as an artifact without quality control. Artifact identification and quality control is discussed further here for future research and operations use.

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