Category: Hailstorm

Study of the total lightning activity in a hailstorm

Study of the total lightning activity in a hailstorm

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Joan Montanyàa, Corresponding Author Contact Information, E-mail The Corresponding Author, Serge Soulab, Nicolau Pinedac, Oscar van der Veldeb, Pere Clapersa, Glòria Solàa, Joan Bechc and D. Romeroa

 

 

aElectrical Engineering Department, Technological University of Catalonia (UPC), Colon, 1, Terrassa (Barcelona) 08222, Spain

bLaboratoire d’Aérologie, UMR 5560 CNRS/UPS, OMP, Université de Toulouse, Toulouse, France

cMeteorological Service of Catalonia, Barcelona, Spain

Received 30 November 2007; 

accepted 13 June 2008. 

Available online 5 September 2008.

 

Abstract

A thunderstorm that developed over northeastern Spain on 16 June 2006 is analyzed. This severe thunderstorm produced hailstones as large as 40 mm and had a lifetime of 3 h and 30 min. Radar cross-sections show strong vertical development with cloud echo tops reaching an altitude of 13 km. The specific characteristics of the lightning activity of this storm were: (i) a large amount (81%) of negative cloud-to-ground (−CG) flashes with very low peak currents (< 10 kA in absolute value), (ii) a very large proportion of intra-cloud (IC) flashes with an IC/CG ratio reaching about 400, (iii) a large number of “short” IC flashes (with only 1-VHF source according to SAFIR detection), (iv) a large increase of the −CG flash rate and of the CG proportion near the end of the storm. The rate of −CG flashes with a low peak current were observed to evolve similarly to the rates of IC flashes. Most of them have been assumed to be IC flashes misclassified by the Spanish Lightning Detection Network (SLDN). They have been filtered as it is usually done for misclassified +CG flashes. After this filtering, CG flash rates remained very low (< 1 min− 1) with +CG flashes sometimes dominant. All the particular lightning activity characteristics similar to those observed in the Severe Thunderstorm Electrification and Precipitation Study (STEPS) campaigns support the hypothesis that this thunderstorm could have had an inverted-polarity or complex charge structure. The maximum IC flash rate (67 min− 1) peaked 24 min before the presence of reflectivity higher than 60 dBZ. The IC activity abruptly decreased during the period when reflectivity was dramatically increasing. The time of maximum reflectivity observed by radar was consistent with the times of reported hail at the ground….

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Forecasting thunderstorms and hailstorms by means of temperature and dew-point anomalies on a time-section chart

Summary Vertical time-section charts for temperature and dew-point anomalies have been plotted. The temperature anomaly decreasing upwards give convection according to Byers and Braham [1]2). The coincidence of temperature anomalies with central minimum and of dew-point anomalies with central maximum, or of upward decreasing trend in temperature anomalies and upward increasing trend in dewpoint anomalies, correspond to the convection associated with greater moisture influx, thus representing the case of a thunderstorm…

Forecasting thunderstorms and hailstorms by means of temperature and dew-point anomalies on a time-section chart

Journal Pure and Applied Geophysics
Publisher Birkhäuser Basel
ISSN 0033-4553 (Print) 1420-9136 (Online)
Issue Volume 89, Number 1 / December, 1971
DOI 10.1007/BF00875214
Pages 178-182
Subject Collection Earth and Environmental Science
SpringerLink Date Wednesday, December 29, 2004

Lalit Kumar and H. S. Rathor1

(1)  Department of Geophysics, Banaras Hindu University, Varanasi-5, U.P., India

Received: 26 October 1970  

Summary  Vertical time-section charts for temperature and dew-point anomalies have been plotted. The temperature anomaly decreasing upwards give convection according to Byers and Braham [1]2). The coincidence of temperature anomalies with central minimum and of dew-point anomalies with central maximum, or of upward decreasing trend in temperature anomalies and upward increasing trend in dewpoint anomalies, correspond to the convection associated with greater moisture influx, thus representing the case of a thunderstorm. The mentioned anomalies have been found to occur in such a way that cells with central maximum are followed by those with central minimum, and vice versa. Thus simultaneous occurrences of upward decreasing anomalies in temperature, i.e. occurrence of cells with central minimum of temperature, and upward increasing anomalies in dew-point, i.e. occurrence of cells with central maximum, can be observed at any station, hence the occurrences of thunderstorms at that station can be predicted. Moreover, the two kinds of anomalies can give the idea (along with that of convection, of coming of the synoptic situation having dry air aloft and moist air below, which is the ideal condition) for the occurrence of a hailstorm (Fawbush andMiller [2]).

http://www.springerlink.com/content/v22786n741151654/

Types of thunderstorms – the supercell

 

  Supercell
 
Supercells are the most powerful of all storms and have updrafts that rotate
 
Supercells produce the most intense tornadoes, largest hailstones, extremely heavy rainfall and strongest straight line winds

 Strong enough rotation throughout a supercell upraft can lead to tornadoes.