Albert Salvador123 *, Nicolau Pineda2, Joan Montanyà1, Glòria Solà3 and Oscar van der Velde1

*Corresponding author: asalvador_ext@meteo.cat

1 Technical University of Catalonia, Terrassa (Barcelona), Spain2 Meteorological Service of Catalonia, Barcelona, Spain

3 Fulgura S.L., Terrassa (Barcelona), Spain

EXPLORING THUNDERSTORM PATTERNS RELATED TO SEVERE WEATHER

WITH LIGHTNING MAPPING ARRAY DATA

It is welll-known that the use of lightning data, mixed withradar observations, is a useful indicator on the short-termforecasting of severe weather. The electrical activity ishighly related to the strength of the updraft os the storms,and a detailed analysis of the behavior of lightningthroughout the storm life-cycle can reveal some patternslinked to the severe weather hazard. In this study, wetake advantage of the large capabilities of the LightningMapping Array to analyze some classical patterns relatedto severity (e.g. IC/CG rate, positive anomalies, lightningjump).

2013/06/18

Furthermore, we analyzed also some less-known patterns(e.g. lightning holes, lightning bubbles) as well as changesin mean peak current, electric charge layer mean altitude,structures with inverted polarity, etc.; All in all, seeking toestablish which patterns can be good predictors of severeweather phenomena. The data used in this study comesform the first Lightning Mapping Array system deployed inEurope, installed in the Ebro’s River Delta in Catalonia (NEIberian Peninsula). Complementary data includes lightningfrom LINET, as well as weather data from theMeteorological Service of Catalonia.

This work has been carried on under the framework of the Industrial DoctoralProgramme, co-funded by the Autonomous Government of Catalonia(Generalitat de Catalunya), the Meteorological Service of Catalonia (ServeiMeteorològic de Catalunya), the Technical University of Catalonia (UniversitatPolitècnica de Catalunya - UPC) and Fulgura S.L.

ABSTRACT

2015/07/31 2015/08/31

Walnut sized hail badly damaged vineyard in Horta de Sant Joan.

FIG. Total Lightning evolution as seen by LINET.

FIG. Average height of the LMA sources. A decrease can beobserved during the hailshaft.

Hail damage in orchards (Mollerussa and Ivars d’Urgell)related to this episode.

Full path of the storm overlayed to the radar CAPPI in 1kmproduct at 17:42 UTC. Numbers correspond to hail diameter (cm)recorded by the hailpad network.

Phtographs of the crops affected by the hail after the storm in themunicipalities of Artesa de Lleida and Torres de Segre.

FIG. CG peak current evolution by LINET. Higher negative peakcurrents are collocated with the hailshaft. It may indicate aregular charge layer structure.

FIG. Multipanel display of a lightning flash detected by the LMAbetween 15:00 and 15:10 UTC. The black squares indicate thelocation and time of the beginning of each flash, and each veryhigh frequency source is colored with time. Lightning hole iscreated by an intense updraft, and that produce that inside thisregion we find unfavorable conditions for charge separation, andconsequently, lightning activity. This makes that hail particles arecoated with liquid water, which can produce, moments later, anincrease in the separation of charges.

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15:54 UTC 16:00 UTC 16:06 UTC 16:12 UTC 16:18 UTC

FIG. CG Positive anomaly associatedto the haishaft (CG peak current byLINET). It mayindicate an invertedcharge structure at these moment.

BOW-ECHO signature in theRADAR MAX producte at 14:00 UTC

FIG. Total lightning from LMA. A step increase precedes thehailshaft.

FIG. Multipaneldisplay of a lightning flash detected by the LMA between 13:15 and 13:20 UTC. VHF sources are colored with time and black squares correspond to initiation points, mainly located between 4-8 km.

9th European Conference on Severe Storms – ECSS 2017Pula, Croatia18 – 22 September 2017

LightningJump

FIG. Evolution of the vertical structure of the storm. Time-heightLMA source density plot (pink-yellow-green color scheme). RadarECHO TOPS product (TOP-12 red dashed and TOP-35 red line).Black bar lines indicate the CG flash rate in a 10-min time stamp.In blue, environmental temperature from vertical soundingprofiles (-10ºC, -40ºC and tropopause heights in km).

FIG. See legend in FIG. of 2013/06/18 FIG EVO. See legend in FIG. of 2013/06/18

Radar MAX product (and cross sections) showing the evolution ofthe storm during the hailshaft, ending in a bow-echo pattern.