THE LIGHTNING JUMP, AN

OPERATIONAL TOOL TO

FORECAST SEVERE WEATHER IN

CATALONIA, AND THE CAMPAING

"PICK UP THE STONE".

Farnell C. and Rigo T.

Servei Meteorològic de Catalunya (SMC).

carme.farnell@gencat.cat

www.meteo.cat

Where is Catalonia?

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Introduction

The LJ is a sudden increase of the total number of lightning rate (Williams

et al. 1999).

It is a consequence of strong updraft which favours the crash between ice

particles and a higher separation of the charge (Williams, 2001).

This tool is used for forecasting SEVERE WEATHER

Hail > 2 cm

Tornados / Waterspout

Downburst

Strong wind gust

Definition

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Font:

Introduction

Examples of Severe Weather recorded in Catalonia

Font: Jesús Coines

Font: Farnell C

Font: O. Rodríguez

Font: F.F: Teixidó

Font: F,F.Teixidó

Before the algorithm …

The LLS of the SMC

operates in both

frequencies, LF and

VHF, allowing the

detection of IC and

CG flashes.

Lightning Location System (LLS)

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Few networks in

Europe have this

capability (IC detection)

The LLS is composed

of 4 detectors, with an

efficiency of > 90%

over the territory

Before the algorithm …

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Detecting two types of flashes: intra-cloud and cloud-to-cloud

VHF

LF

Before the algorithm …

Multiplicity

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CG

IC LJ wM = N1 (with multiplicity)

LJ woM = N2 (without multiplicity)

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Convection starts

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Separation of electrical charge

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Warning is triggered

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Conceptual Outline

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Severe phenomena

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Increase updraft. Increase electrical charge.

Lightning Jump - Algorithm

The tool is an adaptation of research algorithms developed in the USA

(Schultz, Gatlin…) with some different requirements .

We have not considered the threshold to distinguish between severe or

ordinary thunderstorms.

The original algorithm takes into account Radar + Lightning Data.

We only consider Lightning Data. Why?

The Lightning Data allow us to execute the algorithm every minute.

In contrast, we obtain Radar Data every 6 minutes.

Adjustment

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Lightning Jump - Algorithm

How to detect LJ warning?

For each minute, we analyze each thunderstorms

We transform the flashes to points on the map

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Algorithm

How to detect LJ warning?

The points are joined between them

Its center point characterizes the thunderstorm through :

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Coordinates Hour Flashes number Size

The Lightning Jump: a tool for forecasting sever weather

How to detect a severe storm?

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Once we have the point which represents the thunderstorms

t

We see the thunderstorm's track during the last 12 minutes

REQUIRIMENTS

And its evolution of electrical activity

To make the algorithm work, it is necessary to accomplish: - Continuity in space - Continuity in time during the 12 minutes

Algorithm

This period of 12 minutes is divided into periods of 2 minutes. Then, we

calculate the average of Total Lightning (TL) of each period.

How to detect LJ warning?

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Algorithm

The averages are subtracted sequentially between them

How to detect LJ warning?

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The standard deviation of all DFRDT is calculated

Characteristics

This tool needs the TL (intra-cloud (IC) + cloud-to-ground (CG)) to work well.

Total Lightning (TL)

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CLOUD TO GROUND TOTAL LIGHTNING

Lightning Only CG

CG+IC (TL)

Nº alerts (2006 – 2015)

69

5,262

Characteristics

The number of LJ taking into

account multiplicity is higher

than not considering the

multiplicity (only the first node

of IC).

Multiplicity

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Type Of LJ

Without Multiplicity

With Multiplicity

Nº alerts (2016 )

104

426

Nº alerts (2017)

101 326

With Multiplicity Without Multiplicity

2018

748 197 No. of LJ

How it works operationally

Application to operative work

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Results and validation 2018

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SKILLS

SCORES

LEAD TIME

PC: Percentage of correct predictions FAR: False Alarms

POD 87,93

FAR 1,92

BIAIX 89,66POD 87,93

FAR 1,92

BIAIX 89,66POD 87,93

FAR 1,92

BIAIX 89,66

Results – Operative 2018

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LT 32 min

LT 88 min

Vilademuls

Llagostera

2018/01/07

Results – Operative 2018 LT 30 – 120 min.

Results – Operative 2018

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“Picking Up The Stone”

Campaing “Picking Up The Stone” 2017 & 2018

Agreement with County Councils of Lleida and Girona

Agreement with l’ADV Terres de Ponent

Agreement with Leon Universtity (ULE).

Preparation to external level

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Exemple de granímetre

Part de l’anàlisi d’un granímetre.

Campaing “Picking Up The Stone” 2017 & 2018

Preparation of the web meteo.cat

Radio and social media advertising.

Preparation on:

whatsapp, 667051592

Manager of photos,

Social media:

– twitter #meteocatpedra

– Instagram

– Email: xarxes@meteo.cat

Preparation to internal level

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Campaing “Picking Up The Stone” 2018

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Campaing “Picking Up The Stone” 2018

Spatial Distribution of the Observations

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Campaing “Picking Up The Stone” 2018

Monthly Distribution

No. Observations/month No. Warnings/month

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Campaing “Picking Up The Stone” 2018

Hourly Distribution

No. Observations/hour No. Warnings/hour

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NEW AIM !!!

Simulation of severe weather warning

Thank you for your attention