A Study of In-Cloud and Cloud-to-Ground Lightning in Tornado-Bearing Supercells in the Midwest

meatcologneInternet και Εφαρμογές Web

3 Νοε 2013 (πριν από 4 χρόνια και 8 μήνες)

80 εμφανίσεις

A Study of In
Cloud and

Ground Lightning in
Bearing Supercells in
the Midwest

Ben Herzog and Patrick S. Market

Dept. of Soil, Environmental & Atmospheric

University of Missouri

Columbia, MO


Knapp (1994) indicated a correlation
between cloud to ground (CG) lightning
flash frequency and the time of tornado


To verify Knapp’s (1994) work

To determine if identifying CG as well as in
cloud (IC) lightning flash frequency trends
could be used as an effective forecasting
tool to determine tornado touchdown.


Find tornadic thunderstorms

Storm Prediction Center storm reports

Verify tornadoes from the National Climatic Data

Obtain Data

March 2007

June 2007


Appalachian Mountains

Radar data from National Climatic Data Center

Lightning data from Vaisala, Inc

Methodology (cont.)

Break each storm into 5 minute periods to identify
flash trends

Start 60 minutes before first touchdown

Create spread sheets on each storm containing:

Total number of flashes per five minutes

Number of cloud to ground (CG) flashes per five minutes

Number of in cloud (IC) flashes per five minutes

Number of negative CG (CGN) flashes per five minutes

Number of positive CG (CGP) flashes per five minutes

Create a spread sheet containing all data from every


30 total storms analyzed

26092 total flashes analyzed

Some five minute spans had 0 flashes

Some five minute spans had over 300 flashes

53.4% of flashes were CG

89.7% of CG flashes were negative

10.3% of CG flashes were positive

46.6% of flashes were IC


Total Flashes


CG Flashes


IC Flashes


Negative CG Flashes


Positive CG Flashes


CGN Flashes

CGP Flashes


As suggested in the study by Knapp, there is
an identifiable pattern before tornado

Approximately 30 minutes before touchdown, there
is a maxima in flash frequency

Approximately 20 minutes before touchdown, there
is a minima in flash frequency

Approximately 10 minutes before touchdown, there
is another maxima in flash frequency

Approximately 5 minutes before touchdown, there
is another minima in flash frequency

Results (cont.)

The cloud to ground flashes show this pattern
especially well

The negative CG flashes also show this pattern

There are very few PCG flashes, so finding a
pattern in the flash trend may be of little utility.
However, at T
30 minutes before touchdown, we
found 0 total PCG flashes. At that same time, the
maximum number of NCG flashes occurred.

Results (cont.)

There is a pattern associated with the in cloud

There is a pattern of maxima and minima of
flashes in IC storms, but it is not nearly as
pronounced of a pattern as the CG flashes

Future Work

Obtain data on storms from different years
and see is the flash frequency pattern
matches 2007

Classify the storms into different categories

High precipitation supercells

Low precipitation supercells

Classic supercells

Squall lines

Mesoscale convective complexes


Knapp, David I., 1994: Using Cloud
Ground Lightning Data to

Identify Tornadic Thunderstorm Signatures and Nowcast

Severe Weather.
National Weather Digest,
19(2), 35