Investigating the typical
development of thunderstorms using
satellite, radar and lightning observations
U. Hamann, L. Nisi, A. Hering, L. Clementi , M. Gabella, U. Germann
MeteoSwiss, Locarno Monti, Switzerland
Results: Case study of an Convective System over the Po valley, 23th of July 2014
→ During the warm season severe thunderstorms regularly affect the Alpine region.
→ Heavy precipitation, wind gusts, and hail are a thread for aviation, traffic, agriculture and tourism.
→ Multi sensor measurements completes the observation of convection.
→ The typical development of thunderstorms can be used in Nowcasting algorithms.
→ Early warning of strong convection and precipitation contributes to saving lives and property.
1) Observation of convection with a multiple sensors
2) Investigation of the typical development of convective systems
3) Early identification of potentially severe thunderstorms
4) Prediction of the intensification/decay of convective cells
5) Forecast of speed and direction of the thunderstorm movement
Hering, A. M., Morel, C., Galli, G., Sénési, S., Ambrosetti, P., and Boscacci, M.
(2004), Nowcasting thunderstorms in the alpine region using a radar based
adaptive thresholding scheme. Proceedings, Third ERAD Conference, Visby,
Mecikalski, J. R., MacKenzie. W. M. Jr., König, M., and Muller, S. (2010), Cloud-
Top Properties of Growing Cumulus prior to Convective Initiation as Measured by
Meteosat Second Generation. Part II: Use of Visible Reflectance. J. Appl. Meteor.
Climatol., 49, 2544–2558
Morel, C., Sénési, S., Autones, F., and Labatut, L. (2000), The Rapid Developing
Thunderstorms (RDT) product of the nowcasting SAF. Prototyping activities and
quality assessment using GOES images. Proceedings, The 2000 Meteorological
Satellite Data Users' Conference, Eumetsat and CNR, Bologna, Italy, 698-705.
Nisi, L., Ambrosetti, P. and Clementi, L. (2014), Nowcasting severe convection in
the Alpine region: the COALITION approach. Q.J.R. Meteorol. Soc., 140: 1684–
1699. doi: 10.1002/qj.2249
Zinner, T., Mannstein, H., and Tafferner, A. (2008), Cb-TRAM: Tracking and
monitoring severe convection from onset over rapid development to mature phase
using multi-channel Meteosat-8 SEVIRI data. Meteorology and Atmospheric
Physics, Volume 101, Issue 3-4, pp. 191-210
Thanks to the entire staff of MeteoSwiss Locarno-Monti for their help. We
also would like to thank J. Mecikalski (University of Alabama) for the
SATCAST algorithm and M. König (EUMETSAT) for the scientific support.
Federal Office of Meteorology
and Climatology MeteoSwiss
Thunderstorm multi sensor observation Detection of Convection
SEVIRI channel combination suitable for the
detection of convective initiation (Mecikalski, 2010)
09UTC 12UTC 15UTC 18UTC 21UTC 24UTC 09UTC 12UTC 15UTC 18UTC 21UTC 24UTC
echo top 15dBZ
Conclusions & Outlook
This case study shows the
observation from radar and
satellite for the 23th of July
2014. The Swiss radars mea-
sures reflectivities in the order
of 35 to 40 dBZ with the highest
reflectivities from 15:00-
18:00UTC. In the HRoverview
some structure of the cloud top
are observed. The micro-
physics and fog RGBs show
the spread of the ice cloud
cover in redish colors. The
Airmass RGB indicates a cold
air mass approaching from the
West. The convection RGB
indicates active convection in
orange and the most active
parts in yellowish. On the right
hand side the channel differen-
ces proposed by Mecikalsky
are shown. The mean ± one
standard deviation is indicated
in color. All suggested channel
combination show a skill to
detect convection, some suffer
from noisy structure.
The objective of PyTROLL is to provide different free and
open source python modules for the reading, interpretation,
and writing of weather satellite data, among others from
MSG SEVIRI. PyTROLL supports geostationary and polar
platforms, it can read various data formats as hdf, grib,
HRIT, and netCDF. It is able to remap and interpolate
datasets on user defined projections and areas.
Furthermore, PyTROLL can produce standard RGB
composites and offers an interphase for user defined RGB
The PYTROLL software package is used extensively in this study. The
authors would like to thank DMI and SHMI for developing PYTROLL and
making it available.
Radar and satellite observations have been used to observe
the life cycle of an convective system. The lifting and
glaciation of the cloud top as well as an indication of the ice
particle size are illustrated by standard RGB images.
Additionally, the airmass RGB shows an cold airmass
approaching from the west. The satellite channel differences
proposed by Mecikalski (2010) show good skills to identify
convectively active regions.
In future, further parameters like lightning observation,
temporal changes of satellite radiances and brightness
temperatures, retrieved cloud physical products as well as
structural features of the cloud top are investigated for their
potential to identify convective systems as well as to predict
the development of the convective intensity. An additional
focus is on the forecast of the damage potential. The
combination of different predictors can be archived by
physical, statistical, or heuristic methods. A combination of
several methods is possible, too.