| The North-eastern part of Italy is known to be one of the most rainy regions
in Europe. In this paper three extreme events are analysed, using a
multi-sensor observing system including a weather radar and a dense
telemetric network of surface stations, recording precipitation, wind,
temperature and relative humidity. The cases examined comprise two long
lasting rainfall events impacting two distinct areas, and a vigorous
hail-producing thunderstorm event over the plains. In all cases,
inter-comparison between remotely sensed and surface observations, including
estimates and measures of precipitation and wind, helps to better understand
the behaviour of the atmosphere, thus supporting operational fore- and
now-casting.
In the case of widespread precipitation, a relation is suggested between the
wind speed and direction at medium/low levels with the location of the
maximum precipitation relative to the mountains. This reflects the dynamical
interaction between the mountain barrier and the atmospheric flux impinging
upon it. This flux can be estimated by the automatic weather station of Mt. Cesen,
a focal point for a now-casting of the rain in the Veneto Region.
Analysis of strong thunderstorm activity makes extensive use of radar data.
In the examined case the interaction of a sea breeze-like circulation with a
mesoscale trough gave rise to a distinct convergence line that triggered a
severe and long-lived hail-producing multi-cell thunderstorm. The hail was
successfully detected by the radar's hail detection algorithm. |