Usefulness and skill of station-derived predictors in forecasting storm occurrence and intensity

The Friuli Venezia Giulia region (northeastern Italy, hereafter FVG) is an area subject to frequent storm occurrences. The Regional Meteorological Observatory of Friuli Venezia Giulia (hereafter OSMER) manages a spatially dense network of meteorological stations, that provides measures with a maximum sampling frequency of 5 min. Moreover there is a C-band Doppler Polarimetric Radar that provides complete scans every 5 min during the convective events, or every 30 min otherwise. This work aims to characterize the skill of one or more predictors, that are the measurements of such meteorological stations (e.g. wind magnitude, equivalent potential temperature, moisture transport, etc.), when forecasting the highest radar Vertical Maximum Intensity reflectivity (hereafter VMI) measured on the plain and coast of FVG, used as signature of the storm occurrence and intensity.The dataset here used consists of 5-minutes maximum time-resolution VMI (used to define each event) on plain and coast areas of FVG, and 5-minutes time-resolution observations derived from 31 stations, considering a time-lag varying from 30 min to 3 h before the VMI observation. The VMI dataset spans over a period 11 years long (2000–2010) and consists of about 100,000 cases. Both a multiregression study to forecast the maximum VMI value and a classification study of the occurrence of VMI events exceeding certain thresholds have been performed.

► Radar VMI forecast
► Linear multiregression
► Linear discriminant analysis