The Czech Hydrometeorological Institute's severe storm nowcasting system

Radar-based hail detection

“…The radar data provide information with high temporal and spatial resolution. There are two C-band single-polarisation radars that have been operating in Czechia since 2000 (Novak, 2007). Single-polarisation weather radar cannot distinguish among different types of hydrometeors, but some features in the reflectivity data, including high reflectivity occurrences at specific levels, can represent physical processes that are related to hail growth.…”

New Methods of Flash Flood Forecasting in the Czech Republic

“…-COTREC is radar echo extrapolation technique, which uses two consecutive (10-minute or 5-minute step) maximum reflectivity image of Czech Weather Radar Network (CZRAD) for calculation of motion vector fields; the QPFs are being obtained by calculation of the "nowcast" PseudoCAPPI 2km reflectivity in the area of CZRAD domain [3]. -COTREC ext is COTREC applied to the CZRAD extended domain that include radar data from neighboring countries [4].…”

Operational Application of Optical Flow Techniques to Radar-Based Rainfall Nowcasting

“…In fact, in typical implementation of TREC, the block size and resolution are pre-determined, making it impractical to track motion of variable scales. To address the issues, there emerged several alternative approaches, some are also correlation-based such as "COTREC" in [30] and "MTREC" in [31] while others adopt variational optical flow technique, to be described in the following paragraphs.…”