Virtual Workshop: Warm Conveyor Belts – a challenge to forecasting

On 28 February 2018, 57 mm of precipitation associated to a warm conveyor belt (WCB) fell within 21 h over South Korea. To investigate how the large-scale circulation influenced the microphysics of this intense precipitation event, we used radar measurements, snowflake photographs and radiosounding data from the International Collaborative Experiments for Pyeongchang 2018 Olympic and...

The dynamics of extratropical cyclones entails several important near-tropopause flow features, including sharp PV gradients and jet streaks, deep troughs and tropopause folds (positive PV anomalies) and the formation of large pole- and upward expanding ridges (negative PV anomalies). The evolution of these PV features are modified by non-conservative processes, such as cloud latent heating,...

Several case studies have tracked down large medium range NWP errors over the North Atlantic to minor errors in the representation of diabatic processes occurring in mesoscale structures. Different stages of error growth have been identified including: convective instability, the influence of divergent outflow on the tropopause position and interactions between disturbances at tropopause level...