Yesterday lecture concerning the value of ensemble forecasting in COSMO model was conducted by Lars Wiegand from Deutscher Wetterdienst. Contrary to deterministic model outputs, ensemble products show various model scenarios (ensemble members) obtained from the different initial conditions (coming from 4 global models) and model physic pertubations. This kind of product finds its practical application in evaluating places where convection is likely to occur.

Participants at the Testbed in short-range forecasting are equipped with experimental 4-panel chart of COSMO-DE ensemble data concerning:
– maximum value of all ensemble members
– areas with particular values of any ensemble member
– fraction of members exceeding an established treshold
– deterministic forecast

On the image below today’s 15Z forecast of radar reflectivity indicate line of convective cells in north-central Poland. The greatest assurance concerns coastal areas while inland areas denote high uncertainty. Are they going to occur? We will see.