Indirect use of NWP in Nowcasting

Yong Wang, ZAMG, Austria

With introduction of very high model resolution, sophisticated micro-physics, very dense observations in space and time, advanced data assimilation technique and powerful computer, Numerical Weather Prediction (NWP) has been improved very much in the last years. However, NWP can not yet meet the requirement of nowcasting from point of view of operations. This is due to several reasons, for example the spin-up, the assimilation technology, interfacing moist physics and assimilation, and time critical requirement of nowcasting operations etc. In many nowcasting systems, efforts have been put to integrate or to use NWP indirectly.

In this talk a brief overview of the indirect use of NWP in curent nowcasting systems will be given. It will highlights the use of NWP in observation data analysis; in nowcast, including advection, initiation, growth and decay of convection; in blending; in description of the forecast and analysis uncertainties; and in the diagnosis. Some results and case studies with the indirect use of NWP in INCA (The Integrated Nowcasting through Comprehensive Analysis), the operational nowcasting system at Austrian weather services ZAMG, will be shown. Results of comparison between INCA (use of NWP) and a nowcasting system VERA (no NWP) will be introduced for discussions in the workshop.