Nowcasting of hailstorms by the COSMO NWP model

0461312 - ÚFA 2017 GB eng A - Abstract
Sokol, Zbyněk - Pešice, Petr
Nowcasting of hailstorms by the COSMO NWP model.
ISDA 2015: The 5th Annual International Symposium on Data Assimilation. Reading: University of Reading, Data Assimilation Research Centre, 2016.
[International Symposium on Data Assimilation (ISDA) /5th/. 18.07.2016-22.07.2016, Reading]
Institutional support: RVO:68378289
Keywords : nowcasting * COSMO NWP model * hailstorm
Subject RIV: DG - Athmosphere Sciences, Meteorology
http://www.isda2016.net/abstracts/posters/SokolNowcastingof.html

The contribution deals with the evaluation of the possibility of using the current numerical models for nowcasting of large hail (diameter ≥ 2.5 cm). We apply the COSMO NWP model with a two moment cloud microphysics with six hydrometeors including hail. The model is run at a horizontal resolution of 1.1 km and with the assimilation of radar reflectivity. The model forecasts are evaluated for several events with large hail determined by direct observations and derived using a recognition algorithm based on radar and sounding data. The accuracy of model forecasts was evaluated subjectively by eye, by Fractions Skill Score and by bias. Distances between locations of forecasted and observed hail were also analysed and evaluated. We will demonstrate that (i) forecasts up to 90 minutes brings additional information, which can be used to improve nowcasting of hailstorms, however for longer lead times the usefulness of model forecasts is problematic because of large errors and significant underestimation of forecasted hail, (ii) when the model forecasts large hail then there is a 50% chance that large hail will be observed within approximately 30 km.
Permanent Link: http://hdl.handle.net/11104/0260934