COSMO Priority Project ”Quantitative Precipitation Forecasts” Work in Task 1, Langen 8 March 2006 Katarzyna Starosta, Institute of Meteorology and Water Management, Poland

Used data and materials: 1. Bulletin of the national hydrological and meteorological service. (monthly) 2.Every day meteorological bulletin. 3.Every day LM model results (numerical data and maps with every 3 hour forecast, and cumulated precipitation forecast from 3h to 78h) 4.Every day precipitation data from 308 rain gauges stations. 5.Interpolated (bilinear interpolation) data from the model to rain gauges stations. 6.Results of monthly precipitation verification. 7.Difference between 24-precipitation sum in the rain gauges stations and model results.

The results of verification of 24-h accumulated precipitation from January 2004 to December 2005 are presented below. For precipitation we calculated indices from the contingency table for 24-h accumulated forecast data and data from 308 rain gauge stations for 3 day forecast range (1-day, 2-day, 3-day). For verification of precipitation thresholds 0.5, 1, 2.5, 5, 10, 20, 25, 30 mm were used. For each threshold the following scores were calculated: FBI (Frequency bias index), POD (Probability of detection of event), PON (Probability of detection of non-event) FAR (False alarm rate), TSS (True skill statistics), HSS (Heidke skill score), ETS (Equitable skill score). LOCATION OF RAIN GAUGE STATIONS 10 20 30 40 50 5 15 25 35 45

FREQUENCY BIAS INDEX, JANUARY - DECEMBER 2004 FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 0.5 1 1.5 2 2.5 3 FBI THRESHOLD 0.5 [mm] 4 5 6 7 8 I day II day THRESHOLD 10[mm] III day FBI MONTHS

INDICES FOR 24h ACCUMULATED PRECIPITATION, JANUARY - DECEMBER 2004 FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 20 40 60 80 100 % THRESHOLD 0.5 [ mm] 80 100 % POD PON FAR HSS ETS JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 20 40 60 % MONTHS

INDICES FOR 24h ACCUMULATED PRECIPITATION, JANUARY - DECEMBER 2004 FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 20 40 60 80 100 % THRESHOLD 10.0 [ mm] I day 80 100 % POD PON FAR HSS ETS JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 20 40 60 II day % III day MONTHS

2004 April 3 (for 6), 6,7,8 May 7,8 June 7(for 10), 19,20 July 6-9, 27-29 August 12 ,13,14, 17,18(Szczecin) , 19-22 September 14,15,16 October November 4,5, 18 December

2005 January February 12,15 March 6,18 April 8,9,10, 20 May 3,4, 18,19, (23) June (8),9,10,15,16 July 7(Plock),9,10,26, 31 August 3,4,7,8 15,16,23,24 September 11,13,16,17 October November December 6,7,15,16,20,30

3 h 6 h 9 h 12 h Three forecast for the same day 23.08.05 Start of forecast: 21.08.05 00h 22.08.05 00h 23.08. 05 00h 3 h 6 h 9 h 12 h

15 h 18 h 21 h 24 h Three forecast for the same day 23.08.05 Start of forecast: 21.08.05 00h 22.08.05 00h 23.08. 05 00h 15 h 18 h 21 h 24 h

03 h 06 h Three forecast for the same day 24.08.05 Start of forecast: 21.08.05 00h 22.08.05 00h 23.08. 05 00h 03 h 06 h