Verification of rainfall forecasts from the Australian Bureau of Meteorology's Global Assimilation and Prognosis (GASP) system
School of Earth Sciences, University of Melbourne, Parkville, Victoria, Australia
Asutralian Bureau of Meteorology, Victorian Regional Office, Melbourne, Victoria, Australia
The Australian Bureau of Meteorology (BOM) implemented a high resolution version of its Global Assimilation and Prognosis System (GASP) on 22 March 1994. A dataset comprising rainfall forecasts for three Australian cities from the first available 100 days of GASP quantitative precipitation forecasts was constructed and verified against observed rainfall. Several measures of skill were used to evaluate GASP predictions. These were comparisons with persistence, climatology, 'model output statistics', 'perfect prog' and BOM Regional Forecast Centre (RFC) predictions.
GASP generally provided useful guidance up to four days in advance. However, it poorly forecast rain events associated with stream weather and post-frontal cold air, while precipitation accompanying fronts was indicated with considerable reliability.
Citation:
Noone, D., and H. Stern, 1995:
Verifications of rainfall from the Australian Bureau of Meteorology's Global
Assimilation and Prognosis (GASP) system.
Australian Meteorological Magazine, 44, 275-286.