DAILY QUANTITATIVE PRECIPITATION FORECAST BY AN ANALOG TECHNIQUE - OPTIMIZATION OF THE ANALOGY CRITERION

For quantitative precipitation forecasting, model output statistics (M OS) are very useful. We have tried to improve a MOS based on a selecti on of analogue and past situations. Our study concerns the analogue cr iterion: its form, what variables to introduce (predictors), among tho se available (700 and 1000 hPa geopotential fields) and their format ( principal components or PCs, gridded data, etc.). Initially, an Euclid ean distance using predictors as PCs was used. Its replacement by the Teweles-Wobus score, with predictors known in grid format, gave signif icantly improved results. ((C) Academie des sciences / Elsevier, Paris .)