关键词: 冰雹, 数值模式, 客观预报, 配料法

Abstract: The characteristic and variation of key physical quantities before and after historical hail processes under different synoptic background in Guangxi were analyzed based on severe weather observation and social reports in Guangxi, and reanalysis data at 6 h intervals with 0.125°×0.125° spatial resolution from the European Centre for Medium-Range Weather Forecasts (ECMWF) during 2012-2016. Forecasting indices of hail under frontal condition and non-frontal condition were found respectively, which mainly focused on instability energy, water vapor, triggering, vertical wind shear and the height of 0 ℃, -20 ℃ layer. Based on the ingredients-based methodology with dynamic forecast indices, objective forecasting equations for each condition were set up and applied from February to June during 2017-2018. The inspection showed that the equations were effective to hail forecasting in Guangxi. The forecast accuracy was higher under large-scale frontal condition than that under non-frontal condition. Although the hail area forecast had a high false alarm rate, but it mostly overlapped with thunderstorm gale region, so it was available for early warning.

Key words: hail, numerical model, objective forecasting, ingredients-based methodology