Abstract:

Based on the numerical forecast precipitation products from the weather online, the Japan facsimile chart, the United States global forecast system (GFS) and the T639 during August of 2010 to July of 2011, precipitation forecast products in Yingkou region were tested by a statistic method and a synoptic method in terms of forecast time validity, forecast precipitation intensity grades and influence system and so on in order to improve the accuracy of forecast. The results show that the accuracy rates of various numerical forecast products decrease generally with the time, while the forecast effect from the weather online and the GFS is good and stable, then from the Japan facsimile chart. The stability of the T639 is the worst among all methods. The simulated value from the various numerical forecast products is lower than the observed value, especially for the heavy rain forecast with poor stability and small precipitation grade. There is obviously false alarm and failed forecast for light rain. There is failed forecast for the upper trough and cold vortex among all numerical forecast products, and most are in the light rain magnitude.

Key words: Precipitation products from numerical prediction, Inspection, Forecast index