Comparative Analysis of Rain and Snow Weather with Close Interval Time and the Forecast Focus

Aiming at rain and snow weather process with short interval time in February of 2009,the comparison analysis was made from the circulation situation,affecting system,the lower-layer temperature stratification characteristics and the application of numerical forecast products.To determine winter rainfall pattern is rain or snow,in addition to a detailed analysis of the vertical distribution of temperature,the invasion time of cold air and the decline rate of temperature should be accurately forecast.Particularly,the the high-low-temperature threshold matching the critical line of rain and snow is the key point of forecasting rain and snow.Different high-altitude surface temperature before precipitation was main causes of different precipitation prosperities.