A satellite study of an active western disturbance

The study of an active western disturbance which moved across north Pakistan and Jammu & Kashmir in the month of November 1986 has, been presents. The importance of this study lies in the fact that this western disturbance, which had produced widespread precipitation With heavy falls It a number of places, has occurred in a relatively dry month, November, The main emphasis In this study is about the temperature distribution of the top of the clouds associated with the disturbance as seen frOI1l the infrared satellite pictures. An attempt has been made to understand the relation between the cloud top temperatures and the resultant rainfall. Comparison has been made between the rainfall estimate using Arkin's methodology and the actual average rainfall based on rain gauge stations. It IS seen that the threshold cloud top temperature (CIT) of 235° K to give an average rainfall estimate does not give good results in this particular spell. The reasons for this anomaly have been postulated.