Cloud Distributions As Indicators Of Tropical Storm Displacement

This is a preliminary report on use of satellite cloud imagery to forecast tropical cyclone movements. The spatial distribution of cloudiness implicitly indicates information about recent or ongoing processes in the atmosphere. Assuming that as with cloud distribution represents a set of initial conditions, it is reasonable to expect that forecast information can be extracted from these initial conditions. The problem with using satellite imagery as a self-contained forecast tool has been the difficulty in handling the data processing. The Man-computer Interactive Data Access System (McIDAS) is a flexible data management system the advantages of both human decision-making computer. With McIDAS it is relatively simple to assemble composites of images of storms with similar displacement characteristics. These composites reinforce the cloud or cloudless features common to the individual cases and mute randomly distributed clouds. Investigation of typhoon cloudiness in the Pacific indicate that there are different characteristic cloud distributions preceding storms that recurve and those that stay on westerly tracks. In particular there is a confluence of outflow cloudiness from the storm with the clouds of a mid-latitude frontal system in the case of low-latitude westward moving storms in the Philippine and South China Seas. Characteristic cloud patterns associated with other types of storm systems are also suggested by the analysis.