|Description:||Gustav originated from an area of low pressure that had entered the southeastern Caribbean during the night of Saturday, August 23rd. Initially this low pressure center paralleled the northern coast of Venezuela as it moved in a general westward direction. The Tropical Rainfall Measuring Mission satellite (also known as TRMM) has been in service for over 10 years now, and continues to provide valuable images and information on tropical cyclones around the Tropics, using a combination of passive microwave, and active radar sensors. TRMM obtained this image of the area of showers and thundershowers associated with the low pressure.|
The image was taken at 16:46 UTC (12:46 pm EDT) 24 August 2008 and showed the horizontal pattern of rainfall from the showers and thundershowers associated with the low, while it was passing north of Venezuela in the southeastern Caribbean.
Rain rates in the center of the swath come from the TRMM Precipitation Radar (PR), and those in the outer swath from the TRMM Microwave Imager (TMI). The rain rates were overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS). TRMM showed that the area of low pressure was providing the focus for a broad area of shower activity generally composed of light, to moderate rain (blue and green areas, respectively), but with occasional areas of heavier rain (shown by the red areas). At this time, there was very little sign of cyclonic organization; most of the rain activity stretched in a straight line from west-southwest to east-northeast.