Tropical Storm Chantal moved rapidly through the Lesser Antilles and into the eastern Caribbean Sea as a strong tropical storm on July 09, but weakened rapidly, likely to an open tropical wave about 14 hours later, by the time it moved south of Puerto Rico during the early morning hours on Wed July 10th. Its very fast forward motion of nearly 30 mph and its encounter with mid-level dry air associated with the Saharan Air Layer had a negative effect on the rate of intensification of the storm and contributed to its quick demise.
NESDIS QPE 24-hr rainfall composite ending 12 UTC Wed Jul 10.
NESDIS Quantitative Precipitation Estimate (QPE) (image above) shows rainfall over Puerto Rico, the USVI, Hispaniola, and the Caribbean Sea associated with TS Chantal. This rainfall composite map can also give advanced warning on how much rainfall and the degree of impacts expected for locations along the projected track of the storm.
The 24-hr rainfall analysis from AHPS ending 12 UTC Wed July 10.
The Advanced Hydrology Prediction Service (AHPS) Precipitation analysis (image above) shows rainfall associated with TS Chantal over PR and the USVI. The NESDIS QPE image (first image) does a good job in depicting the rainfall pattern over PR, although it misses the small rainfall maxima on the north coast likely due to the coarse resolution of the GOES-IR channel (currently 4km). The AHPS precipitation analysis also has input from other sensors such as radar and gauge data.
The Wide World of SPoRT 
Welcome to the SPoRT blog! Nice feedback on the NESDIS QPE product. Hopefully we can get this in AWIPS for you soon.
Thanks for the great post San Juan! Just curious…will you be able to validate upstream QPE values with any precipitation reports from the Lesser Antilles in a timely manner for your forecast purposes?