At 18Z, the Gaston system was located near 17.1N 52.3W and convection was starting to wrap around the center. Although the system is still quite weak, the developmental environment is becoming a little more favorable as shear begins to decline.

Models offer a variety of solutions, and because of that uncertainty, the eventual strength and track is still uncertain - except near term motion toward the west seems like a certainty. SHIP and the BAM suite develop the system into a hurricane just south of Puerto Rico in three days. The 05/12Z GFDL takes the system well to the south of Hispaniola as a tropical storm while the 05/18Z UKMET brings the system close to southern Jamaica. Finally, the 05/12Z HWRF take the system along the south coast of Puerto Rico, then through the Mona Passage to just off the north coast of the Dominican Republic as a tropical storm in 5 days.
ED