Embedded within a weak steering current, it drifted to the northwest, and strengthened into Tropical Storm Isidore on September 18 near Jamaica. After grazing the island, it quickly intensified to a hurricane late on September 19 while south of Cuba. Isidore's maximum sustained winds reached near the Isle of Youth, and weakened slightly to an hurricane as it made landfall on Cabo Frances late on September 20. The hurricane crossed the island, then slowed as it moved westward across the Gulf of Mexico. Favorable conditions aloft with warm water temperatures allowed Isidore to quickly intensify to a peak of winds on September 21.