The nascent cyclone paralleled the southwestern coastline of Mexico, intensifying into Tropical Storm Adrian shortly after formation and attaining its peak as a Category 2 hurricane with winds of 100 mph (160 km/h) late on July 20.

As extremely deep convection festered within a band west of the disturbance's center, it is estimated the first tropical depression of the season formed around 06:00 UTC on June 18, located about 260 mi (420 km) southeast of Acapulco, Mexico.

[1] Moderate easterly wind shear that had been affecting the developing system began to relax almost immediately after formation,[2] allowing upper-level outflow to expand in most directions and the depression to intensify into Tropical Storm Adrian.

[4] Thus, in accordance with increasing satellite intensity estimates, Adrian was upgraded to the season's first hurricane by 00:00 UTC on June 20 while located about 485 mi (780 km) south-southeast of the southern tip of the Baja California Peninsula.

[10] Along the southern coastline of Chiapas, four people were swept away and drowned by a large wave, while farther inland in northwestern Durango, two men died and a five-year-old girl went missing after attempting to cross a river in a pick-up truck.