Continued strengthening ensued as Calvin curved from its initial westward track northward, and was upgraded to a hurricane on July 6.

Calvin rapidly weakened after landfall, and was a tropical storm when it reemerged into the Pacific Ocean on early on July 8.

As Calvin made a second Mexican landfall near the southern tip of Baja California peninsula late on July 8, it weakened to a tropical depression.

Heavy seas near Lázaro Cárdenas in western Mexico caused a ship, which contained sulfuric acid, to leak.

[2] Hurricane Calvin originated from an area of disturbed weather, characterized with scattered deep convection, that developed south of the Gulf of Tehuantepec on the second day of July.

Despite the lack of concentrated convection, the system was classified using the Dvorak technique, a tool used to measure a tropical cyclone's intensity.

However, during the morning hours of July 4, banding features formed on the southern semicircle of the disturbance, and it is estimated that the system attained tropical depression status at 1200 UTC while centered approximately 315 mi (505 km) southeast of Acapulco.

[4] Intensifying within a favorable atmospheric environment, the depression attained tropical storm status at 0000 UTC on July 5, receiving the name Calvin.

[3] A period of rapid intensification ensued shortly thereafter, and banding-type eye formed in association with Calvin later that day.

[7] Around this time, Hurricane Calvin was embedded within the northeastern portion of a large, monsoon-like deep-layer-mean, which stretched from the Intertropical Convergence Zone to the southwest Mexican coastline.

Furthermore, Calvin was a fairly large cyclone as surface winds of 35 mph (55 km/h) were reported over 200 mi (320 km) from the storm's center.

[6] At 1200 UTC on July 7, Calvin reached its peak intensity of 100 mph (160 km/h) and a minimum barometric pressure of 966 mbar (28.5 inHg).

[6] After weakening greatly due to land interaction with the mountainous terrain of Mexico, Calvin reentered the Pacific at 0000 UTC on July 8.

[6] Calvin weakened to a tropical depression late on July 8 as it made a second landfall along the extreme southern Baja California peninsula.

After crossing the coast, Tropical Depression Calvin dissipated the next day atop of cold sea surface temperatures.

[1] Prior to making landfall, a tropical storm warning and hurricane watch was issued for a portion of the Mexican coast on July 6.

[26] Inland, 16 persons were killed in the states of Mexico and San Luis Potosí, where heavy rains caused mudslides across higher elevations.

[32] Prior to affecting Guerrero, Hurricane Calvin was responsible for heavy rains and widespread flooding across Oaxaca.

In addition, travel from the isthmus was cut off due to mudslides that blocked portions of the Pan-American Highway.

The cities of Tehuantepec, Salina Cruz, Juchtianm, and Tuxtepec were flooded due to extended periods of torrential rains.

[1] Prior to landfall, the storm's outer rainbands began to spread over the region, resulting in flooding.

[34] A mudslide killed a man and a son[28][35] one person was reported dead after trying to save his boat from sinking.

In addition, 13 boats sunk due to high waves, which impeded all maritime activity along the coast.

The Instituto Oceanografico del Pacifico in Manzanillo reported a minimum central pressure of 994 mbar (29.4 inHg) in addition to gale-force winds.

[40] Although initially not expected to pose a threat to the chemicals on the ship Betula,[12] rough seas near Lázaro Cárdenas caused all 4,000 t (4,000,000 kg) of sulfuric acid to leak aboard the previously beached cargo tanker.

[20][27] Shortly after making its first landfall, the storm moved over a sparsely populated portion of Mexico near Puerto Vallarta.

However, further details about impact could not be obtained due to lack of communication, though some places sustained waist-high water.

They distributed around 11,000 blankets, 5,000 mattresses, 8,000 sacks of sand to reinforce dikes, and an additional 20 t (20,000 kg) of food, medicine, and clothes.

[46] Then-Mexican President Carlos Salinas de Gortari announced that the government would channel $11.4 million to three of the hardest-hit states.