In early June 1989, a tropical wave emerged from the west coast of Africa and traversed the Atlantic Ocean, eventually crossing into the eastern North Pacific.
Initially, several centers of circulation were associated with the system.
Continuing organize, the storm is estimated to have attained tropical depression status at 0000 UTC on June 18.
The depression was broad and lacked substantial thunderstorm activity.
However, it did have respectable outflow and banding.
It moved towards the west and intensified into a tropical storm at 0000 UTC on June 20, 48 hours after being classified.

Upon being named, Cosme meandered and remained nearly stationary as it continued to intensify.
It became a hurricane midday UTC on June 21; this upgrade was delayed in real time.
At this time, the hurricane accelerated towards the north.
As the cyclone approached the coast of Mexico, it reached maximum sustained winds of 85 mph (140 km/h) and a minimum barometric pressure of 979 millibars.

During the night of June 21, Cosme made landfall just east of Acapulco.
It moved inland and quickly deteriorated, weakening into a tropical storm shortly after coming ashore.
It trekked northward through eastern Mexico and further diminished into a tropical depression before becoming indistinguishable south of Brownsville, Texas on June 23.
Tropical Storm Allison's development in the Gulf of Mexico was partially related to residual conditions from Cosme's remnants.
In early June 1989, a tropical wave emerged from the west coast of Africa and traversed the Atlantic Ocean, eventually crossing into the eastern North Pacific. Initially, several centers of circulation were associated with the system. Continuing organize, the storm is estimated to have attained tropical depression status at 0000 UTC on June 18. The depression was broad and lacked substantial thunderstorm activity. However, it did have respectable outflow and banding. It moved towards the west and intensified into a tropical storm at 0000 UTC on June 20, 48 hours after being classified.
Upon being named, Cosme meandered and remained nearly stationary as it continued to intensify. It became a hurricane midday UTC on June 21; this upgrade was delayed in real time. At this time, the hurricane accelerated towards the north. As the cyclone approached the coast of Mexico, it reached maximum sustained winds of 85 mph (140 km/h) and a minimum barometric pressure of 979 millibars.
During the night of June 21, Cosme made landfall just east of Acapulco. It moved inland and quickly deteriorated, weakening into a tropical storm shortly after coming ashore. It trekked northward through eastern Mexico and further diminished into a tropical depression before becoming indistinguishable south of Brownsville, Texas on June 23. Tropical Storm Allison's development in the Gulf of Mexico was partially related to residual conditions from Cosme's remnants.
Hurricane Cosme (1989)