The 1989 Pacific hurricane season was a near normal season. It officially started on May 15, 1989, in the eastern Pacific, and on June 1, 1989, in the central Pacific, and lasted until November 30, 1989. These dates conventionally delimit the period of each year when most tropical cyclones form in the northeastern Pacific Ocean. A total of 18 storms and 9 hurricanes formed, which was near long-term averages. Four hurricanes reached major hurricane status (Category 3 or higher) on the Saffir–Simpson scale.
In June, Hurricane Cosme crossed over Mexico as a Category 1 hurricane and killed 30 people. In August, Hurricane Kiko made landfall on the Gulf of California side of the Baja California Peninsula as a Category 3 major hurricane, however, little damage resulted. In October, Hurricane Raymond peaked as a Category 4 major hurricane, the strongest storm of the season. The storm then weakened significantly before making landfall in the Baja California Peninsula as a tropical storm.
Seasonal summary
Overall, the season continued the general trend in the 1980s of near to above-average seasons in the East Pacific. Seventeen cyclones formed. Eight peaked at tropical storm strength. Nine systems became hurricanes, of which four were major hurricanes at Category 3 intensity or higher on the Saffir–Simpson scale. On August 28, three systems were active, one of a few times when there has been three tropical cyclones active simultaneously (Kiko, Lorena, and Manuel) in the east Pacific (west of 140°W). Despite the activity this season, no named storms formed in October. This was the second consecutive season this happened.
Systems
Tropical Storm Winona
During the second week of January, an upper-level trough located east of Hawaii created an area of divergence to its southeast, allowing an area of low pressure to develop alongside deep convection. Initially, the system was hampered by wind shear as it moved west-northwestward to the south of Hawaii; however, by January 11, the system was able to maintain convection over its center and was classified as a tropical depression. During post-storm analysis it was determined that the system became a tropical storm late on January 13. Its strengthening took place north of 20°N, a very unusual latitude for tropical cyclogenesis to occur in January. Meteorologists at the time struggled to forecast the storm as climatological forecast guidance (modeling based on previous cyclones), was not available due to the uniqueness of the storm. On January 15, the system crossed the International Date Line and entered the Western Pacific basin.
As a tropical depression, the storm brought heavy rains to portions of Hawaii, triggering flash flooding on a few islands. No damage resulted from the floods. After becoming a tropical storm, the system brushed Wake Island, bringing gusty winds and moderate rainfall. Several days later, the storm passed near the Mariana Islands and Guam, bringing tropical storm-force wind gusts and heavy rainfall. Minor damage resulted from Winona but there was no loss of life. Operationally, this system was not classified a tropical storm until January 16, when it was given the name Winona; thus it was not warned upon by the Central Pacific Hurricane Center during its early stages.
Tropical Storm Adolph
The first storm of the season developed out of a weak area of low pressure situated about 570 mi (925 km) south-southwest of Acapulco, Mexico. Tracking towards the west, the circulation briefly dissipated on May 30, before redeveloping the following day into Tropical Depression One-E. A ridge of high pressure north of the system steered it towards the west-northwest. By 0600 UTC on June 1, the National Hurricane Center (NHC) upgraded the depression to a tropical storm and gave it the name Adolph. Adolph continued to strengthen until early on June 2, at which time it reached its peak intensity with winds of 65 mph (100 km/h) and a minimum pressure of 994 mbar (hPa). Shortly after peaking, cool, dry air became entrained in the circulation, preventing further intensification. Early on June 3, Adolph weakened slightly due to unfavorable conditions. Later that day, Adolph briefly re-intensified. On June 4, strong wind shear displaced convection associated with the storm to the west of the center of circulation; this resulted in Adolph weakening to a tropical depression by 1800 UTC that day, and Adolph persisted until June 5 at which time it dissipated.
Hurricane Barbara
On June 10, an area of disturbed weather was located several hundred miles southwest of Acapulco, Mexico, and the system slowed to a westward drift. After gradually becoming better organized, the NHC estimated that the wave spawned Tropical Depression Two-E around 1800 UTC on June 15. Initially, the depression towards the northwest before a ridge of high pressure situated over Mexico caused the storm to turn towards the west-northwest. Based on improving satellite presentation, the NHC upgraded the depression to Tropical Storm Barbara. With favorable conditions, Barbara continued to intensify, attaining hurricane-status roughly 24 hours after being named. Six hours later, the storm reached its peak intensity with winds of 80 mph (130 km/h). Satellite images early on June 18 showed that cool, dry air was becoming entrained into the northern inflow of the storm and Barbara was nearing cooler waters. These factors led to the storm weakening below hurricane intensity by 0000 UTC on June 19. Wind shear at this time also began to increase, displacing all convection associated with the storm to the northeast of the center. By June 20, the former hurricane was further downgraded to a tropical depression. The NHC issued their final advisory on the system early on June 21; however, the remnants of the storm persisted until June 27.
Hurricane Cosme
On June 18 a tropical disturbance formed several hundred miles off the coast of Mexico. Ships in the vicinity of the storm, in addition to satellite images, indicated that the disturbance had developed into Tropical Depression Three-E around 1800 UTC. Remaining nearly stationary, the depression gradually strengthened into a tropical storm by June 20, receiving the name Cosme at that time. Early on June 21, Cosme began to track towards the north and intensify. Around 1200 UTC, Cosme strengthened into a Category 1 hurricane on the Saffir–Simpson scale. Several hours later, Cosme reached its peak intensity. Late on June 21, the center of the hurricane made landfall on the Mexican coast, just east of Acapulco with winds of 80 mph (130 km/h). The low associated with the former hurricane was last identified near Brownsville, Texas.
Cosme brought heavy rains, which killed at least 30 people due to drowning. Many adobe homes were destroyed, but a specific cost of damage is not known. The highest rainfall recorded in relation to Cosme was 16.1 in (410 mm) in Yautepec San Bartolo, Mexico.
Tropical Depression Four-E
The fourth tropical cyclone of the season formed as a well-organized depression on July 9. Deep convection associated with the system indicated that intensification into a tropical storm was possible. The system track generally westward in response to high-pressure system to the north. On July 10, the depression quickly became disorganized, with only a small area of convection around the center remaining by midday. Although the depression was nearly at tropical storm intensity, the NHC held off on upgrading it due to its proximity to Tropical Depression Five-E. However, the system failed to intensify. By July 11, the depression entered the Central Pacific hurricane center's area of responsibility. Tracking generally northwest, the system slowly weakened before dissipating on July 14 to the south of Hawaii.
Tropical Depression Five-E
On July 10, a tropical depression formed far from land. Upon formation, there was uncertainty of the location of center. Shortly thereafter, the system became sheared and further intensification was no longer anticipated. On July 11, the low-level center became displaced form the deep convection.
the next day, the center was relocated, and moved to the west. While the NHC noted the possibility of intensification, the depression was forecasted to dissipate in 36 hours. It failed to intensify, and moved into the Central Pacific on July 14. The fast-moving tropical depression dissipated two days later. The remnants of the depression passed far to the south of Hawaii, thus there was no damage.
Hurricane Dalilia
On July 9, a defined low-pressure system formed south of Baja California and increased convective activity led to the NHC classifying it Tropical Depression Six-E on July 11. About 24 hours later, the depression intensified into Tropical Storm Dalilia. By July 13, Dalilia had intensified into a minimal hurricane as it tracked generally toward the northwest. Two days later, the storm took a nearly due west track, which it maintained until July 19. Although the storm tracked near cool waters, a well-developed outflow allowed it to maintain hurricane-intensity. Shortly before crossing into the Central Pacific basin, the storm reached its peak intensity with winds of 90 mph (150 km/h) and a central pressure of 977 mbar (hPa; 28.85 inHg). After crossing 140°W, Dalilia weakened to a minimal hurricane. The storm maintained this intensity until July 19, at which time the system slowed and turned northwest. The following day, the weakening tropical storm brushed the Hawaiian Islands to the south, eventually curving away from the island chain on July 21. Later that day, Dalilia further weakened to a tropical depression, with the Central Pacific Hurricane Center issuing their final advisory at that time. The remnants of the former hurricane continued to track northwest.
While tracking near the Hawaiian islands, Dalilia produced waves up to 20 ft (6.1 m) along south-facing coastlines. Along the coasts of Ka'u and South Kona, winds gusted up to 45 mph (75 km/h); the winds caused minor damage Along the southeast slopes of Mauna Loa, heavy rains caused minor flooding which forced transit officials to shut down several roads. Localized areas received rainfall in excess of 10 in (250 mm).
Tropical Depression Seven-E
On July 16, an area of disturbed weather located 900 mi (1,400 km) organized into a tropical depression. Upon formation, the NHC did not anticipate significant intensification due to it close distance to both cooler waters and Hurricane Dalilia. The next day, however, the center became difficult to locate and the system was no longer forecast to intensity. By the night, only minimal deep convection remained. The depression soon moved into cold water and as such the system was expected to dissipate within 24 hours. It dissipated the next day. The remnants of this system contributed to a surge in the monsoon trough that led to the formation of Tropical Storm Erick. This system never impacted land, and thus no damage or deaths were reported.
Tropical Storm Erick
On July 16, there was a surge in convection in the monsoon trough. The most concentrated area soon separated for the trough and by July 19, satellite imagery indicated an area of deep convection that was located nearly 1,237 mi (1,991 km) away from Mexico. Early that day, the system was upgraded to a tropical depression. Upon becoming a tropical cyclone, only slight intensification was anticipated. The system intensified to a tropical storm 24 hours after forming. Erick soon moved into cooler waters. This quickly weakened the cyclone and was downgraded to a tropical depression on July 20. It dissipated the next day, without ever impacting any land masses.
Tropical Storm Flossie
Flossie originated from a tropical wave that entered the Pacific Ocean on July 20. The system began to show signs of organization two days later. Continuing to organize, the system was upgraded Tropical Depression Nine-E on July 23. Despite being located over warm waters, only gradual intensification was anticipated. It strengthened into Tropical Storm Flossie the next day. Shortly thereafter the upgraded, convection began to diminish. The cyclone then drifted northwest. The upper-level environment rapidly changed, and the cyclones convection became disorganized. The convection separated from the center of circulation. The cluster of convection developed a new center of circulation on July 24. The original center drifted away from Flossie for 12 hours before dissipating. The new center, which was still a tropical storm, drifted northwest. Flossie then encountered an unfavorable environment, and weakened into a depression on July 25. Flossie continued drifting to the northwest until dissipating July 28, while just off the coast of the Baja California Peninsula. Despite its close distance to Mexico, no damage or deaths were reported.