The 2015 Pacific hurricane season was the second-most active Pacific hurricane season on record,[1] and featured the strongest tropical cyclone ever observed in the Western Hemisphere: Hurricane Patricia. The season officially started on May 15 in the Eastern Pacific—east of 140°W—and on June 1 in the Central Pacific—between the International Date Line and 140°W—and ended on November 30. These dates typically cover the period of each year when most tropical cyclones form in the Northeastern Pacific tropical cyclone basin.[2] The season's first storm, Hurricane Andres, developed on May 28; the season's final storm, Tropical Depression Nine-C, dissipated on December 31, well after the official end of the season.
Throughout the season, 31 tropical depressions developed, 26 of which became tropical storms, a record-tying 16 of them reached hurricane strength, and a record-breaking 11 achieved major hurricane intensity.[nb 1] Activity in the Central Pacific shattered records, with 16 tropical cyclones forming in or entering the basin; the previous highest was 11 during the 1992 and 1994 seasons.[4] On August 30, three hurricanes at Category 4 strength—Ignacio, Jimena, and Kilo—existed simultaneously in the Northeastern Pacific, which was a first for the basin.[5] On October 23, Hurricane Patricia became the strongest hurricane ever recorded in the Western Hemisphere, with a minimum atmospheric pressure of 872 mbar (hPa; 25.75 inHg) and maximum sustained winds of 215 mph (345 km/h). Activity in the basin was boosted by the strong 2014–16 El Niño event, which brought anomalously high sea surface temperatures and low vertical wind shear that helped the numerous systems form and intensify.[6][7]
Four time zones are utilized in the basin: Central for storms east of 106.0°W, Mountain from 106.0°W to 114.9°W, Pacific from 115.0°W to 140.0°W,[8] and Hawaii–Aleutian for storms between the International Date Line and 140°W.[9] However, for convenience, all information is listed by Coordinated Universal Time (UTC) first with the respective local time included in parentheses. This timeline includes information that was not operationally released, meaning that data from post-storm reviews by the National Hurricane Center and Central Pacific Hurricane Center are included. This timeline documents tropical cyclone formations, strengthening, weakening, landfalls, extratropical transitions, and dissipations during the season.
Timeline
May
May 15
The 2015 Pacific hurricane season officially begins.[2]
Around 03:30 UTC (9:30 p.m. MDT, June 6) – Hurricane Blanca makes its closest approach to Socorro Island, passing roughly 30 mi (50 km) to the northeast. An automated weather station there records sustained winds of 74 mph (119 km/h), with a peak gust of 101 mph (163 km/h), before it ceases reporting.[11]
Tracks of Tropical Storms Halola (left), Iune (center), and Ela (right) across the Central Pacific basin during July; the Hawaiian islands are shown in the middle of the map.
A weakening Hurricane Dolores southwest of the Baja California Peninsula on July 16
00:00 UTC (6:00 p.m. MDT, July 15) at 18°54′N110°42′W / 18.9°N 110.7°W / 18.9; -110.7 (Hurricane Dolores weakens to Category 2 status) – Hurricane Dolores weakens to Category 2 status as it makes its closest approach to Socorro Island, passing roughly 20 to 25 mi (32 to 40 km) to the northeast. An automated weather station records sustained winds of 79 mph (127 km/h) and a peak gust of 115 mph (185 km/h).[17]
06:00 UTC (11:00 p.m. PDT, August 28) at 12°12′N124°24′W / 12.2°N 124.4°W / 12.2; -124.4 (Hurricane Jimena hits peak intensity) – Hurricane Jimena reaches peak intensity as a high-end Category 4 hurricane, possessing winds of 155 mph (250 km/h) and a minimum pressure of 932 mbar (hPa; 27.52 inHg), around 1,210 mi (1,945 km) southwest of the southern tip of the Baja California Peninsula.[26]
Hurricanes Kilo (left), Ignacio (center), and Jimena (right) at major hurricane strength on August 30. This was the first time that three such systems existed simultaneously over the Pacific Ocean east of the International Date Line since reliable records began.[5]
The nascent Tropical Depression Sixteen-E on September 20. The system's rainbands already cover Baja California Sur and extend into the Gulf of California.
18:00 UTC (12:00 p.m. MDT) – Tropical Depression Sixteen-E dissipates over Sonora, though its remnants continue moving northeastwards and later enter the Southwestern United States.[30]
12:00 UTC (5:00 a.m. PDT) at 9°48′N137°12′W / 9.8°N 137.2°W / 9.8; -137.2 (Hurricane Olaf rapidly reaches Category 3 strength) – Hurricane Olaf rapidly strengthens into a Category 3 hurricane approximately 2,015 mi (3,245 km) west-southwest of the southern tip of the Baja California Peninsula. This gives Olaf the further distinction of being the lowest-latitude major hurricane on record in the Eastern Pacific.[37]
06:00 UTC (8:00 p.m. HST, October 19) at 10°12′N140°00′W / 10.2°N 140.0°W / 10.2; -140.0 (Hurricane Olaf reaches peak intensity) – Hurricane Olaf crosses into the Central Pacific basin and concurrently reaches peak intensity with winds of 150 mph (240 km/h) and a minimum pressure of 938 mbar (hPa; 27.70 inHg), while located about 1,200 mi (1,935 km) east-southeast of Hilo, Hawaii.[37]
Hurricane Patricia approaching Western Mexico at Category 5 strength on October 23. Just minutes after this picture was taken, hurricane hunters observed the Western Hemisphere then-record-low pressure of 879 mbar (hPa; 25.96 inHg), but post-storm analysis concluded that the peak intensity had occurred several hours earlier.
12:00 UTC (7:00 a.m. CDT) at 17°18′N105°36′W / 17.3°N 105.6°W / 17.3; -105.6 (Hurricane Patricia attains its peak intensity) – Hurricane Patricia reaches its peak intensity with winds of 215 mph (345 km/h) and a pressure of 872 mbar (hPa; 25.75 inHg) approximately 150 mi (240 km) southwest of Manzanillo, Mexico. This ranks Patricia as the strongest tropical cyclone ever observed in the Western Hemisphere, surpassing Atlantic Hurricane Wilma in 2005 which attained a pressure of 882 mbar (hPa; 26.05 inHg). It is also the second-most intense tropical cyclone on record worldwide, just shy of Typhoon Tip in 1979 which attained a pressure of 870 mbar (hPa; 25.69 inHg).[38]
18:00 UTC (8:00 a.m. HST) at 25°18′N139°30′W / 25.3°N 139.5°W / 25.3; -139.5 (Tropical Olaf reenters the Eastern Pacific) – Tropical Storm Olaf crosses 140°W from the west and reenters the Eastern Pacific basin roughly 1,440 mi (2,320 km) west-southwest of San Diego, California. This makes Olaf the first tropical cyclone to cross from the Eastern Pacific into the Central Pacific and back into the Eastern Pacific on record.[37]
^The figures for maximum sustained winds and position estimates are rounded to the nearest five units (knots, miles, or kilometers), following the convention used in the National Hurricane Center's operational products for each storm. All other units are rounded to the nearest digit.
^ abcdefghijklmMichael J. Brennan (August 6, 2015). Hurricane Andres(PDF) (Report). Tropical Cyclone Report. Miami, Florida: National Hurricane Center. Retrieved December 6, 2015.
^ abcdefghijklmnopqrstRichard J. Pasch & David P. Roberts (November 30, 2015). Hurricane Blanca(PDF) (Report). Tropical Cyclone Report. Miami, Florida: National Hurricane Center. Retrieved December 8, 2015.
^ abcdefghijJohn L. Beven II & Christopher W. Landsea (October 27, 2015). Hurricane Carlos(PDF) (Report). Tropical Cyclone Report. Miami, Florida: National Hurricane Center. Retrieved December 8, 2015.
^ abcdefghijklmnJohn L. Beven II; Christopher Jacobson (August 17, 2018). Hurricane Ignacio(PDF) (Report). Tropical Cyclone Report. Miami, Florida and Honolulu, Hawaii: National Hurricane Center. Retrieved August 21, 2018.
^ abcdefghijklStacy R. Stewart; Jeffrey Powell (February 4, 2016). Hurricane Jimena(PDF) (Report). Tropical Cyclone Report. Miami, Florida: National Hurricane Center. Retrieved February 9, 2016.
^ abcdeTodd B. Kimberlain (November 28, 2015). Tropical Storm Kevin(PDF) (Report). Tropical Cyclone Report. Miami, Florida: National Hurricane Center. Retrieved December 9, 2015.
^ abcdefghiDaniel P. Brown (November 12, 2015). Hurricane Linda(PDF) (Report). Tropical Cyclone Report. Miami, Florida: National Hurricane Center. Retrieved December 9, 2015.
^ abcdJon Jelsema (June 1, 2016). Tropical Storm Malia(PDF) (Report). Tropical Cyclone Report. Honolulu, Hawaii: Central Pacific Hurricane Center. Archived from the original(PDF) on June 20, 2018. Retrieved June 20, 2018.
^ abcdeJohn P. Cangialosi (January 11, 2016). Tropical Depression Sixteen-E(PDF) (Report). Tropical Cyclone Report. Miami, Florida: National Hurricane Center. Retrieved January 14, 2016.
^ abcdeSam Houston; Thomas Birchard (November 16, 2016). Tropical Storm Niala (Report). Tropical Cyclone Report. Honolulu, Hawaii: Central Pacific Hurricane Center. Archived from the original on February 4, 2019. Retrieved January 8, 2017.
^ abcdefgSam Houston; Derek Wroe (November 21, 2016). Hurricane Oho (Report). Tropical Cyclone Report. Honolulu, Hawaii: Central Pacific Hurricane Center. Archived from the original on September 4, 2018. Retrieved December 23, 2016.
^ abcdefLixion A. Avila (December 8, 2015). Tropical Storm Nora(PDF) (Report). Tropical Cyclone Report. Miami, Florida: National Hurricane Center. Retrieved December 9, 2015.
^ abcdefghijklmnoEric S. Blake; Jon Jelsema (February 9, 2016). Hurricane Olaf(PDF) (Report). Tropical Cyclone Report. Miami, Florida: National Hurricane Center. Retrieved May 7, 2016.
^ abcdefghijTodd B. Kimberlain; Eric S. Blake & John P. Cangialosi (February 4, 2016). Hurricane Patricia(PDF) (Report). Tropical Cyclone Report. Miami, Florida: National Hurricane Center. Retrieved February 9, 2016.
^Eric S. Blake & Stacy R. Stewart (October 24, 2015). Hurricane Patricia Advisory Number 17 (Advisory). Miami, Florida: National Hurricane Center. Retrieved February 9, 2016.
^ abcdJohn L. Beven II (January 20, 2016). Tropical Storm Rick(PDF) (Report). Tropical Cyclone Report. Miami, Florida: National Hurricane Center. Retrieved February 9, 2016.
^ abcdefghijJohn L. Beven II (January 29, 2016). Hurricane Sandra(PDF) (Report). Tropical Cyclone Report. Miami, Florida: National Hurricane Center. Retrieved February 9, 2016.
^ abSam Houston; Thomas Birchard (December 22, 2016). Tropical Depression Nine-C (Report). Tropical Cyclone Report. Honolulu, Hawaii: Central Pacific Hurricane Center. Archived from the original on July 27, 2018. Retrieved January 8, 2017.
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