2023 Pacific hurricane season

Category 2 hurricane (SSHWS)
Duration	June 27 – July 2
Peak intensity	105 mph (165 km/h) (1-min); 970 mbar (hPa)

On June 23, a broad area of low pressure formed off the coast of southern Mexico, in an area which the NHC had for several days been monitoring for potential tropical development.[21] The disturbance quickly became better organized on June 27, and advisories were initiated on Tropical Storm Adrian at 21:00 UTC that same day.[22] Adrian strengthened rapidly, and became the season's first hurricane at 15:00 UTC on June 28, while located about 360 mi (580 km) southwest of Manzanillo, Colima.[23] It then reached Category 2 hurricane status on June 30, with the hurricane maintaining a distinct eye surrounded by a ring of −70 °C (−95 °F) convection on satellite.[24] Adrian reached maximum sustained winds of 105 mph (165 km/h) that day,[25] before entering an environment of stronger wind shear and cool sea surface temperatures, causing it to weaken to a tropical storm the next day. Adrian weakened to a tropical depression early on July 2,[26] and degenerated into a remnant low later that day.[27]

Category 1 hurricane (SSHWS)
Duration	June 29 – July 1
Peak intensity	85 mph (140 km/h) (1-min); 992 mbar (hPa)

An area of low pressure formed near the southwest coast of Costa Rica on June 25.[28] Slow to organize, the disturbance ultimately able to do so, becoming Tropical Depression Two‑E at 09:00 UTC on June 29.[29] Later, at 21:00 UTC, the depression became Tropical Storm Beatriz while located about 105 mi (170 km) south-southwest of Punta Maldonado, Guerrero.[30] Paralleling the coast, Beatriz was upgraded to a hurricane at 15:00 UTC the next day and soon attained peak winds of 85 mph (140 km/h). An eye began to appear on satellite around this time.[31] However, since Beatriz's circulation was severely disrupted by land interaction, the system weakened to a tropical storm early on July 1,[32] and Beatriz dissipated later that day just offshore from Cabo Corrientes, Jalisco.[33]

Due to the threat the developing system posed to southwestern Mexico, the NHC initiated advisories on it early on June 29, designating it as Potential Tropical Cyclone Two‑E.[34] One person drowned in Mazatlán, Sinaloa, on July 1, while surfing the high waves generated by Beatriz' remnants.[35]

Category 3 hurricane (SSHWS)
Duration	July 11 – July 19
Peak intensity	125 mph (205 km/h) (1-min); 955 mbar (hPa)

An area of low pressure formed off the coast of Southern Mexico on July 7.[36] The disturbance became better organized over the course of several days, and developed a well-defined center on the afternoon of July 11, becoming Tropical Depression Three-E.[37] By early the next day, the depression had begun developing a central dense overcast, and exhibiting banding features, and so was upgraded with the 09:00 UTC advisory, becoming Tropical Storm Calvin.[38] Calvin moved westward out to sea within a favorable environment with low wind shear and warm sea surface temperatures, and was upgraded to a Category 1 hurricane at 15:00 UTC on July 13.[39] It then rapidly intensified and became the season's first major hurricane at 15:00 UTC on July 14. It had a well-defined 17-mile-wide (28 km) eye at the time, with a pronounced ring of deep convection surrounding it.[40] A weakening trend began later that day, and by early on July 16, the system had fallen to tropical storm strength.[41] Still moving generally westward, the storm crossed the 140th meridian at around 15:00 UTC on July 17, thus entering the central Pacific basin; its sustained winds at the time were near 50 mph (85 km/h).[42] Then, early on July 19, Calvin passed just south of the Island of Hawaiʻi.[43] Weakened by the close encounter with land, the storm began losing its tropical characteristics. Calvin became post-tropical by 21:00 UTC on July 19.[44]

All state parks on the Big Island, as well as most of Hawaiʻi Volcanoes National Park, were shut beginning the afternoon of July 18, while public schools were closed for the whole of July 19.[45] Eight emergency shelters were opened across the county on July 18.[46] Calvin caused no significant damage; only minor flooding occurred in flood-prone areas of the Big Island.[47] Rainfall reached up to 7.24 in (184 mm) at Honolii Stream, while peak gusts of 72 mph (116 km/h) and 70 mph (113 km/h) were recorded on the summits of Haleakalā and Mauna Kea, respectively.[48]

Tropical depression (SSHWS)
Duration	July 20 – July 21
Peak intensity	35 mph (55 km/h) (1-min); 1006 mbar (hPa)

A tropical wave entered the Eastern Pacific on July 16 after moving across Central America.[49] A broad low pressure area associated with the wave formed south of the coast of southwestern Mexico on July 17.[50] The disturbance became better organized by July 20, and at 12:00 UTC, Tropical Depression Four-E formed southwest of the Baja California peninsula.[49] Later that day, however, the depression's structure began deteriorating. It soon lost all of its deep convection,[51] and degenerated into a remnant low by 00:00 UTC on July 22.[49]

Category 4 hurricane (SSHWS)
Duration	July 31 – August 11 (exited basin)
Peak intensity	145 mph (230 km/h) (1-min); 942 mbar (hPa)

A tropical wave which the NHC had been monitoring since July 16 crossed over Central America into the Eastern Pacific on July 29, off the coast of El Salvador, producing a large area of rain and thunderstorms amid a favorable environment.[52] The system became better organized on July 31, and Tropical Depression Five‑E developed that afternoon.[53] Deep convection increased within the depression, and it strengthened into Tropical Storm Dora early the following day.[54] During August 2–3, Dora rapidly intensified to Category 4 strength, far to the southwest of Cabo San Lucas, Baja California Sur. Then, after undergoing an eyewall replacement cycle,[55] and weakening to a Category 3, it re-intensified to Category 4, with sustained winds reaching 140 mph (220 km/h) early on August 4. Later that day and into the next, the system weakened to Category 2, with winds dropping to 105 mph (165 km/h), before rebounding. Dora reached Category 4 for a third time on August 5, with sustained winds of 145 mph (230 km/h).[11] This re-intensification resulted in Dora acquiring annular traits,[56] displaying a symmetric 17-mile-wide (28 km) eye, surrounded by a thick ring of intense thunderstorm activity, wrapped within bands of showers and thunderstorms revolving around its core.[57] At 15:00 UTC the next day, Dora, experiencing a slight fluctuation in intensity while moving toward the west at 21 mph (33 km/h), crossed over into the Central Pacific basin.[58]

Dora remained a powerful Category 4 hurricane on August 8, as it passed far to the south of the Island of Hawaiʻi with sustained winds of 130 mph (215 km/h).[59][60] Later, on the morning of August 9, Dora strengthened once again, generating winds of 145 mph (230 km/h) amid a low-shear, warm sea surface temperatures environment. It continued to display annular characteristics, with a well-defined, symmetrical 9.2-mile-wide (15 km) eye, surrounded by a compact central dense overcast of less than 120 miles (190 km) wide.[61] Late that same day, Dora's annular structure deteriorated, leaving the system susceptible to dry air intrusions.[62] During this time, the hurricane passed south of Johnston Island.[63] As a result of the change in storm structure, Dora weakened to Category 3 strength on the morning of August 10.[62] As the day progressed, southerly shear caused the hurricane's structure to begin to degrade some as it shifted its course toward the west-northwest along the southwest edge of a high pressure system.[64] At 21:00 UTC on August 11, Dora weakened to Category 2 strength about 900 mi (1,450 km) south of Midway Island.[65] Three hours later, it reached the International Date Line, exiting the Central Pacific basin, and was reclassified as Typhoon Dora.[66][67] According to the Joint Typhoon Warning Center, Dora briefly re-entered the basin as a subtropical depression on August 21, however the CPHC did not monitor it that time.[68]

Though Dora did not pose a direct threat to the Hawaiian Islands, the National Weather Service in Honolulu did issue numerous weather warnings and advisories, especially red flag warnings, for portions of the various islands in expectation of the hurricane helping enhance trade winds in conjunction with an ongoing drought.[69] A steep pressure gradient between a strong anticyclone to the north of Hawaii and Dora to the south produced incredibly strong gradient winds over the islands which in turn helped cause multiple wildfires in Hawaii. The most devastating fire broke out on Maui, where at least 98 people were killed.[70] In addition, more than 2,200 buildings, primarily in Lahaina, were damaged or destroyed. The wildfires became the deadliest natural disaster in recorded Hawaii history.[71][72]

Tropical storm (SSHWS)
Duration	August 5 – August 7
Peak intensity	70 mph (110 km/h) (1-min); 992 mbar (hPa)

On August 2, the NHC first noted a tropical wave located just to the south of Guatemala, which was anticipated to produce an area of low pressure. A low-pressure area developed as predicted late the next day as the wave passed southwest of Mexico.[73] The low showed signs of organization over the following days, and around 15:00 UTC on August 5 the disturbance developed into Tropical Depression Six-E.[74] Moving northwestward near the southern tip of the Baja California peninsula, the cyclone began a quick strengthening trend, becoming Tropical Storm Eugene six hours later.[75] Early on August 6, what appeared on satellite imagery to be a possible eye feature was observed at the center of the storm, but soon deteriorated; Eugene's sustained winds reached 70 mph (110 km/h) at that time.[76] Later, Eugene moved over cold water west of the Baja California peninsula where its diminishing thunderstorm activity ceased, and it transitioned into a post-tropical cyclone on the afternoon of August 7.[77] Its remnants brought isolated rain showers to the San Francisco Bay Area a few days later.[78]

Category 4 hurricane (SSHWS)
Duration	August 12 – August 17
Peak intensity	130 mph (215 km/h) (1-min); 955 mbar (hPa)

On August 11, a broad area of low pressure associated with a tropical wave formed off the coast of southwestern Mexico.[79] A well-defined center of circulation was observed within the disturbance on the afternoon of August 12, marking the formation of Tropical Depression Seven-E in the open ocean south-southwest of the Baja California peninsula.[80] Later that same day, the steadily organizing system strengthened into Tropical Storm Fernanda.[81] Into the next day, Fernanda followed a west-northwestward course, and was displaying signs that it was intensifying, including, very cold central dense overcast cloud tops of near −112 °F (−80 °C), and a well defined upper-level outflow over the western half of its circulation.[82] When a faint eye-like feature became visible on satellite imagery that afternoon, the NHC upgraded the system to a Category 1 hurricane.[83] Thus began a period of rapid intensification, during which it became a major hurricane. By 15:00 UTC on August 14, Fernanda had intensified to Category 4 strength, with sustained winds of 130 mph (215 km/h), and was moving toward the west at 8 mph (13 km/h) away from Baja California.[84] Fernanda remained at that intensity for several hours, before falling to Category 3, while undergoing an apparent eyewall replacement cycle.[85] The system continued to exhibit signs of weakening as the day progressed, and fell below major hurricane strength by day's end.[86] The pace of structural degradation quickened on August 15, due to wind shear, cooling sea-surface temperatures, and low relative humidity levels.[87] Fernanda became a tropical storm the following morning,[88] and, by that evening, had become devoid of any convective activity.[89] By then far west-southwest of Baja California, Fernanda became a post-tropical cyclone on the morning of August 17.[90]

Tropical storm (SSHWS)
Duration	August 14 – August 18
Peak intensity	50 mph (85 km/h) (1-min); 1000 mbar (hPa)

On August 11, a broad area of low pressure associated with a tropical wave formed well to the east-southeast of the Hawaiian Islands.[91] A few days later, shower and thunderstorm activity within the disturbance became better organized, and it developed a well-defined circulation. Consequently, Tropical Depression Eight‑E formed at 03:00 UTC on August 14.[92] The depression strengthened into Tropical Storm Greg six hours later. At the time, the storm was moving westward at 13 mph (20 km/h), and was about to enter the Central Pacific basin.[93] The storm strengthened some on August 15, as an inner core developed and deep convection increased near its center, a result of diminished wind shear and continued warm water temperatures.[94] The wind shear, though relatively light, proved disruptive nonetheless, displacing Greg's convection to the north of the center and causing it to pulsate.[95] This ultimately led to the system becoming increasingly disorganized late the following day.[96] Later, while south of the Island of Hawaiʻi on August 17, it weakened to a tropical depression.[97]

Category 4 hurricane (SSHWS)
Duration	August 16 – August 21
Peak intensity	145 mph (230 km/h) (1-min); 939 mbar (hPa)

On August 12, a tropical wave traversing Central America entered the far eastern Pacific, producing rain showers and thunderstorms.[98] A broad area of low pressure developed within the wave on August 14, off the southern coasts of Mexico, Guatemala, and El Salvador.[99] The disturbance gradually became better organized during the following day, and when a well-defined circulation along with developing convective banding features were observed on the morning of August 16, it was classified as Tropical Storm Hilary by the NHC.[100] Hilary strengthened into a Category 1 hurricane at 12:00 UTC on August 17, while located about 320 mi (515 km) southwest of Manzanillo, Colima.[101] It then proceeded to rapidly intensify, reaching Category 4 strength at 06:00 UTC on August 18.[102] By 15:00 UTC that day, Hilary's intensity leveled off with sustained winds at 145 mph (230 km/h), an increase of 80 mph (130 km/h) over a 24‑hour period.[103] As the steering influences of a trough of low pressure to its north near the California coast and a ridge of high pressure over the central United States began drawing Hilary north-northwestward on the morning of August 19, asymmetrical convective patterns developed as the deep convection on the west side of the system was being eroded by an intrusion of dry and stable air. This caused the hurricane to weaken to Category 3 strength, with winds of 125 mph (205 km/h).[104] By the end of that day, the hurricane had fallen to Category 1 intensity as a result of the adverse effects of cooler waters, drier air, and increasing shear.[105] Then, after weakening to a tropical storm, Hilary made landfall in San Quintín, Baja California, about 215 mi (345 km) south-southeast of San Diego, California, at around 18:00 UTC on August 20, with winds of 65 mph (105 km/h).[106][107] The storm continued to move north-northwestward after landfall, and crossed into California about six hours later, south-southwest of Palm Springs.[108] On the morning of August 21, while moving over southern California and Nevada, Hilary lost all tropical characteristics, becoming a post-tropical cyclone.[109]

Two fatalities, both in Mexico, have been linked to Hilary.[110][111] Additionally, the storm left behind flooded roads, mudslides and downed trees in the Baja California peninsula and in Southern California. Even so, its overall impact on the region was less severe than anticipated.[112][113][114]

Tropical storm (SSHWS)
Duration	August 27 – August 29
Peak intensity	40 mph (65 km/h) (1-min); 997 mbar (hPa)

On August 23, a trough of low pressure formed far to the south of the Baja California peninsula.[115] Early on August 27, the disturbance organized, becoming Tropical Depression Ten-E.[116] Amid marginally favorable conditions, the system was able to strengthen, becoming Tropical Storm Irwin twelve hours later.[117] Irwin remained a poorly organized storm, struggling to generate sustained convection in account of increasingly cooler water temperatures and low relative humidity.[118] Consequently, it degenerated to a post-tropical cyclone on August 29.[119]

Category 5 hurricane (SSHWS)
Duration	September 4 – September 10
Peak intensity	160 mph (260 km/h) (1-min); 929 mbar (hPa)

On September 1, a tropical wave emerged over the far eastern Pacific south of the coasts of El Salvador and Guatemala.[120] A broad area of low pressure formed within it two days later south of the southwestern coast of Mexico.[121] The low became more organized on September 4, a well-defined circulation developed, and a distinct band of deep convection formed around its western half. The NHC classified the system as Tropical Depression Eleven‑E at 21:00 UTC that afternoon.[122] The depression strengthened into Tropical Storm Jova early on September 5,[123] far to the south-southwest of Cabo San Lucas, Baja California Sur. There, Jova underwent a burst of rapid intensification in which it went from a 70 mph (110 km/h) tropical storm to a 160 mph (260 km/h) Category 5 hurricane in a 24‑hour period ending at 03:00 UTC on September 7, an increase of 90 mph (150 km/h).[17] Later that day, Jova started an eyewall replacement cycle, starting a weakening trend.[124][125] The weakening trend continued into September 8, as Jova moved into waters below 79 °F (26 °C),[126] and by that afternoon its winds had decreased to Category 1 hurricane strength.[127] Jova weakened to a tropical storm early on September 9, as persistent dry air intrusion resulted in diminished deep convection and deterioration of the convective banding around the system.[128] Subsequently, all deep convection within the storm ceased and its overall cloud pattern became increasingly unorganized during the morning of September 10. Consequently, Jova degenerated into a post-tropical remnant low with 35 mph (55 km/h) winds later that day.[129] It then meandered westward before opening up into a trough on September 12.[130]

Tropical depression (SSHWS)
Duration	September 15 – September 17
Peak intensity	35 mph (55 km/h) (1-min); 1006 mbar (hPa)

On September 11, the NHC began monitoring a disorganized area of showers and thunderstorms associated with a tropical wave far southwest of the Baja California peninsula.[131] The next day, a broad area of low pressure formed, which began showing some signs of organization the following day.[132] These trends continued, as the deep convection around the developing center of the disturbance became persistent and sufficiently organized on the morning of September 15, for the system to be classified as Tropical Depression Twelve‑E.[133] The depression struggled to produce persistent deep convection during the hours after its formation due to moderate westerly wind shear.[134] Its structure degraded the following morning,[135] and persistent deep convection ceased, resulting in the system degenerating into a post tropical remnant low late in the day on September 16.[136]

Tropical storm (SSHWS)
Duration	September 19 – September 22
Peak intensity	50 mph (85 km/h) (1-min); 1000 mbar (hPa)

On September 16, the NHC began monitoring a newly formed area of disturbed weather far south of the coast of southern Mexico.[137] Showers and thunderstorms within the low pressure area became more persistent over the ensuing couple days, and better organized by the morning of September 19, resulting in the formation of Tropical Depression Thirteen‑E.[138] Moving west that afternoon amid warm sea surface temperatures and favorable atmospheric conditions, the depression was able to strengthen somewhat, and became Tropical Storm Kenneth.[139] Moderate easterly wind shear plagued the system as it continued westward.[140] Despite this, Kenneth was able to become better organized and strengthen slightly, reach its peak intensity on September 20 with maximum sustained winds of 50 mph (80 km/h).[141] After maintaining its strength for another day, Kenneth began to weaken on September 21 in the face of increasing southwesterly vertical wind shear, causing the storm's convection to wane.[142] Early on September 22, Kenneth weakened to a tropical depression[143] and degenerated to a remnant low six hours later.[144]

Tropical depression (SSHWS)
Duration	September 23 – September 25
Peak intensity	35 mph (55 km/h) (1-min); 1007 mbar (hPa)

On September 20, a trough of low pressure formed far south of the southwestern coast of Mexico.[145] Two days later, its showers and thunderstorms began to show signs of organization.[146] The disturbance rapidly became better organized on the morning of September 23, with a marked band of deep convection and very well-defined surface circulation signifying the formation of Tropical Depression Fourteen-E.[147] The depression did not become better organized after formation, as deep convection became erratic near the center and the convective band became indistinguishable by late in the day.[148] Fourteen-E continued to weaken in a fairly hostile environment, characterized by dry air and moderate wind shear, and it degenerated to a remnant low by 03:00 UTC on September 25.[149]

Category 4 hurricane (SSHWS)
Duration	October 3 – October 11
Peak intensity	140 mph (220 km/h) (1-min); 942 mbar (hPa)

On October 1, a large area of persistent showers and thunderstorms being produced by a tropical wave located south of the coast of southern and southwestern Mexico[150] became increasingly concentrated around a developing area of low pressure.[151] The low-pressure area further organized, with satellite and scatterometer data later showing the system had developed a well-defined closed circulation and was producing tropical storm-force winds. On October 3, it was designated as Tropical Storm Lidia.[152] The storm tracked west-northwestward for the next few days, gradually strengthening along the way. Even though Lidia became a little stronger, the most intense deep convection was limited to the western part of the system's circulation on account of persistent easterly wind shear.[153][154] The system meandered generally north-northwestward on October 7,[155] then northward the following day,[156] while it rounded the western edge of a subtropical ridge.[157] Next, the storm made a turn to the northeast during the early hours of October 9.[158] Later, as environmental conditions became increasingly conducive for strengthening, Lidia explosively intensified to Category 4 strength by 21:30 UTC the next day,[159] and accelerated, while being steered to the east-northeast by a nearby mid- to upper-level trough.[160] Lidia then made landfall around 23:50 UTC, with sustained winds of 140 mph (220 km/h), about 15 mi (25 km) south-southeast of Cabo Corrientes, Jalisco.[161] Lidia's structure rapidly deteriorated inland, dissipating several hours later as it moved over the Sierra Madre Occidental.[162]

One person was killed north of Puerto Vallarta after strong winds caused by Lidia downed a tree on a van,[163] and two others were injured in Autlan de Navarro and Cihuatlán in Jalisco.[164] Numerous trees were uprooted and flooding occurred, with floodwaters inundating a hospital and vehicles, leaving several people stranded.[165]

Tropical storm (SSHWS)
Duration	October 8 – October 10
Peak intensity	65 mph (100 km/h) (1-min); 991 mbar (hPa)

On October 3, a trough of low pressure formed south of Central America.[166] Showers and thunderstorms associated with the disturbance gradually became better organized over the next few days. And, as it moved closer to Acapulco on October 7, the NHC initiated advisories on the developing storm, designating it Potential Tropical Cyclone Sixteen‑E.[167] By the following afternoon, the disturbance had developed a well-defined circulation, and was reclassified as a tropical depression.[168] Then, by late evening on October 8, the system strengthened into Tropical Storm Max.[169] Max moved to the north-northeast and strengthened some on October 9, prior to making landfall around 18:00 UTC with winds of 65 mph (100 km/h) just west of Puerto Vicente Guerrero, Técpan de Galeana, Guerrero.[170] Once inland, Max's center of circulation become increasingly ill-defined, and the system dissipated early the next morning over the high mountains.[171]

At least two people were killed and two others were injured in Guerrero.[163]

Category 4 hurricane (SSHWS)
Duration	October 17 – October 23
Peak intensity	130 mph (215 km/h) (1-min); 941 mbar (hPa)

An area of low pressure formed south of the southern coast of Mexico on October 15, producing disorganized showers and thunderstorms.[172] The showers and thunderstorms associated with the disturbance gradually became better organized as it moved parallel with the southwestern coast of Mexico, and by the afternoon of October 17, had developed enough to be classified as Tropical Storm Norma.[173] Norma quickly intensified, and by the following morning was generating intense inner-core convection. Consequently, a ring of very cold cloud tops had formed around its center, within which a ragged eye had emerged.[174] Norma then rapidly intensified from a high-end tropical storm to Category 4 hurricane by the next morning. During the 24‑hour period ending 15:00 UTC on October 19, its maximum sustained winds rose from 70 mph (115 km/h) to 130 mph (210 km/h).[175] Later, moderate wind shear caused the system to weaken below major hurricane strength as it approached the southern end of the Baja California peninsula on the morning of October 21.[176] Shortly after 20:00 UTC that afternoon, the storm made landfall with sustained winds of 80 mph (130 km/h) about 15 mi (25 km) west-northwest of Cabo San Lucas.[177] Several hours later, after weakening to tropical storm strength, Norma moved offshore over the Gulf of California.[178] There, strong wind shear enabled dry mid-level air to penetrate the circulation from the northwest, weakening the system to a tropical depression as it approached the coast of Sinaloa.[179] The depression made a second landfall at about 16:30 UTC on October 23, near El Dorado, Sinaloa, and soon degenerated into a remnant low.[180]

Category 5 hurricane (SSHWS)
Duration	October 22 – October 25
Peak intensity	165 mph (270 km/h) (1-min); 923 mbar (hPa)

On October 18, a broad area of low pressure formed south of the Gulf of Tehuantepec.[181] It drifted there for a few days before becoming a tropical depression on the morning of October 22.[182] Then, that afternoon, it strengthened into Tropical Storm Otis about 500 mi (805 km) south-southeast of Acapulco, Guerrero.[183] Otis underwent an unexpected period of explosive intensification on October 24; in about 12 hours, it intensified from a 50 mph (85 km/h) tropical storm to a 160 mph (260 km/h) Category 5 hurricane, an increase of 110 mph (175 km/h), second only to Hurricane Patricia as the largest 24-hour intensity increase on record in the eastern Pacific.[184] After becoming a Category 5 hurricane, Otis strengthened slightly more, and at 06:25 UTC on October 25, the hurricane made landfall near Acapulco at peak intensity, with winds of 165 mph (270 km/h) and a central pressure of 923 mb (27.26 inHg),[185] becoming the first Pacific hurricane on record to make landfall at Category 5 intensity, thus surpassing Patricia as the strongest landfalling Pacific hurricane.[186] Otis quickly weakened after landfall, weakening to a tropical storm by 18:00 UTC and dissipating within the following three hours.[187]