1991 Pacific hurricane season

1991 Pacific hurricane season
Seasonal boundaries
First system formed	{{{First storm formed}}}
Last system dissipated	{{{Last storm dissipated}}}
Seasonal statistics
Total fatalities	Unknown
Total damage	Unknown

The 1991 Pacific hurricane season officially started on May 15, 1991 in the eastern Pacific, and on June 1, 1991 in the central Pacific, and lasted until November 30, 1991. These dates conventionally delimit the period of each year when most tropical cyclones form in the northeastern Pacific Ocean.

There are few notable systems this year. Tropical Depression Five-E killed one person in Mexico. Elsewhere, Hurricane Fefa caused flooding in Hawaii. Hurricane Kevin resulted the longest lasting hurricane in the northern Eastern Pacific Basin and Hurricane Nora became the strongest November storm at that time, as Hurricane Sergio during the 2006 season broke the record recently.

Season summary

Saffir–Simpson scale
TD	TS	C1	C2	C3	C4	C5

The 1991 season in the eastern North Pacific Ocean had a total of sixteen tropical cyclones developed, featuring ten hurricanes, 4 tropical storms and 2 tropical depressions. These totals are close to the climatological averages established since 1966, when satellite surveillance began. Nevertheless, 1991 had some important peculiarities. First of all, this season had the second earliest start, only behind last year. The season also ended late with the first November hurricane since the last quarter of century. On the other hand, the months of July and August, often the most active ones in this basin, only produced two tropical cyclones at all.

None of the tropical storms or hurricanes made landfall. One of the two tropical depressions of the season, Five-E, came ashore near Salina Cruz, Mexico, on the last day of June. The depression caused the only fatality of the season and 500 injuries with 2 people reportedly missing. Delores, Ignacio and Marty threatened the coast of Mexico. Also, Tropical Storm Ignacio was also responsible for 40 injuries as the system passed just offshore of Lázaro Cárdenas, Mexico.

Several tropical cyclones grew into specially long-lived and intense overwater systems. In fact, Hurricane Kevin endured as a hurricane for 12½ days to the east of 140°W, establishing a new record for longevity in the eastern Pacific. It is also important to remark that most of the cyclones this season originated from African tropical waves.

Activity

With fourteen cyclones, this season was slightly below average. There were ten hurricanes, five hurricanes of Category 3 intensity or higher on the Saffir-Simpson Hurricane Scale, and four tropical storms. No storms formed in the Central Pacific.

Tropical Storm Andres

Duration	Unknown – Unknown
Peak intensity	Winds not specified;

The first tropical depression of 1991 in the eastern Pacific formed about 1000 nautical miles (1850 km) southwest of the southern tip of Baja California on May 16. This was the second earliest date for a tropical depression to form in this basin since weather satellite monitoring started in 1966. The earliest was the year before, when the depression which later became Hurricane Alma formed on May 12.

A tropical disturbance organized into Tropical Depression One-E on May 16. The depression moved into a slow cyclonic loop and became Tropical Storm Andres the next day. Andres then developed rapidly, with a minimum pressure of 994 mb and corresponding maximum winds of 60 mph (95 km/h). This intensity was mantained for a day and subsequently weakened as upper level shear increased. Andres was downgraded to a tropical depression on May 19 and finally dissipated on May 20.

There were no reported damages or casualties caused by Andres.

Tropical Storm Blanca

Duration	Unknown – Unknown
Peak intensity	Winds not specified;

A well organized tropical wave over northern Africa that formed for the last three days, moved off on May 31 and the convection became disorganized while traveling westward across the tropical Atlantic. In fact, it was difficult to distinguish convection associated with the system from convection along the ITCZ, even after the wave emerged into the eastern North Pacific on June 10. On June 13, the convection associated with the wave became better organized and the next day, Tropical Depression Two-E was formed, about 450 nautical miles (830 km) from Acapulco, Mexico.

For the next 48 hours, the depression moved toward the west and then northwest in response to a weakening ridge to the northwest. Initially the environment was not favorable for development. However , on June 17, the strong shear relaxed somewhat and the exposed center moved under the deep convection again. Thus, the depression strengthened into a tropical storm about 630 nautical miles (1165 km) south of the southern tip of Baja California. Tropical Storm Blanca experienced limited development, reaching its peak intensity of 60 mph (95 km/h) early on June 20. Then, the center of Blanca became exposed again and weakened into a tropical depression on June 21. Finally, it dissipated on June 22 over colder waters about 1285 nautical miles (2380 km) southwest of the southern tip of Baja California.

There were no casualties or damages attributed to Blanca.

Hurricane Carlos

Duration	Unknown – Unknown
Peak intensity	Winds not specified;

A tropical wave left the African coast on June 4 showing some cyclonic curvature in the low clouds. It passed Barbados six days later, where a low-to-mid wind shift was detected. The wave was followed by a low level wind surge which was observed in Curaçao on June 12. Most of the shower activity associated with the wave moved westward over South America, and then over Panama on June 14. The convection became organized and developed into Tropical Depression Three-E, 300 nautical miles (560 km) south of Salina Cruz, on June 16. It became a tropical storm one day later. Carlos reached minimal hurricane strength on June 18 but two days later, Carlos was briefly downgraded to tropical storm status. A strong high pressure system forced Carlos to move over warmer waters and Carlos began to reintensify. Carlos regained hurricane status and developed a well-defined eye and excellent upper level outflow. On June 24, Carlos peaked at 955 mb and 115 mph (185 km/h) maximum sustained winds. The hurricane then weakened when it moved west over colder waters and encountered upper level shear. Carlos dissipated on June 27.

There were no reported damages or casualties caused by Carlos.

Hurricane Delores

Duration	Unknown – Unknown
Peak intensity	Winds not specified;

Delores developed from a tropical wave which moved from Africa to the Atlantic on June 7. And it was not until June 22 when it gained organization and was identified as an area of disturbed weather south of Mexico.

The system immediatly showed signs of rotation and it was upgraded to Tropical Depression Four-E the same day. It was centered about 450 nautical miles south-southeast of Manzanillo, Mexico. Then, the depression reached storm strength, enough to be called Delores on June 24 while 150 nautical miles (230 km) from the coast of Mexico. It rapidly intensified to a hurricane the next day as it approached to the coast. However it repidly weakened and on June 27 it was downgraded to tropical storm status as it was moving over colder waters. Its deep convection gradually diminished and its west-northwestward motion abruptly halted as the system was being sheared. It weakened to a depression on June 28 near Socorro Island and it dissipated on June 29.

No damages or casualties caused by Delores were reported.

Tropical Depression Five-E

Duration	Unknown – Unknown
Peak intensity	Winds not specified;

A tropical disturbance south of the Gulf of Tehuantepec became better organized on June 29 and became a tropical depression. Strengthening was very limited as the depression was approaching to land. It made landfall later that day very near of Salina Cruz, Oaxaca. It dissipated the next day, bringing torrential showers to Oaxaca.

The depression caused the year's lone fatality and occasionated the most significant damage as it destroyed up to 118 homes, caused 500 injuries and two people reportedly missing. Rainfall totals as large as 235 mm (0.80 ft) in 24 hours accompanied the depression over Mexico.

Hurricane Enrique

Duration	Unknown – Unknown
Peak intensity	Winds not specified;

Enrique formed from westward-moving tropical wave that crossed the Atlantic between the June 30 and July 8. A short-lived cyclonic circulation center within the wave was detected on satellite imagery when the system was over the eastern Atlantic. However, persistent deep convection did not occur until the wave neared the Gulf of Tehuantepec in the eastern Pacific Ocean on July 11.

On July 12, the convection became more concentrated about 500 nautical miles south of Acapulco, near a mid-level vortex within the wave and the convection had diminished the next day. The organization of the system began in July 14, becoming Tropical Depression Six-E the next day. The depression intensified further and became Tropical Storm Enrique. Then, on July 17 reached hurricane intensity for a brief period of time and an eye was identified. But due to shear associated with a trough, Enrique began to feel the effects and hence to weaken. Also Enrique entered over cooler waters and its center became exposed. Enrique was downgraded to a depression on July 19 and it eventually dissipated the 20th.

No damages or casualties were caused by Enrique.

Hurricane Fefa

Main article: Hurricane Fefa

Duration	Unknown – Unknown
Peak intensity	Winds not specified;

A wave became better organized and it developed into Tropical Depression Seven-E while 850  n mi south-southeast of Cabo San Lucas on July 29. The depression intensified quickly and became Tropical Storm Fefa the same day. Fefa continued to strengthen over the warm Pacific water and reached hurricane status on July 31. Satellite imagery showed the appearance of an eye the next day. Fefa peaked on August 2 at a pressure of 959 mb and 120 mph maximum sustained winds, making it a Category 3 hurricane in the Saffir-Simpson Hurricane Scale. Later, on August 5, Fefa crossed into the north Central Pacific basin.

After crossing into the basin, shear had increased and Fefa began to weaken as it approached rapidly to the Hawaiian Islands as a tropical storm on August 7. Fefa passed over the Big Island and rapidly weaken further into a tropical depression later that day and finally dissipated the next day over the northwest waters of Kauai.

The remnants of Fefa caused heavy rains and strong winds in the counties of Hawaii and Kauai. Localized flash flooding was reported in the Kohala and Hamakua districts. Lightning caused injuries to two persons on the Big Island.

Hurricane Guillermo

Duration	Unknown – Unknown
Peak intensity	Winds not specified;

The tropical wave that ultimately produced Guillermo emerged from the northwest coast of Africa on July 22. The wave had a large amplitude, but very little deep convection while moving westward across the tropical Atlantic. The convection associated with the southern portion of the wave passed over the Windward Islands on July 28 and crossed Central America on July 31.

Signs of organization were evident late on August 2 when the wave was south of Gulf of Tehuantepec. Then, on August 4, Tropical Depression Eight-E was formed while centered 300 miles south-southeast of Acapulco, Mexico. The depression gradually intensified in the presence of easterly shear as the center moved toward the west-northwest, paralleling the coast of Mexico. Then, it reached tropical storm strength the same day as it was centered south-southwest of Acapulco, Mexico. It peaked the next day with a central pressure of 993 mb and maximum sustained winds of 75 mph as a minimal hurricane, while 220 nautical miles of Manzanillo, Mexico. After its peak, Guillermo began to weaken as it was losing convection, first to tropical storm status and then to a depression. It dissipated on August 10.

There were no damages or casualties associated with Guillermo.

Tropical Storm Hilda

Duration	Unknown – Unknown
Peak intensity	Winds not specified;

Satellite imagery showed a convective area with some cyclonic turning in conection with a tropical wave over Africa on July 22. The convection gradually diminished as the system moved west-southwest into the Atlantic. On July 31, the wave passed south of Trinidad, where a low-level wind shift was detected. For the next couple of days, this system passed over Colombia and Venezuela. It was not until August 6, when the system was south of Guatemala, that convection became organized and a tropical depression developed about 200 nautical miles south-southwest of Acapulco, on August 8. The system intensified further and became Tropical Storm Hilda the next day. The storm reached its peak on August 11 with estimated 60 mph maximum winds and a pressure of 993 mb. The tropical storm moved on a general west-northwest track for a couple of days and then turned toward the north on August 13, under the influence of an upper level trough. Later on that day, Guadalupe Island, Mexico, located about 150 nautical miles to the east-northwest of the center of Hilda, reported tropical storm force winds. Hilda gradually weakened over cool waters bout mantained a rather large level of circulation which produced some rain over California. The depression dissipated on August 14. The proces of dissipation was slower than usual, probably due to the large size of Hilda's circulation. There were no casualties or damages reported from Hilda.

Tropical Depression Ten-E

Duration	Unknown – Unknown
Peak intensity	Winds not specified;

A tropical disturbence southwest of Manzanillo became a tropical depression on September 12 as its convection became persistent around the new formed circulation center. But the development of the conditions were not favorable because it was embedded in a strong shear environment caused by a trough. Then the depression took a northwesternward and then a northward track to finally dissipate next day as it was being sheared in southern Gulf of California.

Tropical Depression Ten-E brought heavy showers to the states of Jalisco and Colima, but there were no reported deaths or damages.

Tropical Storm Ignacio

Duration	Unknown – Unknown
Peak intensity	Winds not specified;

The waves had moved westward across the Atlantic during the first ten days of September. Tropical Storm Erika formed over the east-central Atlantic from the trailing wave. Otherwise, the waves were accompanied by only a small amount of cloudiness before entering the eastern Pacific between September 10 and September 12.

The area of convection developed southeast of an upper level low centered about 250 nautical miles west of the southern tip of Baja California peninsula. A trough axis extended southward from the low, to the west of the convection. By September 15, the area of disturbed weather included some convective bands. The organization of the convection improved and the cloud system became Tropical Depression Eleven-E the next day. The trough that was near the depression moved the cyclone to the north-northwest and during that period it strengthened and became Tropical Storm Ignacio that same day. The influence of the trough over Tropical Ignacio diminished. The track of the tropical storm was a small clockwise loop (see track at the right of the text), which Ignacio reached the northernmost point on September 17. The storm was centered about 25 nautical miles offshore and was near its peak intensity, 60 mph. Further intensification was precluded by the storm's proximity to land and by shear associated with the low near the Baja California peninsula. As Ignacio turned toward the east, its forward motion slowed. When the storm began moving to the south, it lost its identity very rapidly. Ignacio weakened to depression status and dissipated six hours later. The remnants of Ignacio moved toward the west-southwest over the next two days.

Ignacio caused street flooding in Acapulco. However, no further damages or casualties were reported from this storm.

Hurricane Jimena

Duration	Unknown – Unknown
Peak intensity	Winds not specified;

The tropical wave from which Jimena originated moved off the coast of Africa on September 5 as a fairly active-looking system. This wave Tropical Storm Danny over the eastern Atlantic. The southern portion of the system proceeded westward uneventfully over the Caribbean. As it passed over Panama and Costa Rica during September 14 and September 15, the convective activity increased. The system moved westward as an area of disturbed weather in the Pacific ITCZ over the next few days. The convection became sufficiently well organized. Intensification took some time due to an upper level anticyclone north on Mexico. But on September 20 the cloud pattern had increased and was upgraded to a tropical depression.

It took about one day the depression to strengthen into a tropical storm, as it improved her banding features. The cyclone was tracking in a northwestward direction. After becoming tropical storm, the ensuing developement was rather rapid, particularly after September 22 as a banding type eye was forming. Further rapid development took place over the next 24 hours and the maximum sustained winds increased to near 130 mph by the afternoon of September 23. Later, on September 24 Jimena reached her peak with maximum winds of 140 mph and a minimum central pressure of 945 mb. Jimena mantained herself as a powerful hurricane for three days, moving practically due west until September 26, when it turned toward the west-northwest. Jimena began to weaken on September 27, when it was only a Category 2 hurricanes, but mantained a definite for the next day. A northwestward movement commenced on September 29 in response to a large trough which developed in its northwest. It continued to weaken and on September 30 ite weakened back to a tropical storm and the next day it was downgraded to a depression. On October 2 had lost its identity and was declared dissipated.

There were no casualties or damages reported from Jimena.

Hurricane Kevin

Duration	Unknown – Unknown
Peak intensity	Winds not specified;

Kevin formed from a westward-moving tropical wave which emerged from the northwest coast of Africa on September 11. The wave crossed into the Pacific basin on September 21 with no signs of developement. Cloudiness and convection became better organized on the first hours of September 24, becoming Tropical Depression Thirteen-E the next day as it was located about 350 nautical miles southeast of Acapulco, Mexico. Then the depression moved toward the west.

The banding pattern became more pronounced and the depression was upgraded to Tropical Storm Kevin later that day, being centered about 275 n mi south-southeast of Acapulco. The convective banding increased for the next 24 hours and Kevin strengthened to hurricane status on September 26, while 200 nautical miles south-southwest of Acapulco. Kevin continued to strengthen and showed intermitten glimpses of an eye the days 27 and 28 September. By September 29, Kevin had a well-defined eye and this feature persisted for several days. The hurricane continued to strengthen and on October 1 reached its peak intensity while centered 350 nautical miles south-southwest of the soutern tip of Baja California, with estimated 145 mph maximum winds and a minimum pressure of 935 mph. Kevin was moving toward the west at this time, but turnes toward the west-southwest in response of a strong high pressure system located northwest of the hurricane. Then, Kevin began to weaken gradually and its eye became poorly defined on October 4. It weakened to a minor hurricane on October 6 as the hurricane began turning toward the northwest and continued this general motion for the next few days.

However, a well-defined eye reappeared in the system and Kevin reintensified to a low-end Category 4 hurricane with maximum winds of 115 mph and a minimum pressure of 960 mb on October 7. But this was short-lived and on October 8 the hurricane began to weaken again and on the next day it had entered into the North Central Pacific basin as a waning Category 1 hurricane. After this crossing, it was subsequently downgraded to storm strength the same day and on October 11, to a depression. It dissipated that same day. The remnant circulation, however, did persist a while longer as it slowly drifted north to finally lose its identity late on October 14. Kevin had been a hurricane for 12½ days while over the Eastern Pacific basin. This is the longest a system has remained as a hurricane in the basin since improved satellite imagery began.

There were no reported casualties or damages from Kevin.

Hurricane Linda

Duration	Unknown – Unknown
Peak intensity	Winds not specified;

The tropical wave that ultimately produced Hurricane Linda emerged from the northwest coast of Africa on September 16. It could be tracked reasonably well across the tropical Atlantic. The convection increased markedly upon approaching the Lesser Antilles on September 21. The northern part splitted from the wave and caused showers in Jamaica, the Bahamas and Cuba while the southern part continued and crossed Panama into the Pacific basin on September 25 as a group of disorganized cloud clusters. It took many days to organized and it was not until October 3 when organization improved and the wave became Tropical Depression Fourteen-E that same day.

The tropical depression moved toward the northwest while strengthening and became Tropical Storm Linda within 12 hours. As Linda then drifted to the north it was upgraded to a hurricane on October 5. Then, the hurricane reached its estimated peak intensity of 120 mph and a minimum central pressure of 957 mb that same day. Linda began to weaken as it was following Kevin's track and entered to colder waters. Linda turned the west-northwest and produced 80 mph sustained winds on Socorro Island on October 7 as the center of Linda was only 50 nautical miles from the island. Later that day, Linda weakened to a tropical storm. On October 9, as Linda was following Kevin's track, the cyclone had been sheared near the center and it had been downgraded to a depression, although deep convection continued to intermittently appear. Finally, on early October 14, Linda dissipated.

There were no reported casualties or damages from Linda.

Hurricane Marty

Duration	Unknown – Unknown
Peak intensity	Winds not specified;

A series of weak tropical waves, of relatively short wave length, exited the African during the last part of September. They traveled across the Atlantic and the Caribbean, encountering a hostile environment for develoment. On October 5, one of the waves crossed Central America and it began to organize the next day.

Based on satellite classifications, the weather system was upgraded to tropical depression status about 240 nautical miles south of the Gulf of Tehuantepec on October 7. It became Tropical Storm Marty the next day and reached hurricane status early on October 10 while moving parallel to the coast of Mexico. There were several occasions when an eye was becoming apparent in satellite imagery but it never fully developed. An upper trough over the western United States forced Marty to moved toward the northwest and north for a while, bringing the hurricane to waters previously cooled by hurricanes Kevin and Linda. Then, Marty disorganized and weakened into a tropical storm. Also, the trough which forced Marty northward moved out of the area, which made that Marty turned sharply to the west, then west-southwest around a high pressure system. Marty weakened further and remained as a tropical depression. It finally dissipated on October 18. There were no associated casualties or damages with Marty.

Hurricane Nora

Duration	Unknown – Unknown
Peak intensity	Winds not specified;

A tropical wave organized into a tropical depression on November 7. It moved to the northwest and strengthened into Tropical Storm Nora the next day. On November 9, Nora became the first hurricane to form in November in the northern East Pacific basin since the 1966 season. It peaked as a Category 2 hurricane on November 10. A large trough moved in from the west and formed a low. Shear increased and disrupted Nora's convection. The low also caused an abrupt change of course to the northeast. Nora weakened to a depression on November 11 and dissipated the next day. Nora's remnants continued to the northeast, showing brief flare-ups of convection, causing rain in Sinaloa and Nayarit. Effects were minor.

Hurricane Nora is one of only six known tropical cyclones to reach hurricane intensity east of the dateline in November or December. The others were Hurricane/Typhoon Ruby in 1972 season, Hurricane Iwa in the 1982 season, Hurricane Winnie in the 1983 season, Hurricane Rick in the 1997 season, and Hurricane Sergio in the 2006 season.

Season statistics

Timeline

The season began with the formation of Tropical Depression One-E on May 16 and ended with the dissipation of Tropical Depression Nora on November 12. One named storm formed in May, three in June, two in July, two in August, three in September, two in October, and one in November. Very unusually, a category 2 hurricane formed in November, when strong shear and cold waters are often present in the basin. This has happened only six times, incluiding Nora.

Accumulated Cyclone Activity (ACE)

ACE (104 kt2) – Storm
1	52.14	Kevin	8	6.00	Guillermo
2	33.3	Jimena	9	5.50	Delores
3	22.13	Carlos	10	3.51	Enrique
4	19.57	Fefa	11	3.47	Blanca
5	10.34	Linda	12	3.14	Hilda
6	7.62	Marty	13	2.53	Andres
7	7.18	Nora	14	1.92	Ignacio
Total= 177.93

The table on the right shows the ACE for each storm in the season. ACE is, broadly speaking, a measure of the power of the hurricane multiplied by the length of time it existed, so storms that last a long time, as well as particularly strong hurricanes, have high ACEs. ACE is only calculated for full advisories on tropical systems at or exceeding 34 knots (39 mph, 63 km/h) or tropical storm strength and it is used to rank hurricane seasons as above-normal, near-normal, and below-normal. It defines below-normal as having an ACE less than 95*10⁴ kt²; It defines above normal as having an ACE above 150*10⁴ kt² along with the numbers of any two of the following above average: tropical storms (15), hurricanes (9), or major hurricanes (4); It defines near-normal as having an ACE between 100*10⁴ kt² and 150*10⁴ kt², or an ACE above 150*10⁴ kt² with fewer than two of the numbers of the following above average: tropical storms (15), hurricanes (9), or major hurricanes (4).

The cumulative ACE for the Eastern Pacific this season fell within the official "Above Normal" grading, being one of the most active. This occurred because the season had many intense storms that lasted for a long period of time, including Kevin that took almost the third part of the total season ACE, as it held hurricane status for 12½ days in the basin.

1991 storm names

The following names were used for named storms that formed in the eastern Pacific in 1991. The names not retired from this list were used again in the 1997 season. This is the same list used for the 1985 season. In previous seasons, "Delores" was spelled "Dolores", but it was misspelled this year. After this season, the typo was corrected. No central Pacific names were used; the first name used would have been Ekeka. Names that were not assigned are marked in gray.

Andres Blanca Carlos Delores Enrique Fefa Guillermo Hilda

Ignacio Jimena Kevin Linda Marty Nora Olaf (unused) Pauline (unused)

Rick (unused) Sandra (unused) Terry (unused) Vivian (unused) Waldo (unused) Xina (unused) York (unused) Zelda (unused)

Retirement

The World Meteorological Organization retired one name in the spring of 1992: Fefa. It was replaced in the 1997 season by Felicia.

See also

• List of notable tropical cyclones
• 1991 Atlantic hurricane season
• 1991 Pacific typhoon season
• 1990-91 Southern Hemisphere tropical cyclone season
• 1991-92 Southern Hemisphere tropical cyclone season
• 1990-1994 North Indian cyclone seasons

External links

• NHC 1991 Pacific hurricane season archive
• Central Pacific Hurricane Center archive