Hurricane Leslie (2018)

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Hurricane Leslie
Category 1 hurricane (SSHWS/NWS)
Leslie 2018-10-11 1515Z.jpg
Hurricane Leslie near peak intensity southwest of the Azores on 11 October
Formed23 September 2018
Dissipated16 October 2018
(Extratropical after 13 October)
Highest winds1-minute sustained: 90 mph (150 km/h)
Lowest pressure969 mbar (hPa); 28.61 inHg
Fatalities2 direct, 14 indirect
Damage≥ $411.2 million (2018 USD)
Areas affectedAzores, Bermuda, East Coast of the United States, Madeira, Iberian Peninsula, France
Part of the 2018 Atlantic hurricane and
2018–19 European windstorm seasons

Hurricane Leslie (known as Storm Leslie or Cyclone Leslie in Portugal and Spain while extratropical) was the strongest cyclone of tropical origin to strike the Iberian Peninsula since 1842. A large, long-lived, and erratic tropical cyclone, Leslie was the twelfth named storm and sixth hurricane of the 2018 Atlantic hurricane season. The storm was of non-tropical origin, developing from a large low-pressure system that developed over the northern Atlantic Ocean on 22 September. The low quickly acquired subtropical characteristics and was classified as Subtropical Storm Leslie on the following day. The cyclone meandered over the northern Atlantic and gradually weakened, before merging with a frontal system on 25 September, which later intensified into a powerful hurricane-force low over the North Atlantic.

While Post-Tropical Cyclone Leslie began to weaken on 27 September, it simultaneously began to reacquire subtropical characteristics, and by late on 28 September, Leslie had completed the transition to a subtropical storm once again. Leslie gradually intensified, becoming a hurricane early on 3 October, and initially peaked with winds of 130 km/h (80 mph) later that day. Leslie gradually weakened, falling to tropical storm intensity late on 4 October. The cyclone continued to slowly weaken before beginning to re-strengthen on 8 October. On 10 October, Leslie reached hurricane status for the second time. Leslie continued to slowly strengthen, reaching peak intensity with sustained winds of 150 km/h (90 mph) and a minimum central pressure of 969 hPa (28.6 inHg), on 12 October. Leslie then began to gradually weaken over the next day, while accelerating towards the northeast, before transitioning into an extratropical cyclone just off the coast of Portugal on 13 October, before making landfall shortly afterward. Leslie's remnant continued moving eastward while rapidly weakening, dissipating on 16 October over western France.

Hurricane Leslie prompted the issuance of tropical storm watches and warnings for Madeira Island, the first in its history.[1] The storm was also responsible for 16 deaths, including 2 in Portugal and 14 in France.[2][3]

Meteorological history[edit]

Origins and initial extratropical transition[edit]

Map plotting the track and the intensity of the storm, according to the Saffir–Simpson scale

On 19 September, in the midst of an active month of tropical cyclone formation in the North Atlantic basin, the National Hurricane Center (NHC) began monitoring the potential for a non-tropical low pressure system to form several hundred kilometres southwest of the Azores, with the possibility of the low gradually acquiring tropical or subtropical characteristics.[4] Three days later, on September 22, a non-tropical low formed along a frontal boundary associated with the remnants of Hurricane Florence about 1,400 km (850 mi) south-southwest of the Azores.[5] The low quickly acquired subtropical characteristics as it meandered over the northeastern Atlantic, and at 15:00 UTC on 23 September, the NHC initiated advisories on Subtropical Storm Leslie.[6]

Leslie shortly after being classified as a subtropical storm on 23 September

Initially, the future evolution of Leslie was rather uncertain, due to the possibility of a larger low pressure system becoming dominant and absorbing Leslie, although some global forecast models maintained Leslie as the dominant system.[7] Over the next couple of days, Leslie drifted eastward without changing in intensity, before weakening into a subtropical depression at 03:00 UTC on 25 September.[8][9]

Six hours later, Leslie became an extratropical cyclone. Microwave data showed that the system had a surface circulation elongated around an intruding baroclinic zone.[10] At 18:00 UTC on 25 September, the NHC forecasted that Leslie would regain subtropical characteristics in a couple days.[11] Soon afterward, Leslie merged with an approaching frontal system and subsequently strengthened; on 27 September, at 00:00 UTC, Leslie acquired hurricane-force winds, due to baroclinic processes.[12] As Leslie began to regain subtropical characteristics, it weakened to tropical storm force strength.[13] At 21:00 UTC on 28 September, the NHC resumed issuing advisories on Leslie as a subtropical storm, as its organization had increased and baroclinic features had disappeared.[14]

Tropical transition, initial peak and subsequent weakening[edit]

Hurricane Leslie at its initial peak intensity on 3 October

Soon after being reclassified as a subtropical storm, Leslie began to turn due to interactions with the subtropical ridge to the west and a large deep-layer low that was forming to the east. Over the course of a day, the storm turned from a westerly direction to the southwest.[14][15] At the same time, Leslie was acquiring more tropical characteristics. On 29 September at 21:00 UTC, it became fully tropical after developing an anticyclonic outflow to its northeast and southeast as well as in its main convective band. Additionally, Leslie had transitioned to a warm core structure.[16]

For the next day-and-a-half, Leslie meandered over the north Atlantic without any change in intensity. At 09:00 UTC on 1 October it began to strengthen, with the NHC noting an increase in convective banding in the north and northwest.[17] Leslie continued to slowly strengthen over the next couple of days, before becoming a hurricane on 3 October at 09:00 UTC.[18] At that time, deep convection surrounding Leslie had immensely improved and a well-defined low-level eye had developed. Additionally, steering currents that had been taking Leslie southwestward over the previous several days completely collapsed, resulting in the hurricane becoming stationary.[19] Six hours later, at 15:00 UTC, Leslie reached its initial peak intensity with maximum sustained winds of 130 km/h (81 mph) and a minimum central pressure of 975 hPa (28.79 inHg).[20] At 21:00 UTC, Leslie began to move northward, under the influence of a shortwave trough to the northwest and a mid-level ridge to the southeast.[21]

The hurricane maintained peak intensity for twelve hours before beginning to weaken.[22] On 4 October at 21:00 UTC, Leslie weakened into a tropical storm.[23] Its structure continued to degrade, with the NHC noting that the system lacked an inner wind core.[24] Over the next few days, Leslie turned from the north to the southeast, as it encountered the southern edge of the mid-latitude westerlies.[25] It continued to gradually weaken as a result of increased wind shear, weakening to a tropical storm with winds of 85 km/h (53 mph) on 8 October, at 03:00 UTC.[26]

Peak intensity, second extratropical transition and demise[edit]

Hurricane Leslie approaching the Iberian Peninsula on 13 October

On 8 October, the storm began to intensify once more.[27] Convection had deepened and an inner core was trying to form in the tropical storm. Additionally, the cloud pattern of Leslie had become more symmetric.[28] Over the next day, intensification continued, with Leslie re-achieving hurricane status for a second time at 03:00 UTC on 10 October.[29] At 09:00 UTC, Leslie turned southward, under the influence of a broad mid- to upper-level trough.[30] Over the next eighteen hours, Leslie turned from the south to the east-northeast, due to a mid-latitude trough.[31] It later reached its peak intensity with sustained winds of 150 km/h (93 mph) and a minimum central pressure of 969 hPa (28.6 inHg), on 12 October at 03:00 UTC.[32] The hurricane maintained its peak intensity for six hours before beginning to weaken once more.[33]

Leslie continued to gradually weaken over the next day, as it accelerated to the northeast.[34] At 18:00 UTC on 13 October, Leslie fell below hurricane strength as it transitioned into an extratropical cyclone, while situated about 190 kilometres (120 mi) west-northwest of Lisbon, Portugal.[35] Three hours later, the NHC issued its last advisory on Leslie as it approached the western coast of Portugal.[36] Soon afterward, Leslie's extratropical remnant made landfall in Figueira da Foz at 21:10 UTC, causing damage throughout the country's central coast.[37] Afterward, Leslie rapidly weakened while moving northeastward, reaching western France by 15 October.[38][39] Early on 16 October, Leslie's remnant dissipated over western France.[40]

Preparations and impact[edit]

Deaths by country
Country Deaths
Portugal 2
France 14
Total 16

United States[edit]

From late September through early October, Leslie brought high surf to the East Coast of the United States, inducing the highest swell observed in some locations for years. Leslie also generated the single-longest period of tropical swells observed in the Outer Banks in the last 20 years, producing surf at chest-height or higher. The highest surf was observed on 26–28 September, when Leslie was a powerful extratropical cyclone with hurricane-force winds.[41]

Madeira[edit]

Late on 11 October, the Government of Portugal issued a tropical storm watch for Madeira Island,[42] which was changed to a tropical storm warning six hours later.[43] It was the first known tropical storm warning issued for that island in recorded history.[1] Madeira officials closed beaches and parks.[44] The threat of the storm caused eight airlines to cancel flights into Madeira. More than 180 sports matches on the island were canceled, more than half of which affecting the Madeira Football Association.[45] The warnings were discounted on 13 October as Leslie moved away from the islands.[46]

Mainland Portugal[edit]

In advance of Leslie, IPMA issued red warnings for high winds or dangerous coastal conditions for 13 out of its 18 districts, including the capital Lisbon.[47] Several events were canceled or postponed, including the Revenge of the 90s party scheduled for the night of 13 October in Lisbon being postponed to the 20th. A Mafalda Veiga concert in Campo Pequeno, the play "Baixa Terapia" at the Tivoli BBVA, and the evening session of the French Film Festival were also canceled.[48] In addition, the final match of the Rink Hockey Female European Championship, played on 14 October in Mealhada, was suspended with less than two minutes left.[49]

At 21:10 UTC on 13 October, Leslie made landfall in Figueira da Foz as a storm-force extratropical cyclone with winds of 110 km/h (70 mph). It was the first cyclone of tropical origin to hit the Iberian Peninsula since Vince in 2005, and the strongest cyclone to hit the peninsula since 1842. Winds up to 175 km/h (109 mph) were recorded in Figueira da Foz, which has been attributed to a sting jet.[50] Heavy rains and strong waves affected the entire country, leaving 324,000 homes without power, more than 60 people needed to be evacuated. At least 1,000 trees were uprooted in the coastal areas.[51] The storm caused 2 deaths, and slightly injured 28 others.[2] Damage in the Centro region exceeded €86 million (US$99.3 million),[52][53] while insured loss estimated at €70 million (US$80.9 million).[54]

Spain[edit]

Winds of up to 96 km/h (60 mph) were reported near Zamora. Villardeciervos also recorded winds of 87 km/h (54 mph); strong winds caused trees to be uprooted. AEMET issued the yellow level warnings due to the risk of storms related to Leslie, advising citizens to beware objects that may fall on public roads. There are no reports of fatalities due to Leslie in Spain.[55]

France[edit]

The moisture of Leslie's dissipating extratropical remnant fed a quasi-stationary cold front over southwestern France, generating heavy thunderstorms and leading to flash flooding in that area.[56] Carcassonne received 160–180 mm (6.3–7.1 in) of rainfall within five hours; water level in the city rose 8 m (26 ft) during that period. At least 14 people died because of the flash flood, mainly in the town of Villegailhenc, Aude. This was partially due to the fact that the Aude River rose to a height of 7 m (23 ft), its highest level since 1891.[57] Wind gusts of 111 km/h (69 mph) and wave heights of 7.8 m (26 ft) were recorded in Sète.[58] Damage in Aude were calculated at €200 million (US$231 million).[59]

See also[edit]

References[edit]

  1. ^ a b Eric S. Blake (October 12, 2018). Hurricane Leslie Discussion Number 63 (Report). Miami, Florida: National Hurricane Center. Retrieved October 12, 2018.
  2. ^ a b "Leslie. 28 feridos e mais de duas mil ocorrências. O que se sabe até agora" (in Portuguese). SAPO 24. October 13, 2018. Retrieved October 13, 2018.
  3. ^ "France: le bilan des inondations dans l'Aude monte à 14 morts".
  4. ^ David Zelinsky (September 21, 2018). NHC Graphical Tropical Weather Outlook Archive (Report). Miami, Florida: National Hurricane Center. Retrieved September 22, 2018.
  5. ^ Michael J. Brennan (September 22, 2018). NHC Graphical Tropical Weather Outlook Archive (Report). Miami, Florida: National Hurricane Center. Retrieved September 23, 2018.
  6. ^ Lixion Avila (September 23, 2018). Subtropical Storm Leslie Discussion Number 1 (Report). Miami, Florida: National Hurricane Center. Retrieved September 23, 2018.
  7. ^ Lixion Avila (September 23, 2018). Subtropical Storm Leslie Discussion Number 3 (Report). Miami, Florida: National Hurricane Center. Retrieved October 8, 2018.
  8. ^ Roberts, Dave. Subtropical Storm Leslie Advisory Number 6. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 11 October 2018.
  9. ^ Zelinsky, David. Subtropical Depression Leslie Advisory Number 7. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 11 October 2018.
  10. ^ Roberts, Dave. Post-Tropical Cyclone Leslie Discussion Number 9. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 11 October 2018.
  11. ^ Pasch, Richard. NHC Graphical Outlook Archive. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 11 October 2018.
  12. ^ Berg, Robbie. NHC Graphical Outlook Archive. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 11 October 2018.
  13. ^ Zelinsky, David. "NHC Graphical Outlook Archive". National Hurricane Center. National Oceanic and Atmospheric Administration. Retrieved 11 October 2018.
  14. ^ a b Beven, Jack. Subtropical Storm Leslie Discussion Number 10. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 11 October 2018.
  15. ^ Zelinsky, David. Subtropical Storm Leslie Advisory Number 13. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 12 October 2018.
  16. ^ Zelinsky, David. Tropical Storm Leslie Discussion Number 14. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 12 October 2018.
  17. ^ Brown, Daniel. Tropical Storm Leslie Discussion Number 20. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  18. ^ Brown, Daniel. Hurricane Leslie Discussion Number 28. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  19. ^ Brown, Daniel. Hurricane Leslie Discussion Number 28. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  20. ^ Cangialosi, John. Hurricane Leslie Advisory Number 29. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  21. ^ Cangialosi, John; Onderlinde, Matthew. Hurricane Leslie Discussion Number 30. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  22. ^ Berg, Robbie. Hurricane Leslie Advisory Number 32. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  23. ^ Beven, Jack. Tropical Storm Leslie Advisory Number 34. National Hurricane Center (Report). Retrieved 13 October 2018.
  24. ^ Avila, Lixion. Tropical Storm Leslie Discussion Number 35. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  25. ^ Beven, Jack. Tropical Storm Leslie Discussion Number 38. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  26. ^ Avila, Lixion. Tropical Storm Leslie Advisory Number 47. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  27. ^ Blake, Eric. Tropical Storm Leslie Advisory Number 50. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  28. ^ Blake, Eric. Tropical Storm Leslie Discussion Number 60. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  29. ^ Blake, Eric. Hurricane Leslie Advisory Number 55. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  30. ^ Cangialosi, John. Hurricane Leslie Discussion Number 56. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  31. ^ Zelinsky, David. Hurricane Leslie Discussion Number 58. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  32. ^ Blake, Eric. Hurricane Leslie Advisory Number 63. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  33. ^ Brennan, Michael. Hurricane Leslie Advisory Number 65. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  34. ^ Avila, Lixion. Hurricane Leslie Advisory Number 69. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  35. ^ Avila, Lixion. Post-Tropical Cyclone Leslie Tropical Cyclone Update. National Hurricane Center (Report). National Oceanic and Atmospheric Administration. Retrieved 13 October 2018.
  36. ^ Stewart, Stacy. Post-Tropical Cyclone Leslie Advisory Number 70. National Hurricane Center (Report). Retrieved 13 October 2018.
  37. ^ "A tempestade Leslie entrou pela Figueira da Foz e fustigou o Centro" (in Portuguese). Diário de Notícias. October 14, 2018. Retrieved October 14, 2018.
  38. ^ "Europe Weather Analysis on 2018-10-14". Free University of Berlin. October 14, 2018. Retrieved October 16, 2018.
  39. ^ "Europe Weather Analysis on 2018-10-15". Free University of Berlin. October 15, 2018. Retrieved October 16, 2018.
  40. ^ "Europe Weather Analysis on 2018-10-16". Free University of Berlin. October 15, 2018. Retrieved October 16, 2018.
  41. ^ Matt Pruett (10 October 2018). "Hurricane Leslie Wasn't Perfect..." Surfline. Retrieved 15 October 2018.
  42. ^ David Zelinsky (October 11, 2018). Hurricane Leslie Advisory Number 62 (Report). Miami, Florida: National Hurricane Center. Retrieved October 12, 2018.
  43. ^ Eric S. Blake (October 12, 2018). Hurricane Leslie Advisory Number 63 (Report). Miami, Florida: National Hurricane Center. Retrieved October 12, 2018.
  44. ^ "Arquipélago da Madeira em "alerta máximo" devido ao furacão Leslie" (in Portuguese). Diário de Notícias. October 12, 2018. Retrieved October 12, 2018.
  45. ^ "Furacão Leslie: mais de 180 jogos cancelados na Madeira e duas exceções nas modalidades" (in Portuguese). O Jogo. October 12, 2018. Retrieved October 12, 2018.
  46. ^ Lixion A. Avila (October 13, 2018). Hurricane Leslie Intermediate Advisory Number 68A (Report). Miami, Florida: National Hurricane Center. Retrieved October 13, 2018.
  47. ^ "Storm Leslie: Portugal hit by 110mph winds as thousands of homes lose power". Sky News. October 14, 2018. Retrieved October 14, 2018.
  48. ^ Lusa, Carolina Branco, Rita Cipriano, Agência. "Furacão Leslie. A major tempestade desde 1842". Observador (in Portuguese). Retrieved 2018-10-14.
  49. ^ "The assignation of the title of Female European Championship is suspended". World Skate Europe. 14 October 2018. Retrieved 14 October 2018.
  50. ^ "STING JET ASSOCIADO AO LESLIE". www.ipma.pt (in Portuguese). 14 October 2018. Retrieved 29 October 2018.
  51. ^ "'Zombie' storm Leslie smashes into Portugal". Agence France-Presse. October 14, 2018. Retrieved October 14, 2018.
  52. ^ "Furacão: Prejuízos na região Centro ultrapassam 80 milhões de euros". Mundo Lusíada (in Portuguese). Lusa. October 17, 2018. Retrieved October 17, 2018.
  53. ^ "Furacão Leslie causou 38 milhões de euros de prejuízos na Figueira da Foz". Communication Matters Journal (in Portuguese). Lusa. October 31, 2018. Retrieved October 31, 2018.
  54. ^ "Sinistros do Leslie participados às seguradoras custam 70 milhões de euros". TSF (in Portuguese). Lusa. October 29, 2018. Retrieved October 30, 2018.
  55. ^ "Tropical storm Leslie arrives in Zamora with gusts of wind over 96 km / h". International News. October 14, 2018. Retrieved October 15, 2018.
  56. ^ "Épisode pluvio-orageux exceptionnel dans l'Aude le 15 octobre". www.keraunos.org (in French). Keraunos. October 15, 2018. Retrieved October 15, 2018..
  57. ^ "France: le bilan des inondations dans l'Aude monte à 14 morts".
  58. ^ CASTAN Patrice (October 15, 2018). "Sète : des rafales de vent à 111 km/" (in French). MidiLibre. Retrieved October 15, 2018.
  59. ^ Thomas Guien (October 21, 2018). "Inondations meurtrières dans l'Aude : le montant des dégâts estimé à 200 millions d'euros" (in French). La Chaîne Info. Retrieved October 21, 2018.

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