User:Hurricane Noah/Hurricane Leslie (2018)

Meteorological history
The National Hurricane Center (NHC) began forecasting on 19 September, 2018, that an extratropical low would form in a few days between the Azores and Bermuda. This system developed along the boundary of a front early on 22 September, approximately 805 mi (1,295 km) west-southwest of Flores Island. Amid favorable environmental conditions, the system separated from the front and its banding features became better established, signaling the formation of Subtropical Storm Leslie by 12:00 UTC on 23 September. Around that time, Leslie was within an upper-level low and the former's gale-force winds were displaced from the center. The subtropical cyclone was located within an area of minimal steering currents, causing the storm's movement to be erratic. Moderate vertical wind shear and dry air hindered the development of thunderstorm activity or convection outside the southeastern portion of the system as it tracked generally southwest. The cyclone turned towards the south and later the east on 24 September. During that time, Leslie's cloud pattern became irregular, with several cloud swirls existing within a broadening circulation. Leslie weakened into a subtropical depression around 00:00 UTC on 25 September due to the continuing wind shear and dry air. The storm began a southeastward motion later in the day, followed by a turn back to the east. Leslie became an extratropical cyclone around 12:00 UTC after its circulation expanded along a baroclinic zone. At that time, an expansive stratocumulus cloud shield was becoming established and cold, stable air was entering the region.

During the next couple of days, Leslie's track consisted of an incomplete counterclockwise loop. At the same time, the baroclinic processes strengthened the extratropical cyclone, leading to hurricane-force winds of 75 mph (120 km/h) by 00:00 UTC on 27 September. A weakening trend commenced during the middle of the day and persisted into 28 September. However, as Leslie tracked westward, it began to reacquire tropical characteristics and was declared a subtropical storm once more around 12:00 UTC. The storm had reestablished bands of convection near its center and its wind field had shrunk considerably. While Leslie had transitioned from a cold core to a warm core system, it was still located within a sizable low-pressure system. Over the next couple of days, the cyclone experienced minimal change in strength as it tracked south of west around the western edge of an extensive cyclonic circulation. Thunderstorm activity developed near Leslie's center and anticyclonic outflow materialized to the northeast and southeast of the system. As a result, Leslie became a tropical storm by 18:00 UTC on 29 September while it was located approximately 1,150 mi (1,850 km) west-southwest of Flores Island in the Azores.

Located within a region of cool sea surface temperatures and strong northwesterly wind shear, the tropical storm intensified little during the next couple of days. Banding features began to increase on October 1 as the wind shear subsided. Leslie continued a west-southwestward to southwestward motion over the next day or so while located in weak steering currents and positioned between high-pressure systems that were located to the west and northeast. As Leslie began to strengthen more quickly on 2 October, convection increased both in intensity and organization. Microwave imagery displayed that Leslie had developed an eye at its low-levels. The storm intensified into a hurricane around 06:00 UTC on 3 October. Meanwhile, Leslie became stationary, with its southerly movement ending. Leslie reached its initial peak at 18:00 UTC as a Category 1 hurricane, with maximum sustained winds of 140 km/h (85 mph). At the time, the storm had a large, irregular eye, with sporadic dry air entrainment. The storm began to track northward between a shortwave trough, which was located to the northeast, and a mid-level ridge, which was located to Leslie's southeast.

Moving over cooler, 26 C sea surface temperatures, Leslie began to weaken slowly on 4 October. The cyclone weakened to a tropical storm around 18:00 UTC. By 5 October, Leslie's inner core had dissipated, and the storm only possessed small bands of convection on the outer limits of its circulation. Convection refired over the storm's center later that day, although the maximum winds were located 165–185 km (105–115 mi) away. Leslie turned towards the east from late 5 October to 6 October under the influence of mid-latitude westerly flow. Although the tropical storm traversed a region of even colder, 24–25 C sea surface temperatures during the next couple of days and was located in a region of moderate wind shear, the storm changed little in strength. Leslie's convection became more organized on 6 October as banding features became more defined and a mid-level eye formed to the southeast of the storm's low-level center. Leslie turned towards the east-southeast on 7 October, still under the influence of the westerly flow. Leslie bottomed out as a 85 km/h (50 mph) tropical storm at 00:00 UTC as it passed over an area of cool sea surface temperatures.

Leslie began to restrengthen later on 8 October as an inner core began to develop and convection became more intense. While the storm continued to track in a southeastward direction, traversing an environment of warmer sea surface temperatures and lower wind shear, a mid-level eye feature began to develop. Turning towards the south, Leslie restrengthened into a hurricane around 06:00 UTC on 10 October. Around that time, the storm's strongest convection was concentrated towards the north and an irregular eye had emerged on satellite imagery. The cyclone began to proceed east-northeastward early on 11 October as strengthening continued. Leslie peaked at 00:00 UTC on 12 October as a Category 1 hurricane, with maximum sustained winds of 150 km/h (90 mph) and a minimum central pressure of 968 mbar, while located approximately 1,065 km (660 mi) south-southwest of Flores Island. The storm had a small, cloud-filled eye around that time.

Leslie began to slowly weaken once more later that day as sea surface temperatures decreased to 23–24 C and wind shear increased. The mid-lattitude westerly flow began to rapidly accelerate Leslie towards the east-northeast, with the cyclone passing 325 km (200 mi) north-northwest of Madeira Island around 06:00 UTC on 13 October. Shortly after, Leslie began to transition to an extratropical cyclone as colder air entered from the south and west and the system's mid-level eye decayed. The cyclone's convection continued to disentigrate as a result of even colder 20 C sea surface temperatures and strong wind shear. The NHC issued its final advisory on Leslie around 21:00 UTC on 13 October after the storm became fully extratropical. At that time, the cyclone moved ashore near Figuiera da Foz, with winds of 120 km/h (75 mph). Leslie's center decayed as it traversed the Bay of Biscay on 14 October. The system reached western France by 15 October. Early on 16 October, Leslie's remnant was absorbed into Hurricane Michael's extratropical remnant, which was situated to the west, following a brief Fujiwhara interaction.

France
The Aude, Hérault, Pyrénées-Orientales, Tarn, Haute-Garonne, and Aveyron departments in France were all placed on orange alert due to the expectation of strong winds and flooding rainfall from the approaching Leslie. Leslie and another system combined to cause severe flooding in the Aude, which prompted the issuance of a red alert for the department; the floods were considered to have been the worst since 1891. A 12-hour rainfall total of 295 mm was reported in the town of Trèbes. Around 1,000 people were evacuated in the Pezens Municipality after a dam overflowed. In the village of Veillardonnel, houses and streets were flooded and vehicles were swept away by floodwaters. In Veillardonnel and Conques-sue-Orbiel, floodwaters reached the height of first-floor windows. The Aude River rose over 7 m to reach 7.6 m in Trèbes. In Puichéric, the Aude River reached a level never before seen, besting the previous record which was set in October 1871. Floodwaters up to 1 m deep flooded homes in Villegailhenc. A bridge also collapsed in the town. At least 210 mm of rain fell in Hérault. Around 6,000 people lost power in the Aude and another 2,000 in Hérault. Police asked citizens in the Aude to remain in their houses and stay off flooded roadways.

The Leclerc promenade in Sète was closed due to 7.6 m high surf and 111 km/h wind gusts. A total of 15 people were killed throughout the Aude as a result of the floods: six in Trèbes, three in Villegailhenc, two in Villalier, one in Veillardonnel, one in Carcassonne, and one in Saint-Couat-d'Aude. At least 75 additional people were injured in the department. Flooding interrupted railway traffic along the Béziers-Narbonne section and other routes in Carcassonne. Several roads in Carcassonne were either blocked by felled trees and cars swept away by floodwaters or destroyed. Schools and universities throughout the city were closed from 15–16 October. In the villages surrounding Carcassonne, flashflooding overturned vehicles, damaged roadways, and caused homes to collapse. Multiple waterspouts occurred in the Gallic portion of France. At least 700 municipalities experienced flood damage, with an estimated total of €220 million (US$254 million).

After the storm, victims in the Aude proceeded to shelters or lodged with their neighbors, and schools were closed. Around 700 firefighters, 160 police officers, and rescue agencies took part in cleanup and rescue operations in the department. Seven helicopters and one plane were mobilized for search and rescue missions in the Aude. Authorities responded to at least 250 emergencies. The French Insurance Federation recorded 35,000 claims of damage in regards to the floods caused by Leslie, with 27,000 of those occurring in the Aude. Collectively, €17 million (US$20 million) was paid in advance to claimants.

Spain
A yellow alert was declared for 25 provinces in Spain during the storm. An orange alert was issued for the provinces of Barcelona, Castellón, Huesca, Lleida, Navarra, Tarragona, Teruel, Zaragoza,​​ Girona, and the Balearic Islands. In Seville, parks were closed on October 13 as a precaution due to Leslie's approach. All parks but the Parque de Los Príncipes were reopened the next day, which was closed for repairs.

Leslie caused at least 17 injuries across Spain. Heavy rainfall caused the Sió river to overflow in Catalonia. At least 45 landslides occurred in the region. Around 247 firefighters responded to over 1,000 emergency calls in Catalonia. In Castilla y León, 100 km/h winds downed trees and branches on roads in dozens of locations. The R1, R2, and R11 lines of the Rodalies de Catalunya and five roads, including the C-17 highway in Barcelona, were closed as a result of fallen trees. Girona and Barcelona experienced 14,000 power outages and 12 roads were impassable due to floodwaters; the latter forced the suspension of school transportation services for six municipalities. A gas station roof was blown off in the Malgrat del Mar neighborhood in Barcelona. Six people had to be evacuated from surrounding properties when a building collapsed in Tortosa. Over 200 L of water per square meter (10.76 sq ft) fell in Montseny and 209.3 in Viladrau. Strong winds caused a wall to collapse in Santo Ángel, forcing the closure of a road. The Albujón highway was closed in Cartagena due to the storm. A fair was canceled in Avenida de Los Toreros after a tree fell and roofs of two stalls were ripped off. The Toledo Cathedral sustained damage to its cornice, with a 20 kg piece falling off. A tunnel flooded in Beniaján, entrapping a vehicle.

Several skates turned upside down in El Prat de Llobregat, and in Palomares, the masts of two skates were snapped and another was bent. Detritus plant matter and other dregs were swept onto the Sant Salvador beach by the storm, covering most of it.

An electrical cable snapped in Zamora, sparking a ditch fire and leaving 390 residences without power. A crane toppled over, striking a building in Soria.

Portugal
Much of Portugal was placed under a red alert on 14 October in anticipation of adverse weather conditions from Leslie. Fishing vessels were asked to return to port and surfers were ordered to move ashore. As the cyclone reached the Portuguese Coast, it brought wind gusts of 190 km/h; Leslie was considered the worst cyclone to affect Portugal since 1842. The storm made landfall near Figueira da Foz, which is located 200 km north of Lisbon. Authorites in Lisbon requested that all residents remain indoors. Around 800 people took refuge in a concert hall in Figueira da Foz. Wind gusts of 176 km/h downed trees and traffic signs, with the former causing several traffic accidents. Leslie left 324,000 customers without power and injured a few dozen people in Portugal. Across the country, thousands of trees were felled by the storm. Scaffolding attached to buildings collapsed in Lisbon and houses were deroofed in the Coimbra district. The power company EDP declared a state of emergency in Coimbra as a result of damage to electrical infrastructure. A number of high voltage power poles were either felled or bent by the storm. In Soure, damage was estimated to be at least €1,000,000 (US$1,208,000), with around €600,000 (US$725,000) in damage being to sports infrastructure alone. Schools in the town were closed due to damage and power outages. At least 29 flights were canceled in Lisbon and Funchal, and 12 others were canceled in Porto. Two metro stations and several pavilions were utilized as shelters for the homeless in Lisbon during the storm. Several shows and events in the city, including the Lisbon Marathon, were either canceled or postponed. The European women's roller hockey championship, which was taking place in Mealhada, was stopped in its final minutes after the roof of the sports facility was damaged, windows shattered, and debris littered the track. Players took refuge in locker rooms. Nine ports in Portugal were closed to naval traffic due to the storm.

At least 61 people had to be evacuated from their houses due to damage from the storm. One person was killed by a falling tree in Amieiro.

Damage from Leslie in Portugal was estimated to be around €120 million (US$145 million), with half of the total stemming from 28,000 insurance claims for storm damage. The Portuguese government provided €1.4 million (US$1.7 million) in aid to 24 municipalities in 2019 and another €3.6 million (US$4.3 million) in 2020.

Elsewhere
The Alta, a freighter ship, experienced an unrepairable mechanical issue. The United States Coast Guard and the crew considered towing the ship, but ultimately abandoned it due to the nearby Hurricane Leslie. The ship ran ashore in Ireland on 16 February, 2020.

Météo-France issued a yellow alert for the overseas territory of Martinique on 3 October due to high surf generated by Leslie. The highest surf experienced in Martinique was 2.5 m in the Dominica Channel.

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.