User:Hurricane Noah/Hurricane Sergio (2018)

Hurricane Sergio was a powerful and long-lived tropical cyclone that affected the Baja California Peninsula as a tropical storm. Sergio became the eighth Category 4 hurricane in the East Pacific for 2018, breaking the old record of seven set in 2015. The twentieth named storm, eleventh hurricane, and ninth major hurricane of the season, Sergio originated from a broad area of low pressure that formed a few hundred miles south-southeast of the southern coast of Mexico on September 26. The National Hurricane Center monitored the disturbance for a few days until it organized into a tropical storm, after which it was assigned the name Sergio. The system gradually strengthened for the next couple of days, becoming a hurricane on October 2. Sergio then began a period of rapid intensification, becoming a major hurricane later that day. Intensification then halted for about twelve hours before resuming on October 3. The next day, Sergio peaked as a Category 4 hurricane with maximum sustained winds of 140 mph (220 km/h) and a minimum central pressure of 942 mbar (27.82 inHg). Sergio maintained peak intensity for six hours before beginning to weaken. On October 5, the system bottomed out as a low-end Category 3 hurricane. Sergio then began another period of intensification, achieving a secondary peak on October 6. The next day, Sergio began to weaken again, falling below major hurricane strength. At the same time, Sergio unexpectedly assumed the structure of an annular tropical cyclone. By October 9, Sergio had weakened into a tropical storm. On October 12, Sergio made landfall as a tropical storm on the Baja California Peninsula, and later in northwestern Mexico as a tropical depression before dissipating early on October 13.

On October 10, Sergio's approach warranted the issuance of tropical storm watches and warnings along the western and eastern coasts of Baja California. Sergio made landfall in western Baja California Sur and Sonora on October 13 as a weak tropical storm, causing over US$2 million1 in damage, over a thousand school closures, and a few hundred evacuations due to severe flooding. The remnants of Sergio also brought heavy rainfall to Arizona, resulting in the closure of its state fair. Throughout Mexico and Arizona, no injuries or deaths were reported. Heavy rainfall also occurred in Texas and Arizona, resulting in around US$548,000 in damage. Multiple tornadoes also spawned as a result of the increased moisture.

Meteorological history
The origins of Hurricane Sergio can be traced to a system that was located over northwestern South America on September 24. On September 25, the National Hurricane Center (NHC) forecasted that an area of low pressure would form a few hundred miles south or southwest of the Gulf of Tehuantepec in a couple days. On September 26 at 12:00 UTC, a broad area of low pressure formed a few hundred miles south-southeast of the southern coast of Mexico. The NHC continued to track the disturbance for a couple more days as it moved west-northwest. On September 29 at 12:00 UTC, Tropical Storm Sergio formed approximately 345 miles (555 km) south-southwest of Acapulco, Mexico. The NHC later discussed that Sergio was indeed a tropical storm, but without an inner wind core. Instead, the maximum sustained winds were located in a band approximately 125 mi (205 km) east of the center.

Sergio continued to gradually intensify over the next couple of days, becoming a hurricane on October 2 at 00:00 UTC. At this time, the storm had a well defined eye underneath a deep convective overcast with cloud tops around -85 C. Sergio then began a period of rapid intensification, becoming a major hurricane at 18:00 UTC. Soon after, the intensification halted as northwesterly shear affected the system's inner core, with microwave data indicating an open eyewall on the north side of the hurricane. Sergio maintained its intensity for 18 hours before resuming intensification. At the same time, the mid-level ridge to the north had weakened, resulting in the storm travelling to the northwest. On October 4 at 00:00 UTC, Sergio became the eighth Category 4 hurricane of the season, breaking the old record of seven set in 2015. Six hours later, Sergio peaked with maximum sustained winds of 140 mph (220 km/h) and a minimum central pressure of 942 mbar (27.82 inHg). The storm maintained peak intensity for 12 hours before beginning to weaken. At 03:00 UTC on October 5, it was noted that Sergio's structure had deteriorated, with cloud tops warming and the eye becoming ragged and less distinct. At 09:00 UTC, the cyclone began to turn due to a mid-level ridge that was developing to the northwest. Over the next couple of days, Sergio turned from the northwest to the southwest. At 06:00 UTC, Sergio bottomed out as a low-end Category 3 hurricane.

Late on October 5, Sergio began another period of intensification, reaching a secondary peak with winds of 125 mph (205 km/h) on October 6 at 00:00 UTC. Twelve hours later, a shortwave trough weakened the ridge to the northwest, resulting in the commencement of another turn. Over the next few days, Sergio turned from the southwest to the northeast. After maintaining secondary peak intensity for eighteen hours, Sergio began to weaken due to upwelling at 00:00 UTC on October 7. On October 7, after having weakened to a Category 2 hurricane, Sergio unexpectedly acquired the structure of an annular hurricane. At the same time, it was reported that the eye had doubled in size overnight. At 00:00 UTC the next day, Sergio weakened to a Category 1 hurricane. On October 9, at 18:00 UTC, the system weakened to a tropical storm, due to deteriorating conditions. Around 12:00 UTC on October 12, Sergio made landfall near Los Castros, Baja California Sur, as a tropical storm, with winds of 50 mph (85 km/h). Shortly after 18:00 UTC, the storm made landfall near Guaymas, Sonora, as a tropical depression. At 00:00 UTC on October 13, Sergio dissipated over northwestern Mexico.

Mexico
On October 10, the Government of Mexico issued a tropical storm watch along the western coast of the Baja California Peninsula from Punta Eugenia to Cabo San Lazaro and along the eastern coast from Bahia San Juan Bautista to San Evaristo. Early the next day, as Sergio rapidly approached the peninsula, the tropical storm watch on the west coast was upgraded to a tropical storm warning. The watches on the east coast were also upgraded to warnings later the same day. All watches and warnings were discontinued as Sergio moved inland.

Sergio made landfall in western Baja California Sur and Sonora, bringing heavy rains and strong winds to northern Mexico. In Baja California Sur, multiple roads and schools in Loreto were damaged. In Sonora, almost 400 people had to evacuate to a temporary shelter due to the threat of flooding. Strong winds up to 70 kph downed trees, utility poles, and damaged homes and businesses in Guaymas, causing approximately MX$40 million (US$2.12 million) in damage. In Punta de Aqua II, over 5.05 in of rain was reported. Additionally, Mazatlán and Plutarco Elías Calles reported rainfall totals of 4.59 in and 4.53 in, respectively. More than 1,000 schools were closed in Chihuahua and classes in 8 municipalities of Sinaloa were suspended. However, there were no deaths or injuries. Throughout the state of Michoacán, the combined effects from Sergio and nearby Hurricane Rosa destroyed 35000 ha of crops.

United States
The moisture from Sergio's remnants moved into Arizona, California and Texas, generating heavy rains and spawning multiple tornadoes. In Arizona, a Pacific upper-level low and moisture from Sergio led to heavy rainfall, with some areas in Phoenix recording rainfall totals of 3 in and ankle-deep flooding. The Arizona State Fair was closed due to flooding, the first time in "recent memory". Damage on the fairgrounds and to the surrounding roads was estimated at US$50,000. A portion of Old U.S. Route 80 was closed between Gila Bend and Buckeye after rainfall exceeding 1 in per hour caused flooding in the area. Moderate to heavy rainfall in the deserts southeast of Phoenix caused flash flooding, halting traffic on State Route 187 between state routes 87 and 387. Runoff from heavy rainfall in the Maricopa Mountains flowed across State Route 238, resulting in multiple closures from Mobile to Bosque and US$2,000 in damage. Numerous other road closures2 occurred throughout the Phoenix Metropolitan Area as a result of flash floods, with damage in the region totaling approximately US$73,000. Moisture from Sergio's remnants also entered Southern California, producing thunderstorms mainly to the south of Point Conception. Widespread storms caused flash floods throughout the Coachella Valley, with a 12-hour rainfall total of 0.72 in observed at Palm Desert. In nearby Indio, hail up to 1 in in diameter was reported. Floodwaters up to 1.5 ft deep were reported on a segment of Interstate 10 near Cactus City. Multiple flood-related road closures also occurred near Rimlon and Thousand Palms.

The remnants of Sergio moved through Texas from October 12–13, producing severe thunderstorms that caused US$475,000 in damage throughout the state. About US$15,000 in damage was reported after 60 kn wind gusts damaged a storage unit between Eureka and Mildred. Wind gusts of 65 kn caused about US$4,000 in damage to power lines and a carport near Greenwood. Outside of Shiloh, 65 kn wind gusts destroyed a metal barn and either damaged or destroyed multiple trees, resulting in US$5,000 in damage. Wind gusts between 56–60 kn were reported3 in numerous other counties.

At least ten tornadoes spawned in Texas as a result of the increased moisture. An EF2 tornado near Knickerbocker extensively damaged a metal building and either uprooted or snapped many trees, causing US$200,000 in damage. In Brady, an EF0 tornado uprooted one tree, caused another to fall on a home, and generated roof damage, resulting in US$150,000 in damage. Approximately US$25,000 in damage occurred near Sardis when an EF0 tornado damaged a corner of a gymnasium, broke out windows on cars, bent down lightpoles and handicap signs in a parkinglot, and threw a trailer into a nearby field. Two tornadoes occurred near Chat. The first was an EF0 tornado that damaged a few trees as well as shingles and fences at multiple homes, generating US$15,000 in damage. The second was an EF1 tornado that substantially damaged one home, damaged the roof and deck of another, destroyed a shed, and tossed a boat and RV trailer, resulting in about US$50,000 in damage. An EF0 tornado near Brandon caused about US$5,000 in tree damage. At least four more EF0 tornadoes occurred:3 two in Navarro County, one in Freestone County, and one in Panola County.