Tropical Storm Olga was a short-lived tropical cyclone that caused unexpected severe damage as a non-tropical system along its track across the Central United States in late October 2019. The storm began as a distinct tropical wave that moved off Africa on October 8 and organized into a tropical storm over the Bay of Campeche early on October 25. It moved north-northeast, transitioning into an extratropical cyclone within 12 hours. The remnants of the cyclone made landfall in central Louisiana early on October 26 and continued across the Eastern United States and into Ontario, where it dissipated on October 28.
The severity of the storm along its track from Louisiana through Tennessee caught meteorologists by surprise. Intense winds inflicted severe damage, and downed numerous trees onto homes, vehicles, and roadways. In Louisiana, power was cut to 132,000 customers statewide. A peak rainfall accumulation total of was observed near Ponchatoula, with lesser amounts across the state. The remnants of the storm continued into Mississippi, where 772 homes were damaged or lost, 26 businesses impacted, and 27 roads damaged or destroyed; effects were particularly severe in Tupelo. At least 154,000 power outages were reported across the state; in the storm's wake there, a 34-year-old man was killed cleaning tree debris, although this death was not acknowledged by the National Hurricane Center (NHC) in its Tropical Cyclone Report. In Tennessee, a wide swath of winds up to resulted in nearly 65,000 power outages that forced school closures for up to two weeks in several counties, and a 63-year-old man was killed by a downed tree. Total damage along the path of the cyclone was estimated at $400 million.
Meteorological history
A well-organized tropical wave moved off the western coastline of Africa on October 8. High wind shear across the tropical Atlantic hampered the wave from developing into a tropical cyclone even as it showed intermittent signs of convective organization. The disturbance progressed into the eastern Caribbean Sea on October 17 and reached Central America five days later. After crossing the Yucatán Peninsula into the Bay of Campeche by October 24, the wave spawned a broad area of low pressure. The diffuse circulation became better defined the next morning, when satellite-derived wind data indicated it was already producing gale-force winds. As such, the NHC upgraded the system to Tropical Storm Olga at 12:00 UTC on October 25 when it was about south-southwest of Lake Charles, Louisiana. The system's cloud pattern was characterized by a large cluster of deep thunderstorm activity within the northeastern quadrant. A broad upper-level trough to the west of the newly formed cyclone directed it on a general northeastward course.
Shortly after the time of formation, a reconnaissance aircraft found that a cold front was already impinging on Olga's circulation, while maximum sustained winds had increased to ; slightly stronger winds trailed the frontal boundary. However, since the boundary had not yet moved through the system's circulation, Olga persisted as a tropical cyclone. The final passes conducted by the reconnaissance aircraft a few hours later found strong northwesterly flow and a sharp gradient in temperature and dew point near the center that had either been overtaken by the front or become poorly defined. As such, Olga transitioned into an extratropical cyclone by 00:00 UTC on October 26, with winds of as the earlier measurements behind the front became representative of the overall system. It was positioned roughly south-southeast of Lake Charles at the time. The post-tropical cyclone continued north-northeast and crossed the southeastern Louisiana coastline around 07:00 UTC. It progressed inland across the Eastern United States, crossed Lake Huron, and finally dissipated over southeastern Ontario by 00:00 UTC on October 28.