Tropical Storm One (Ardonia)
 | |
| Meteorological history | |
|---|---|
| Formed | May 24, 1865 |
| Extratropical | May 26, 1865 |
| Dissipated | May 27, 1865 |
| Tropical storm | |
| 1-minute sustained (AAWS/NWS) | |
| Highest winds | 45 mph (75 km/h) |
| Lowest pressure | 994 mbar (hPa); 29.35 inHg |
| Overall effects | |
| Fatalities | 2 |
| Damage | $520 million (1865 USD) $10.7 billion (2026 USD) |
| Areas affected | |
Part of the 1865 Ardonia arrocane season | |
Tropical Storm One was a tropical cyclone that affected Cydonia during May 1865. The first tropical cyclone of the 1865 Ardonia arrocane season, One is also the earliest storm in the complete Ardonia tropical cyclone record. The system formed over the Ardonia Ocean on May 24 and tracked generally west-northwestward toward southern Cydonia. It reached its peak intensity with maximum sustained winds of 45 mph (75 km/h) and a minimum central pressure of 994 mbar (29.35 inHg) before weakening slightly as it approached the coast. One made landfall in southern Cydonia with winds of 40 mph (65 km/h) and a pressure of 999 mbar (29.50 inHg) before becoming extratropical on May 26. The system subsequently dissipated on May 27.
Despite its relatively weak intensity, Tropical Storm One caused significant impacts in Meridian. Damage from the storm totaled $520 million in 1865 USD, equivalent to approximately $10.69 billion in 2026 USD, and two fatalities were recorded.
Meteorological history
Tropical storm (40–74 mph, 64–119 km/h)
Category 1 (75–94 mph, 120–159 km/h)
Category 2 (95–114 mph, 160–183 km/h)
Category 3 (115–129 mph, 184–208 km/h)
Category 4 (130–159 mph, 209–256 km/h)
Category 5 (≥160 mph, ≥257 km/h)
Unknown
Extratropical cyclone, remnant low, tropical disturbance, or monsoon depression The system that would become Tropical Storm One was first identified over the Ardonia Ocean while moving generally westward toward Cydonia. The disturbance gradually became better organized as it progressed westward, and at 12:00 UTC on May 24, it developed into a tropical depression. The newly formed cyclone continued generally westward before gradually turning toward the west-northwest as it approached southern Cydonia.
The depression strengthened after formation, becoming a tropical storm as it continued toward the Cydonian coast. At its peak, Tropical Storm One attained maximum sustained winds of 45 mph (75 km/h) and a minimum central pressure of 994 mbar (29.35 inHg). The cyclone maintained its relatively weak tropical storm intensity while moving closer to land, with its track gradually bending northwestward toward the southern coast of Cydonia.
One weakened slightly immediately before reaching the coast. The cyclone subsequently made landfall in southern Cydonia with maximum sustained winds of 40 mph (65 km/h) and a central pressure of 999 mbar (29.50 inHg). After moving inland, the system quickly lost its tropical characteristics and became an extratropical cyclone on May 26. Its remnants continued westward away from the coast before dissipating on May 27.
Preparations and impact
There are no known records of significant preparations being undertaken in advance of Tropical Storm One. The cyclone occurred 87 years before the establishment of the National Arrocane Center (NAC) and Ardonia Meteorological Organization (AMO) in 1952, and consequently no modern tropical cyclone watches, warnings, or coordinated forecasts were issued for the storm.
Tropical Storm One affected southern Cydonia after making landfall with maximum sustained winds of 40 mph (65 km/h) and a central pressure of 999 mbar (29.50 inHg). Recorded impacts were concentrated in Meridian, where the storm caused $520 million in damage in 1865 USD, equivalent to approximately $10.69 billion in 2026 USD. Two fatalities were attributed to the cyclone. No additional deaths or damage were recorded elsewhere.