page_title: Subtropical Cyclone Katie
section_title: Meteorological history
hierarchical_section_title: Subtropical Cyclone Katie / Meteorological history
caption_attribution_description: English: Track map of “Katie” the 2015 Southeast Pacific cyclone of the 2014-15 South Pacific cyclone season. The points show the location of the storm at 6-hour intervals. The colour represents the storm's maximum sustained wind speeds as classified in the Saffir–Simpson scale (see below), and the shape of the data points represent the nature of the storm, according to the legend below. Saffir–Simpson scale Tropical depression≤38 mph≤62 km/h Category 3111–129 mph178–208 km/h Tropical storm39–73 mph63–118 km/h Category 4130–156 mph209–251 km/h Category 174–95 mph119–153 km/h Category 5≥157 mph≥252 km/h Category 296–110 mph154–177 km/h Unknown Storm type Tropical cyclone Subtropical cyclone Extratropical cyclone / Remnant low / Tropical disturbance
context_page_description: Subtropical Cyclone Katie, unofficially named by researchers, was an unusual weather event in early 2015. After the 2014–15 South Pacific cyclone season had officially ended, a rare subtropical cyclone was identified outside of the basin near Easter Island, during early May, and was unofficially dubbed Katie by researchers. Katie was one of the few tropical or subtropical systems ever observed forming in the far Southeast Pacific, outside of the official basin boundary of 120°W, which marks the eastern edge of RSMC Nadi's and RSMC Wellington's warning areas, during the satellite era. Due to the fact that this storm developed outside of the official areas of responsibility of the warning agencies in the South Pacific, the storm was not officially included as a part of the 2014–15 South Pacific cyclone season. However, the Chilean Navy Weather Service issued High Seas Warnings on the system as an extratropical low.
context_section_description: On April 29, 2015, near the end of the 2014–15 South Pacific cyclone season, an extratropical disturbance developed in the far Southeastern Pacific, before transitioning into a subtropical depression soon afterward. The storm transitioned into a subtropical depression at 102.9°W, well to the east of the South Pacific basin's eastern boundary of 120°W. Around this time, the Chilean Navy Weather Service began including the storm in their High Seas Warnings, continuing this until May 4. During the next couple of days, the system drifted to the southwest, before turning to the southeast. On May 1, the storm intensified into a subtropical cyclone of tropical storm intensity, and looped westward. During this time, the system encountered water temperatures about 1 °C above average and low wind shear, due to an extremely strong El Niño event, allowing the storm to organize further. On May 2, the storm reached its peak intensity, with maximum sustained winds of 72 km/h (45 mph; 39 kn), and a minimum low pressure of 993 hPa (29.32 inHg). Around this time, the storm was identified by researchers and unofficially named Katie. During the next day, Katie slowly tracked westward while gradually weakening. On May 4, Katie weakened into a subtropical depression and began accelerating to the northwest, passing to the east of Easter Island, before weakening further into a remnant low. With this degeneration, the Chilean Navy Weather Service ceased issuing warnings on the storm. On May 6, Katie's remnant low dissipated. During Katie's entire existence, the storm remained east of 120°W, outside of the South Pacific basin's official boundary.
caption: Map plotting the track and the intensity of the storm, according to the Saffir–Simpson scale
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