page_title: Cyclone Pat
section_title: Meteorological history
hierarchical_section_title: Cyclone Pat / Meteorological history
caption_attribution_description: English: Track map of Severe Tropical Cyclone Pat of the 2009-10 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 / Monsoon depression
context_page_description: Severe Tropical Cyclone Pat was a small but strong tropical cyclone that passed directly over Aitutaki, Cook Islands, in southern Pacific Ocean on February 10, 2010. Part of a series of storms to impact the group of islands early that year, Pat was first identified as a tropical depression on February 6 well to the northeast of the Samoan Islands. The storm steadily organized as it moved generally southeast, becoming a tropical cyclone on February 8. Turning to the south, intensification began in earnest and the system acquired hurricane-force winds within 48 hours of being named. The 445 km wide system displayed annular characteristics and a 19 km wide eye. Pat reached its peak strength early on February 10 as a severe tropical cyclone with winds of 140 km/h and a barometric pressure of 960 mbar. Hours later it struck Aitutaki, producing gusts in excess of 185 km/h on the island. Hostile wind shear then prompted rapid weakening of the cyclone. The system degraded below gale-intensity on February 11, just 24 hours after it peaked, and was last noted early on February 12.
  Battering Aitutaki with wind gusts in excess of 185 km/h, Cyclone Pat devastated the island.
context_section_description: Between January and March 2010, the Australian monsoon trough extended unusually far east over the southern Pacific Ocean. With above-average sea surface temperatures, stemming from a moderate-strength El Niño, multiple low pressure systems were able to develop across the region. An unusual spree of tropical cyclogenesis in rapid succession ensued, including four hurricane-strength storms: Oli, Pat, Rene, and Tomas. On February 6, the Fiji Meteorological Service (FMS) began monitoring a tropical depression, dubbed 09F, well to the northeast of the Samoan Islands. Embedded within a well-developed trough, the system displayed curved convective banding features. Environmental conditions in the area, including low wind shear, high ocean heat content, and upper-level outflow, favored cyclogenesis. Additionally, an active Madden–Julian oscillation phase moving into the region was expected to bolster development. Steady improvement of the system's convective structure ensued and early on February 7, the Joint Typhoon Warning Center (JTWC) issued a Tropical Cyclone Formation Alert. The low trekked generally east-southeast in response to a near-equatorial ridge anchored to the north. The storm's appearance continued to improve and Dvorak classifications rose to T2.5, indicating gale-force winds were likely present. Accordingly, the JTWC began issuing advisories on the system at 18:00 UTC and dubbed it Tropical Cyclone 14P. Forecasters noted, however, that the small size of the cyclone could lead to erroneously low Dvorak estimates. The FMS followed suit six hours later and assigned the name Pat to the cyclone, assessing it as a Category 1 on the Australian cyclone scale.
  Convection became increasingly symmetric on February 8, and a small eye feature appeared on microwave satellite imagery. Spanning no more than 445 km (275 mi), the developing storm began a gradual turn to the south as steering currents shifted from the equatorial ridge to a subtropical ridge. Based on increasing Dvorak numbers, the JTWC assessed Pat to have reached hurricane-intensity by 06:00 UTC on February 9. The eye feature became more pronounced throughout the day, with convection consolidating inward and becoming more symmetric. Accordingly, the FMS accordingly upgraded Pat to a Category 3 severe tropical cyclone by 18:00 UTC. The system became annular in nature on February 10, characterized by a lack of prominent banding features and uniform convection which surrounded its 19 km (12 mi) wide eye. Pat reached its peak intensity at 06:00 UTC that day as it began turning to the southwest. Maximum winds were estimated at 140 km/h (85 mph) alongside a barometric pressure of 960 mbar (hPa; 28.35 inHg). At the same time, the JTWC assessed Pat to have been a Category 2-equivalent on the Saffir–Simpson hurricane scale with one-minute sustained winds of 165 km/h (105 mph). Weakening began shortly thereafter as wind shear over the system increased. Pat passed directly over the island of Aitutaki between 12:00 and 18:00 UTC.
  The low-level center of Pat began decoupling from convection late on February 10 once it cleared Aitutaki. The storm rapidly weakened amid strong shear, with the center being left completely exposed early on February 11. A solitary band remained along the south side of the storm by that time, and the FMS no longer considered it a tropical cyclone after 06:00 UTC. The lone band of convection dissipated later that day and with no residual thunderstorm activity, the skeletal low turned westward in response to westerly flow. The JTWC maintained Pat as a tropical storm until 18:00 UTC and as a tropical depression until its dissipation early on February 12.
caption: Map plotting the track and the intensity of the storm, according to the Saffir–Simpson scale
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