page_title: Cyclone Ann
section_title: Meteorological history
hierarchical_section_title: Cyclone Ann / Meteorological history
caption_attribution_description: English: Track map of Tropical Cyclone Ann of the 2018-19 Australian region 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: Tropical Cyclone Ann was a small and relatively weak off-season tropical cyclone that brought minor impacts to the Solomon Islands, Far North Queensland and coastal regions of the Northern Territory's Top End during May 2019. Ann was the twenty-fifth tropical low, eleventh tropical cyclone, ninth Category 2 tropical cyclone and second off-season tropical cyclone of the 2018–19 Australian region cyclone season. The system developed from a tropical low that formed on 7 May in the South Pacific cyclone region. The low gradually intensified while moving southwards, and strengthened into a tropical cyclone on 11 May. The storm then turned to the west-northwest and continued to strengthen over the Coral Sea. Ann reached peak intensity on 12 May as a Category 2 tropical cyclone on the Australian scale, with ten-minute sustained winds of 95 km/h and a central barometric pressure of 993 hPa. One-minute sustained winds of 100 km/h made Ann equivalent to a strong tropical storm on the Saffir-Simpson hurricane wind scale. The storm began to decay soon afterwards, and weakened to a gale-force tropical low on 14 May.
context_section_description: During late April and early May, a strong pulse of the Madden-Julian Oscillation tracked eastwards across the tropical Indian Ocean and the Maritime Continent. Despite the traditional Australian wet season having concluded at the end of April, the pulse led to the redevelopment of monsoonal conditions to the north of Australia. Additionally, the presence of the pulse led to environmental conditions which were more favourable for tropical cyclogenesis than normal for the cyclone off-season. As the pulse continued into the Pacific Ocean, the Australian Bureau of Meteorology (BOM) noted the formation of a weak tropical low embedded within a low-pressure trough on 7 May, located within the northwestern South Pacific cyclone region. The BOM assigned the system the identifier code 26U.
  The tropical low moved slowly towards the southwest while organisation gradually proceeded in a generally favourable environment. By 00:00 UTC on 8 May, the system was located just to the east of Honiara in the Solomon Islands. After passing over the Solomon Islands, the developing low assumed a more southerly track under the influence of a mid-level high-pressure ridge located to the east. Over the following few days, the tropical low skirted the boundary of the Australian cyclone region and South Pacific cyclone region, passing between the two basins three times in total. By 10 May, disagreement emerged between meteorological agencies regarding the prospect of future development for the system. The BOM anticipated that further development into a tropical cyclone was very unlikely, citing an atmospheric environment that they expected to be unconducive for maintaining a significant tropical system. Conversely, the United States' Joint Typhoon Warning Center (JTWC) analysed the environment to be supportive of tropical cyclogenesis overall, and forecast a gradual strengthening to tropical cyclone intensity over the following days, in accordance with numerical weather prediction model solutions. Aided by warm sea surface temperatures and the favourable outflow provided by an anticyclone in the upper troposphere, deep convection continued to grow over the consolidating low-level circulation centre on 11 May. The storm was upgraded to a Category 1 tropical cyclone on the Australian scale by the BOM at 18:00 UTC on 11 May, while located approximately 1420 km (880 mi) east of Cairns. Located just within the Australian region at this time, the newly formed cyclone was named Ann by the BOM. The JTWC indicated that Ann had become equivalent to a tropical storm on the Saffir-Simpson hurricane wind scale at this time.
  An eastwards-propagating trough in the upper troposphere began to erode the ridge which had been steering the strengthening system southwards. A new mid-level ridge to the south began to develop, causing Ann to accelerate west-northwestwards across the Coral Sea towards Queensland. Environmental conditions remained favourable for development, and the system quickly reached high-end Category 1 intensity at 00:00 UTC on 12 May. Soon afterwards, however, competing environmental influences began to arrest the intensification trend. The cyclone was maintained at Category 1, although the BOM noted that this assessment may have been conservative, with the possibility that the system may have already reached marginal Category 2 intensity. Analysis of satellite imagery indicated that easterly vertical wind shear had begun to increase near the system, and that drier air had started to become entrained into the circulation from the southwest. Ann reached peak intensity at 18:00 UTC on 12 May as a low-end Category 2 tropical cyclone on the Australian scale, generating ten-minute sustained winds of 95 km/h (60 mph) and gusts to 130 km/h (80 mph), with a central barometric pressure of 993 hPa (29.32 inHg). The JTWC reported that one-minute sustained winds reached an estimated 100 km/h (65 mph) at this time, equivalent to a strong tropical storm on the Saffir-Simpson hurricane wind scale.
  Ann began to weaken on 13 May. Good poleward outflow provided by the t
caption: Map plotting the track and the intensity of the storm, according to the Saffir–Simpson scale
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