Cyclone Joni (2009)

Cyclone Joni (RSMC Nadi designation: 11F, JTWC designation: 20P) formed as a weak tropical disturbance late on March 9, about 770 km (475 miles) west of Tahiti. A Tropical Cyclone Formation Alert was then issued by the Joint Typhoon Warning Center, the following day as the disturbance had a well defined low level circulation center. Later that day the Regional Specialized Meteorological Centre, in Nadi, Fiji, started to issue advisories on the tropical disturbance while upgrading it to Tropical Depression 11F, while a cyclone gale warning was declared for parts of the southern Cook Islands. On March 11 the Tropical Depression continued to intensify and was upgraded to a Tropical Cyclone by RSMC Nadi and the JTWC with RSMC Nadi assigning the name Joni to the storm, which was a name that had been retired following its previous use in 1992. The next day both RSMC Nadi and the JTWC reported that Joni had reached its peak winds of 100 km/h (65 mph), which made it a Category Two cyclone on the Australian Tropical Cyclone Intensity Scale and a Tropical storm on the Saffir-Simpson Hurricane Scale. As Cyclone Joni reached its peak intensity, RSMC Nadi passed primary warning responsibility to the Tropical Cyclone Warning Center in Wellington, New Zealand. Early on March 14 TCWC Wellington downgraded Joni to an extratropical low, they then issued their final advisory, early the next day. There was only minimal impact reported in the southern Cook Islands.

Meteorological history
On March 9, 2009, a weak tropical disturbance formed about 800 km, (500 miles), to the west of Tahiti, French Polynesia. Early the next morning the Joint Typhoon Warning Center, issued a Tropical Cyclone Formation Alert on the developing disturbance, as it had a good chance of developing further. The disturbance at this time had a well defined low level circulation center, with convective banding wrapping into the disturbance and was located in a trough of low pressure. Later that day the Regional Specialized Meteorological Centre (RSMC) in Nadi, Fiji, reported that the disturbance had become organised enough, to be designated as Tropical Depression 11F.

Early on March 11, the JTWC reported that the depression had intensified enough to be designated as a Tropical Cyclone and assigned the designation of 20P to the Cyclone. Later that morning RSMC Nadi also upgraded the depression to a Tropical Cyclone and assigned the name Joni to the storm. The next day RSMC Nadi reported while Cyclone Joni was moving to the southwest through the Southern Cook Islands that Cyclone Joni had continued to intensify and upgraded it to a category two cyclone. Later that day as RSMC Nadi passed primary warning responsibility for Cyclone Joni to the Tropical Cyclone Warning Center (TCWC) in Wellington, New Zealand, both the JTWC and RSMC Nadi reported that Joni had reached both its 1-minute and 10 minute peak wind speeds of 100 km/h (65 mph). On March 13, Cyclone Joni started to weaken, becoming a Category one Cyclone and then into an extratropical low early the next day. Early on March 15 both the JTWC and TCWC Wellington issued their final warning on the extratropical cyclone that was Cyclone Joni as it had dissipated.

Preparations, impact and naming
As soon as Tropical Depression 11F had formed late on March 10, RSMC Nadi started to issue special weather bulletins for the Southern Cook Islands as a Gale warning had been declared for Aitutaki, Mauke, Mangaia as well as other nearby smaller islands. Early the next day, a Gale warning was declared for Rarotonga, while the warning for Aitutaki was downgraded to a strong wind warning. All warnings for the Southern Cook Islands were then cancelled late on March 12. There were several reports of heavy rain in Mangaia that were caused by Cyclone Joni, however the overall damage was minimal.

This is the second time a cyclone has been named Joni, after last being used in the 1992–93 South Pacific cyclone season. The name Joni was retired after that season as it caused significant damages to Fiji, however for unknown reasons the name Joni remained on the naming lists.