The 2009–10 Australian region cyclone season was a below average tropical cyclone season, with eight tropical cyclones forming compared to an average of 12. The season began on 1 November 2009 and ran through until it end on 30 April 2010. The Australian region is defined as being to south of the equator, between the 90th meridian east and 160th meridian east. Tropical cyclones in this area are monitored by five Tropical Cyclone Warning Centres (TCWC's): Jakarta, Port Moresby, Perth, Darwin, and Brisbane, each of which have the power to name a tropical cyclone. The TCWC's in Perth, Darwin, and Brisbane are run by the Australian Bureau of Meteorology, who designate significant tropical lows with a number and the U suffix. The Joint Typhoon Warning Center also issues unofficial warnings for the region, designating significant tropical cyclones with the "S" suffix when they form west of 135°E, and the "P" suffix when they form east of 135°E. Timeline December 10 December 0600 UTC — TCWC Darwin reports that Tropical Low 01U has formed northeast of Darwin. 13 December 0000 UTC — TCWC Darwin reports that Tropical Low 01U has become a Category One Tropical Cyclone and is named as Cyclone Laurence. 14 December 2100 UTC — TCWC Darwin upgrades Tropical Cyclone Laurence to a Category 2 cyclone. 15 December 0300 UTC — TCWC Darwin upgrades Tropical Cyclone Laurence to a Category 3 cyclone. 1800 UTC — TCWC Perth upgrades Laurence into a Category 4 cyclone. 16 December 0000 UTC — TCWC Perth upgrades Severe Tropical Cyclone Laurence to a Category 5. 0300 UTC — TCWC Perth downgrades Laurence to a Category 3 cyclone. 2100 UTC — TCWC Perth downgrades Laurence to a Category 2 cyclone. 17 December 2100 UTC — TCWC Perth downgrades Laurence to Category 1 strength. 18 December 1200 UTC — TCWC Perth downgrades Laurence to a Tropical Low. 19 December 0400 UTC — TCWC Perth re-upgrades Tropical Low Laurence to a Category 1 cyclone. 1600 UTC — TCWC Perth re-upgrades Tropical Cyclone Laurence to a Category 2 cyclone. 20 December 1500 UTC — TCWC Perth re-upgrades Laurence to a Category 3 cyclone. 2000 UTC — TCWC Perth re-upgrades Severe Tropical Cyclone Laurence to a Category 4 cyclone. 21 December 0300 UTC — TCWC Perth re-upgrades Laurence to a Category 5 cyclone. 1200 UTC — TCWC Perth downgrades Laurence to a Category 4 cyclone. 2000 UTC — TCWC