Cyclone Graham
Encyclopedia
Cyclone Graham of the 2002–03 Australian region cyclone season was a weak tropical storm that affected Australia during late February and early March 2003. Graham originated from an area of convection
Atmospheric convection
Atmospheric convection is the result of a parcel-environment instability, or temperature difference, layer in the atmosphere. Different lapse rates within dry and moist air lead to instability. Mixing of air during the day which expands the height of the planetary boundary layer leads to...

 the emerged onto water after sitting over Australia on 23 February. The interaction with a monsoon trough
Monsoon trough
The monsoon trough is that portion of the Intertropical Convergence Zone which extends into or through a monsoon circulation, as depicted by a line on a weather map showing the locations of minimum sea level pressure, and as such, is a convergence zone between the wind patterns of the southern and...

 formed an area of low pressure
Low pressure area
A low-pressure area, or "low", is a region where the atmospheric pressure at sea level is below that of surrounding locations. Low-pressure systems form under areas of wind divergence which occur in upper levels of the troposphere. The formation process of a low-pressure area is known as...

 that developed into Tropical Cyclone Graham on 27 February. The storm moved slowly to the east-southeast, and after turning to the south it peaked as a tropical storm and made landfall on Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...

 the next day. The cyclone weakened as it moved inland, and dissipated on 1 March. The storm dropped heavy rainfall and caused high winds, which produced flooding and downed trees. One fatality occurred, though no significant damages were reported.

Meteorological history

On 23 February 2003, an area of convection
Atmospheric convection
Atmospheric convection is the result of a parcel-environment instability, or temperature difference, layer in the atmosphere. Different lapse rates within dry and moist air lead to instability. Mixing of air during the day which expands the height of the planetary boundary layer leads to...

 that was situated over land for roughly a week emerged over open waters along the northern coast of Australia. The strengthening of a deep, persistent monsoon trough
Monsoon trough
The monsoon trough is that portion of the Intertropical Convergence Zone which extends into or through a monsoon circulation, as depicted by a line on a weather map showing the locations of minimum sea level pressure, and as such, is a convergence zone between the wind patterns of the southern and...

 contributed to cyclogenesis, and a low pressure area
Low pressure area
A low-pressure area, or "low", is a region where the atmospheric pressure at sea level is below that of surrounding locations. Low-pressure systems form under areas of wind divergence which occur in upper levels of the troposphere. The formation process of a low-pressure area is known as...

 formed. By 25 February, the low developed a banding feature in which the highest winds were located. Though the storm was located in an area of unfavorable wind shear
Wind shear
Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and direction over a relatively short distance in the atmosphere...

, the Australian Bureau of Meteorology (BoM) began to issue gale warning
Gale warning
A gale warning is a warning issued by weather services in maritime locations about the existence of winds of gale force or above or the imminent occurrence of gales at sea...

s on the system at 0100 UTC the next day, while the low was located several hundred miles north-northeast of Port Hedland
Port Hedland, Western Australia
Port Hedland is the highest tonnage port in Australia and largest town in the Pilbara region of Western Australia, with a population of approximately 14,000 ....

. The disturbance was initially nearly stationary as it showed signs of organization due to relaxed shear, and at 0700 UTC on 27 February, the Joint Typhoon Warning Center
Joint Typhoon Warning Center
The Joint Typhoon Warning Center is a joint United States Navy – United States Air Force task force located at the Naval Maritime Forecast Center in Pearl Harbor, Hawaii...

 (JTWC) designated the storm as Tropical Cyclone Graham, as it had attained 80 km/h (50 mph) 10-minute maximum sustained winds. The first warning was issued on Graham later that day.

Initially exhibiting characteristics of a monsoonal low
Monsoon
Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea...

, a mid-level ridge
High pressure area
A high-pressure area is a region where the atmospheric pressure at the surface of the planet is greater than its surrounding environment. Winds within high-pressure areas flow outward due to the higher density air near their center and friction with land...

 to the south of Graham caused strong westerly winds that moved the storm slowly east-southeastward. However, a deep trough
Trough (meteorology)
A trough is an elongated region of relatively low atmospheric pressure, often associated with fronts.Unlike fronts, there is not a universal symbol for a trough on a weather chart. The weather charts in some countries or regions mark troughs by a line. In the United States, a trough may be marked...

 eroded the ridge, allowing the cyclone to move more towards the south. According to the JTWC, the storm had intensified late on 28 February, though at the same time the BoM noted the slight weakening of the storm. Graham reached its peak intensity that day while nearing the coast.

The storm made landfall at Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...

's Eighty Mile Beach at 1400 UTC on 28 February, and began to weaken. The storm had dissipated on 1 March; the BoM issued their last advisory on the cyclone at 0400 UTC that day, while similarly, the JTWC issued their last advisory just two hours later. The storm's remnants died out in the country's desert
Desert
A desert is a landscape or region that receives an extremely low amount of precipitation, less than enough to support growth of most plants. Most deserts have an average annual precipitation of less than...

.

Impact

In advance of the cyclone, the communities of Wallal, Sandfire
Sandfire, Western Australia
Sandfire is a location and roadhouse on the Great Northern Highway in Western Australia between Port Hedland and Broome. It is the only fuel station in the 610km between those two towns....

, Punmu and Telfer
Telfer, Western Australia
Telfer is a minesite in the Pilbara region of Western Australia, within the Great Sandy Desert. Telfer was previously the state's most isolated town, located north-east of the state capital Perth...

 were put on alert. A warning was issued for Bidyadanga, Pardoo and Cotton Creek. The storm's landfall in Western Australia brought heavy rainfall and high winds. The storm dropped 163 mm (6.4 in) of rain at Telfer in one night, over half the town's annual average; total rainfall reached 175 mm (6.9 in) there. The heavy rain caused flooding and road closures, and swelled a river passing through Fitzroy Crossing
Fitzroy Crossing, Western Australia
Fitzroy Crossing is a small town in the Kimberley region of Western Australia, 400 km east of Broome and 300 km west of Halls Creek. It is approximately 2,524 km from the state capital of Perth....

, though the river only topped its banks slightly. Near that town, at Blue Bush Creek, while a group of people attempted to cross floodwaters, two men were swept away. Both men were rescued, though one died before emergency services arrived. In addition to the flooding, a number of trees were downed. No significant damages were reported.

Following the storm, the name Graham was retired from the Australian region basin.
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