Radar

Geographical Situation: The Wollongong (Appin) radar is located on the Woronora plateau about 18 km north-northwest of the Wollongong CBD. The site, at an elevation of 449 metres above sea level, gives the radar an excellent view in all directions. The rough topography of the Great Dividing Range and the Southern Highlands slightly compromise coverage in the northwest, west and southwest sectors, but coverage to the north, east and south is largely unobstructed. Based on detecting echoes at an altitude of 3,000 metres altitude, the radar coverage extends north across Newcastle and Singleton, northwest across the Bathurst region to Rylstone and Blayney, southwest to around Lake George (between Goulburn and Canberra) and south to Braidwood and Batemans Bay. Meteorological Aspects: The radar will readily detect thunderstorms and deep rain-bearing systems approaching from any direction, often at greater range than quoted above. The high sensitivity of the radar assists the detection of drizzle and light shower activity over Wollongong and the Illawarra/Southern Highlands region as well as over southern parts of Sydney, but, as with other radars, at longer range these shallow weather systems may be under the radar beam and therefore not detected. While the Wollongong radar provides useful coverage of Sydney, users in that area are encouraged to use the Sydney (Terrey Hills) radar which will provide superior coverage in most circumstances. Similarly, people in Newcastle should refer to the closer Newcastle radar and Canberra residents the nearer Canberra (Captains Flat) radar. Non-meteorological Echoes: In most cases, processing of the radar signal removes permanent echoes caused by hills, buildings and other solid objects, but sometimes a few remain. These usually show up as small, stationary or erratically moving specks, mostly over the higher ground of the Great Dividing Range and Southern Highlands. On cold clear winter nights and mornings these echoes may become stronger or increase in number due to downward refraction of the radar beam. Ships are regularly observed over the sea. These appear as specks or short arcs (oriented perpendicular to the direction of the radar). They can often be tracked moving towards or away from port over a series of images. In strong winds and very rough seas, the Wollongong radar may show sea clutter off the coast out to a range of about 100 km. This sea clutter tends to remain in the same area and can therefore be distinguished from rain echoes, which generally move with the wind. Areas of light stationary echo often appear close to the radar (within about 50 km) around sunset and can persist for much of the night. These are due to the collective activity of flying nocturnal insects and other wildlife.