About Namoi (Blackjack Mountain) Radar

Geographical Situation

The radar is located on Black Jack Mountain, about 8 km WSW of Gunnedah, at nearly 700 metres above sea level. This gives the radar an excellent view in all directions. Based on detecting echoes at an altitude of 3,000 metres, the radar coverage extends north across Moree, northeast over Inverell andGuyra, east to Armidale, southeast to Scone and the Upper Hunter, south to Mudgee, southwest towards Dubbo and Gilgandra, west to Coonamble and northwest over Burren Junction.

Meteorological Aspects

The radar should provide excellent coverage of the Namoi region, including Tamworth and the Liverpool Plains. The radar is well placed to detect thunderstorms and deep rain-bearing systems in almost all directions, often at greater range than quoted above. An obstruction at a bearing of about 228 degrees suppresses weather echoes through a narrow sector in this direction, which extends towards Dubbo. The rugged terrain of the region may compromise the radar's view of low-level conditions in some directions. In particular, the Liverpool Ranges and Warrumbungles to the south and southwest of the radar obstruct the radar's view of low-level conditions beyond about 100 km in these quadrants. This means that light showers and drizzle activity over the Upper Hunter and the Dubbo/Gilgandra regions may not be detected by the Namoi radar. People in the Hunter region are advised that the Newcastle radar will provide superior coverage in most conditions. Similarly, the Nandewar Ranges will somewhat compromise detection of light showers and drizzle over the Gwydir region, including Inverell and Bingara. The Moree radar, though less sensitive, will provide an alternative view of these areas. The Great Dividing Range affects longer range coverage in the eastern quadrants and the better situated Grafton and Newcastle radars will generally provide better coverage over eastern parts of the Northern Tablelands.

Non-meteorological Echoes

In most cases, the processing system at the radar removes permanent echoes caused by mountains, hills, buildings and other solid objects. Occasionally, however, some may not be completely removed from the display. These usually show up as small, stationary, erratically visible specks, mostly over the higher ground of the Great Dividing Range, the Liverpool Ranges, the Warrumbungles and the Nandewar Ranges. On cold clear winter nights and mornings these echoes may become stronger and increase in number due to downward refraction of the radar beam by the cold air near the Earth's surface.