Storm Australian Severe Weather Forum
Severe Weather Discussion => General Weather - all topics not current severe weather. => Topic started by: Antonio (stormboy) on 17 January 2009, 06:50:00 PM
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i dont know why but all the time i look at the Grafton radar its very specky and dose not give a good picture of rain activity
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I noticed an interesting radar effect on either Wednesday or Thursday when it was so hot (I think Wednesday from memory).
The Sydney radar was showing rainfall immediately off the coast towards Newcastle and nothing local. The Newcastle radar was showing rainfall off the coast south of Norah Head to Sydney and nothing local.
Obviously with the hot weather and conditions a lot of tropospheric ducting was occurring (FM signals audible from New Zealand by tropo), and for some reason it confused the radars. Not noted on any others.
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Because Grafton is old, obsolete radar that doesn't have advanced detection features of a Doppler radar. As for the false echoes, just ignore those, they're seen frequently on Brisbane's and Gympie's as well. If you read the Bureau's FAQ (http://www.bom.gov.au/weather/radar/about/radar_image_faq.shtml) on radar images, it should explain to you why the radar sometimes mistakes various atmospheric conditions as rain. On Gympie's radar in particular, there is sometimes a noticeable false echo to the north of Frasier Is which sometimes passes off as a rain band. I don't see why that can't be fixed as the previous radar didn't have that issue that I knew of.
Speaking of radars, Mt Stapylton went down again yesterday. Darn it. You would think the Bureau would invest in strengthening the radar and make it more reliable during storm days!
*end of rant*