A trend persists only if the conditions that started in the first place are persisting and reinforcing in nature...
meaning news events, and reinforcement of price cascade in the direction of the initiated trend.. ie support/resistance failure..
notice the previous historical ...behavior..
chart to follow.. site wont let me attach files.
<a href="http://content.screencast.com/media/46e915ea-2da3-41cc-aef4-b7c9f822a65b_e4e7210a-d70e-4e9a-b1ea-ac06782ba068_static_0_0_05052008-141808.jpg"><img src="http://content.screencast.com/media/46e915ea-2da3-41cc-aef4-b7c9f822a65b_e4e7210a-d70e-4e9a-b1ea-ac06782ba068_static_0_0_05052008-141808.jpg" width="1254" height="850" border="0" /></a>