In the ancient world, many signs and symbols carried with them deep meanings and were often the key to unlocking the future. Changes in weather, the direction that birds flew, the reading of tea leaves, all were interpreted and gave direction towards what tomorrow holds in store.
Having said that – being modern times and all – signs and portents can be read in a much more benign and maybe even accurate manner (at least sometimes). Newspapers, blogs, reports, sources – you get the picture. And, if you really pay attention and look for them sing and portents can be very potent.