small puff of smoke into a full raging, all consuming fire. norah: why firefighters are struggling to contain the blazes. the fire is moving pretty quickly. it s a difficult situation and it s a rapidly changing situation. norah: the record-breaking heat wave for much of the country. cbs evening news starts now. fast-moving wildfires, record-breaking heat, and a tropical storm threat. good evening. i m norah o donnell and thank you for being with us. and the weather is where we re going to begin tonight because right now, americans are facing extreme conditions from coast-to-coast. 76 million people are suffering under oppressive heat across 24 states, as high temperatures scorch the midwest and northeast. and the worst of the heat is yet to come. down south, parts of texas are under tropical storm warnings. as we track a system in the gulf of mexico that is likely to become the first named storm of the season. and out west, dozens of wildfires are raging, includi