i'm fredericka whitfield and you're in the "newsroom." we're about to hear from president obama. he's about to give a campaign speech in 20 minutes from now and maybe earlier than that in that location urbandale, iowa. the president has been hitting the campaign trail hard in the runoff in the democratic convention that gets under way tuesday. our athena jones is in urbandale. it looks like a sizeable crowd. what is the president hoping to accomplish here that perhaps he won't or maybe it's the warm-up to the convention? >> reporter: hi, fred. that's exactly what it is. today launches what the campaign is calling their road to charlotte which is, of course, the road to the big speech he'll be giving on thursday night in charlotte at the democratic convention accepting his party's nomination once again. his goal is to continue to draw contrasts between the plans he has and what he's already done to help the middle class in terms of tax cuts or affordable access to health care and college and what he says his opponents do which is offer plans and proposals that will favor the rich.

>> fredericka, the computer models are suggesting perhaps the eastern edge of missouri could see some significant rainfall. this is a slow, lumbering system, but it is losing a lot of its punch, but it is potentially going to trigger some storms across illinois, the central mississippi river valley and the ohio valley, but look at who got most of the rainfall. in louisiana on the seventh anniversary of katrina it made landfall in louisiana with 20-plus inches of rainfall in new orleans and just about 450,000 people still without power in southeastern louisiana. the temperature right there right now 90 degrees and that's a hot temperature if you're doing without air-conditioning, but this is what it feels like with that heat index. it feels like it's 103 degrees and it could take several more days before the electricity gets turned back on. we have two tornado watches. this one across south central portions of illinois and into kentucky as well as missouri goes into 9:00 local time. here ate back side and the remnants of what is left of isaac and this will continue to swirl around and

. >>> hello, everyone, i'm fredericka whitfield, you hear plenty of noise and lots of spin on the campaign trail, for the next hour, cnn will help you fixture out where the candidates stand on them, we'll size up the issue, issue by issue and how barack obama and mitt romney plan to tackle these key american challenges. before we get to that, here's a look at some of the top stories making news today. >>> a desperate search for two tennessee children today, their home burned down a week ago but police say still no trace of the children. suzannesan candiotti is joining. >> reporter: at this hour, state investigators are using teams of people using dogs to search a wider area of the woods on both sides of the road around the house that was insin rated. with absolutely no physical evidence that the children were home when their grand charparen died in that fire, investigators are doing all they can to find those children. investigator have found no sign of 9-year-old chloe and 7-year-old gauge daniel. no signing the youngsters were there and so far no evidence they weren't when an inferno swe

i'm fredericka whitfield. it is crunch time for the presidential candidate, president obama and mitt romney only have three days to prepare for their first debate. president obama will prepay in nevada. he already arrived there, he'll be holding an evening rally and then concentrate on preparing for wednesday night's showdown. so what is at stake in this first debate? athena jones takes a look. >> reporter: both the obama and romney campaigns are doing their best to lower expectations ahead of wednesday's debate. >> we have expected all along that governor romney will have a good night, he's prepared more than any candidate in history. >> president obama is a very gifted speaker. the man's been on the national stage for many years, he's an experienced debater, he's done these kinds of debates before, this is mitt's first time on this kind of a stage. >> romney -- the president was widely regarded as one of the most talented political communicators in modern history. myers even pointed to a cnbc poll. the obama