* WHAT...Dangerously hot conditions with heat index values up to 108 southwest Iowa and the Omaha metro.
* WHERE...In Iowa, Fremont, Mills, Montgomery, Page, Pottawattamie, and Shelby Counties. In Nebraska, Douglas and Sarpy Counties.
* WHEN...Until 9 PM CDT Tuesday.
* IMPACTS...Heat related illnesses increase significantly during extreme heat and high humidity events.
* ADDITIONAL DETAILS...Overnight heat indices in the upper-70s will make it difficult for homes without air conditioning to cool down. Hot weather is expected to persist through the week.