The National Weather Service in Shreveport has issued a …EXCESSIVE HEAT WARNING IN EFFECT UNTIL 7 PM CDT SATURDAY… * WHAT…Dangerously hot conditions with heat index values up to 113 expected. * WHERE…In Louisiana, Claiborne Parish, Bienville Parish and Natchitoches Parish. In Arkansas, Union County. * WHEN…From noon today to 7 PM CDT Saturday. *…