You're a gentleman and a scholar!
<?php
$message = "EASTRIVANN RES STRUCTURE FIRE AD: 4966 TURKEY SAG RD CTY: AC LOC: ATAC4 FIRE IN STRUCTURE/ALARM CO CONFIRMED W/HOMEOWNER XST: 2751 BELL ACRES XST2: 2312 PETERS MTN RD";
$delimiters = array("EASTRIVANN", "AD:", "CTY:", "LOC:", "XST:", "XST2:");
$replaceWith = "~";//replace the non-bolded text with a tilde character
$newMessage = str_replace($delimiters, $replaceWith, $message);
//now explode on the ~ character to get all the pieces.
$array = explode($replaceWith, $newMessage);
echo "Call Type:<br>";
echo $array[1];
echo "<br>Address:<br>";
echo $array[2];
echo "<br>Location:<br>";
echo $array[3];
echo "<br>Cross Street 1:<br>";
echo $array[4];
echo "<br>Cross Street 2:<br>";
echo $array[5];
?>
Thanks so much for the help!