Unusued Local Variable - Variable Variables?

PHPStorm indicates $aColsHeavy and $aColsLight are unused. How do I tell PHPStorm that this these variables ARE used?

  $aColsHeavy = explode(",", $sColsHeavy);
  $aColsLight = explode(",", $sColsLight);

  foreach($aGrid as $aValues){

   $iStep  = $aValues[$aColsStep[0]];
   $aHeavyLight = array();

   foreach(array("aColsHeavy", "aColsLight") as $sHeavyLight){

    foreach($$sHeavyLight as $iColHeavy){

     if(!is_numeric($iColHeavy)) continue;

     $sValue = str_replace(" ", "", $aValues[$iColHeavy]);
     $sValue = str_replace("_", " ", $sValue);

     $aHeavyLight[$sHeavyLight][] = mysql_escape_string($sValue);

    }

   }

   $aInsert[] = "($iStep, '".Comma($aHeavyLight['aColsHeavy'])."', '".
       Comma($aHeavyLight['aColsLight'])."', NOW(), "._USERID.")";

  }