Renaming duplicate files while uploading uploads the file but gives WARNINGS

WHAT I AM TRYING TO DO

• I am uploading multiple files using the following PHP script and am trying to rename files having same names.
• Add a real time progress bar (radial).

PROBLEMS

• I am receiving errors yet my files are being uploaded with the new name.
• Have no idea how to go about having the progress bar to update in real time.

PHP

<?php

if(isset($_FILES['uploadfile'])){
    $total_files = count($_FILES['uploadfile']['name']);
    if( $total_files > 0){

        for($i=0; $i<$total_files; $i++) {

            $file_name = $_FILES['uploadfile']['name'][$i];
            $file_size = $_FILES['uploadfile']['size'][$i];
            $file_tmp  = $_FILES['uploadfile']['tmp_name'][$i];
            $file_type = $_FILES['uploadfile']['type'][$i]; 

            $upload_Path = "storage/".$file_name;

            if($file_size > 8000000){
                $errors = 'Total upload size must be less than 8 MB.';
                die;
            }   

            if($file_tmp == ""){
                $errors = 'There is no file path.'; 
                die;    
            }
            else{
                if(!file_exists($upload_Path)){
                    move_uploaded_file($file_tmp, $upload_Path);
                }
                else{
                    $name = pathinfo($file_name, PATHINFO_FILENAME);
                    $ext  = pathinfo($file_name, PATHINFO_EXTENSION);
                    $new_name = $name.rand().'.'.$ext;

                    $new_Path = "storage/".$new_name;
                    rename ($file_tmp, $new_Path);
                    move_uploaded_file($file_tmp, $new_Path);
                }
            }
        }
    }
}
?>

ERRORS

Warning: move_uploaded_file(C:wamptmpphp35CF.tmp): failed to open stream: No such file or directory in C:wampwwwuploadermupld.php on line 36

Warning: move_uploaded_file(): Unable to move 'C:wamptmpphp35CF.tmp' to 'storage/instructions5361.txt' in C:wampwwwuploadermupld.php on line 36