You probably need to do what I did and put in a few more "$message = preg_replace" in the script.
Find the section near the bottom of the script that looks like this...
$message = preg_replace('|this afternoon|i','Aft.noon',$message);
// $message = preg_replace('| night|is',' nite',$message);
$message = preg_replace('|chance|is','Chc',$message);
$message = preg_replace('|Partly|is','Ptly',$message);
then add a few more that may be hanging you up. Here is some of mine...
$message = preg_replace('|this afternoon|i','Aft.noon',$message);
$message = preg_replace('| night|is',' nite',$message);
$message = preg_replace('|chance|is','Chc',$message);
$message = preg_replace('|Partly|is','Ptly',$message);
$message = preg_replace('|showers|is','Shwrs',$message);
$message = preg_replace('|Mostly|is','Mstly',$message);
$message = preg_replace('|Scattered|is','Sctd',$message);
$message = preg_replace('|increasing|is','Incr.',$message);
$message = preg_replace('|Cloudy|is','Cldy',$message);
$message = preg_replace('|Thunder storm|is','Tstm',$message);
$message = preg_replace('|Isolated|is','Iso',$message);
$message = preg_replace('|T-Storms|is','Tstm',$message);
Make a copy of your original first in case you make an error.