Calling xmessage from rc.d/local not working

Can anyone explain why calling xmessage from rc.d/local does not work?
If I just run the following script manually from a terminal, then xmessage works.

I wrote the following to suspend the laptop when the battery level drops below 10%. Just before that, I want to display a pop-up message in front of the monitor.

Thanks!

Code:$ cat /etc/rc.d/rc.local

#!/bin/bash

/etc/rc.d/rc.low-battCode:$ cat /etc/rc.d/rc.low-batt

#!/bin/sh

/home/ala/bin/low-batt &Code:$ cat /home/ala/bin/low-batt

#!/bin/sh

while sleep 60
do
battlev=`cat /sys/class/power_supply/BAT0/capacity`

if test $battlev -lt 10
then
xmessage -geometry 300x200+400+200 -title "Battery" \
-buttons okay:1,quit:0 -default okay \
"Batt level Low - Suspending" &
sleep 5
loginctl suspend
fi

done