How to make a temporary file in RAM?

I have a script that will pipe its output to |tee scriptnameYYMMDD.txt. After each cycle of the for loop in which the output is generated, I'll be reversing the file contents with tac scriptnameYYYYMMDD.txt > /var/www/html/logs/scriptname.txt so that the log output is visible in a browser window with the newest lines at the top.

I'll have several scripts doing this in parallel. I'm trying to minimize the disk activity, so output from |tee scriptnameYYYYMMDD.txt to a RAMdisk would be best. mktemp creates a file in the /tmp folder, but that doesn't appear to be off-disk.