Powershell script to return value from even log event...

I'm trying to find/create a script that will query an even in windows even log and pull a value from it. I have server temp monitor that drops the temp in a windows even log. I'm trying to monitor this but I don't know how to pull the data.

Found this but not sure how to get the actual message text out of it so that a value is returned.

Get-WinEvent -FilterHashtable @{logname='application'; ProviderName='Tempalert'} | where-object { $_.Message -like '*' }