How to colorise PowerShell output of Format-Table

I try to colorise the column RAM in red if the value is greater than 100 MB:

Get-Process | Format-Table @{ Label = "PID"; Expression={$_.Id}},
            @{ Label = "Name"; Expression={$_.Name}},
            @{ Label = "RAM (MB)"; Expression={[System.Math]::Round($_.WS/1MB, 1)}},
            @{ Label = "Responding"; Expression={$_.Responding}}

I try with Write-Host -nonewline, but the result is wrong.

Get-Process | Format-Table @{ Label = "PID"; Expression={$_.Id}},
            @{ Label = "Name"; Expression={$_.Name}},
            @{ Label = "RAM (MB)"; Expression={write-host -NoNewline $([System.Math]::Round($_.WS/1MB, 1)) -ForegroundColor red}},
            @{ Label = "Responding"; Expression={ write-host -NoNewline $_.Responding -fore red}}

You could colorize the row making use of a regular expression...

filter colorize-row{

    Get-Process | Select-Object Id, Name, WS, Responding | foreach {

        # Print 'red' row if WS greater than 100 MB
        if([System.Math]::Round($_.WS/1MB,1) -match "^([0-9]|[0-9][0-9]|[1-9][0-9]?$|^100$)$"){
            [console]::ForegroundColor="white"; $_;
        } else {
            [console]::ForegroundColor="red"; $_;
        }
    }
}

colorize-row

Output: