2003 Jetta TDI coolant leak while parked

So I drove home last night, about 250 miles. I came out this morning and noticed a puddle under my jetta. I figured out it was coolant. I make long drives regularly with the car and haven't had this issue. I replaced the thermostat not too long ago and had no leaks or issues. Any ideas on why the coolant might have leaked out

2003 Jetta TDI coolant leak while parked