Hey Odie -
Couldn't get exactly what you wanted, but this should be close enough.
At 6PM the water in the Houma Navigation Channel at Dulac was 47 degrees.
At 7:24 PM the water in Barataria Pass at Grand Isle was 43 degrees.
And you can safely bet that north of those points - and in the river-effected areas below Venice - are a tad chillier than those are!
The site you need to scrutinize is USGS Water Data. Get it, then clilck on Real-time data, then again on the image of Louisiana, and finally on the button where you want the data from. Good scoop!
Bon chance!
Pete