As Clark mentioned. There is some debate on the SST anomaly in the GOM. I have seen several print articles with different anomalies listed. The 12 dgeree anomaly is the highest one that I've seen thus far.
I use Dr Nan Walker's (Project Director) site at LSU for my GOM SST information.
This site lags a few days behind the Navy and NOAA, due to workdays and data delay.
The most current map for this month is the 15th of March, 2006.
Compare with the same calendar week from last year.
Note: the numbers shown on the contour intervals, are Sea Surface Height anomaly in centimeters. This is in correlation with the Sea Surface Temperature-SST under the contours.
( You may have to browse a few days before or after the date to get a cloud free image. Image are slow to load on DSL. May take quite a bit longer on dialup connections.~danielw)
Here's a link to the prestorm SSTs for Ivan '04, Katrina '05 and Rita '05.