Isaac upgraded to hurricane, storm surge underway

At 11:20am EDT, NHC upgraded Isaac to a hurricane.  It has been steadily marching across the Atlantic for the past 12 days, and now, just hours before its final landfall, it nudges past the hurricane threshold.

But that is merely a name change at this point... the difference in wind speed is minimal from what it was before.  The important part is that it's a very large and dangerous storm.  Areas along the coasts of Alabama, Mississippi, and Louisiana are already experiencing 3-5' storm surges, and that will increase throughout the day.  In many locations however, the receeding tide will help offset the encroaching surge, but not completely.  Here is the latest storm surge forecast using the most current track and intensity data (this is the 10% excedance version):

• Visit the Tropical Atlantic Headquarters.
• Subscribe to get these updates emailed to you.
• Follow me on Twitter