Hurricane katrina devastated the coastal areas of Louisiana, Mississippi, and Alabama. What air mass did katrina originate? List 2 explanations for why Katrina decreased in intensity, making landfall as a Category 3 hurricane?

This question belongs in "Meteorology".

Be that as it may.

NOAA has a pretty good history section in their "Tropical" weather section. Go to a NOAA weather forecast site and look down (usually) the left side.