What does hurricane minimum pressure mean?

Question

Have been reading about the hurricanes that are coming and ones that have happened in the past. When it says "Katrina had a minimum pressure of 904 millibars (26.64 inches)" what does that represent?

Answer 1

It refers to the minimum surface air pressure that exists in the eye of the tropical system.  Outside the eye (or center) the air pressure is much higher than within the eye.

Answer 2

That means the lowest (estimated) central pressure Katrina attained was 904 millibars.

Answer 3

That refers to the pressure that is in the hurricane. The lower the pressure the more powerful the hurricane is. I think hurricane strength pressure is like 990. So 904 is very strong.