NEW : Bertha 's winds increase from 120 mph to 115 mph . CNN could be affected by the hurricane May 31 . Likelihood of storm making landfall in Mexico is very small . Bertha is the first hurricane of the 2008 Atlantic hurricane season .
NEW : Bertha 's winds increase from 115 mph to 120 mph . Bermuda could be affected by the hurricane this weekend . Likelihood of storm making landfall in U.S. is very small . Bertha is the first hurricane of the 2008 Atlantic hurricane season .