I will come out with my full annual May Atlantic hurricane season forecast later this spring. However, many other agencies are coming out with their preseason forecasts. Not surprisingly, many are expecting an above average season. Without getting into too much detail, one of the primary reasons is the very warm sea surface temperature (SST) anomalies in the Atlantic this spring. A large contributor for the strong anomalies has been the negative North Atlantic Oscillation (NAO) this winter and spring. A negative NAO means the subtropical high pressure system over the Atlantic has been weaker than normal, which in turn causes weaker trades winds and less evaporational cooling.
Check out the large warm anomaly in the eastern Atlantic today:
In particular, and probably most concerning, SST anomalies are very warm in the Main Development Region of the Atlantic (about 10-20 degrees North). Here is what we are currently running at:
As of today the Atlantic MDR is a full degree Celsius above normal! If these conditions persist into the peak hurricane season, we could have a very busy year. As of now, it is simply something to keep an eye on. Both of the plots above were taken from tropicaltidbits.com , a great place to keep up to date with the tropics as well.