The 168,666 ton Anthem of the Seas departed Bayonne, New Jersey last Saturday with about 4,500 guests and 1,600 crewmembers for a scheduled 7-day roundtrip to the Bahamas. During Sunday the vessel was sailing southward to a schedule port call at Port Canaveral, Florida when it encountered a large, hurricane-force storm off of Cape Hatteras, North Carolina.
As early as Wednesday afternoon, the NOAA 96 hour forecast chart was showing a rapidly deepening low forming east-southeast of Cape Hatteras early Sunday reaching storm force by early Monday morning.
Updated forecasts late Friday night indicated that storm force winds likely would occur closer to the North Carolina coast than the earlier forecast by late Sunday with conditions reaching hurricane force winds by early Monday.
By Saturday evening the updated NOAA Forecast chart issued just after midnight Saturday night indicated hurricane force winds with waves to 24 feet should be expected just off the Carolina coast by Sunday evening instead of early Monday morning.
Role of the Gulf Stream
The warm waters of the Gulf Stream move up the US Coast from the Florida Straits and pass close to Cape Hatteras before turning eastward. The warm water in conjunction with cold air moving off the East Coast during winter often provides the dynamics to produce rapidly deepening storms off the US East Coast. In addition, when strong winds blow over strong currents moving in the opposite direction waves tend to shorten in length and increase in height. Near the north wall of the Gulf Stream this is a well known phenomena where there is a higher risk for rouge waves during these conditions.
As of this writing, I have not seen the actual position reports of the Anthem of the Seas so it would be difficult to say what track options were available to the master or what decisions were made. Given that the early forecasts suggested storm force conditions with the heaviest weather developing overnight Sunday into early Monday, perhaps the voyage plan might have taken the vessel clear of this area before the onset of the worse conditions.
Forecast updates issued late Friday night indicated that the area of storm force winds would likely occur closer to the coastline but the heaviest conditions still developing Sunday night and early Monday. By late Saturday night, the voyage was already underway when the updated forecast indicated that the storm would produce hurricane force winds with seas over 20 feet.
The storm did, in fact, deepen rapidly during Sunday with hurricane force winds and waves to over 30 feet developing by early Sunday evening just off the North Carolina Coast when the vessel encountered severe weather conditions near where the Gulfstream comes closest to the North Carolina coast.
The master indicated winds were 150-160 knots but the best evidence so far is that peak winds were in the 65-75 knot range late Sunday afternoon into early Sunday evening which would have been severe enough. Given sustained winds of 65-75 knots it is likely that wind gusts could have been in the range of 80-95 knots (90-110 mph)! These conditions are not uncommon with intense winter storms over the North Atlantic, however, this is likely an extreme event for this particular location.
The NOAA/NESDIS RAPIDSCAT (satellite derived surface winds) for late Sunday afternoon suggest winds may have already reached as high as 75 knots (see below).
Ocean Weather Services