Tropical Storm Karl is now expected to pass within 400 nm of Bermuda within the next 72 hours as of the 12pm advisory. This latest advisory from the National Hurricane Center takes the center of Karl about 260 nm to the south of Bermuda in the next 72 hours. Karl is forecast to pass closer to Bermuda between 72 and 120 hours from this advisory and adverse weather is possible from Karl.
At this time, Bermuda can expect dangerous surf and sea conditions over the weekend. Further, strong to possibly tropical storm force winds are to be expected beginning late on Friday through Saturday. The final track of Karl will determine the strength and direction of winds and whether or not any significant rains will fall.
Karl has been steered to the west in the flow south of the Bermuda-Azores ridge of high pressure over the last few days. This steering is expected to continue for the next day or so. Karl then turns more to the northwest as the storm approaches a weakness in the ridge that is moving in from the west of Bermuda. By Friday, Karl begins to turn northwards, moving into this weakness in the ridge. Karl then becomes entrained in deep-layered southwesterly flow that accelerates the storm to the northeast.
Dry air surrounding the cyclone and persistent strong vertical wind shear have kept Karl weak and disorganized thus far. However, Karl is entering a more moist environment with higher sea surface temperatures. These factors should support more vigorous convection around the storm. Further, vertical wind shear is expected to weaken at the same time. This should allow deep convection to organize. Both of these factors support a strengthening storm in the coming days and Karl could be at or nearing Hurricane strength as it passes Bermuda.
Hurricane reconnaissance aircraft (ie. hurricane hunters) are scheduled to begin regular investigations into Karl this afternoon and this will give us a better idea of Karl’s current strength and structure, and how favorable the environment is.
As always, follow the official weather sources for the latest information.