2011-08-25
By staff reporter
Major Hurricane Irene, located approximately 645 miles (1,040 kilometers) south of Cape Hatteras, North Carolina, is currently tracking north-northwest at 13 mph (20 kph).
A report issued by Aon Benfield research centre said although the radius of maximum wind is larger today than yesterday, satellite and aircraft data have not been very conclusive of evidence of a secondary eyewall at this time. While the eye is a little more evident in the last few visible satellite images, it said, it is not as clear as it was yesterday morning.
The Air Force aircraft has measured winds that roughly support the initial intensity of 115 mph (185 kph).
"Center fixes from the aircraft overnight and this morning indicate that the expected north-northwestward turn has occurred. A northward turn is expected tonight or early Friday as Irene moves through a break in the Atlantic ridge. A mid/upper-level trough moving through the Great Lakes region is expected to then turn Irene toward the north-northeast in a couple of days. This trough is forecast to bypass Irene, leaving the hurricane in deep southerly flow between a trough over the central United States and a building ridge over the Atlantic Ocean," the report reads.
This pattern, Benfield believes, will likely keep the hurricane very near the east coast of the US. The forecast computer model guidance envelope has shifted a little westward on this cycle, and the new official track has been nudged west as well. "The new NHC forecast now lies generally close to the overall model consensus. Since Irene is such a large tropical cyclone, significant impacts are likely along the US East Coast regardless of the exact track it takesm," it continues.
The environment remains conducive for some additional strengthening during the next day or two. The main influencing factor during the short term will likely be eyewall cycles which are difficult to predict. After 48 hours, southwesterly wind shear is forecast to increase which will likely start the weakening process. However, since Irene has such a large and intense circulation, it will probably be slow to weaken.
Hurricane-force winds are currently spreading over the northwestern Bahamas. Hurricane or tropical storm-force winds are still occurring over portions of the central Bahamas, but should begin to diminish later today. Tropical storm-force winds are possible within the watch area along the coast of North and South Carolina by late Friday.
In areas of onshore winds near the center of Irene, an extremely dangerous storm surge will raise water levels by as much as 7 to 11 feet above normal tide levels over the central and northwest Bahamas. Water levels will gradually subside over the southeastern Bahamas through tonight. Near the coast, the surge will be accompanied by large and dangerous waves.
Irene is expected to produce rainfall accumulations of 6 to 12 inches over the Bahamas.
Swells generated by Irene are affecting portions of the coast of the southeastern US. These swells will cause life-threatening surf and rip current conditions.
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