Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather
By: Dr. Jeff Masters , 1:55 PM GMT on September 13, 2005
Ophelia is stuck in place yet again, but this time she threw anchor over some relatively warm water (83F)--right over the Gulf Stream, where a deep, 75-meter thick layer of warm water exists. As a result, Ophelia is slowly strengthening again, and long range radar out of Wilmington, NC is showing the beginnings of an inner eyewall of about 20 miles diameter trying to form inside Ophelia's 100-mile wide cloud-free center. The deep warm water should resist the mixing effect of her winds and prevent water cooler than 80F from upwelling and inhibiting Ophelia's strengthening, at least for the 12 - 18 hours that she is expected to remain stationary.
The latest hurricane hunter flight at 9:20 am EDT found about the same pressure as always, 989 mb, and unimpressive flight level peak winds of 66 knots on the northeast side. Ophelia is in reality a weaker tropical storm than advertised by the NHC; I'd estimate maximum winds near the surface are closer to 60 mph than the 70 mph advertised. Still, the storm is getting better organized, and surface winds may increase back to 70 mph later today, but not much higher. Although the shear is low (5 knots) and the upper-level outflow good, there is still too much dry air and cool water surrounding Ophelia to support anything stronger than a minimal 80 mph Category 1 hurricane. NHC is posting hurricane warnings, and this is reasonable, not so much for the expected wind damage (which should be low), but for the storm surge. Ophelia's winds have had a lot of time to pile up a big mound of water near her center, and the storm surge of 4 - 6 feet she will likely carry to shore in her current state as a tropical storm is more characteristic of a Category 1 hurricane.
The exact landfall point for Ophelia is much less important than for most hurricanes; Ophelia doesn't have the narrow concentrated area of winds that usually make the precise landfall point such a big deal. There will be a large area of the coast that will receive tropical storm force winds, which extend out about 160 miles from the center, an exceptionally large area for a tropical storm. Flooding from rain could be a problem in some places; areas near Wilmington, NC have already received 2 - 3 inches, and will get much more from this very wet storm. Fortunately, much of eastern North Carolina is under mild drought.
Figure 1. Rainfall estimate from the Wilmington radar. The estimates in northern NC at the top of the image are bogus.
Computer model forecasts
All of the computer model forecasts keep Ophelia puttering around her current location most of today, but then turn her north and then northeast just offshore Cape Fear, NC and accelerate her rapidly northeastward out to sea. Some of the models indicate that New England (particularly Cape Cod, MA) and Nova Scotia may receive tropical storm force winds from Ophelia on Friday and Saturday, respectively.
Elsewhere in the tropics
The rest of the tropics are quiet, and it is likely we will get about a one week break in the action. Next week, several of the long-range global models indicate that conditions for tropical storm formation are expected to improve over much of the tropical Atlantic.
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