Ophelia churns up NC coast

The north and west eyewall of Ophelia have whipped near-hurricane force winds over Wilmington, NC and the surrounding waters the past few hours. NOAA buoy 41013 located south of Wilmington, saw maximum sustained winds of 63 mph, gusting to 72 mph. A NOAA reporting station at Wrightville Beach North Carolina recorded 6-minute average wind speed of 68 mph with a gust to 77 mph. A Wilmington Personal Weather Station, NC State Ports, recorded maximum sustained winds of 66 mph, gusting to 72 mph at 2:25pm. A peak gust of 78 mph occured there a few minutes later. The NOAA aircraft's SFMR instrument measured surface winds of 65 kt (minimum hurricane force), over a small area on the southwest side of the hurricane at 12:30pm today. Thus, NHC's estimate of hurricane force winds extending out 50 miles from the center is misleading; there are probably only a few small pockets of sustained hurricane force winds at the surface. Given that Ophelia now has an easterly component of motion and is expected to move nearly parallel to the coast, it is unlikely that any portion of North Carolina will see sustained hurricane force winds today. On Thursday, Cape Hatteras may see hurricane force winds, but I think this is unlikely, given the track of the storm and the possibility that she may weaken. The winds at the Cape Lookout CMAN station located in the just outside the east eyewall should be interesting to watch the next 18 hours, as Ophelia should pass directly overhead. Peak winds last hour were 57 mph, gusting to 66 mph there.


Figure 1. Surface wind estimates at 12:30pm this afternoon from the NOAA aircraft's SFMR instrument show only a small area of hurricane force winds (65 knots) on Ophelia's southwest side.

Radar out of Morehead City, NC has shown little change in the storm's organization the past few hours, and the last six hours of hurricane hunter reports have shown a relatively constant pressure, oscillating between 979 and 980 mb. Ophelia is likely as strong as she is going to get, and I expect we will see some slow weakening the next 36 hours as she continues her slow march along the coast.

The predominant danger from Ophelia remains her storm surge, which is more characteristic of a strong Category 1 or weak Category 2 hurricane. A long-lasting storm surge of 6 - 8 feet is possible in many coastal areas of North Carolina. Already, storm surges of up to 7 feet have been reported in some areas, equalling the storm surges generated from Category 2 Hurricane Isabel in 2003. Isabel did about $130 million in damage to North Carolina, and I expect we'll see damages around the $100 million mark for Ophelia.



Flooding of low-lying areas from rain could be a problem in some places; Oak Island south of Wilmington, NC on Cape Fear has already received nine inches or rain. Another 5 - 10 inches of rain is likely from this wet, slow-moving storm.


Figure 2. Rainfall estimates from the Wilmington Doppler radar.

Elsewhere in the tropics
A large tropical wave near 9N 43W or about 1000 miles east of Venezuela and the Windward Islands was very disorganized this morning, but has become quite well organized this afternoon. Upper level winds shear is 10 - 15 knots and falling, and some upper level outflow has developed on the north side of the disturbance. Winds observed by the QuikSCAT satellite show two circulation centers associated with the disturbance, one near 9N 43W and the other near 11N 46W. This disturbance has the potential to develop into a tropical depression later this week or early next week. Another disturbance south of the Cape Verde Islands, near 8N 28W is also starting to develop some impressive deep convection. However, this disturbance lies at the south edge of a large area of dry, dust-laden air which will slow any development that might occur.

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Jeff Masters