The usual Ophelia story

Ophelia has now spent nine days lurching around the ocean areas south of North Carolina, and is certainly not in a hurry to end the ordeal. She'll be with us at least one more day before finally clearing the Outer Banks of North Carolina and heading out to sea. Radar out of Wilmington, NC has shown a slow increase in intensity and coverage of the rainfall the past 24 hours. Ophelia will soon be moving over waters of approximately 80F (26.5C), which is the limiting temperature below which a hurricane cannot intensify. Because of this factor, and the fact that Ophelia's northern eyewall is over land, little or no further intensification is likely for the remainder of Ophelia's trek along the coast. The upper level outflow remains good, and wind shear is low, so Ophelia should still stay a large and well-organized storm through the next two days.

Although NHC has been advertising peak winds of 80 mph and hurricane force winds extending out 50 miles from the center, the actual maximum sustained winds measured at the surface by NOAA buoy 41013 when it was in the north eyewall, were only 54 mph. At 8:00 am the Bald Head Island Marina measured a gust of 77 mph. Wilmington International Airport measured sustatined winds of 41 mph and a peak wind gust of 56 mph this morning. Scattered power outages have occurred across the area, and there are reports of minor roof damage. 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 susustained 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.


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.

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.



Flooding of low-lying areas from rain could be a problem in some places; areas just south of Wilmington, NC on Cape Fear have already received 4 - 5 inches or rain. Another 5 - 10 inches of rain is likely from this wet, slow-moving storm. If eastern North Carolina were not under mild drought conditions, this would have been a much more serious storm.

Elsewhere in the tropics
There are currently no other threats in the tropics worthy of attention. However, the ITCZ is becoming more active, and most of the global computer models are consistently predicting tropical storm formation early next week in the region between Africa and the Leewards Islands. The amount of dry, dust-laden Saharan air over the tropics has declined in recent days, making the area more favorable for tropical storm development. A large new dust storm is over the Cape Verde Islands today, so development in that area is not expected.

New community chat room
For those of you tired of hitting refresh constantly and wanting to talk about the tropics, we now have a new community chat room. Just click on the link at the upper right of the blog page.

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Jeff Masters