BOSTON, July 28, 2011- According to catastrophe modeling firm AIR Worldwide, Tropical Storm Don is moving across the southern Gulf of Mexico toward the Texas coast near Corpus Christi, where it is expected to make landfall sometime late Friday or early Saturday. The storm will pass near several areas where offshore oil production is conducted, and several petroleum companies have begun evacuating support workers. A tropical storm warning is in effect for the Texas coast from Port Mansfield north to San Luis Pass.
Tropical Storm Don officially became a tropical storm yesterday afternoon at 5:00 pm (EDT), when a Hurricane Hunter aircraft discovered that the winds of “Tropical Depression 4” had reached 39 mph, strong enough for the tropical storm designation. “Tropical Storm Don is passing through an area of low-to-moderate vertical wind shear, and a region in which the air is also relatively moist,” explained Dr. Tim Doggett, principal scientist at AIR Worldwide. “Given the storm’s relatively small size-its storm-force winds extend outward up to 60 miles-it should maintain its tropical storm status, and, in fact, some slow intensification is anticipated.”
According to the 11:00 am (EDT) National Hurricane Center (NHC) Public Advisory, Tropical Storm Don is about 480 miles east-southeast of Brownsville and 520 miles east-southeast of Corpus Christi, moving at near 14 mph toward the west-northwest. “Following a northward shift in its movement this morning, current NHC projections estimate Don will make landfall less than 50 miles north of Corpus Christi-however, the NHC cone of uncertainty extends over 210 miles of coastline,” added Dr. Doggett. While its maximum winds at present are 45 mph with higher gusts, Don is expected to increase in intensity over the next 36 hours to perhaps as much as 60 mph before making landfall, just short of becoming a Category 1 hurricane on the Saffir-Simpson Hurricane Wind Scale.
Tropical Storm Don already has forced several offshore energy operators to evacuate support workers as a precautionary measure. Royal Dutch Shell has evacuated about 70 non-essential personnel from production and drilling operations in the extreme southwest oil-producing region of the Gulf and from the western Gulf, where Apache Corp and Anadarko Petroleum Corp also are evacuating workers. BHP Billiton and BP Plc are evacuating support workers from central Gulf platforms. As of Thursday morning, no production has been shut, and Tropical Storm Don’s size and intensity suggest that it should not damage any platforms or bring harm to remaining workers. Don’s path will avoid the largest concentrations of production platforms, which lie south of New Orleans.
The NHC forecasts tropical storm conditions to begin within the warning area by late Friday or Friday night. The storm should produce total rainfall accumulations of three to five inches to rain-starved Texas, from the central Texas coast westward into south central Texas. Isolated areas could receive as much as seven inches. Additionally, a modest storm surge of one to two feet can be expected, mainly along the immediate coast near and to the northeast of where the center makes landfall. This area also will be accompanied by large and damaging waves. According to AIR, these conditions are not at this time expected to produce significant insured loss to the region.
AIR is continuing to monitor Tropical Storm Don and will provide additional information as events warrant.