Tropical Storm Don (2011)

Storm Active: July 27-30

Around July 17, a vigorous tropical wave emerged off of Africa, quickly associating convection with it as it tracked over the open Atlantic. On July 22, it began to affect the Lesser Antilles with areas of heavy rain, and briefly developed a low pressure center. However, a small area of unfavorable wind shear passed over the system, and it remained disorganized. Development was hampered further on July 24, as the wave passed directly over the Dominican Republic and Haiti. During the next few days, this was followed by interactions with Jamaica and Cuba, which kept thunderstorm activity to a minimum. However, on July 26 the wave moved over the waters of the Caribbean south of Cuba. Slow organization occurred over the next day, and by July 27, a low pressure center had formed. During that morning, however, the low lacked a closed circulation and the convection was divided into two hemispheres, with the area of low pressure not directly associated with any one part of the system. Finally, during the afternoon of July 27, a circulation became evident at the northern tip of the system's western half, and the low was upgraded to Tropical Storm Don just north of the Yucatan Peninsula.

A ridge of high pressure to the northeast of Don steered it in a generally northwestward course through the Gulf of Mexico. Over the next day, convection increased, particularly on the southern side of the circulation, and modest strengthening occurred despite shear and dry air from the north. On July 29, the ridge became stronger, and turned Don more to the west-northwest, toward southern Texas. During that day, Don reached its peak intensity of 50 mph and a minimum pressure of 997 mb. The presence of Don generated significant tropical moisture along the northwestern Gulf coast, including Louisiana and parts of Texas. However, as the system made landfall, most rain was concentrated near the center and on the south side, and southernmost Texas therefore received the most rain. Tropical storm force winds enveloped a larger area of the coast, but quickly diminished as Don made landfall. Over land, the system weakened rapidly to a remnant low, causing no damage or fatalities.



Don near peak intensity shortly before landfall in Texas.



Track of Don.